khambe vishal krishna€¦ · a formal presentation of mere words is scarcely indicative of my...

ऱहसुन की य ांत्रिकी कट ई के डिज इन म नकों पर अध्ययन

STUDIES ON DESIGN PARAMETERS OF MECHANICAL

HARVESTING OF GARLIC

KHAMBE VISHAL KRISHNA

DIVISION OF AGRICULTURAL ENGINEERING

INDIAN AGRICULTURAL RESEARCH INSTITUTE

NEW DELHI -110012

2012

STUDIES ON DESIGN PARAMETERS OF MECHNICAL

HARVESTING OF GARLIC

A Thesis

By

KHAMBE VISHAL KRISHNA

Submitted to the Faculty of Post-Graduate School,

Indian Agricultural Research Institute, New Delhi,

In partial fulfillment of the requirements

for the degree of

MASTER OF TECHNOLOGY

IN

AGRICULTURAL ENGINEERING

2012

Approved by the Advisory Committee:

Chairman: ____________________

(Dr. Dipankar De)

Co-Chairman: ____________________

(Dr. P. K. Sahoo)

Member: ____________________

(Dr. Cini Varghese)

Member: ____________________

(Dr. S. K. Jha)

CERTIFICATE

This is to certify that the thesis entitled, “Studies on Design Parameters of

Mechanical Harvesting of Garlic” submitted to the Faculty of the Post-Graduate

School, Indian Agricultural Research Institute, New Delhi, in partial fulfillment of the

requirements for the award of the degree of MASTER OF TECHNOLOGY in

AGRICULTURAL ENGINEERING is a record of bonafide research work carried out

by Mr. KHAMBE VISHAL KRISHNA, Roll No. 20014 under my guidance and

supervision. No part of this thesis has been submitted for any other degree or diploma.

It is further certified that all the assistance and help availed during the course of

investigation as well as all sources of information have been duly acknowledged by him.

Date: 14th Sept. 2012 (Dr. Dipankar De)

Place: New Delhi Chairman,

Advisory Committee

Division of Agricultural Engineering,

Indian Agricultural Research Institute,

New Delhi –110012.

Dr. Dipankar De

Principal Scientist

Dedicated To My Aai - Appa

and My Sisters

ACKNOWLEDGEMENTS

Fervently and modestly, I extol the genuine cooperation, inspiration and affectionate

encouragement offered to me by the my Mentor, Chairman of advisory committee, Dr.

Dipankar De, Principal Scientist, Division of Agricultural Engineering, IARI, New Delhi,

right from the initiation of my work to drafting of the manuscript. The present work bears at

every stage the impression of his concrete suggestions, careful, seasoned criticism,

indefatigable guidance and meticulous attention to details. It was indeed a rare privilege

for me to work under his emending inspiration and indomitable spirit.

A formal presentation of mere words is scarcely indicative of my venerable gratitude

and indebtedness to my Co-Chairman of advisory committee, Dr. P. K. Sahoo, Senior

Scientist, Division of Agricultural Engineering IARI, New Delhi, for his highly inspiring,

enthusiastic guidance with never dyeing spirit, sound counseling, meticulous suggestion,

enduring encouragement, untiring attention and constructive criticism which led this work

to its successful completion and shall remain a lifelong gifted memory for me.

With endless pleasure, I extend my indebtedness and deep sense of gratitude to Dr. D. V.

Samuel, Head and Professor, Division of Agricultural Engineering, IARI, New Delhi for

his encouragement, expert guidance, sustained help and for providing me the necessary

facilities throughout the study.

I humbly place on record my respect and gratitude to Dr. Cini Varghese, Senior

Scientist, IASRI, New Delhi, Dr. S. K. Jha, Senior Scientist, Division of Post Harvest

Technology, IARI, New Delhi, members of my advisory committee for his valuable guidance

and whole-hearted help and keen interest evinced throughout the course of this

investigation and preparation of the thesis is gratefully acknowledged.

I gratefully acknowledge the help and inspiration received from Dr. N. P. S. Shirohi,

Additional Director General (Farm Machinery and Power), Dr. Ranjan Shrivastava,

Principal Scientist, Er. M. S. Kalra, Principal Scientist, Dr. J. K. Singh, Principal Scientist,

Dr. S. S. Tomar, Principal Scientist, Dr. P K Sharma, Principal Scientist, Dr. Adarsh

Kumar, Senior Scientist, Dr. Indramani Mishra, Senior Scientist, Dr. J. P. Sinha, Senior

Scientist, Dr. T. K. Khura, Senior Scientist, Dr. Satish Lande, Scientist, Division of

Agricultural Engineering, IARI, New Delh, Dr. Subodh Joshi, Principal Scientist, Division

of Vegetable Sciences and Dr. Anjani Kumar, Incharge, KVK, Shikopur.

I give my immense pleasure to express my thanks to Shri. Lalita Prasadji, Shri

Rameshji, Shri Premji, Shri Panditji, Shri Sunilji, Shri Ram Lakhanji for their

willingness, unconditional and timely help and support given to me during the research

work. I also express my thanks to Shri Eliyasji, Vishwanathji, Rajakji, Roopchandji,

Inderjitji, Subhashji, Satyavanji, Hiraji, Dineshji and Raoji of Division of Agricultural

Engineering, for their assistance and cheering me during course of my research work.

I am unable to acknowledge adequately the selfless sacrifice made and affection

showered on me by my parents Sh. Krishna B. Khambe and Smt. Gokula K. Khambe, my

Sisters Pramila, Sharada, Sarika, Asharani and Gauri, my uncle Sh. Laxman B. Khambe

and aunt Smt. Sharada L. Khambe, my brothers Tejas, Tushar and Akshay for their rock

like faith on me that boosted my moral and self esteem and saved me through the thick and

thin of my course of study.

Seniors and friends are angels who lift us to our feet when our own wings have

trouble remembering how to fly. Inexplicable is my sense of affection especially to

Ashutosh Sir, Varun Sir, Tushar Sir, Gopal Sir and my dear friends Shyam and Saci.

No words can describe the unending love, moral support and help by my dear friends,

Priyank, Rahul, Pramod, Aslam, Sagar, Dr. Khade, Jitendra, Rajkumar, Vijith, Chetan,

Datta, Ashish, Tushar, Manjit, Gajanan, Dipak Singh, Amit, Dipak, Kuldeep,

Manimaran, Gopal, KrishnaPrakash, Romen, Rakesh, B. Raju, Vasnaram, Soobedar,

Muzamil, Arun. I am very much thankful to my seniors, Sangram sir, Chandu sir, Bharat

sir, Bhushan sir, Vinayak sir, Patle sir, Borase sir, Kapil sir, Somnath sir, Pravin sir,

Vishal sir, Ajinath sir, Yogesh, Pratap, Vijay, Samadhan, Ragvendra, Siddhangauda,

Sujeet and my juniors Dipak, Navnath, Ravi, Jiten, Satish, Manmohan, Darshan for their

valuable support. My heartfelt thanks are also to Friends Circle, Pd. Dr. DYPCAET,

Talsande, for their unending inspiration, guidance and ever willing help during my studies.

My study needs special acknowledgement to the ICAR, for providing financial

assistance in the form of Junior Research Fellowship during the course of my study, and to

IARI library, for giving me the best of the knowledge and resources for my course of study.

And all the great souls who helped me keep my composure and for being there when I

needed them the most.

Date: 14

th Sept. 2012

Place: New Delhi (Khambe Vishal Krishna)

CONTENTS

Sr. No. Chapters Page No.

I INTRODUCTION 1

II BACKGROUND 5

III MATERIALS AND METHODS 13

IV RESEARCH PAPER -I 37

V RESEARCH PAPER -II 58

VI DISCUSSION 74

VII SUMMARY AND CONCLUSIONS 77

ABSTRACT (ENGLISH) i

ABSTRACT (HINDI) iii

BIBLIOGRAPHY v

APPENDICES ix

LIST OF TABLES

Table

No. Title

Page

No.

3.1 Plan of experiments on test set up 28

4.1 Plan of experiments on test set up for garlic harvesting system 43

4.2 Biometric properties of garlic plant 44

4.3 Engineering properties of garlic plant 45

4.4 Soil bulk density at respective soil moisture content 46

4.5 Garlic harvesting percentage for different soil-machine parameters

combinations

47

4.6 Analysis of variables for garlic harvesting percentage 48

4.7 Garlic damage percentage for different soil-machine parameters

combinations

50

4.8 Analysis of variables for garlic damage percentage 50

4.9 Soil separation index for different soil-machine parameters combinations 51

4.10 Analysis of variables for soil separation index 52

4.11 Power requirement (kW) for different soil- machine parameters

combinations

53

4.12 Analysis of variables for power requirement (kW) 53

5.1 Bill of materials used for fabrication 71

5.2 Performance parameters for garlic harvester 71

LIST OF FIGURES

Fig.

No. Title

Page

No.

1.1 Trend of garlic production in India 3

1.2 State wise garlic production in India 3

3.1 Field preparation for garlic cultivation 15

3.2 Garlic crop at its maturity stage 15

3.3 Measurement of polar diameter of garlic bulb with digital vernier

caliper

19

3.4 Texture analyzer for measurement of crushing and cutting resistance 19

3.5 Field testing of experimental set up of garlic harvesting system 30

3.6

Garlic plants discharged at rear end soil separator 32

3.7 Garlic bulbs damaged during harvesting 32

4.1 Relatioship between soil moisture and soil bulk density 46

4.2 Infleunce of soil moisture cotnet and machine rake angle on garlic

harvetsing pecentage

49

4.3 Infleunce of machine rake angle on garlic damage pecentage at

different soil moisture levels

49

4.4 Infleunce of soil moisture content and machine rake angle on soil

separation index

54

4.5 Infleunce of machine rake angle and speed of operation on soil

separation index

54

5.1 Soil reactions acting on a simple digging share 63

5.2 Design of tractor operated garlic harvester prepared in software Pro-

Engineer

66

5.3 Fabricated unit of tractor operated garlic harvester 66

LIST OF ABBREVIATION

± plus or minus

0C degree centigrade

ANOVA analysis of variance

mm

cm

m

millimeter

centimeter

meter

d.b

w.b

dry basis

wet basis

Fig. figure

h hour

ha hectare

hp horse power

N Newton

Hz hertz

i.e. that is

IARI Indian Agricultural Research Institute

ICAR Indian Council of Agricultural Research

kg kilogram

kN kilogram Newton

kW kilowatt

km kilometer

MS mild steel

g gram

%

Rs.

Mt

Mha

percent

rupees

million tonnes

million hectare

FAO Food and Agriculture Organization

sec

yr

second

year

TNAU Tamil Nadu Agricultural University

viz

Fig.

w.r.t.

Eqn

namely

figure

with respect to

equation

1

CHAPTER I

INTRODUCTION

In today's era of diversification of agriculture, farmers are shifting from

traditional subsistence agriculture to commercial agriculture. In India, 64.8% of

farmers are marginal (0-1 ha), and the average land holding per capita is 1.23 ha

(Anon, 2010) as compared to the world’s average land holding of 5.5 ha (FAOSTAT,

2010). Vegetable farming is one of the best options for small and marginal farmers.

Like cereals and pulses, vegetables are important component of a balanced diet. These

are high in vitamins, minerals and rich in folic acid, vitamin C, potassium,

magnesium, etc. Vegetables give energy to the body to fight against diseases and

boost immunity. So, the increasing importance of vegetables production is clearly

reflecting, as India is the largest producer of vegetables (14.47%), in world second to

China with an annual production of about 134.10 Mt (Anon, 2010). Between 1970-71

and 2009-10, harvested area of vegetables in India increased from 3.48 to 8.01 Mha,

and the production increased steadily from 25.98 to 134.10 Mt. Though the

productivity of vegetable per hectare has also increased from 7447.6 kg.ha-1

to

13406.9 kg.ha-1

during this period, it is low as compared to China with highest

productivity of 22988.3 kg.ha-1

(FAO, 2010). India is blessed with varied agro-

climatic conditions which make it possible to grow a wide variety of vegetable crops

round the year. India has the distinction of growing the largest number of vegetable

crops compared to any other country of the world. As many as 61 annual and 4

perennial vegetable crops are commercially cultivated. Among those vegetables garlic

is one of the main bulbous crops.

Garlic (Allium sativum L.) is a bulbous crop from Alliaceae family, native to

central Asia and has long been a staple in the Mediterranean region and a frequent

seasoning in Asia, Africa, and Europe. It is used as both food and medicine in many

cultures for thousands of years, since when the Giza pyramids were built. It has been

found to have antibacterial, antiviral, and antifungal activity. It is also helpful for the

prevention of heart disease (including atherosclerosis, high cholesterol, and high

blood pressure) and used to prevent certain types of cancer, including stomach and

http://en.wikipedia.org/wiki/Giza_pyramid_complex

http://en.wikipedia.org/wiki/Atherosclerosis

http://en.wikipedia.org/wiki/Cholesterol

http://en.wikipedia.org/wiki/High_blood_pressure



2

colon cancers. Garlic cloves have a characteristic pungent, spicy flavour that mellows

and sweetens considerably with cooking. With all these aspects of importance of

garlic, its production and area under cultivation in India has increased steadily since

1970. India is the second largest producer of garlic in the world with an annual

production of about 0.834 Mt (Anon, 2010). The area under garlic cultivation has

increased from 0.027 to 0.166 Mha, between 1970 and 2010 (FAO, 2010). At the

same time, the production has increased from 0.100 to 0.834 Mt as shown in Fig. 1.1

and productivity of garlic has increased from 3703.7 to 5000.3 kg.ha-1

(FAO, 2010).

Gujarat is the leading producer of garlic in India followed by Madhya Pradesh, Uttar

Pradesh, Rajasthan and Maharashtra, Fig. 1.2.

Garlic is grown under a wide range of climatic conditions. However, it cannot

stand too hot or too cold weather. Short days are very favourable for the formation of

garlic bulbs. It can be grown well at elevations of 1000 to 1300 m above the mean sea

level. Garlic requires well drained loamy soils, rich in humus, with fairly good content

of potash. Garlic is also grown in sandy or loose soil. Garlic is propagated by cloves.

Healthy cloves free from disease and injuries should be used for sowing at the rate of

500 kg.ha-1

. Generally, cloves are placed 75 mm apart from each other in rows which

are 150 mm apart from each other, and then covered with loose soil. June-July and

October-November are the normal planting seasons for garlic.

Though India is second largest producer of garlic, its productivity is low as

compared to world average productivity of 16673.4 kg.ha-1

(FAO, 2010). There are

many factors contributing to low productivity in India, low level of mechanization

being a major factor. In India, garlic harvesting is mostly done by hand picking,

which is time consuming and labour-intensive. The sequence of manual operations

normally practiced is as following:

i) Digging/pulling of garlic from the bed, at appropriate soil moisture

ii) Picking digged garlic with green tops

iii) Separating green tops from garlic crop, and

iv) Cleaning of garlic bulb.

http://en.wikipedia.org/wiki/Flavor

3

Fig. 1.1: Trend of garlic production in India (FAO, 2010)

Fig. 1.2: State wise garlic production in India (Anon, 2010)

4

On an average, 300-350 man.h.ha-1

are required for digging or pulling of

garlic. Besides the quantum of labour, manual harvesting involves considerable

drudgery and human discomfort. The labour has to stoop forward while digging or

pulling garlic plant from the bed and also during picking up. Stooping posture results

physical stress in the back and has higher energy consumption as compared to other

working positions. The labour engaged in harvesting has to squat to move to next

harvesting position. Continuous use of bare hands for pulling out garlic crop may

cause bruises on hands leading to infection. Both stooping and squatting postures are

not ergonomically desirable and, therefore, garlic harvesting operation involves

considerable human drudgery.

Manual harvesting is not only laborious and time consuming, but labour

unavailability during the peak season of harvesting is also a major problem. At times,

labour unavailability delays the harvest, which results in damage to crop. The

harvesting operation of garlic needs to be mechanized for time saving, reduced

drudgery, improved field efficiency and reduced harvesting cost. In India, no such

major work is reported on mechanical harvesting of garlic.

Objectives:

Keeping in view the above, it has proposed to determine design parameters of

mechanical harvester of garlic. The study was undertaken the following objectives:

1. To determine crop and soil-machine parameters influencing mechanical harvesting

of garlic.

2. To develop and evaluate a garlic harvesting system based on design parameters.

5

CHAPTER II

BACKGROUND

Over the last few years, there has been considerable progress in agriculture

mechanization, but this progress is mainly related with cereal crops like paddy, wheat etc.

On the other hand, levels of mechanization in vegetable cultivation are far from

satisfactory. The scenario has been changing since the last few decades. The area under

cultivation of garlic and its production has steadily increased. Human drudgery during

various farm operations and labour unavailability during peak season of harvesting has

increased immediate need of mechanization of garlic crop cultivation to enhance

productivity and quality of garlic during harvesting. Development of a suitable garlic

harvester can overcome this problem with timely harvesting and less labour requirement.

In India, no such major work is reported on mechanical harvesting of garlic. This chapter

reviews the available published information related to bulbous, tuberous and root crop

harvesting machines.

