Mr. C K Patel

Sr. Manager Agronomy

Ck.patel@netafim.com

SBU-WEST-NETAFIM

9687696657

Importance of fertigation scheduling

2

Scheduling must be based on law of Minimum

Essential elements for plant

Crop growth stage

Nutrients uptake by various crops

Cation exchange capacity

Soil fertility & texture

Soil PH & EC

Salt tolerance of crops

Fertilizers compatibility

soil temperature

Proper fertigation scheduling can maximize the

fertilizers use efficiency & Crop yield

Different factors affecting the

fertigation scheduling

3

The Law of Minimum

The element which is in shortest supply

(in this case, K) limits the yieldJustus von Liebg 1840

4

Ca Mg S

Fe Zn Cu

Mn Mo

B

C H O

N P K

Cl

Micro Nutrient

Essential elements for plant

Natural

Primary Nutrient

Secondary Nutrient

5

Fertigation scheduling

V/S

Crop growth stageNUTRIENTS APPLICATION ACCORDING TO THE UPTAKE RATE OF THE CROP

0

1

2

3

4

5

0 50 100 150

Days after emergence or transplanting

NP

K d

aily u

pta

ke r

ate

(kg

ha

-1d

ay

-1)

N

P

K

Broccoli“spoon feeding”

KP

N

Nutrient Uptake by various crops

6

Nutrient Uptake

Soil analysis

Available nutrients in soil

LAI

Plant density

Crop growth phase

Targeted yield/Variety

Efficiency factors

Fertilizers nutrients

requirement

7

Cation Exchange Capacity

Soil Texture CEC Range ( meq /100gm soil )

Organic soils > 50

Fine (clay) 25-50

Medium (silt) 8-30

Coarse(sand) 5-15

8

Fertigation scheduling on the

basis of soil fertility & texture

Influence of soil pH on the availability of plant nutrients

9

Optimal pH value: 5 – 6

– Maximal nutrient availability

High pH values:

– Reduced nutrient availability

Low pH values:

– Reduced nutrient availability

– Toxic levels of Al, Mn

Fertilizers Grade FormulapH

(1 g/L at 20oC)

Urea 46 – 0 – 0 CO(NH2)2 5.8

Potassium nitrate 13 – 0 – 46 KNO3 7.0

Ammonium sulfate 21 – 0 – 0 (NH4)2SO4 5.5

Urea ammonium

nitrate32 – 0 – 0 CO(NH2)2 . NH4NO3

Ammonium nitrate 34 – 0 – 0 NH4NO3 5.7

Mono ammonium

phosphate12 – 61 – 0 NH4H2PO4 4.9

Calcium nitrate 15 – 0 – 0 Ca(NO3)2 5.8

Magnesium nitrate 11 – 0 – 0 Mg(NO3)2 5.4On

ly F

ert

iga

tio

n g

rad

e

Nitrogen - N

10

Fertilizers Grade FormulapH

(1 g/L at 20oC)

Phosphoric acid 0 – 52 – 0 H3PO4 2.6

Monopotassium

phosphate0 – 52 – 34 KH2PO4 5.5

Mono ammonium

phosphate12 – 61 – 0 NH4H2PO4 4.9

Urea Phosphate 17-44-00 2.5

Phosphorous-P

11

Fertilizers Grade Formula

pH

(1 g/L at

20oC)

Other

nutrients

Potassium

chloride 0 – 0 – 60 KCl 7.0 46 % Cl

Potassium

nitrate13 – 0 – 46 KNO3 7.0 13 % N

Potassium

sulfate 0 – 0 – 50 K2SO4 3.7 18 % S

Potassium

thiosulfate0 – 0 – 25 K2S2O3 17 % S

Monopotassium

phosphate0 – 52 – 34 KH2PO4 5.5 52 % P2O5

Potash - K

12

Divisions for Relative Salt Tolerance(EC)

Ratings of Agricultural Crops

13

(Source: Mass, 1984)

FIELD CROPS

100% 90% 75% 50%

0%

“maximum”3

ECe ECw ECe ECw ECe ECw ECe ECw ECe ECw

Barley 8 5.3 10 6.7 13 8.7 18 12 28 19

Cotton ( 7.7 5.1 9.6 6.4 13 8.4 17 12 27 18

Sugarbet 7 4.7 8.7 5.8 11 7.5 15 10 24 16

Sorghum 6.8 4.5 7.4 5 8.4 5.6 9.9 6.7 13 8.7

Wheat 6 4 7.4 4.9 9.5 6.3 13 8.7 20 13

Soybean 5 3.3 5.5 3.7 6.3 4.2 7.5 5 10 6.7

Cowpea 4.9 3.3 5.7 3.8 7 4.7 9.1 6 13 8.8

Groundnut 3.2 2.1 3.5 2.4 4.1 2.7 4.9 3.3 6.6 4.4

Rice (paddy) 3 2 3.8 2.6 5.1 3.4 7.2 4.8 11 7.6

Sugarcane 1.7 1.1 3.4 2.3 5.9 4 10 6.8 19 12

Corn (maize) 1.7 1.1 2.5 1.7 3.8 2.5 5.9 3.9 10 6.7

Flax 1.7 1.1 2.5 1.7 3.8 2.5 5.9 3.9 10 6.7

Broadbean 1.5 1.1 2.6 1.8 4.2 2 6.8 4.5 12 8

Bean (Phaseolus vulgaris) 1 0.7 1.5 1 2.3 1.5 3.6 2.4 6.3 4.2

fertilizer compatibility

14

CaSO4 precipitate (gypsum)Calcium nitrate + Sulfates

Calcium nitrate + Phosphates Ca phosphate precipitate

Magnesium + di- or mono-

ammonium phosphateMagnesium Phosphate precipitate

Ammonium sulfate + KCl or KNO3 K2SO4 precipitate

Phosphorus + iron iron phosphates precipitate

Fertilizers mixtures in the tank which reduce the solubility of the mixture

due to formation of precipitates

Compatibility chart for water soluble fertilizers

15

Source: Marwaha-2003

Effect of temperature on the uptake of nutrients by plant

16

17

How long it takes ?

NH4+ nitrification NO3

-

How long it takes ?

Half life of this process at

25 0 C and Field capacity

moisture content is about

1-2 weeks

Nitrification

Cotton Fertigation schedule

18

Source: BCI-GGRC

19

Conclusion

Fertigation scheduling with balance

nutrients programme , including all criteria

like EC,PH, CEC, soil texture, soil fertility

status & crop growth stage, can only

maximize the crop yield

20

Subtitle, date, Presenter’s name should be in lowercase

- AN INTRODUCTION

YOUTHANK

22

Fertigation schedule for cotton (one acre)

Basal application

FYM (t/a)SSP

(kg/a)Micronutrients (Kg/a) Targeted Yield

6 250 5 1.6 t/aFertigation (kg/acre)

DAS DAYS UREA ASMAP-