2.1 Research Area I: Determination of Design Parameters Influencing Mechanical

Harvesting of Garlic

2.1.1 Biometric and engineering properties of garlic plant and soil properties

Soil bulk density is an important factor in terms of soil-tool reactions, and

indicates the extent of soil compaction at any period of time. Bulk density plays an

important role in deciding the power requirement of any working tool or machinery. Sahu

et al. (2006) studied the draft requirements of tillage implement combinations and

experiments to measure the draft requirements of a reference tillage tool (single disk) and

two combinations (mould board plough with disk gang and cultivator with disk gang)

tillage implements at different depths (50, 75 and 100 mm), wet bulk densities (in the

range of 1270–1850 kg.m-3

) and speeds (1.2, 2.2, 3.2 and 4.2 km.h-1

). They reported that

the draft of the implements increases with increase in soil compaction, depth and speed of

operation.

6

The depth and speed of operation during digging has direct relation with draft

requirement and the amount of plant-soil mass to be handled by a garlic harvester. The

relationship between tool forces and speed is important in evolving management

strategies for optimum performance. The effect of speed on tillage tool forces were

experimentally studied for wide and narrow plane tillage blades operating in a soil bin

(Onwualu et al., 1998). The tools were tested at two depths (100 mm and 150 mm for

wide blade, 114 mm and 229 mm for narrow blade), two rake angles (450and 90

0) and

eight speed levels. Experimental results showed that the tool force (draft and vertical

force) is a function of speed and square of speed, respectively.

The interaction between digging blade of a harvester and the soil has a major

impact on its overall performance. Shmulevich et al. (2007) studied the interaction

between soil and a wide cutting blade using discrete element method. They modelled

wide cutting blade interaction using a 2D discrete element code-PFC2D and the soil

particles by clumps of two disks with a cohesion force contact model between the

particles and four different blade shapes experimentally by a soil box filled with sand.

The simulations indicated an increasing horizontal force applied on the blades during

motion as a result of the piling effect of the soil in front of the blade. They also found that

the soil flow beneath the blade tip can affect the vertical force applied on the blade.

Soil moisture also plays an important role by affecting different machine

parameters. Soil parameters like bulk density, angle of internal friction, porosity, soil

strength depend on soil moisture (Zhang et al., 2001). Soil strength properties, namely

shear strength and cone index decreases with increase in soil moisture content (Ahaneku

et al., 2008). Soil moisture is one of the important factors that affect draft requirements

and depth of operation of any soil working tool. In case of disc plough operating in sandy

loam soils, depth of operation was changed from 80 to 210 mm when the soil moisture

changed from 4.9% to 9.4% and draft changed from 3.39 to 7.45 kN (Olatunji and

Davies, 2009).

Agbetoye et al. (1998) evaluated three pre-lift soil loosening devices for cassava

root harvesting in terms of soil disturbance and soil forces acting on them in laboratory

7

soil bin and in field under similar soil conditions. They concluded that power requirement

increased with decrease in soil moisture. With increase in soil moisture the coefficient of

friction at soil-tool interface increases, which in turn resulted into increase in the draft up

to upper plastic limit of soil. There is sudden decrease in the coefficient of friction with

small change in moisture content of soil (Kepner et al., 2005).

Biometric and engineering properties of garlic plant like weight of plant, plant

length, polar diameter, equatorial diameter of garlic bulb and angle of rolling resistance

affects the design parameters of harvester. These properties influences design parameters

as spacing between the rods of soil separator, material handling capacity of soil separator,

etc. Physical and mechanical properties of onion (Allium cepa L.) crop of three varieties

viz. Agrifound Dark Red, Pusa Red and NP-53 relevant to mechanical detopping were

studied by Vijaya Rani et al. (2006). Linear relationship was observed between polar and

equatorial diameter as also weight of bulbs (with leaf). The shape of onion crop was

considered oblate to spherical. The cutting force increased with neck diameter for all the

three varieties.

Mishra et al. (2009) determined engineering properties of turmeric rhyzome as a

function of moisture content. They reported that the average length, width, and thickness

of turmeric were 42.77, 10.85, 9.51 mm, respectively, at 12.4% moisture content (db).

The surface area and angle of repose were observed as 7925.33 mm2 and 33

0,

respectively. The bulk density and true density were observed as 622.33 kg.m-3

and

1253.93 kg.m-3

, respectively. The mean value of peak compressive force to fail the

rhyzome was 172.15 N.

Khura et al. (2010) determined the biometric and mechanical properties of onion

crop relevant to component designs of machine for its harvesting. They reported that

plant length of onion crop ranged from 110 to 320 mm, with a mean of 177.6 mm. The

average equatorial diameters for small, medium and large onion were reported as 34.5,

49.82 and 64.68 mm, respectively and that of polar diameter were 33.8, 41.41 and 53.20

mm, respectively. The average weights of onion bulb with leaves were 21, 52 and 112 g

for small, medium and large sizes, respectively.

8

2.1.2 Machine parameters

In any bulbous or root crop harvesting system, digging and cleaning process of

the crop are important factors. The design factors of digging unit like rake angle affects

the depth of operation, damage to crop and draft. Similarly, speed of operation of garlic

harvester affects the digging from the field and cleaning of garlic crop. The available

information on these two components is presented under the different headings.

2.1.2.1 Digging unit

The power required to pull any harvester is expressed in terms of draft, which

depends upon various factors like field condition, type of load to be handled, cutting tool

design etc. Among those, tool geometry has great influence on power requirement. The

tool geometry is governed by rake angle of the blade and internal friction angle of soil.

Rake angle is the angle between the leading edge of a cutting tool and a perpendicular to

the surface being cut. In case of cohesive soils, a study was carried on prediction and

field measurements of tillage tool draft forces (McKyes and Desir, 1984). The specific

draft force per unit soil area and degree of soil loosening were observed to increase with

relative narrowness of the tillage blades and with rake angle.

Chamen et al. (1979) developed and tested high output rotary digger for sugar

beet. They reported that bite length was the most important factor affecting the output of

digger. The most effective rotor design to provide the required 250 mm bite length was 4

L-shaped blades bolted on one side of extended flanges. Chisel tines working behind and

100 mm below the working depth of the rotor stabilized the machine, particularly at

higher forward speeds. They found that the performance in a wide range of crop residues

and soils was satisfactory with a work rate of about one hectare per hour on heavy soil

with a 56 kW tractor.

Saqib et al. (1986) designed and tested a vibratory digger blade sweet potato

harvester. They evaluated effect of peak acceleration of vibration and combined effect of

forward velocity, amplitude and frequency of vibration on the geometric mean diameter

of clod size and on per cent reduction in soil bulk density after treatment. The study

9

suggested that vibratory digger, as compared with non-vibratory, produced smaller soil

clods and greater reduction in soil bulk density.

Study on shape of blade was conducted by Agbetoye et al. (1998) for cassava root

harvesting in terms of soil disturbance and soil forces acting on them in a laboratory soil

bin and in field under similar soil conditions. The devices included L-tine, A-blade and a

combination of curved chisel tine worked at a depth of 100 mm ahead of L-tine. Results

showed that A-blade had least soil forces and specific resistance followed by L-tines, and

L-tines were most suitable for pre-lift soil loosening in cassava harvesting due to their

simplicity of fabrication, reduced damage and adjustable width. Khura et al. (2011)

conducted another study on onion digger with six different shapes of digging blade viz.

straight, convex, triangular fork, concave, inverted V and V-shaped blade for draft

evaluation. The draft on the blades was minimum of 613.50 N and maximum of 843.66 N

for inverted V and straight blades, respectively. Therefore, an inverted V shaped digging

blade was used for the design of garlic harvester.

2.1.2.2 Speed of operation

Speed of operation while working in the field is an important factor to be studied

to decide the optimum power requirement of a harvester. Too high or too low speed

affects the draft requirement as well as the digging efficiency of a harvester. Maw et al.

(1998) developed the principles of operation of a mechanical harvester for sweet onions.

They reported that a maximum ground speed of 2.4 km.h-1

was appropriate for harvester

operation in sandy soil condition. In another study by Gupta et al. (1999), a vibrating

cassava root harvester consisting of triangular share and a slat type plane bottom

(inclined at 25-300 rake angle) was found to require 16 kW draft at a speed of 6.1 km.h

-1,

at 370 mm depth in sandy loam soil at 18.6% moisture content (db).

Kang et al. (1991) developed a two-row vibrating blade potato digger and

examined the effects of amplitude, frequency of vibration and travel speed on potato

damage, unrecovered potatoes and draft requirement. They reported that travel speed was

dominant factor among all variables measured. Increased travel speed decreased both

10

shatter bruise and blackspot as more soil was retained on the vibrating blade. Blackspot

increased as frequency increased, with highest blackspot (24.9%) observed at highest

frequency of 1227 rpm and slowest travel speed of 1.7 km.h-1

. Unrecovered potatoes

significantly increased (7.2 to 24.0%) as travel speed increased from 1.7 to 3.3 km.h-1

.

Draft force decreased as vibration frequency increased and travel speed decreased. Draft

varied from 7.9-12.2 kN over the range of combinations of frequency and travel speed

levels. Average draft requirement per unit area of furrow slice was 3.3 and 4.2 N.cm-2

at

1.7 and 3.3 km.h-1

operation, respectively.

Padmanathan et al. (2006) designed, developed and evaluated a tractor operated

groundnut combine harvester. They reported that the groundnut combine harvester

obtained maximum harvesting efficiency of 92.30%, threshing efficiency of 82.30%,

cleaning efficiency of 72.30% and minimum percentage of broken pods of 4.43 for

prototype tractor operated groundnut combine at 1.5 km.h-1

forward speed. The operation

of groundnut combine harvester resulted in 39.00% and 96.00% saving in cost and time,

respectively, when compared to conventional method of manual digging and stripping.

In India, no study has been reported on design parameters of mechanical garlic

harvester. Information is also not available on effect of bulk density of soil and soil

moisture condition on the performance of garlic harvester. Researches have been mainly

conducted on root and bulbous crops like cassava, turmeric rhyzome, onion, groundnut,

potato, sugar beet, etc. In consideration of above, parameters relevant to the research

work were studied. The first objective of this research work is to experimentally

determine the engineering and biometric properties of garlic plant as also the optimum

soil moisture content based on the performance of garlic harvester at different rake angles

and speeds of operation. Also various parameters of related to garlic harvester like

harvesting index, percentage of garlic damaged, soil separation index and wheel slip will

be studied.

11

2.2 Research Area – II: Development and Evaluation of Garlic Harvester

The adaptability of any machine depends upon the ease of operation, technical

suitability, economic viability and environmental sustainability. The field performance of

bulbous plant harvester with respect to harvesting quality, crop damage, soil separation

and power requirement are important parameters to be focussed.

The damage to harvested plant material is of prime concern while designing any

agro machinery. Jadhav et al. (1995) developed a 5 hp self propelled onion digger

windrower. They evaluated the machine with prevalent local practices in different

seasons at different locations and reported that percentage of damaged bulbs was from

2.63-3.45 and actual field capacity of machine ranged between 0.16 and 0.19 ha.h-1

.

Digging efficiency was in the range of 89.66-93.23 per cent.

Kathirvel et al. (1998) developed a power tiller based single-row ridge type

sliding potato digger. They tested the digger with two power tiller models (VST and

TNAU model), and compared with manual digging on the basis of parameters as

coverage, potato digging and damage. Results showed that damage to potatoes were 5.2

and 1.4% for VST and TNAU model, respectively, as compared to 1.1% damage in case

of manual harvesting. Another case study on the performance, evaluation of a tractor

drawn 2-row trailed type potato digger windrower was undertaken by Singh (1999). The

effective field capacity of prototype was 1.6 ha.day-1

while digging and windrowing

efficiencies were 98 and 90%, respectively. Tuber bruising was 1.5% and labour

requirement for picking of dug tubers was approximately 50% less as compared to those

dug by an elevator digger.

The technical, economic feasibility of a machine is important for its acceptability

by the users. A case study was conducted by Singh et al. (2004) to assess the comparative

performance of potato digger elevator with conventional method of harvesting at farmers

scale. The results indicated that the actual field capacity was 0.50, 0.021, 0.25 and 0.025

ha.h-1

in tractor mounted potato digger elevator, manual digging by Khurpa, tractor

drawn cultivator and bullock drawn desi plough respectively. The labour requirement in

12

different treatments showed a saving of 1280 man.h.ha-1

in case of machine as compared

to manual harvesting. The lowest tuber damage was recorded (0.8%) in potato digger-

elevator as compared to other methods.

Singh (2006) designed, developed and tested a tractor mounted multipurpose

potato digger. Prototype was successful in digging both early (60–65 days, without

removing haulms) and main crop at optimum moisture conditions, and also in dry

conditions at row-to-row spacing of 610 as well as 686 mm. In digging early crop, labour

requirement was reduced by 37% and damage reduced by 72% as compared with

complete manual harvesting with khurpa.

Khura et al. (2011) developed a tractor drawn onion harvester and studied various

crop-machine and operational variables related to design of mechanical onion harvester.

The mean draft of 625.6 N was observed for inverted V- shaped blade. The optimal

design values of variables like length, speed ratio and slope of elevator were determined

as 1200 mm, 1.25:1 and 15°, respectively. The onion harvester had digging efficiency of

97.7%, separation percentage of 79.1%, bulb damage of 3.5%, and required 10.78 kN of

draft. The saving in cost of onion digging with digger was found to be Rs. 1170 per

hectare as compared to manual harvesting.

Most of the available literature was related to the study of potato digger and onion

digger. Since no such study was reported on the performance, evaluation of garlic

harvester as well as the study of biometric and engineering properties of garlic plant.

Keeping in view the upcoming potential of commercial farming of garlic, the study on

mechanization of garlic harvesting is important to reduce the cost of cultivation with

better harvesting efficiency. Hence, studies on design parameters of mechanical

harvesting of garlic suitable for Indian condition were undertaken.

13

CHAPTER III

MATERIALS AND METHODS

A study was carried out to determine the effect of biometric and engineering

properties of garlic plant, soil- machine relationship on the mechanical harvesting of

the garlic. A tractor operated garlic harvester was designed, developed and evaluated

considering the optimum values of biometric, engineering properties of plant and

relevant soil properties. This chapter deals with the materials and methods used to

conduct the research. The experiments were conducted in the following sequence to

obtain desired results:

1. Field preparation and garlic crop cultivation,

2. Determination of biometric and engineering properties of garlic plant,

3. Determination of relevant soil properties at harvesting stage of garlic crop,

4. Determination of design parameters of a garlic harvester, and

5. Development and performance evaluation of a tractor drawn garlic harvester

based on optimum design values.

3.1 Garlic Crop Cultivation

In India, garlic crop is generally planted in two season’s viz. June-July and

October-November varying in agro climatic region. The October-November season is

generally followed in Northern India. Accordingly, field of 2800 m2 was prepared in

the months of September-October, 2011. The farm of Division of Agricultural

Engineering, IARI, New Delhi was chosen for cultivation of garlic crop. The field

was situated at 28.380

N, 77.20

E at an altitude of 228.7 m above sea level. The study

area is in semi-arid and sub-tropical climate with hot summers and cool winters with

an average rainfall of 708.6 mm. The soil of the experimental farm is classified as

alluvial soil group having sandy loam texture. Before field operation, FYM was

applied at the rate of 50 t.ha-1

, and the seedbed prepared by ploughing, harrowing,

14

bund forming to make the soil healthy for garlic cultivation. Then field preparation

was carried out with various farm operations like ploughing, harrowing etc. (Fig. 3.1).

Garlic cloves (Yamuna Safed-3 (G 282)) were planted manually on a flat bed

in the month of October, 2011 at the rate of 500 kg cloves per hectare. Bulbs of

uniform shape and size were used for planting. Row-row distance of 150 mm and

plant to plant distance of 75 mm was maintained. The recommended rate of fertilizers

(N:P:K) was applied at rate of 100:50:50 kg per hectare in 2 splits at the time of

sowing, and 45 days after sowing. Proper irrigation was applied to crop during its life

period. During vegetative growth, irrigation was applied after every 10 days and

during maturity stage it was applied after every 10-15 days as per requirement. Crop

at its maturity stage is shown in Fig. 3.2.

3.2 Biometric Properties of Garlic Plant

Biometric properties of garlic plant are important for design of a garlic

harvester. These properties were measured at the harvesting stage of crop with the

help of measuring scale and vernier caliper. The different parts of garlic crop are

roots, bulb, crown, neck and leaves. The part of the leaves protruding from the garlic

bulb is known as top. The surface at which the top leaves are attached to the garlic

bulb is referred as crown, and the tops immediately above crown are referred as the

neck. Biometric properties which are relevant to the study were measured. To

determine the position of garlic bulb with respect to ground surface and the quantity

of material to be handled by harvester while operating in the field, following

measurements were taken:

i. Number of leaves per garlic plant

ii. Length of garlic plant

iii. Depth of garlic bulb below ground surface

iv. Equatorial diameter of garlic bulb

v. Polar diameter of garlic bulb

vi. Weight of garlic bulb with leaves.

http://www.nhrdf.com/htmlfiles/Garlic/Gar_var4.htm

15

Fig. 3.1: Field preparation for garlic cultivation

Fig. 3.2: Garlic crop at its maturity stage

16

3.2.1 Number of leaves

Observations were taken by counting number of matured and green leaves per

plant of thirty garlic plants randomly selected from the field, and the mean value

determined.

3.2.2 Length of garlic plant

The length of garlic plant was used for designing of total length of the soil

separator to pass the dug material from blade to end of soil separator. Thirty garlic

plants were selected randomly and their lengths were measured with a linear scale,

and the mean value determined.

3.2.3 Depth of bulb in soil

The depth of garlic bulb in soil was used to estimate the volume of soil to be

handled by the harvester. Depth of bulb with respect to ground surface was measured

for thirty randomly selected garlic plants. The measurement was done with the help of

a linear scale and a flat plate. Vertical soil section was first cut along the plant to

expose the bulb of a standing plant. The flat plate was kept horizontal along the

ground and the scale was placed vertically in soil up to the bottom of garlic plant, and

the mean value determined.

3.2.4 Equatorial diameter

The equatorial diameter was the maximum width of the garlic in a plane

perpendicular to the distance between garlic crown and the point of root attachment to

the garlic. The equatorial diameter of garlic bulb was relevant to the design of spacing

between the rods of soil separator. The equatorial diameter of the smallest bulb was

used to set the distance between the rods of soil separator. The equatorial diameter

was measured with the help of a digital vernier caliper having least count of 0.1 mm.

The equatorial diameter was observed for thirty randomly selected garlic plants, and

the mean value determined.

17

3.2.5 Polar diameter

The polar diameter of the garlic bulb was used to determine the spacing

between rods of the soil separator. Polar diameter is the distance between the garlic

bulb crown and the point of root attachment to the bulb. This polar diameter was

measured with the help of a digital vernier caliper having least count of 0.1 mm for

thirty randomly selected garlic plants (Fig. 3.3), and mean value calculated.

3.2.6 Weight of garlic bulb with plant

The weight of garlic plant was measured using an electronic weighing balance

with least count of 0.01 g for thirty randomly selected plants, and mean value

determined. The weight of garlic plant would govern the material handling capacity of

the soil separator of garlic harvester.

3.3 Engineering Properties of Garlic Plant

Engineering properties of garlic bulb, relevant to the design of garlic harvester

were determined. The properties evaluated were:

i. Shape factor

ii. Coefficient of static friction

iii. Crushing resistance of garlic bulb

iv. Cutting resistance of garlic bulb

3.3.1 Shape factor

Shape of garlic bulb was used to determine the spacing between the rods of

soil separator of the garlic harvester. Garlic bulbs were considered either oblate or

prolate depending upon the ratio between equatorial diameter and polar diameter. The

ratio of the equatorial diameter to the polar diameter is known as the shape factor. If

this ratio is greater than one, then shape of bulb is oblate and if less than one, then the

shape of bulb is prolate. The values of equatorial and polar diameter of garlic bulbs

determined (3.2.4 and 3.2.5) were used to calculate the shape factor.

18

3.3.2 Coefficient of static friction

Angle of rolling resistance of garlic plant was measured on mild steel surface

by inclined plane method. The garlic plant was kept horizontal on the plate of the

instrument and the slope was gradually increased. The angle at which impending slip

occurred was measured. The value of coefficient of static friction was used to decide

the inclination of rods of soil separator and calculated by using following formula:

Coefficient of static friction = tan ø ………….. (3.1)

Where,

ø = Angle of rolling resistance

The experiment was replicated thirty times and the mean value of ø for garlic

bulb was determined for calculation of coefficient of static friction.

3.3.3 Crushing resistance

Crushing resistance of garlic bulb is an important property in relation to

crushing of garlic bulbs during digging. Crushing strength was measured with the

help of texture analyzer, shown in Fig. 3.4. Texture analyzer consists of a crushing

probe fixed at the lower end of load cell. A base plate fixed at the lower end of texture

analyzer hold a garlic bulb in such a way that the centre of bulb faced the crushing

probe. After settings of texture analyzer garlic bulb was kept on the base plate and the

crushing probe was moved in downward direction crushing the bulb at the centre.

Vertical loading of 500 N was applied at a test speed of 0.2 m.s-1

. The peak force of

crushing was recorded. The experiment was replicated for thirty times, and mean

value determined.

3.3.4 Cutting resistance

Cutting resistance of garlic bulb was measured by using same procedure as in

section 3.3.3 by replacing the crushing probe with cutting probe of a texture analyzer.

The experiment was replicated for 30 times, and mean value determined.

19

Fig. 3.3: Measurement of polar diameter of garlic bulb with digital vernier

caliper

Fig. 3.4: Texture analyzer for measurement of crushing and cutting resistance

20

3.4 Soil Properties at Harvesting Stage

Digging blade a tractor drawn garlic harvester is engaged in soil to dig up the

garlic plants and transfer them to the soil separator. Hence, soil properties directly

affect the digging performance of the harvester. Following properties of soil were

evaluated before actual testing of the harvester:

i. Moisture content

ii. Bulk density

3.4.1 Soil moisture content

To determine the soil moisture content, soil samples were taken up to a depth

of 100 mm. The samples were collected randomly from ten locations in the field. The

samples were weighed and kept in an oven at 105±50 C for 24 hours. The moisture

content was determined by using the following formula:

. …… (3.2)

Where,

MC = Soil moisture content, %,

W1 = Initial weight of soil sample, g, and

W2 = Final weight of dry soil sample, g.

3.4.2 Soil bulk density

Bulk density of soil was determined by using core sampler of 50 mm diameter

and 300 mm length, marked at 10 mm interval along its length. It was initially

vertically inserted in the soil up to 50 mm and the soil collected in it was immediately

removed. Same procedure was repeated for collection of nine samples from random

locations. Sample were weighed and kept in the oven for 105±50 C for 24 hours. The

weight of dry soil was recorded and bulk density determined by using the following

relationship:

……… (3.3)

21

Where,

ρ = Bulk density of soil, g.mm-3

,

M = Weight of dry soil, g, and

V = Volume of core sampler, mm3.

3.5 Design of Garlic Harvester

The harvester was designed to dig garlic plants from soil, and to separate the

plant mass from dug soil. Garlic plants separated from soil mass would be windrowed

at the rear, to be later picked up manually. Hence, two major working components of

garlic harvester were the digging unit and the soil separator. The main aim of research

work was to design a harvester which would require minimum power, low damage to

plant material and maximum soil separation at economic cost of operation. Field tests

were carried at different levels of soil-machine variables to determine the optimal

design values.

The design values of tool geometry parameters of garlic harvester were

determined based on the experiments on the test setup of harvester. The data was

analysed to reach final design values. Based on these design values, a harvester was

finally designed and fabricated for field evaluation. The performance of the garlic

harvester was evaluated for different combinations of experimental variables.

Performance of the harvester was determined in terms of harvesting percent, percent

of garlic damaged, soil separation index and power requirement.

3.5.1 Functional requirements of garlic harvester

Different components of garlic harvester were designed from the stand point

of its functional and structural requirement.

Following functional requirements were set for the design of harvester:

a) The harvester should dig garlic crop planted on flat bed of total row width of

450 mm, leaving four rows simultaneously in a single operation.

b) The harvester should dig the garlic crop from soil in such a way that a

minimum amount of soil should be lifted with the plant mass.

22

c) The harvester should leave garlic plants open on the soil surface at the rear of

the tractor-harvester system, which could be picked up manually with

minimum efforts and in minimum time.

d) Damage to garlic bulbs during harvesting operation i.e. cut, crush and bruise

should be as low as possible.

e) It should be operated by tractors of 25 to 35 kW range, being the common size

of tractor available on Indian farm.

f) The harvester should be simple in design and construction, and efficient in its

performance.

3.5.2 Structural design of garlic harvester components

The following main components of the harvester were designed from strength

consideration:

i. Digging blade

ii. Soil separation unit

For designing of the above components the following information were required:

a. Draft on the blade while harvesting, which could be determined theoretically by

using blade dimensions as also soil and operational parameters.

b. Design of the soil separation unit based on various biometric and engineering

properties of garlic plant.

3.5.2.1 Determination of draft on digging blade

The working depth of digging blade is an important parameter from a design

point of view as it directly affects the power requirement of a garlic harvester. This

working depth of digging blade is mainly dependent on the depth of garlic bulb in the

soil. The study on biometric properties of garlic carried out in the field yielded that

depth of garlic bulb was in range of 68-86 mm with a modal value of 76 mm.

Considering the probable variation in depth of garlic bulbs of different varieties in soil

and to harvest them without damage, minimum depth of operation was selected as 120

mm.

23

The draft of the share was calculated using the general soil mechanics

equation for a blade deforming the soil in two dimensions (Hettiarachi, 1966) given

by Equation 3.4. It takes into account different soil properties and tool geometry

parameters as following:

Pp = γ Z12 Nγ + CZ1Nc + CaZ1Nca + qZ1Nq ...…… (3.4)

Where,

Pp = Passive resistance of soil acting at an angle of soil-metal friction with the normal

to interface, kg per meter width,

γ = Bulk density of soil, kg.m-3

,

Z1 = Depth of operation, m,

C = Cohesion of soil, kg.m-2

,

Ca= Soil-interaction adhesion, kg.m-2

, and

q = Surcharge pressure on soil from surface above the failure plane, kg.m-2

.

Nγ, Nc , Nq and Nca are dimensionless N- factors, which describe the shape

of soil failure surface and are thus, function of angle of shearing resistance of soil (Φ),

angle of soil metal friction (δ) and geometry of loaded interface i.e. rake angle (α).

For determination of draft, the following assumptions were made (Shirwal, 2010):

i. Soil is homogenous and isotropic,

ii. Average bulk density of soil is 1450 kg.m-3

,

iii. Soil is in friable range of moisture content with cohesion (C) of 710 kg.m-2

,

angle of internal friction (Φ) of 25° and angle of soil metal friction (δ) of 20°

for bulk density of 1450 kg.m-3

,

iv. Adhesion of soil is zero i.e. Ca=0, assuming soil-metal friction to be zero as

soil scouring over the blade,

v. The surcharge in front of the soil above soil failure zone is negligible, i.e. q=0,

vi. Usual variations in rake angle of the digging blade range between 10° and 20°

in the experiments. A rake angle of 15° was considered for determination of

expected draft, as 15° was the mean value of rake angle selected for

experimentation.

24

Based on the above assumptions, the Equation 3.4 could be reduced as follows

Pp = γ Z12 Nγ + CZ1Nc ………. (3.5)

The relationship between the N-factor and the rake angle at different angle of

internal friction for a perfectly smooth (δ=0) and perfectly rough (δ = Φ) interface is

presented in Appendix A. The values of N-factor for intermediate degree of roughness

of the interface could be interpolated using the following equation:

..……. (3.6)

Where,

N = Required value of the appropriate N-factors (N δ or Nc), and

N δ=0 and N δ = Φ = Corresponding value of the N-factor at δ =0 and δ = Φ,

respectively, obtained from the appropriate chart.

Following values for the different parameters in the Equation 3.6 were used

for determination of passive resistance of the blade:

γ = 1450 kg.m-3

, C = 710 kg.m-2

, Φ = 25.58°, δ = 25.31°, α = 15°, Z1 = 0.12 m

Using the relationship shown in Appendix A, the value of N-factors were

calculated as follows:

Nγ = 1.83, Nc = 1.68

Substituting the values of Nγ and Nc, determined as above, in the Equation

3.5 the passive resistance (Pp) per unit width of the blade was obtained as:

Pp = 1450 x (0.12)2 x 1.83 + 710 x 0.12 x 1.68

= 181.35 kg.m-1

Therefore, Pp for an effective width of cut of 0.45 m of blade is 81.61 kg.

The passive resistance Pp was acting at an angle of friction (δ) with normal to

the interface, hence the component parallel to the blade face (Pp1) was given as:

25

Pp1 = 81.31 x cos 70°

= 27.91 kg

And component perpendicular to the blade face (Pp2 ) was given as

Pp2 = 81.31 x cos 20°

= 76.38 kg

The obtained value of Pp1 and Pp2 were used to determine the bending

moment of the digger blade.

3.5.2.2 Design of digger blade

Digger blade would execute initial digging of garlic plants from soil along

with soil. The width of digger blade was an important factor as it would cover all

plant rows in a bed without damaging standing crop. Therefore, it was decided on the

basis of the width of the bed on which the garlic crop was grown in four rows. The

blade was designed for its thickness on the basis of load acting on it. This could be

determined theoretically analysing various forces acting on the blade.

Pp2 is perpendicular component of Pp1, and would cause bending moment

whereas Pp1 is the horizontal component that would induce direct stress in the blade.

The force would act at the centre of resistance of the blade. It was assumed that

average soil resistance of the blade acts at a distance of 0.2z1 measured from the

cutting edge (Bernacki, 1972) Fig 5.1.

The centre of resistance was at a distance of 24 mm from the cutting edge on

central axis of the width of blade. The blade was supported on nuts and bolts at a

distance of 200 mm from each side of the cutting edge. Therefore, the distance

between the centre of resistance and point of support could be determined as:

200 – 24 = 176 mm

Therefore, the bending moment (B.M.) due to Pp2 is:

B.M. = 76.38 x 176 = 13442.9 kg.mm, and

26

Bending stress (σb) is represented as:

……… (3.7)

Where,

B.M = Bending moment, kg.mm

b = Width of blade at its point of mounting, mm, and

t = Thickness of the blade, mm.

Bending stress was calculated as:

……… (3.8)

And, direct stress (σd) due to Pp1 was calculated as:

……… (3.9)

Hence,

Total stress = σ = σb + σd

……… (3.10)

By taking factor of safety as 1.2 and equating the total stress (σ) with safe

stress 600 kg.mm-2

of mild steel, the thickness of blade (t) was determined as:

.……. (3.11)

or, t = 9.82 mm ≈ 10 mm

Hence, thickness of blade was kept as 10 mm and the total width of blade was

kept as 600 mm as per requirement of digging operation.

27

3.5.2.3 Design of soil separation unit

Material dug by a digging unit would be directly forwarded to a separation

unit. The soil separation unit was placed just behind the blade to receive the dugout

garlic and soil mass. To separate the soil from garlic plant, the rods were arranged

length-wise along the line of travel of the harvester. Biometric properties of garlic

plant i.e. length of garlic plant, polar and equatorial diameter of garlic bulb were used

to determine the various dimensions of soil separator. The gap between the two

consecutive rods of soil separator was kept in the range such that a garlic plant should

not fall from the gap.

From the data of biometric properties it is clearly seen that the average range

of polar and equatorial diameter varied from 33.13-40.48 mm and 31.58-39.21 mm,

respectively. For free and efficient dropping of soil-mass from the separator, the rod

spacing was kept as 50 mm. The average plant length was observed as 693.4 mm.

Hence, for free and for early dropping of plant material from soil separation unit, its

length was kept about 1.5 times the average length of garlic plant. Then, the length of

soil separator was kept as 1000 mm. The soil separator slots were fabricated using

M.S rods of 10 mm in diameter.

3.6 Performance Parameters for Garlic Harvester

Harvester to be designed was tested in field conditions to evaluate its field

performance. Different test parameters, divided into three groups namely,

independent, dependent and constant parameters were used. Following table shows

the plan of experiment used to carry out the field tests.

28

Table 3.1: Plan of experiments on test setup

Sr.

No. Parameter Level Performance parameter

I

Independent

1. Soil parameter

Moisture content, (%)

2. Machine parameter

Rake angle, degree

3. Tractor parameter

Forward speed (km.h-1

)

15, 12, 9

10, 15, 20

1.5, 3, 4.5

Bulk density of soil was

measured at respective soil

moisture content

II Dependent

Machine performance

1. Harvesting percentage, %

2. Damage percentage, %

3. Soil separation index

4. Power requirement, (kW)

III Constant parameter

i) Length of blade, mm

ii) Length of soil

separator, mm

3.6.1 Test procedure

Garlic cultivar Yamuna Safed-3 (G 282) was raised in farm of the Division of

Agricultural Engineering, IARI, New Delhi as per recommended agronomical

practices. The total area of experiment was 2800 m2. Matured crop was harvested

using experimental set-up of mechanical garlic harvester. The ultimate objective of

research work was to evaluate a garlic harvester in terms of its performance

parameters as mentioned in Table 3.1. The observations on performance parameters

were recorded for each test run. All the test runs were replicated thrice to eliminate


29

any experimental bias. As mentioned in Table 3.1, the experiments on test set-up were

planned by varying soil moisture (15, 12 and 9%), rake angle (10°, 15° and 20°) and

speed of operation (1.5, 3 and 4 km.h-1

) and garlic harvesting percentage, garlic

damage percentage, soil separation index and wheel slip were determined for each test

run and their replications. As soil moisture content was an independent variable and

all other parameters were compared at respective soil moisture content, it was

maintained at desired level by allowing the field to dry after irrigation. Soil bulk

density was also measured at respective moisture content of soil. All the experiments

were conducted for bed length of 10 m for every replication according to the plan of

experiments, Table 3.1.

The first test of experiment was carried out at 15 % soil moisture content with

rake angle kept at 10° and the data was recorded at three different speeds of operation.

The rake angle was next fixed at 15° and observations were recorded for three levels

of speed of operation by keeping all other variables constant. Similarly, tests were

conducted for rake angle of 20° and all performance observations were recorded.

Each test run was replicated thrice. Similar set of experiments was carried out at 12%

and 9% soil moisture contents. Thus a total number of 81 runs were completed and

performance data was recorded. Garlic harvester working under test conditions is

shown in Fig. 3.5.

Data were recorded for number of garlic plants harvested, number of garlic

plants not harvested, number of plants damaged, weight of soil collected with garlic

plant mass and distance travelled by wheel with and without load for a test length of

10 m. From this test data, the following performance parameters were determined to

evaluate the machine:

3.6.2 Performance parameters

Following performance parameters were calculated from the field data:

3.6.2.1 Harvesting percentage

It is the ratio of the number of garlic plants successfully harvested to the total

number of garlic plants present in a given area before harvesting, and expressed as:

30

Fig. 3.5: Field testing of experimental set up of garlic harvesting system

31

…… (3.12)

After each test run of garlic harvester, the successfully harvested garlic plants

were manually collected. Fig. 3.6 shows garlic plants discharged at the rear by soil

separator. Total number of garlic plants present in the field was noted before each run

of harvesting operation. A higher percentage of garlic plants harvested, indicates

better performance of garlic harvester.

3.6.2.2 Damage percentage

During harvesting operation, different types of damages occur to garlic bulb in

the form of cut, crush, sliced or bruised as shown in Fig. 3.7. Improper depth of

operation during harvesting was one of the main cause of cutting and slicing of garlic

bulb. Bruises were caused due friction of the garlic plant with metal parts of the

harvester and also due to friction between soil particles while flow of plant-soil mass

from blade to soil separation unit. Harvested garlic plants per unit run were examined;

damaged bulbs were separated from the stack and counted. Damage percentage was

calculated as:

…. (3.13)

3.6.2.3 Soil separation index

The index is a measure of the weight of unseparated soil from the garlic

plants. Less is the soil separation index, better is the performance of garlic harvester.

It is the ratio of weight of the soil collected with garlic plant behind the soil

separation unit to the theoretical weight of soil that was cut by the blade with garlic

plant mass at recommended depth of operation.

……… (3.14)

32

Fig. 3.6: Garlic plants discharged at rear end soil separator

Fig. 3.7: Garlic bulbs damaged during harvesting

33

Where,

Wa = Actual weight of soil and garlic plan collected at rear end of soil

separator, kg, and

Wt = Theoretical weight of soil cut by blade along with garlic plant at a

working depth of operation, kg

The value of Wt for a width of cut of 0.45 m and depth of cut of 0.12 m was

determined as 174 kg.

3.6.2.4 Wheel slip

It is the ratio of difference of the distance travelled by a tractor with load to the

distance travelled by the tractor without load for same number of wheel revolutions

(Dahab et.al., 2007), and expressed as:

………. (3.15)

Where,

Da = Actual distance travelled by tractor with load, m, and

Dt = Theoretical distance travelled by tractor without load, m

Wheel slip along with traction equations was used to determine the power

requirement to operate a garlic harvester.

3.6.2.5 Power requirement

Power required to pull the garlic harvester in sandy loam soil was calculated

using the standard analytical traction performance equations. Dwyer (1984) provided

a good overview in the development of analytical and empirical relationship for

tractive performance of wheeled vehicles. Wismer and Luth (1974) further developed

the utility of this approach for predicting tractive performance. According to

Lijiedahl et.al. (1997), nine pertinent variables are involved in traction equations.

Seven dimensionless ratios are required to formulate a prediction equation (Freitag,

1985). A complete set of dimensionless ratios relating to the variables is:

34

……… (3.16)

Where,

TF = Towed force, N,

W = Normal load on traction device, N,

F = Gross traction force, N,

H = Pull, N,

CI = Cone index, N.cm-2

,

b = Tyre section width, cm,

d = Overall tyre diameter, cm, and

r = Tyre rolling radius, cm

S = Wheel slip, %.

Motion resistance ratio (ρ), net traction coefficient (μ) and gross traction

coefficient (μg) were determined to calculate pull by using traction equation.

Motion resistance ratio (ρ) is defined as the rolling resistance force divided by

the normal load on the traction device. The towed force or motion resistance of a

pneumatic tyre is dependent on load, size and inflation pressure, as well as soil

strength. For soils not very soft and tyres that are operated at nominal tyre inflation

pressure, the towed force can be predicted from, the following relationship:

……… (3.17)

Where,

Cn = Wheel numeric ……… (3.18)

Rolling resistance is attributed to tyre flexing and scrubbing. Equation 3.17

was developed for tyre with a tyre width/diameter (b/d) ratio of approximately 0.3.

35

Any large deviation from this width/diameter ratio can be expected to change the

quantitative relation of towed force function.

The variations of the gross tractive force with soil strength and slip have been

incorporated into a relation including the effect of wheel load and tyre size. The gross

tractive coefficient was given by:

………. (3.19)

Net traction coefficient (μ) is defined as net pulled produced to the dynamic

normal load on the traction device. Net traction coefficient is also the difference

between gross traction coefficient (μg) and motion resistance ratio (ρ), and expressed

as:

μ = μg – ρ ……… (3.20)

From Equations 3.17 and 3.19,

……… (3.21)

By definition, net traction force is given as,

……… (3.22)

The following values for different parameters in Equation 3.21 were used for

determination of the net traction coefficient

CI = 192.5 N.cm-2

for sandy loam soils at 200 mm depth (Saleh et.al., 1997);

d=1400 mm; b = 400 mm; total weight of tractor as 31.245 kN and assuming 60% of

tractor weight is acting on the rear wheels. Therefore, the normal force acting on the

rear wheels was 18.746 kN.

Now, substituting the vales of CI, d, b and W in Equation 3.18 wheel numeric was

calculated as:

……… (3.23)

36

By using the wheel numeric value and wheel slip measured at combination of

variables were substituted in Equation 3.17 and 3.19 to obtain gross traction

coefficient and motion resistance ratio. The value of net traction coefficient is

calculated by using Equation 3.21. From Equation 3.22, pull is calculated as

H = W x ……… (3.24)

The power required to pull the garlic harvester was determined at respective

speed of operation by using the following formula:

P (kW) = Pull (kN) x Speed (m.s-1

) ……… (3.25)

3.7 Development and Evaluation of Garlic Harvester

All field experiment test data were analysed by using SPSS and MS-Excel

software. Based on optimal values of design parameters, a tractor drawn 4-row garlic

harvester was fabricated in the workshop of Division of Agricultural Engineering,

IARI, New Delhi.

The machine was evaluated for its performance in the field in an area of 2800

m2 for garlic cultivar Yamuna Safed-3 (G 282). The following performance

parameters of the garlic harvester were determined:

i. Harvesting percentage, %,

ii. Damage percentage, %,

iii. Soil separation index,

iv. Power requirement, (kW),

v. Field capacity, ha.h-1

, and

vi. Cost of operation, Rs.ha-1

The machine was operated by a 33.57 kW New Holland (3630) tractor. Soil

and crop properties were determined before field evaluation of garlic harvester. The

effective field capacity was determined as per standard procedures. Percentage of

garlic plants harvested, garlic damage percentage, soil separation index and power

required to operate the harvester were determined as explained in section 3.6.


37

CHAPTER IV

RESEARCH PAPER I

Determination of Biometric and Engineering Properties of Garlic Plant and Soil-

Machine Parameters Influencing Mechanical Harvesting of Garlic

4.1 Abstract

Garlic (Allium sativum L.) is the second most important bulbous crop from

Alliaceae family after onion. Though India is the second largest producer of garlic in

the world, mechanization in garlic crop cultivation has not reached the desired level.

Among the major operations, harvesting is still performed manually. The present

study was carried out to determine the relevant biometric and engineering properties

of garlic plant as well as the soil-machine parameters influencing mechanical

harvesting of garlic. Garlic plants (Yamuna Safed-3 (G 282) variety) found to have 5-

7 number of garlic leaves per plant with modal value of 7 while the length of plant

varied from 649 to 755 mm, with mean of 693.4 mm. Depth of garlic bulb which

affects the depth of operation were in the range of 68-86 mm with modal value of 76

mm. Polar and equatorial diameters which affects spacing between rods of soil

separator ranged from 33.13-40.48 and 30.26-36.82 mm, and their respective means

were 37.24, 34.06 mm, respectively. Mean shape factor was observed as 0.96. Also,

cutting and crushing resistance of garlic plant ranged from 442.32-486.01N and

202.54-231.53 N with mean of 463.72 N and 218.23 N, respectively. Experimental set

up for determination of influence soil-machine parameters on mechanical garlic

harvesting was used. Experiments were conducted at three different levels of each

parameter namely soil moisture content (15.28±0.38, 12.23±0.35 and 9.33±0.18%),

machine rake angle (100, 15

0 and 20

0) and speed of operation (1.5, 3 and 4.5 km.h

-1).

Highest garlic harvesting percentage and maximum soil separation was obtained at

12.23±0.35% soil moisture. The harvesting system required minimum power of 4.04

kW at 12.23±0.35% soil moisture, but it was close to power requirement at other two

levels of soil moisture content by keeping other parameters constant. Rake angle was

a key factor which affected all the performance parameters of garlic harvesting

system. Highest garlic harvesting percentage was observed at 150 rake angle while


38

minimum damage occurred at 200 rake angle. Speed of operation had a great influence

over power requirement and it is resulted that, at any soil moisture and rake angle,

minimum power required at 1.5 km.h-1

speed of operation.

Keywords: Garlic, biometric, engineering properties, soil-machine parameters,

mechanical harvesting.

4.2 Introduction

India is blessed with varied agro-climatic conditions which make it possible to

grow a wide variety of vegetable crops round the year. India has the distinction of

growing the largest number of vegetable crops compared to any other country.

Among these vegetables, garlic is one of the main bulbous crops from Alliaceae

family after onion. It is native from central Asia, and presently grown across most part

of the world. It is used both as food and medicine since ancient period.

India is the second largest producer of garlic in the world with an annual

production of about 0.834 Mt (Anon, 2010). The area under garlic cultivation has

increased from 0.027 to 0.166 Mha, between 1970-71 to 2009-10. Gujarat is the

leading producer of garlic in India followed by Madhya Pradesh, Uttar Pradesh,

Rajasthan and Maharashtra etc. This clearly marks the trend of farmer’s attraction

towards the cultivation of garlic crop. But, though the area under garlic crop increased

steadily, this crop is lagging behind in its mechanisation like other vegetable crops.

This has made garlic farming labour intensive, drudgery oriented and uncomfortable

for human. Moreover, labour unavailability during peak season of harvesting is a

major constraint to the farmers. At times, labour unavailability delays the harvest

which results in damage to crop. To improve this scenario, engineering interventions

are necessary for its mechanisation. Therefore, studies on biometric and engineering

properties affecting mechanical garlic harvesting sytem are needed to be studied.

Engineering properties of bulbous crop are important from design point of

view of harvester. Khura et al. (2010) studied engineering properties of onion crop

relevant to design of onion digger. They reported that the mean plant length,

equatorial diameter and polar diameter of onion were 177.6 mm, 34.5 mm and 33.8

mm, respectively. The coefficient of static friction decreased with increase in size of

39

the bulb. These determined properties were used to design different components of an

onion digger. Similarly, Majunatha et al. (2008) studied some engineering properties

of garlic cultivar G-282. They reported that the values of mean diameter, weight, bulk

density, mean length, width, thickness, geometric mean diameter, sphericity and mass

weight of 1000 garlic segment at 40% moisture content (wb) were 51.2 mm round,

28.64 g, 414.40 kg.m-3

, 26.25 mm, 10.36 mm, 8.73 mm, 13.34mm, 0.51 and 1813.60

g, respectively. Coefficient of static friction increased with increase in moisture

content.

Similarly, soil-machine interaction parameters are also important to

understand the working behaviour of the machine under field conditions. The

interaction between digging blade of the harvester and soil has a major impact on its

overall performance. Soil moisture content directly affects various soil parameters

like bulk density, angle of internal friction, porosity, soil strength, etc. Research on

soil moisture content concluded that power requirement to operate root harvester

increases with decrease in soil moisture. Also increase in soil moisture increases the

coefficient of friction at soil-tool interface (Agbetoye et al., 1998). Bulk density is an

indicator of soil compaction and influences performance of root crop harvesting

system. Sahu et al. (2006) studied the draft requirements of tillage implements and

reported that the draft of implements increases with increase in soil compaction, depth

and speed of operation.

Digging unit and soil separator are the key components of root crop harvesting

system. Rake angle of digger blade has major influence over power requirement and

harvesting percentage of a harvester. Soil separator design affects the soil separation

of a dug mass during harvesting operation. Shirwal (2010) reported that highest

harvesting percentage of 97.4% for carrot harvesting was obtained at a rake angle of

25°. Average power requirement of carrot harvester at a speed of 2.3 km.h-1

was 4.44,

5.3 and 5.75 kW at rake angle of 15°, 25° and 35°, respectively. Soil separation index

was most affected by length and angle of soil separator. A minimum soil separation

index of 0.23 could be obtained at 800 mm and 20° of length and angle of soil

separator, respectively.

40

Information available on root and bulbous crop harvesting system mainly

pertains to crops like potato and onion. Comprehensive information is not available

on garlic harvesting system. The present study was undertaken the crop and soil-

machine parameters influencing mechanical harvesting of garlic in order to arrive at

optimal design and operational parameters.

4.3 Materials and methods

Garlic cultivar Yamuna Safed-3 (G 282) was cultivated in the farm of the

Division of Agricultural Engineering, IARI, New Delhi as per recommended

agronomical practices. Biometric and engineering properties of garlic plant, affecting

the harvester design were determined at its maturity stage.

4.3.1 Biometric properties of garlic plant

The part of leaves protruding from the garlic bulb is known as top. The surface

at which the top leaves are attached to the garlic bulb is referred to as crown, and the

top immediately above the crown are referred as the neck. Following biometric

properties relevant to the study were determined:

i. Number of leaves per plant

ii. Length of garlic plant

iii. Depth of garlic bulb below ground surface

iv. Equatorial diameter of garlic bulb

v. Polar diameter of garlic bulb

vi. Weight of garlic bulb with leaves.

Observations were taken by counting the number of matured and green leaves

per plant at the crop harvesting stage. Length of garlic plants was measured with the

help of a linear scale to determine the total length of soil separator while the depth of

garlic bulb below ground surface was used to decide the proper depth of harvesting

with minimum power requirement and maximum harvesting percentage. Weight of

garlic plant was measured with the help of an electronic weighing balance (least count

0.01 g) to estimate material handling capacity of the soil separator of garlic harvester.

Polar and equatorial diameter of garlic bulb was important parameters for the design


41

of soil separator. These were measured with the help of a digital vernier calliper (least

count 0.1 mm) to determine the spacing between rods of soil separator. Thirty garlic

plants were selected randomly for the measurement of all properties, and the mean

value determined.

4.3.2 Engineering properties of garlic plant

Following engineering properties of garlic plant relevant to the research work

were determined:

i. Shape factor

ii. Angle of rolling resistance

iii. Crushing resistance of garlic bulb

iv. Cutting resistance of garlic bulb

Shape factor, decides whether garlic bulb is oblate or prolate depending upon

the ratio between equatorial diameter and polar diameter. The value of angle of rolling

resistance was used to decide the inclination of rods of the soil separator. Angle of

rolling resistance of garlic plant was measured on mild steel surface by inclined plane

method. The garlic plant was kept horizontal on the plate of the instrument and the

slope was gradually increased. The angle at which impending slip occurred was

measured. The experiment was replicated for thirty times, and mean value

determined.

Crushing and cutting resistance of garlic bulb are important in relation to

crushing and cutting of garlic bulbs during digging. These were measured with the

help of texture analyzer. Texture analyzer consists of a crushing probe fixed at the

lower end of load cell. A base plate fixed at the lower end of texture analyzer hold a

garlic bulb in such a way that the centre of bulb faced the crushing probe. After

settings of texture analyzer garlic bulb was kept on the base plate and the crushing

probe was moved in downward direction crushing the bulb at the centre. Vertical

loading of 500 N was applied at a test speed of 0.2 m.s-1

. The peak force of crushing

42

was recorded. The experiment was replicated for thirty times, and mean value

determined.

4.3.3 Soil properties at harvesting stage of garlic crop

Any digger working under field conditions is largely influenced by soil

properties as soil moisture and soil bulk density. To determine the soil moisture

content, soil samples were taken up to a depth of 100 mm. The samples were

collected randomly from ten locations in the field. The samples were weighed and

kept in an oven at 105±50 C for 24 hours.

Bulk density of soil was determined by using core sampler of 50 mm diameter

and 300 mm length, marked at 10 mm interval along its length. It was initially

vertically inserted in the soil up to 50 mm and the soil collected in it was immediately

removed. Sample were weighed and kept in the oven for 105±50 C for 24 hours. The

weight of dry soil was recorded and bulk density was determined.

4.3.4 Machine performance parameters

For evaluation of performance of the garlic harvesting system at different soil-

machine parameters and to study their effects on harvester in terms of its performance

parameters as harvesting percentage, damage percentage, soil separation index and

power requirement were considered. Machine parameters maintained. Rake angle is

the angle between the leading edge of a cutting tool and a perpendicular to the surface

being cut. The experiments on test set-up were undertaken at varying soil moisture

(15, 12 and 9%), rake angle (10°, 15° and 20°) and speed of operation (1.5, 3 and 4.5

km.h-1

).

As soil moisture content was an independent variable and all other parameters

were compared at respective soil moisture content, it was kept at desired level by

allowing the field to dry after irrigation. All experiments were conducted for a bed

length of 10 m for every replication according to the plan of experiments, Table 4.1.

The first set of experiments was carried out at 15% soil moisture content. At

the same time, rake angle was kept at 10° and data was recorded at three speeds of

operation. The rake angle was increased at 15° and observations were recorded again

43

for three levels of speed of operation by keeping all other variables constant.

Similarly, tests were conducted for rake angle of 20° and all observations were

recorded. Each test run was replicated thrice. Similar set of experiments was carried

out at 12% and 9% soil moisture content. Thus a total number of 81 runs were

completed and performance data was recorded.

Table 4.1: Plan of experiments on test setup for garlic harvesting system

Sr.

No. Parameters Levels Performance parameters

I

Independent

1. Soil parameter

Moisture Content (%)

2. Machine parameter

Rake angle, degree

3. Tractor parameter

Forward Speed (km.h-1

)

15, 12, 9

10, 15 ,20

1.5, 3, 4.5

Bulk density of soil was

measured at respective soil

moisture content

II Dependent

Machine performance

1. Harvesting percentage

2. Soil separation index

3. Damage percentage

4. Power requirement (kW)

III Constant parameters

i) Length of blade, mm

ii) Length of soil

separator, mm

44

4.4 Results

4.4.1 Biometric properties of plant

Various biometric properties of garlic plant studied at crop harvesting stage

are reported in Table 4.2.

Table 4.2: Biometric properties of garlic plant

Sr.

No.

Parameter Range Mean Coefficient of

Variation (%)

1 Number of leaves per plant 5-7 7* 13.21

2 Length of plant, mm 649-755 693.4 4.53

3 Bulb depth form surface, mm 68-86 76* 6.24

4 Equatorial diameter of bulb, mm 31.58-39.21 35.55 5.21

5 Polar diameter of bulb, mm 33.13-40.48 37.24 5.04

6 Weight of plant, g 33.27-44.56 39.55 7.01

(* indicates modal value)

The number of leaves per plant at its harvesting stage ranged from 5 to 7, with

a modal value of 5 and coefficient of variation of 13.21 percent. The length of garlic

plant varied from 649 to 755 mm, with a mean value of 693.4 mm and 4.53%

coefficient of variation. The depths of garlic bulb in soil were in the range of 68-86

mm with modal value of 76 mm and 6.24% coefficient of variation. The variation in

geometry and in depth of the bulb was probably due to individual plant vigour and

local soil condition. Digging blade of a harvester would, therefore, be required to

operate below the maximum depth of garlic bulb, and it was decided to keep depth of

operation as 120 mm. Similarly, weight of garlic plant ranged from 33.27-44.56 g

with mean of 39.55 g and coefficient of variation of 7.01 percent. Polar and equatorial

diameters are parameters which were used to determine the spacing between rods of

soil separator. Data showed that polar and equatorial diameters ranged from 33.13-

40.48 and 30.26-36.82 mm, respectively. Their respective means were 37.24, 34.06

45

mm and coefficient of variation were 5.04 and 4.78 percent. The coefficients of

variation of all parameters, except number of leaves per plant, were below 10 percent.

4.4.2 Engineering properties of plant

Tree major engineering of garlic plant relevant to research work were studied

and data resulted as shown in the Table 4.3.

Table 4.3: Engineering properties of garlic plant

Sr.

No

Parameter Range Mean Coefficient of

Variation (%)

1 Shape factor 0.87-1.06 0.96 6.55

2 Angle of rolling resistance (0) 19-25.50 22.67 8.91

3 Crushing resistance of garlic

bulb (N)

442.32-486.01 463.72 2.52

4 Cutting resistance of garlic

bulb (N)

202.54-231.53 218.23 3.42

Shape factor ranged from 0.87-1.06 with mean of 0.96 and coefficient of

variation 6.55 percent. This showed that some garlic bulbs had oblate (shape factor >

1) while some had prolate shape (shape factor < 1). However, mean value suggested

that majority of the bulbs were of oblate shape. Angle of rolling resistance varied

from 19-25.500, with mean of 22.67

0. Also, crushing and cutting resistance ranged

from 442.32-486.01 N and 202.54-231.53 N with means of 463.72 N, 218.23 N with

2.52, 3.42% coefficient of variation, respectively. The coefficients of variation of the

parameters were below 10 percent.

4.4.3 Soil properties

The soil of the experimental farm was classified as alluvial soil group having

sandy loam texture. Soil moisture content and soil bulk density were measured. Soil

moisture content was an independent parameter while bulk density of soil measured at

respective soil moisture content. Fig. 4.1 and Table 4.4 show the variations in soil

46

bulk density at respective soil moisture. It was observed that bulk density of soil

increased with increase in soil moisture content and had a linear relationship.

Table 4.4: Soil bulk density at respective soil moisture content

Sr. No. Moisture content (%) Bulk Density (kg.m-3

)

1 15.28±0.38 1589±0.17

2 12.23±0.35 1450±0.01

3 9.33±0.18 1368±0.01

Fig. 4.1: Relatioship between soil moisture and soil bulk density

4.4.4 Optimization of soil-machine parameters influencing mechanical

harvesting of garlic

Soil-machine parameters were optimised at their different combinations and

interactions, to determine their optimum values affecting the mechanical harvesting of

garlic.

47

4.4.4.1 Influence of soil-machine parameters on garlic harvesting percentage

The influence of soil moisture, rake angle and speed of operation on garlic

harvesting percentage are presented in Table 4.5. Garlic harvesting percentage was

found to be affected by both soil and machine parameters.

Table 4.5: Garlic harvesting percentage for different soil-machine parameters

combinations

Moisture

content (%) Rake angle (

0)

Harvesting percentage (%)

Speed of operation (km.h-1

)

1.5 3 4.5

15.28±0.38

10 91.47 89.66 90.65

15 93.05 93.31 93.88

20 91.79 91.86 89.88

12.23±0.35

10 91.97 92.10 91.85

15 96.70 95.94 95.97

20 93.36 93.90 93.46

9.33±0.18

10 90.77 89.82 90.69

15 93.43 93.96 93.97

20 90.11 89.82 89.91

Results showed that garlic harvesting percentage ranged from 89.66 to 96.70

percent for different soil- machine parameters combinations. Statistical analysis of the

data in SPSS 16.0 version indicated that soil moisture content and rake angle of

harvester had significant influence on harvesting percentage at 1% level of

significance, Table 4.6.

Further the post–hoc analysis of significant variables at 5 percent level of

significance showed that 12.23±0.35% soil moisture content (d.b) and 150 rake angle

were most influencing values for harvesting percentage with highest garlic harvesting

percentage (96.70%) as shown in Fig. 4.2.

48

Table 4.6: Analysis of variables for garlic harvesting percentage

Source Sum of

Squares df

Mean

Square F-Value p-Value

Model 367.56 28 13.13 1.45 0.123

MC 93.96 2 46.98 5.18 <0.009

RA 175.91 2 87.95 9.70 <0.0001

SO 0.98 2 0.49 0.05 0.947

MC*RA 18.04 4 4.51 0.50 0.738

MS*SO 1.62 4 0.41 0.04 0.996

RA*SO 3.26 4 0.82 0.09 0.985

MC*RA*SO 10.71 8 1.34 0.15 0.996

Error 471.62 52 9.07

Corrected Total 839.18 80

R Squared = 0.438 (Adjusted R Squared =0 .135) 1% Level of significance

Note: MC = Soil moisture content, RA = Rake angle, SO= Speed of operation

4.4.4.2 Influence of soil-machine parameters on garlic damage percentage

Any harvesting system could be considered to function properly, when the

damage caused to harvested material is minimum. In case of garlic plant, the bulb is

the only edible part and during harvesting precaution should for its minimum damage.

Following patterns of damage of bulb was obtained for different soil-machine

parameter combinations as shown in Table 4.7.

Data showed that garlic damage percentage varied from 4.75-9.45% for

different soil-machine parameter combinations. Lowest damage was observed at rake

angle of 200 and 1.5 km.h

-1 speed of operation. Statistical analysis in SPSS 16.0

version indicated that rake angle of machine had significant influence on garlic

damage percentage at 1% level of significance, Table 4.8. Although moisture content

and speed of operation affected damage to plant, but their influence was not

significant. Further, post–hoc analysis of significant variable (rake angle) at 5% level

of significance showed that 200 rake angle was most influencing and caused least

garlic damage percentage (4.75%), Fig. 4.3.

49

Fig. 4.2: Infleunce of soil moisture content and machine rake angle on garlic

harvetsing pecentage

Fig. 4.3: Infleunce of machine rake angle on garlic damage pecentage at different

soil moisture levels

50

Table 4.7: Garlic damage percentage for different soil- machine parameters

combinations

Moisture

content Rake angle (0)

Damage percentage (%)

Speed of operation (km.h-1

)

1.5 3 4.5

15.28±0.38

10 7.29 7.76 8.77

15 6.29 6.69 8.15

20 4.75 5.50 5.40

12.23±0.35

10 7.48 9.26 8.77

15 6.31 6.42 8.06

20 5.30 6.07 5.95

9.33±0.18

10 7.91 9.45 9.33

15 7.99 7.43 8.64

20 5.96 6.70 6.66

Table 4.8: Analysis of variables for garlic damage percentage

Source Sum of

Squares df

Mean


Model 129.94 28 4.64 1.04 0.437

MC 12.86 2 6.43 1.45 0.245

RA 91.78 2 45.89 10.31 <0.0001

SO 14.83 2 7.41 1.67 0.199

MC*RA 0.79 4 0.20 0.04 0.996

MS*SO 1.84 4 0.46 0.10 0.981

RA*SO 4.72 4 1.18 0.26 0.899

MC*RA*SO 2.11 8 0.26 0.06 1

Error 231.42 52 4.45




51

4.4.4.3 Influence of soil-machine parameters on soil separation index

Soil separation index indicates the extent of separation of soil from garlic plant

after operation of harvester. Lesser is the index, better is the separation. Soil

separation index is a function of moisture content and travel time of soil over soil

separator in addition to area over which soil mass is spread. Observations taken under

field conditions indicated that, it ranged between 0.25 and 0.35, Table 4.9.

Table4.9: Soil sepration index for different soil-machine parameter combinations

Moisture

Content

Rake Angle

(0)

Soil separation index

Speed of Operation (km.h-1

)

1.5 3 4.5

15.28±0.38

10 0.32 0.28 0.27

15 0.32 0.30 0.27

20 0.33 0.32 0.30

12.23±0.35

10 0.28 0.26 0.27

15 0.27 0.28 0.25

20 0.30 0.31 0.27

9.33±0.18

10 0.30 0.30 0.31

15 0.34 0.30 0.30

20 0.35 0.34 0.32

Statistical analysis showed that soil separation index has significantly affected

by all soil-machine parameters namely, soil moisture content, rake angle, and speed of

operation at 1% level of significance, Table 4.10. Further, post-hoc analysis of

significant variables at 5% level of significance revealed that highest soil separation

occurred at 12.23±0.35% soil moisture content (d.b), 150 rake angle and highest speed

of operation of 4.5 km.h-1

as shown in Fig. 4.4.

52

Table 4.10: Analysis of variables for soil separation index

Source Sum of

Squares df

Mean


Model 0.0769 28 0.0027 11.3926 < 0.0001

MC 0.018 2 0.009 33.7376 < 0.0001

RA 0.009 2 0.005 17.9014 < 0.0001

SO 0.011 2 0.005 20.1451 < 0.0001

MC*RA 0.0068 4 0.0001 0.3490 0.843

MS*SO 0.003 4 0.0004 3.0005 0.026

RA*SO 0.003 4 0.0004 2.9280 0.029

MC*RA*SO 0.0031 8 0.000 1.6170 0.174

Error 7.4939 81




4.4.4.4 Influence of soil-machine parameters on power requirement

Power requirement is a crucial factor from cost economics of any agricultural

machinery. Power requirement was determined by using traction equations, and by

measuring wheel slip during actual field experiments. The pattern of power

requirement for harvesting operation at different combinations of soil-machine

parameters is shown in Table 4.11.

Power requirement ranged from 4.04-14.02 kW for different soil-machine

parameter combinations. Statistical analysis of data indicated that, rake angle and

speed of operation of machine significantly affected power requirement at 1% level of

significance, Table 4.12. Power requirement varied at different levels of soil moisture

content, but was not significantly affected.

53

Table 4.11: Power requirement (kW) for different soil-machine parameters

combinations

Moisture

Content

Rake Angle

(0)

Power requirement (kW)

Speed of Operation (km.h-1

)

1.5 3 4.5

15.28±0.38

10 4.06 8.68 13.12

15 4.50 8.89 13.47

20 4.68 9.14 13.53

12.23±0.35

10 4.04 8.64 13.12

15 4.43 8.80 13.54

20 4.59 9.11 13.72

9.33±0.18

10 4.23 8.56 13.63

15 4.38 8.77 13.88

20 4.56 9.07 14.02

Further, post-hoc analysis of significant variables at 5% level of significance

showed that least power requirement (4.04 kW) was required at rake angle of 100 and

1.5 km.h-1

speed of operation while maximum power requirement (14.02 kW)

required at rake angle of 200 and operational speed of 4.5 km.h

-1, Fig. 4.5.

Table 4.12: Analysis of variables for power requirement (kW)

Source Sum of

Squares df

Mean


Model 1151.87 28 41.14 84.01 <0.0001

MC 0.08 2 0.04 0.08 0.919

RA 6.22 2 3.11 6.35 <0.003

SO 1136.98 2 568.49 1160.93 <0.0001

MC*RA 0.75 4 0.19 0.38 0.819

MS*SO 3.43 4 0.86 1.75 0.153

RA*SO 0.99 4 0.25 0.51 0.73

MC*RA*SO 3.11 8 0.39 0.79 0.61

Error 25.46 52 0.49



Note: MC = Soil Moisture Content, RA = Rake Angle, SO= Speed of Operation

54

Fig. 4.4: Infleunce of soil moisture content and machine rake angle on soil

separation index

Fig. 4.5: Infleunce of machine rake angle and speed of operation on soil

separation index

55

4.5 Discussions

4.5.1 Biometric and engineering properties of garlic plant

Biometric and engineering properties of garlic plant were studied to decide

design dimensions of various components of garlic harvesting system, for an efficient

harvesting system. Length of plant is a major parameter which affects the dimensions

of soil separator unit of harvesting system. The mean plant length was observed as

693 mm. Hence, for free and early falling of plant material from soil separation unit,

its length was kept about 1.5 times the mean length of garlic plant. The length of soil

separator was accordingly kept as 1000 mm. Polar diameter, equatorial diameter and

shape factor were used to decide the spacing between rods of soil separator of a

harvesting system. The distance between two consecutive rods of soil separator was

kept in the range such that a garlic plant should not freely fall from the gap. From the

data of biometric properties it was seen that the polar and equatorial diameter of bulb

ranged between 33.13-40.48 mm and 31.58-39.21 mm, respectively. Some soil mass

would also stick to the bulbs at this stage. Therefore, for free and efficient fall of

independent soil-mass off the separator, the rod spacing was kept as 50 mm. Depth of

garlic bulb in soil was in range of 68-86mm. Thus, by taking into consideration the

probable irregular maximum depth of garlic bulbs in soil and to harvest them without

damage, the minimum depth of digging blade during harvesting operation was kept as

120 mm.

Weight of garlic plant was taken into consideration for deciding the strength of

material used for components of garlic harvesting system. Also, cutting and crushing

resistance of garlic plant were parameters used to consider the strength of digging unit

of a harvesting system. A mean angle of rolling resistance of garlic plant was

observed as 22.670. The same angle was used to determine the slope provided to the

rods of the soil separator unit of garlic harvesting system.

4.5.2 Soil properties

Soil-machine parameters are important from design point of any harvesting

system. The interactions between these parameters directly affect the performance of

harvesting system in terms of harvesting percentage, damage percentage, soil

56

separation and power requirement to operate the machine under field conditions. Soil

bulk density measured under field conditions (sandy loam soil) at respective soil

moisture indicated the linear relationship between them. Soil moisture content would

affect almost all performance parameters of garlic harvesting system, but had

significant effect on garlic harvesting percentage and soil separation index. Highest

garlic harvesting percentage (96.70%) occurred at soil moisture of 12.23±0.35 percent

(d.b). This was due to the fact that soil at this moisture content was crumby and

friable, which was favourable for operation of the harvesting system in field. At

higher moisture content (15.28±0.38%), harvesting percentage was less due to lower

soil separation and excessive soil-mass with harvested plant mass. Similarly, at lower

soil moisture content (9.33±0.18%), more clod formation had negative impact on

harvesting percentage.

Soil separation was a key parameter which affected harvesting percentage.

More the soil separation (lesser the soil separation index), better was the performance

of harvesting system. It was significantly affected by soil moisture content. Maximum

soil separation (0.25) was obtained at 12.23±0.35% soil moisture content (d.b). This

was due to the fact that, at 12.23±0.35% soil moisture (d.b), soil was crumby leading

to easy separation of soil from plant mass, which was not available at soil moisture of

9.33±0.18 and 15.28±0.38% percent (d.b). Minimum power requirement (4.04 kW)

for operation garlic harvesting system also occurred at 12.23±0.35% soil moisture

(d.b). In consideration above, it was observed that all performance parameters were

optimum at soil moisture level of 12.23±0.35% (d.b), therefore it would be good for

performance evaluation of garlic harvester.

4.5.3 Machine parameters

Rake angle a machine parameter, had major influence on the performance of

garlic harvesting system. It had significant effect on all four performance parameters.

Highest garlic harvesting percentage (96.70%) was obtained at 150 rake angle, when

the volume of soil-plant mass digged was optimum and at proper depth as compared

with the two rake angles. At lower rake angle (100), less depth of operation occurred

than required depth, while at higher rake angle (200) excessive soil-plant mass was to

be handled leading to less soil separation. On the other hand, rake angle of 200

caused

57

minimum damage percentage (4.75%). At higher rake angle (200), the depth of

digging was appropriate with respect to the position of bulbs in soil. At lower rake

angles (100, 15

0), the depth of operation was inadequate, causing higher damage to

bulbs. Highest damage percentage (9.45%) thus occurred at rake angle of 100.

Rake angle also had influence on soil separation during harvesting operation.

Highest soil separation was obtained at 100 rake angle. It caused minimum amount of

soil-plant mass digged as compared to higher rake angles resulting in less soil to be

separated by separation system. Higher rake angle contributed to more soil-plant mass

digging, which adversely affected the performance of soil separation. Though at rake

angle of 200, higher power (mean power requirement of 9.15 kW) was required to

operate harvesting system, but it was very close to the mean power requirements at

100 and 15

0 levels of rake angle i.e. 8.69 and 8.96 kW, respectively. Taking in to

consideration the above, it is observed that rake angle of 200 was most satisfactory for

performance of garlic harvesting system.

Speed of operation had significant influence on soil separation index and

power requirement of garlic harvesting system. Highest operational speed (4.5 km.h-1

)

increased the velocity of soil-plant mass passing over the separation unit with lower

contact time resulting into higher impact on fall of soil-plant mass on soil surface after

discharge at rear of the harvesting system, causing better soil separation. Power

required to operate garlic harvesting system had direct relation with the speed of

operation. Minimum power requirement (4.04 kW) was observed at 1.5 km.h-1

speed

of operation while maximum power requirement (14.02 kW) was observed at 4.5

km.h-1

speed of operation. Increase in forward speed of travel required more power to

maintain momentum of machine as also more energy for moving the soil-plant mass

at higher velocity. Therefore, lower speed of operation (1.5 km.h-1

) has been suitable

for evaluation of garlic harvesting system.

58

CHAPTER V

RESEARCH PAPER II

Design, Development and Performance Evaluation of Tractor operated

Garlic Harvester

5.1 Abstract

Harvesting is one of main important operation in garlic cultivation. In India, it

is performed by manual method which is time consuming, and labour unavailability

during peak harvesting seasons also adds problems to farmer. To alleviate all this, a 4-

row tractor operated garlic harvester was designed and developed. The major

components of garlic harvester were digging unit and soil separation unit. Digging

unit consisted of V-shape blade having width, length and thickness of 600 mm, 300

mm, and 10 mm, respectively. Soil separator unit was of 1000 mm long, 650 mm

wide, and having rod spacing of 50 mm. The thickness of rods used on soil separator

was 10 mm. The harvester was evaluated under field conditions in sandy loam soil for

its evaluation and results were satisfactory. The mean harvesting percentage was

observed as 96.12%, with 5.94% plant damage, soil separation index of 0.26, power

requirement of 4.54 kW and field capacity of 0.24 ha.h-1

. The total cost of the

machine was Rs. 12,700/- and its estimated cost of operation Rs. 1670/- per ha. The

saving in harvesting cost was about Rs. 2080/- per hectare as compared to manual

harvesting (Rs. 3750/- per ha) of garlic. The breakeven point of machine was 218.12

h.yr-1

with a pay back period of 3.63 years.

Key words: design, development, evaluation, cost economics, garlic harvester.

5.2 Introduction

Farm mechanization has brought significant improvement in agricultural

production. Timeliness in farm operation is of utmost importance to maximise

production, and can be achieved through farm mechanization. Since 1960’s, India

steadily achieved a remarkable progress in its agricultural mechanization but this is

mainly concentrated over few crops like paddy, wheat etc. Though vegetable

59

contributes significant role in agriculture, vegetable farming lagged behind in its

mechanization. Garlic is one of the main bulbous vegetable crop cultivated in India.

India is the second largest producer of garlic in the world with an annual

production of about 0.834 Mt (Anon, 2010). Gujarat is the leading producer of garlic

in India followed by Madhya Pradesh, Uttar Pradesh, Rajasthan and Maharashtra.

Among various operations in garlic cultivation, harvesting is one of the most

important and labour intensive. During peak seasons, due to non-availability of labour

in time, delay in harvesting results in heavy loss to the farmer. In addition, migration

of agricultural labour force from rural areas has aggravated the problem to the

farmers. One of the solution for increasing the profit and productivity is to mechanise

harvesting operation in garlic cultivation and to do the same, a mechanical garlic

harvesters has been developed.

Any root or bulbous crop harvester has two main functions, digging the crop

from soil and separating the plant mass from digged soil to windrow them at rear. A

harvester should dig with highest possible harvesting percentage, less plant damage

and with less power requirement. If any harvester can accomplish the same, it will be

accepted by the farmers. Padmanathan et al. (2006) designed, developed and

evaluated tractor operated groundnut combine harvester. They reported that harvester

could achieve the maximum harvesting efficiency of 92.30%, threshing efficiency of

82.30%, cleaning efficiency of 72.30% and minimum percentage of broken pods of

4.43% at 1.5 km.h-1

forward speed. Research conducted on evaluation of carrot digger

reported 97.8% carrot harvesting, 4.56% carrot damage, 0.21 soil separation index

and power requirement of 5.18kW with field capacity of 0.21 ha.h-1

when operated at

a speed of 2.3 km h-1

. This carrot digger saved Rs. 1440/- per ha as compared to

manual harvesting (Shirwal, 2010).

Jadhav et al. (1995) developed a 5 hp self propelled onion digger

windrower. They evaluated the machine with prevalent local practices in different

seasons at different locations and reported that percentage of damaged bulbs ranged

between 2.63 and 3.45% and actual field capacity of the machine ranged between 0.16

and 0.19 ha.h-1

. Digging efficiency was in the range of 89.66-93.23 per cent. A study

conducted on comparative performance of potato digger elevator with conventional

60

method of harvesting at farmers scale reported saving of 1280 man.h.ha-1

as compared

to manual harvesting (Singh et al., 2004).

Available literature is mostly related to mechanical harvesting of crops like

potato, onion, carrots, etc. In India, no such work is reported on mechanical

harvesting of garlic. Therefore, it is proposed to design, develop and evaluate a tractor

operated garlic harvester suitable under Indian conditions.

5.3 Materials and Methods

A tractor operated harvester was designed for digging of garlic plant from soil,

transferring the dug mass to a soil separator for removing soil mass from garlic plants,

and windrowing clean garlic plants at the rear with low power requirement.

5.3.1 Design of Garlic Harvester

There were two important components of garlic harvester from design point of

view i.e. digging unit and soil separator.

5.3.1.1 Design of digging unit

The working depth of digging blade is an important parameter from design

point of view, as it directly affects the power requirement of garlic harvester. The

working depth of digging blade mainly depends upon the depth of garlic bulb in soil.

By taking into consideration the maximum depth of garlic bulb in field (86 mm), it

was decided to keep minimum depth of operation at 120 mm.

The draft of share was calculated using the general soil mechanics equation for

a blade deforming the soil in two dimensions (Hettiarachi, 1966) given by Equation

5.1. It takes into account different soil properties and tool geometry parameters as

following:

Pp = γ Z12 Nγ + CZ1Nc + CaZ1Nca + qZ1Nq ...…… (5.1)

Where,

Pp = Passive resistance of soil acting at an angle of soil-metal friction with the normal

to interface, kg per meter width,

61

γ = Bulk density of soil, kg.m-3

,

Z1 = Depth of operation, m,

C = Cohesion of soil, kg.m-2

,

Ca= Soil-interaction adhesion, kg.m-2

, and

q = Surcharge pressure on soil from surface above the failure plane, kg.m-2

Nγ, Nc , Nq and Nca are dimensionless N- factors, which describe the shape

of soil failure surface and are thus function of angle of shearing resistance of soil (Φ),

angle of soil metal friction (δ) and geometry of loaded interface i.e. rake angle (α).

Based on the above assumptions, the Equation 5.1 could be reduced as following:

Pp = γ Z12 Nγ + CZ1Nc ………. (5.2)

Following values for the different parameters were used for the determination

of the passive resistance of the blade for operation in sandy loam soil:

γ = 1450 kg.m-3

, C = 710 kg.m-2

, Φ = 25.58°, δ = 25.31°, α = 15°, Z1 = 0.12 m

Using the relationship shown in Appendix A, the value of N-factors was

calculated as follows:

Nγ = 1.83, Nc = 1.68

Substituting the values of Nγ and Nc, determined as above, in the Eqn. 5.2,

the passive resistance (Pp) per unit width of the blade was obtained as:

Pp = 1450 x (0.12)2 x 1.83 + 710 x 0.12 x 1.68

= 181.35 kg.m-1

Therefore, Pp for an effective width of cut of 0.45 m of blade is 81.61 kg.

The passive resistance Pp was acting at an angle of friction (δ) with normal to

the interface, hence the component parallel to the blade face (Pp1) was given as:

Pp1 = 81.31 x cos 70°

62

= 27.91 kg

The component perpendicular to the blade face (Pp2 ) was given as

Pp2 = 81.31 x cos 20°

= 76.38 kg

The obtained value of Pp1 and Pp2 were used to determine the bending moment of the

digger blade.

5.3.1.2 Design of digger blade

Digger blade would execute initial digging of garlic plants from soil along

with soil. The width of digger blade was an important factor as it would cover all

plant rows in a bed without damaging standing crop. A harvester ha to cover four

rows of garlic planted at a row-row distance of 150 mm and plant to plant distance of

75 mm. Therefore, width of digging blade was decided on the basis of the width of the

bed and was kept as 600 mm. The blade thickness was designed on the basis of load

acting on it. This could be determined theoretically analysing various forces acting on

the blade.

Pp2 is perpendicular component of Pp1, and would cause bending moment

whereas Pp1 is the horizontal component that would induce direct stress in the blade.

The force would act at the centre of resistance of the blade. It was assumed that

average soil resistance of the blade acts at a distance of 0.2z1 measured from the

cutting edge (Bernacki, 1972), Fig 5.1.

63

Fig 5.1: Soil reactions acting on a simple digging share (Shirwal, 2010)

The centre of resistance was at a distance of 24 mm from the cutting edge on

central axis of the width of blade. The blade was supported on nuts and bolts at a

distance of 200 mm from each side of the cutting edge. Therefore, the distance

between the centre of resistance and point of support could be determined as:

200 – 24 = 176 mm

Therefore, the bending moment (B.M.) due to Pp2 is:

B.M. = 76.38 x 176 = 13442.9 kg.mm, and

Bending stress (σb) is represented as:

……… (5.3)

Where,

B.M = Bending moment, kg.mm

b = Width of blade at its point of mounting, mm, and

t = Thickness of blade, mm.

By solving Eqn. 5.3, the thickness of blade was determined as

64

t = 9.82 mm ≈ 10 mm

Hence, thickness of blade was kept as 10 mm and the total width of blade was

kept as 600 mm as per requirement of digging operation.

5.3.1.3 Design of soil separation unit

The material digged by a digging unit was directly forwarded to a separation

unit. To separate the soil from garlic plant, rods were arranged length wise along the

line of travel of the harvester. Biometric properties of garlic plant (length of garlic

plant, polar and equatorial diameter of garlic bulb including volume of soil sticking to

bulb) were used to determine the various dimensions of soil separator. From the study

data on biometric properties it was decided to keep the rod spacing as 50 mm and the

length of soil separator as 1000 mm. The soil separator’s slot is fabricated using mild

steel rods of 10 mm in diameter.

After deciding basic dimensions of the major parts of garlic harvester,

dimensions of other components were decided accordingly. While deciding

dimensions of components of the harvester, importance was given to both structural

strength as well as cost economics of garlic harvester design. The final drawing of

tractor operated garlic harvester was prepared in software Pro-Engineer version 4.0 as

shown in Fig. 5.2.

5.3.2 Development of Garlic Harvester

A tractor drawn garlic harvester was fabricated in the workshop of Division of

Agricultural Engineering, IARI, New Delhi, with the following procedure:

i. List of all the material needed for fabrication of garlic harvester was prepared

and purchased from local market.

ii. Digging blade was fabricated with mild steel sheet of 300 x 300 x 10 mm. As

per design, the shape of blade was V-shape with an angle of 450. Two units of

blade were joined together to form a digger blade of desired width of 600 mm

with the help of two mild steel flats of 600 x 50 x 8 mm bolted to it, to make a

single unit.

65

iii. The main body of soil separator was made with angle iron of 50 x 50 x 8 mm

along both sides of the unit. The length of soil separator was kept as 1000 mm

as per design of harvester. Two slots of mild steel rods of 10 mm diameter was

fabricated and attached with two mild steel flat of 650 x 50 x 8 mm across the

length of soil separator, by keeping the length of rod in direction of travel.

Side support plates for guiding the digged mass over soil separator unit were

fabricated with mild steel flat of 900 x 100 x 10 mm.

iv. A square pipe of cross sectional area 65 x 65 mm and 1200 mm length was

used for fabrication of square frame along with mild steel plates of 1600 x 125

x 16 mm size to make hitching arrangement of the garlic harvester.

v. Two side support mild steel sheets of size 450 x 50 x 10 mm required to attach

the main square frame to the combined unit of digging blade and soil separator

was fabricated.

vi. Finally, all components were assembled together to develop a single unit of

garlic harvester.

The final fabricated unit of a tractor drawn garlic harvester is shown in Fig. 5.3.

5.3.3 Performance Evaluation of Garlic Harvester

The garlic harvester was evaluated in sandy loam soil to check its performance

in of the following parameters at recommended levels of soil-machine parameters

terms in the test area of 800 m2, and was replicated five times.

5.3.3.1 Harvesting percentage

After each test run, successfully harvested garlic plants were collected

manually while total number of garlic plants present in the field was noted before

each run of harvesting operation. Higher the percentage of garlic plants harvested,

better is performance garlic harvester.

…… (5.4)

66

Fig. 5.2: Design of tractor operated garlic harvester prepared in software Pro-

Engineer

Fig. 5.3: Fabricated unit of tractor operated garlic harvester

67

5.3.3.2 Damage percentage

It was determined by following formula,

…. (5.5)

5.3.3.3 Soil separation index

The index is a measure of the weight of unseparated soil from the garlic

plants. Less is the soil separation index, better is the performance of garlic harvester.

……… (5.6)

Where,

Wa = Actual weight of soil and garlic plan collected at rear end of soil

separator, kg, and

Wt = Theoretical weight of soil cut by blade along with garlic plant at a

working depth of operation, kg.

5.3.3.4 Power requirement

For calculation of power requirement the wheel slip was measured and by

using analytical traction performance equations power required to pull the garlic

harvester was determined. The equations used are as follows:

.…….. (5.7)

……… (5.8)

……… (5.9)

P (kW) = Pull (kN) x Speed (m.s-1

) ……... (5.10)

68

Where,

Cn = Wheel numeric,

CI = Cone index, N.cm-2

,

b = Tyre section width, cm,

d = Overall tyre diameter, cm,

μ = net traction coefficient,

S = Wheel slip, %,

W = Normal load on traction device, N, and

H = Pull, N.

5.3.4 Cost Economics of Garlic Harvester

Any agricultural machine should be designed, taking into consideration of its

cost economics. A machine designed should have minimum cost with good field

performance. Therefore, to examine the garlic harvester on same basis, its cost

evaluation was determined by straight line method. Total cost of garlic harvester was

determined by adding both the net cost of material used for fabrication and labour cost

for fabrication. Similarly, total cost of operation was calculated on the basis of fixed

and variable cost as follows and shown in Appendix B.

5.3.4.1 Fixed cost of tractor and garlic harvester

i. Depreciation

ii. Interest

iii. Insurance and taxes

iv. Housing

5.3.4.2 Variable cost of tractor and garlic harvester

i. Fuel cost

ii. Lubricant cost

iii. Labour charges

iv. Repair and maintenance charges

69

The obtained cost of operation was compared with manual harvesting of

garlic. The breakeven point and payback period were computed for garlic harvester.

5.3.4.3 Breakeven point

………… (5.11)

Where,

BEP = Breakeven point, h.yr-1

FC = Annual fixed cost, Rs.yr-1

,

C = Operating cost, Rs.h

-1,

CH = Custom hiring charges, Rs.h-1

, and

= (C + 25 per cent over head) + 25 per cent profit over new cost

5.3.4.4 Payback period

…………. (5.12)

Where,

PBP = Payback period, yr,

IC = Initial cost of machine, Rs, and

ANP = Average net annual profit, Rs.yr

-1,

= (CH – C) x AU

Where,

AU = AA x EC …………. (5.13)

Where,

AA = Average annual use, h.yr-1

, and

EC = Effective capacity of machine, ha.h

-1.

70

5.4 Results

Relevant crop properties and soil-machine parameters were studied to design

and develop garlic harvester. Following recommendations on design values of

harvester were made by optimization of the variables:

i. Soil moisture content = 12.23±0.35%

ii. Rake angle = 150

iii. Speed of operation = 1.5 km.h-1

Based on those parameters, dimensions of various components of harvester

were determined as the following.

5.4.1 Specifications of Major Components of Garlic Harvester

A) Digging unit:

i. Length = 300 mm

ii. Width = 600 mm

iii. Thickness = 10 mm

B) Soil separation unit:

i. Length = 1000 mm

ii. Width = 650 mm

iii. Thickness of rod = 10 mm

iv. Spacing between rods = 50 mm

v. Number of rods = 22

5.4.2 Bill of Materials

Bill of material used for fabrication of garlic harvester was prepared as per

market rate to compute its cost of fabrication. Labour charge for fabrication was

added to bill of materials to compute total cost of fabrication of harvester as shown in

the Table 5.1.

71

Table 5.1: Bill of materials used for fabrication

Sr.

No.

Name of

Component

Material used

for construction

Size Cost

(Rs.)

1 Digging unit MS flat 600 x 300 x 10 mm 850

MS flat 1200 x 50 x 8 mm 440

2 Soil separation

unit MS angle iron

2000 x 50 x 50 x 8

mm 2150

MS flat 1300 x 50 x 8 mm 480

MS flat 900 x 100 x 10 mm 880

MS rods 450 mm x 22 1320

3

Main frame MS square pipe 1200 x 65 x 65 mm 1150

MS sheet 1600 x 125 x 16 mm 2100

4 Side support MS flat 900 x 50 x 10 mm 750

Total 10120 /-

Total material cost Rs. = 10120 /-

Labour charges @ 25 per cent, R = 2530 /-

Total cost of fabricaton, Rs. = 12650 /- ≈ 12700 /-

5.4.3 Performance Evaluation of Garlic Harvester

Fabricated garlic harvester was tested under field conditions for its

performance evaluation as per recommended values of soil-machine parameters and

following results were obtained as shown Table 5.2.

Table 5.2: Performance parameters for garlic harvester

Sr. No. Performance parameter Result

1 Harvesting percentage (%) 94.12 - 97.87

2 Damage percentage (%) 4.17 - 7.16

3 Soil separation index 0.24 - 0.31

4 Power requirement (kW) 4.18 - 4.66

5 Field capacity (ha.h-1

) 0.24

72

5.4.4 Cost Economics

The cost of operation of garlic harvester was calculated by taking into

consideration costs of both harvester and tractor to operate it in the field. Then, it was

compared with cost of manual harvesting of garlic, and comparative cost saving was

determined. The break even point of garlic harvester was calculated along with

payback period.

Fixed cost of tractor, Rs.h-1

= 133.65

Variable cost of tractor, Rs.h-1

= 238.02

Fixed cost of garlic harvester, Rs.h-1

= 12.04

Variable cost of garlic harvester, Rs.h-1

= 24.54

Cost of operation of garlic harvester with tractor, Rs.h-1

= 396.39 ≈ 400

Cost involved in mechanical harvesting of garlic, Rs.ha-1

= 1670

Cost involved in manual harvesting, Rs.ha-1

= 3750

Cost saving, Rs.ha-1

= 2080

Cost saving, % = 55 %

Break even point, h.yr-1

= 218.12

Payback period, yr = 3.63

5.5 Discussions

A 4-row tractor operated garlic harvester was designed for harvesting with

minimum plant damage and power requirement. Studies on an impact of soil-machine

parameters on garlic harvesting quality led to optimized values of three major soil-

machine parameters viz. soil moisture content, rake angle and speed of operation for

design and development of a prototype garlic harvester.

The digging unit, soil separator and frame of the tractor operated garlic

harvester were designed based on crop geometry and material strength point of view.

73

A prototype garlic harvester was fabricated in the workshop of Division of

Agricultural Engineering, IARI, New Delhi. The major specifications of digging

blade such as length, width and thickness were kept as 300 mm, 600 mm and 10 mm,

and for soil separation unit as 1000 mm, 650 mm and 10 mm. respectively. After

fabrication, its performance was evaluated under field conditions in sandy loam soil at

12.75±0.68% soil moisture (d.b) and at speed of 1.5 km.h-1

for parameters such as

harvesting percentage, damage percentage, soil separation index, power requirement,

and field capacity. Field tests showed that garlic harvesting percentage ranged

between 94.12 - 97.87% with mean of 96.12%. Similarly, damage percentage, soil

separation index and power requirement varied from 4.17 to 7.16%, 0.24 to 0.31 and

4.18 to 4.66 kW with means of 5.94%, 0.26 and 4.54 kW, respectively. At soil

condition of 12.75±0.68% soil moisture (d.b), it was crumby and friable in nature

which offered proper environment for digging at the optimum speed of operation of

1.5 km.h-1

. At rake angle of 150, the amount of digged mass was optimum at desired

depth of operation. Field capacity of the garlic harvester was observed as 0.24 ha.h-1

.

The performance of the harvester was thus satisfactory. Since the power requirement

was 4.54 kW, there is scope to increase the field capacity by increasing the width of

digging unit for being operated by a 25-35 kW tractor commonly used by farmers.

From farmer’s point of view, cost economics of any agricultural machine is of

prime importance. A machine cost should be reasonable, and then only it can be

popular among farmers. Its performance in terms of cost saving should be better as

compared to any other method of harvesting. The total cost of machine was Rs.

12700/- and its estimated cost of operation Rs. 1670/- per ha. This cost of operation is

much lower than cost of manual harvesting (Rs. 3750/- per ha), which saves up to

55% operational cost as compared to manual harvesting. The garlic harvester had a

breakeven point at 218.12 h.yr-1

with a pay back period of 3.63 years.

74

CHAPTER VI

DISCUSSION

Mechanization of agriculture is key to increase agricultural production. India

has achieved a remarkable progress in cereal crop mechanization, but vegetable

farming is still lagging behind in its level of mechanization. Among those vegetables,

Garlic (Allium sativum L.) is one of important bulbous crop from Alliaceae family,

and India is second largest producer in world after china with an annual production of

about 0.834 Mt (Anon, 2010). In India, garlic harvesting is mostly done by hand

picking, which is time consuming and labour-intensive. Labour unavailability during

the peak season of harvesting delays the harvest, which results in damage to crop. No

major work is reported in India on mechanical harvesting of garlic. Therefore, by

taking into considerations of all above, a study on design parameters of mechanical

harvesting of garlic was carried out.

Biometric and engineering properties of garlic crop relevant to a garlic

harvester design were determined. The observations on these properties were used to

design an efficient garlic harvester. Number of garlic leave per plant at harvesting

stage varied from 5 to 7 with modal value of 7 while mean plant length was observed

as 693 mm. Hence, for free and early falling of plant material from soil separation

unit, its length was kept about 1.5 times the average length of garlic plant. Thus, the

length of soil separator was kept as 1000 mm. The polar and equatorial diameter of

garlic bulb varied from 33.13-40.48 mm and 31.58-39.21 mm, respectively. For free

and efficient falling of soil-mass off the separator, the rod spacing was kept as 50 mm

so that garlic bulbs with adhered soil did not fall. Since the depth of garlic bulb in soil

was in range of 68-86 mm, minimum depth of operation was selected as 120 mm

considering the probable variation in depth of garlic bulbs of different varieties in soil

and to harvest them without damage. Studies conducted by Khura et al. (2010) on

engineering properties of onion relevant design of onion digger gave similar results.

Soil-machine parameters influencing mechanical harvesting system of garlic

were also studied and were optimised for performance of garlic harvester. Three

levels of soil moisture (15, 12 and 9%), rake angle (10°, 15° and 20°) and speed of

75

operation (1.5, 3 and 4.5 km.h-1

) were used in different combinations to observe their

effect on mechanical garlic harvesting in terms of performance parameters like garlic

harvesting percentage, damage percentage, soil separation index and power

requirement, etc.

Soil moisture content was a key factor which affected almost all performance

parameters of garlic harvesting system. But, it had significant effect on garlic

harvesting percentage and soil separation index. Highest garlic harvesting percentage

(96.70%) and maximum soil separation (0.25) was obtained at 12.23±0.35% soil

moisture content (d.b). This was due to soil remained crumby and friable at this

moisture content, which was favourable for operation of the harvesting system in

field. At higher moisture content (15.28±0.38%), there was less soil-plant mass

separation and excessive soil-mass with harvested plant mass while at lower soil

moisture content (9.33±0.18%), clod formation occurred. Minimum power

requirement for operation of the garlic harvesting system was 4.04 kW at

12.23±0.35% soil moisture (d.b), and was close to power requirement at other two

levels of soil moisture content by keeping other parameters constant. Similar level of

soil moisture content was recommended by Shirwal (2010) for carrot harvesting, as he

observed maximum of 97.03% carrot harvesting and 5.48 percentage of damage and

minimum soil separation index of 0.26 at moisture content of 12%.

Rake angle a machine parameter, had significant effect over the performance

of garlic harvesting system. Highest garlic harvesting percentage (96.70%) was

obtained at 150 rake angle as the soil-plant mass was dug at proper depth and volume

of soil-plant mass was optimum as compared to other two rake angles. At lower rake

angle (100), the depth of operation was lower than desired depth resulting to higher

garlic damage percentage, while at higher rake angle (200), the volume of soil-plant

mass was excess for proper soil separation. Hance, rake angle of 150 was

recommended as optimum for field operation of garlic harvester. Trivedi and Singh,

(1975) had reported that at 20° rake angle of tractor drawn potato digger, harvesting

percentage was maximum.

Speed of operation had major influence on soil separation index and power

requirement of garlic harvesting system. Higher speed of operation (4.5 km.h-1

)

76

reduced the travel time of dug soil-plant mass over the soil separation unit of garlic

harvesting system and imparted higher momentum to soil-mass exiting the separation

unit resulting in lesser soil separation index (0.25). Not much variation existed in soil

separation index at lower operational speeds. On the other hand, maximum power

requirement (14.02 kW) was observed at 4.5 km.h-1

speed of operation, while

minimum power requirement (4.04 kW) was observed at 1.5 km.h-1

speed of

operation. This clearly indicated that lower the speed of operation, least would be the

power requirement for garlic harvesting system. Similar trend of increase in power

requirement with increase in speed of operation was observed by Kang et al. (1991).

Based on observations of biometric and engineering properties of garlic plant

and recommended value of rake angle for digging unit, a garlic harvester was

designed. A prototype of tractor operated 4-row garlic harvester was fabricated in the

workshop of Division of Agricultural Engineering, IARI, New Delhi. The prototype

evaluated in sandy loam soil at recommended values of soil-machine parameters.

Harvesting percentage, damage percentage, soil separation index, and power

requirement were observed as 96.12%, 5.94%, 0.26, and 4.37 kW, respectively, and

the performance was satisfactory. Field capacity of harvester was 0.24 ha.h-1

.

The total cost of fabrication of garlic harvester was Rs. 12700/- with


and payback period of 3.63 yrs. The cost economics

of garlic harvester showed that it would save harvesting cost by Rs. 2080/- per ha as

compared to manual harvesting of garlic resulting in about 55% savings in cost of

harvesting operation. Kathirvel et al. (1998) had also reported cost saving up to 44.7

and 43.7% for a single row ridger type sliding potato digger with two power tiller

models as VST and TNAU power tiller.

As the 4-row harvester required 4.18-4.66 kW of power for its operation,

opportunity exists to increase the capacity of the machine to be operated by a 25-35

kW tractor commonly used in Indian farm. With increase in field capacity, the cost of

operation would be expected to reduce. Incorporation of vibratory soil separation unit

can further improve soil separation while use of gauge wheels can help in maintaining

constant desired depth of operation.

77

CHAPTER VII

SUMMARY AND CONCLUSIONS

India has the distinction of growing largest number of vegetable crops

compared to any other country of the world, and is blessed with varied agro-climatic

conditions which make it possible to grow a wide variety of vegetable crops round the

year. This made India second largest producer of vegetables in the world with an

annual production of about 134.10 Mt (Anon, 2010), which contributed about 15%

share of world’s total production. Over the years, India has shown steady increment in

its vegetable production. Among those, garlic (Allium sativum L.) is an important

bulbous crop with an annual production of 0.834 Mt (Anon, 2010), second largest in

the world, and grown on 0.166 Mha land. Gujarat is the leading producer of garlic in

India followed by Madhya Pradesh, Uttar Pradesh, Rajasthan and Maharashtra.

Though its production is in increasing trend since 1970’s, but like other vegetables the

level of mechanization in garlic crop is far from satisfactory. In India, it is still

harvested by manual method where garlic plant is pulled from soil and then picked up

manually requiring about 300-350 man.h.ha-1

. Additionally, labour unavailability

during peak harvesting season adds more problem to the farmers. Mechanization of

garlic harvesting thus assumes great importance. In India, no major work is reported

on mechanical harvesting of garlic. Therefore, the present study was conducted on

identification of design parameters of mechanical harvesting of garlic through

evaluation of biometric and engineering properties of garlic plants and optimization of

soil-machine parameters. Consequently, a mechanical garlic harvester was designed,

developed and evaluated for its performance under field conditions.

Based on the results, following conclusions were made:

7.1 Biometric and Engineering Properties of Garlic Plant

Biometric and engineering properties of garlic plant influencing mechanical

harvesting of garlic were studied for garlic cultivar Yamuna Safed-3 (G 282) at its

harvesting stage cultivated in the farm of Division of Agricultural Engineering, IARI,

New Delhi. Biometric properties viz. length of plant, number of leaves per plant,

depth of garlic bulb below ground surface, equatorial and polar diameter of garlic


78

bulb, weight of garlic plant and engineering properties namely shape factor, crushing

resistance, cutting resistance, and angle of rolling resistance were determined.

Similarly, soil-machine parameters as soil moisture content, rake angle and speed of

operation were optimized for a garlic harvesting system.

Number of garlic leaves per plant at harvesting stage varied from 5 to 7 with

modal value of 7, while the length of garlic plant varied from 649 to 755 mm with

mean of 693.4 mm. Depth of garlic bulb which affects the depth of operation were in

the range of 68-86 mm with modal value of 76 mm. Polar and equatorial diameters

which affects spacing between rods of soil separator ranged from 33.13-40.48 and

30.26-36.82 mm, and their respective means were 37.24, 34.06 mm, respectively.

Mean shape factor was observed as 0.96. Also, cutting and crushing resistance of

garlic plant ranged from 442.32-486.01N and 202.54-231.53 N with means of 463.72

N and 218.23 N, respectively.

Observations on biometric and engineering properties of garlic were used in

the component design of garlic harvester. The depth of garlic bulb with respect to soil

surface was considered to decide the minimum depth of operation of digging blade in

soil during harvesting operation and accordingly minimum depth of operation was

kept as 120 mm. Cutting and crushing resistance of garlic plant were considered for

design the digging unit of harvesting system. Plant length at the time of harvesting

was used to decide the length of soil separator and accordingly it was kept as 1000

mm. Shape factor, polar diameter and equatorial diameter were used to decide the

lateral spacing between rods of soil separator and was kept as 50 mm. Slope of rods of

soil separator was kept at 250 considering the angle of rolling resistance of garlic

plant. Weight of garlic plant and accompanying soil mass was taken into

consideration for deciding the strength of material of the components of garlic

harvesting system.

7.2 Optimization of Soil-Machine Parameters

Influence of soil-machine parameters was determined under field conditions

on experimental set up of garlic harvesting system in terms of garlic harvesting

percentage, damage percentage, soil separation index and power requirement. The soil

of the experimental farm was of alluvial group having sandy loam texture.

79

Experiments were conducted at three levels of soil moisture content (15.28±0.38,

12.23±0.35 and 9.33±0.18%), rake angle (100, 15

0 and 20

0) and speed of operation

(1.5, 3.0 and 4.5 km.h-1

). Bulk density of soil was measured at respective soil

moistures under field condition, and had a linear relationship between them.

Experimental results were statistically analyzed, and post hoc analyses conducted on

the significant variables for identification of the optimal values for best performance.

Soil moisture content had a significant effect over garlic harvesting percentage

and soil separation index. Highest garlic harvesting percentage (96.70%) and

minimum soil separation index (0.25) was observed at 12.23±0.35% soil moisture

(d.b). Also, minimum power requirement (4.04 kW) to operate the garlic harvesting

system occurred at 12.23±0.35% soil moisture level (d.b), and was close to power

requirements at other two levels of soil moisture. Rake angle, a machine parameter,

significantly influenced all performance parameters. Highest garlic harvesting

percentage (96.70%) and minimum soil separation index (0.25) was observed at rake

angles of 150

and 100, respectively. However, highest percentage of garlic damage

(9.45%) occurred at rake angle of 10 degrees. Similarly, speed of operation had a

significant influence over soil separation index and power requirement for harvesting.

At lowest speed of operation (1.5 km.h-1

), average power requirement (4.39 kW) was

minimum and vice-versa. Therefore, taking into consideration the above observations,

soil moisture of 12.23±0.35% (d.b), rake angle of 150 and 1.5 km.h

-1 speed of

operation were recommended for performance evaluation of a garlic harvester.

7.3 Performance Evaluation of a Tractor Operated Garlic Harvester

A 4-row tractor operated garlic harvester was accordingly designed and

fabricated in the workshop of Division of Agricultural Engineering, IARI, New Delhi.

The prototype was field evaluated for its performance. Cost economics of harvesting

with garlic harvester and manual garlic harvesting was compared.

Tractor operated garlic harvester was operated under field conditions in sandy

loam soil for its performance evaluation at recommended soil moisture and machine

forward speed. The tests were conducted at 12.75±0.68% soil moisture content (d.b)

at respective soil bulk density of 1414±0.03 kg.m-3

. Garlic harvesting percentage

ranged between 94.12 and 97.87% with mean of 96.12%, while damage percentage,

80

soil separation index and power requirement varied from 4.17 to 8.16%, 0.24 to 0.31

and 4.18 to 4.66 kW with means of 5.94%, 0.26 and 4.54 kW, respectively, and were

satisfactory. Actual field capacity of the garlic harvester was 0.24 ha.h-1

. The total

cost of fabrication of machinery was Rs. 12700/- and its estimated cost of operation as

Rs. 1670/- per ha. The harvester could save about Rs. 2080/- per ha of harvesting cost

as compared to manual harvesting (Rs. 3750/- per ha) of garlic. Breakeven point of

the machine was at 218.12 h.yr-1

, with a payback period of 3.63 years.

i

STUDIES ON DESIGN PARAMETERS OF

MECHANICAL HARVESTING OF GARLIC

ABSTRACT

Since 1960’s, India steadily achieved remarkable progress in its agricultural

mechanization, but mainly concentrated for few crops like paddy, wheat, etc. Though

vegetable contributes significantly in Indian agriculture, vegetable farming lagged

behind in its mechanization. Garlic (Allium sativum L.) is one of the main bulbous

vegetable crop from Alliaceae family grown in India. Manual garlic harvesting is time

consuming operation and requires high man-hours. For mechanised garlic harvesting

under Indian conditions, studies were conducted on optimisation of design parameters

of mechanical harvesting of garlic through evaluation of biometric and engineering

properties relevant to mechanical harvesting of garlic. An experimental set up of

garlic harvesting system was fabricated to determine the influence of soil-machine

parameters on mechanical harvesting of garlic at three levels of soil moisture content

(15, 12 and 9%), rake angle (100,15

0 and 20

0) and speed of operation (1.5, 3.0 and 4.5

km.h-1

). Field experiments were conducted to determine optimum values for design of

garlic harvester. The design values were incorporated in design of a garlic harvester

and field evaluated.

Observations on biometric and engineering properties of garlic plant such as

plant length were used to decide the length of soil separator and accordingly, it was

kept as 1000 mm. Shape factor, polar diameter and equatorial diameter were used to

decide lateral spacing between rods of soil separator as 50 mm. Depth of garlic bulb

with respect to soil surface was used to decide the minimum depth of digging blade in

soil during harvesting operation, and was decided as 120 mm. Slope of rods of soil

separator was kept at 250 considering the angle of rolling resistance of garlic plant.

Weight of garlic plant was taken into consideration for deciding the strength of

material used for components of garlic harvesting system. Cutting and crushing

resistance of garlic plant were used to consider the strength of digging unit of a

harvesting system.

Influence of soil-machine parameters on experimental set up of garlic

harvesting system was determined in terms of garlic harvesting percentage, damage

ii

percentage, soil separation index, and power requirement. Observations showed that

soil moisture content significantly affected harvesting percentage and soil separation.

Highest garlic harvesting percentage (96.70%) and maximum soil separation (0.25)

was obtained at 12.23±0.35% soil moisture content (d.b). Also, minimum power (4.04

kW) required was observed at 12.23±0.35% soil moisture (d.b).

Rake angle had influence over all performance parameters. Highest garlic

harvesting percentage (96.70%) and minium damage percentage (4.75%) was

obtained at 150 and 20

0 rake angle, respectively. However, soil separation was lower

at rake angle of 200. By considering overall performance, rake angle of 15

0 was most

satisfactory. On the other hand, speed of operation had effect on soil separation index

and power requirement. Highest speed of operation (4.5 km.h-1

) resulted in lower soil

separation index (0.25), without significant difference at other two levels of

operational speed. High speed required maximum power requirement (14.02 kW),

while lowest speed (1.5 km.h-1

) required minimum power (4.04 kW). Considering the

above, soil moisture of 12.23±0.35% (d.b), rake angle of 150 and 1.5 km.h

-1 speed of

operation were recommended as design operational parameters of a garlic harvester.

A 4-row tractor operated garlic harvester was accordingly designed and field

evaluated in sandy loam textured field. Harvesting percentage, damage percentage,

soil separation index, power requirement and field capacity were observed to be

96.12%, 5.94%, 0.26, 4.54 kW and 0.24 ha.h-1

, respectively, and were satisfactory.

The total cost of fabrication of garlic harvester was Rs. 12700/-. Operational cost of

machine harvesting was estimated to be Rs. 1670/- for one hectare, which was much

lower than cost of manual harvesting (Rs. 3750/- per ha), leading to about 55 %

savings in cost of harvesting operation. The prototype garlic harvester had a


, with a pay back period of 3.63 years.

iii

रहसुन की म ॊत्रिकी कट ई के डडज इन भ नकों ऩय अध्ममन

स य 1960 के दशक स े ब यत न ेतेजी स ेअऩनी कृषष मॊिीकयण भें उल्रेखनीम प्रगतत ह ससर की है,

रेककन मह भशीनीकयण भुख्म रूऩ स ेध न, गेह ॊ आदद जैस ेकुछ पसरों ऩय ही कें दित है। ह र ॊकक सब्जी,

कृषष भें फड मोगद न देती है, रेककन सब्जी की खेती म ॊत्रिकीकयण भें अबी बी फहुत ऩीछे है।

रहसुन (एसरमभ सदटवभ एर.), एसरम सस ऩरयव य स ेएक भहत्वऩ णण ग ॉठव री सब्जी है। भ नवीम

रहसुन कट ई फहुत सभम रेन ेव र क मण है औय इसके सरए भजद यों के फडी सॊख्म आवश्मक है।

ब यतीम ऩरयस्थथततमों भें रहसुन की मॊिीकृत खेती कयन े हेत,ु रहसुन म ॊत्रिक कट ई डडज इन

भ नकों ऩय अध्ममन ककम गम । रहसुन की म ॊत्रिक कट ई कयन ेके सरए प्र सॊगगक फॉमोभीदिक

औय इॊजीतनमरयॊग गुणों क अध्ममन ककम गम । एक रहसुन कट ई प्रण री, रहसुन म ॊत्रिक

कट ई ऩय सभट्टी भशीन भ नकों के प्रब व को तनध णरयत कयन ेके सरए प्रमोग त्भक थतय ऩय तैम य

की गमी। मह सभट्टी की नभी स भग्री (15, 12 औय 9%), येक कोण (10o,15o औय 20o), औय

आऩयेशन गतत के (1.5, 3 औय 4.5 ककभी प्रतत घॊट ) तीन थतयों भें यखन ेके द्व य ककम गम

थ । रहसुन ह यवेथटय की डडज इन के सरए इष्टतभ भ ल्मों को तनध णरयत के सरए ऺेि प्रमोगों क

आमोजन ककम गम । इन गुणों को, जफकक एक रहसुन ह यवेथटय को डडज इन कयन ेभें श सभर

ककम गम ।

फॉमोभीदिक औय इॊजीतनमरयॊग गुण के दटप्ऩणणमों ऩय आध रयत जैस ेकक, ऩौधे की रॊफ ई

अनुस य सभट्टी षवब जक रॊफ ई तम ककम गम औय तदनुस य मह 1000 सभभी रूऩ यख गम थ ।

इसी तयह, आक य क यक, ध्रवुीम व्म स औय ब भध्म व्म स सभट्टी षवब जक के आध य ऩय डडज इन

भें सभट्टी षवब जक छडों के फीच क अॊतय 50 सभभी यख गम थ । इसके अर व , सभट्टी की सतह

सरए सम्भ न स थ रहसुन फल्फ गहय ई आऩयेशन कट ई दौय न सभट्टी भें खदु ई ब्रेड न्म नतभ

गहय ई तम ककम गम थ औय मह 120 सभभी के रूऩ भें न्म नतभ गहय ई यख गम थ । रहसुन

ऩौधे की योसरॊग प्रततयोध के कोण ऩय षवच य कय सभट्टी षवब जक की छड क ढर न 25o यख गम

थ । रहसुन ऩौधे के वजन को ध्म न भें यखकय रहसुन कट ई प्रण री स भग्री की त कत तम

कय दी गमी थी। इसके अर व , रहसुन ऩौधे के क टन ेऔय कुचर प्रततयोध क इथतेभ र खदु ई

इक ई की त कत तनस्ित कयन ेके सरए ककम गम । सभट्टी भशीन भ नकों क प्रब व रहसुन कट ई

iv

प्रण री ऩय, रहसुन कट ई प्रततशत, ऺतत प्रततशत, सभट्टी जुद ई स चक ॊक, औय शडि की

आवश्मकत के सॊदबो ऩय तनध णरयत ककम गम थ । दटप्ऩणणमों स ेऩत चर कक, सभट्टी की नभी

स भग्री कट ई प्रततशत औय सभट्टी जुद ई को क पी प्रब षवत कयती है। उच्चतभ रहसुन कट ई

प्रततशत (96.70%) औय अगधकतभ सभट्टी जुद ई (0.25), सभट्टी की नभी स भग्री 12.23±0.35%

ऩय प्र प्त हुई थी। इसके अर व , न्म नतभ शडि (4.04 ककरोव ट), 12.23±0.35% सभट्टी की नभी

ऩय प्र प्त हुई।

यैक कोण क स ये प्रदशणन भ नकों ऩय प्रब व ऩड । उच्चतभ रहसुन कट ई प्रततशत

(96.70%) औय न्म नतभ ऺतत प्रततशत (4.75%) 15o औय 20o यैक कोण को, क्रभश् प्र प्त हुई

थी। रेककन सभट्टी जुद ई 20o के येक कोण को कभ थी। सभग्र प्रदशणन ऩय षवच य कयके, 15o क

येक कोण सफस ेसॊतोषजनक थ । इसी प्रक य, आऩयेशन की गतत न े सभट्टी जुद ई स चक ॊक औय

शडि की आवश्मकत को प्रब षवत ककम थ । आऩयेशन के उच्च गतत स े(4.5 ककभी प्रतत घॊट )

कभ सभट्टी जुद ई स चक ॊक (0.25) की प्र तप्त हुई। रेककन मह ऩरयच रन की गतत के अन्म दो

थतयों स ेफहुत अरग नहीॊ थ । मह उच्च गतत अगधकतभ शडि आवश्मकत (14.02 ककरोव ट) क

क यण फन , जफकक कभ गतत (1.5 ककभी प्रतत घॊट ) भें कभ शडि की आवश्मकत (4.04

ककरोव ट) रगी। अत् उऩयोि को ध्म न भें रे कयके, 12.23±0.35% सभट्टी नभी क थतय, 15o

के येक कोण औय 1.5 घॊट प्रतत ककभी आऩयेशन की गतत स े रहसुन ह यवेथटय के प्रदशणन

भ ल्म ॊकन के सरए की ससप रयश की थी।

िेक्टय सॊच सरत 4 ऩॊडि क रहसुन ह यवेथटय डडज इन ककम गम थ औय येतीरे गचकनी

फरुई सभट्टी के ऺेि भें भ ल्म ॊककत ककम गम । कट ई प्रततशत, प्रततशत ऺतत, सभट्टी जुद ई

स चक ॊक, त्रफजरी की आवश्मकत औय ऺेि ऺभत क्रभश् 96.12%, 5.94%, 0.26, 4.54

ककरोव ट औय 0.24 हेक्टेमय प्रतत घॊट प्र प्त हुई। रहसुन की पसर क टन ेकी भशीन तनभ णण

कुर र गत 12,700/- रुऩमे थी औय इसस ेकट ई र गत प्रतत हेक्टेमय 1670/- रूऩमे की रगती

है, जो कक भ नवीम कट ई र गत (3750/- रुऩमे प्रतत हेक्टेमय) स ेफहुत कभ है। मह कट ई

आऩयेशन की र गत भें 55% फचत कयत है। प्रोटोट इऩ रहसुन ह यवेथटय क ब्रेक त्रफ ॊद ु218.12

घॊटे प्रतत स र औय 3.63 वषण की बुगत न व ऩस अवगध है।

v

CHAPTER X

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ix

APPENDIX A

xiv

APPENDIX B

Calculations of Cost of Operation of Prototype Tractor Operated Garlic Harvester

I. Cost of Operation of prime mover (i.e. tractor)

Assumptions

i. Average annual use, h= 1000

ii. Life of tractor, yrs = 10

iii. Salvage Value = 10% of initial cost

iv. Rate of interest = 14% of capital cost

v. Fuel cost, Rs.lit-1

= 41

vi. Initial investment on tractor = 4,50,000

A. Fixed Cost

Initial cost of tractor (45 hp), Rs = 4,50,000

Depreciation (Rs.h-1

) = = = 40.50

Interest (Rs.h-1

) = = = 34.65

Housing, taxes and insurance cost @ 3 % of the initial investment per year,

Rs.h-1

= 13.50h

Repair and maintenance cost @ 10 % of the initial investment per year,

Rs.h-1

= 45.00

Fixed cost of tractor, Rs = 40.50 + 34.65 + 13.50 + 45.00 = 133.65

xv

B. Variable cost

Fuel cost, Rs.h-1

= 4 x 41 = 164.00

Lubricants @ 30% of fuel cost, Rs.h-1

= 164 x 0.30 = 49.20

Wages of tractor driver @ Rs. 200 per day of 8 hours

Wages, Rs.h-1

= 200/8 = 25

Variable cost of tractor, Rs.h-1

= 164 + 49.20 + 25 = 238.20

Total cost of tractor operation, Rs.h-1

= 133.65 + 238.20 = 371.85

II. For garlic harvester

i. Average annual use = 250 h

ii. Life of garlic harvester = 10 years

iii. Salvage value = 10% of initial cost

A. Fixed Cost

Cost of garlic harvester with all accessories = Rs. 12700

Depreciation, Rs.h-1

= = 4.57

Interest on investment,

(@ 14 per cent per annum), Rs.h-1

= = 3.92

Taxes, Insurance and shelter charges,

(@ 2 per cent of the initial cost per annum), Rs.h-1

= = 1.01

Repair and maintenance cost

(@ 5 per cent of the initial cost per annum), Rs.h-1

= = 2.54

Total fixed cost for garlic harvester, Rs.h-1

= 4.57 + 3.92 + 1.01 + 2.54 = 12.04

xvi

B. Variable cost

Assumption

i. One labour is required to utilize the full capacity of the garlic harvester

ii. Wage rate of Rs. 100 per man per day of 8 hours

Labour cost of one person, Rs.h-1

= 12.50

Operating cost of garlic harvester, Rs.h-1

= 12.04 + 12.50 = 24.54

C. Cost involved in mechanical garlic harvester

Operating cost of garlic harvester with tractor, Rs.h-1

= 371.85 + 24.54 = 396.39

≈ 400

Field capacity of garlic harvester = 0.24 ha/h

The cost of mechanical garlic harvesting, Rs.ha-1

= Rs.1666.67 ≈ 1670

D. Cost involved in Manual garlic digging

Man hour required to harvest one hectare of garlic = 300.00

Wage rate of Rs. 100 per man per day of 8 hours

The cost of manual digging of garlic per ha, Rs =

Breakeven point

= 218.12 h.yr-1

FC, Rs.yr-1

= Fixed cost = 250 x 12.04 = 3010

CH, Rs.h-1

= Custom hiring charges = (Cost of operation per hour + 25% of overhead

charges) x 25% profit over new cost

= (24.54 + (24.54 x 0.25)) x 1.25

= 38.34

C, Rs.h-1

= Operating cost = 24.54

xvii

Hence,

BEP = 52.35 ha.yr-1

Annual utility, ha= 0.24 x 250 = 60 ha

Therefore, BEP is achieved at about 87.25 % ((52.35/60) x 100) of the annual utility of

250 hrs of use of garlic harvester.

Payback period

IC, Rs = Initial cost = 12700,

ANP, Rs yr-1

= Average net annual profit = (CH – C) x AU

= (38.34 – 24.54) x 250

= 3450

PBP, yr = 12700/3450 = 3.63

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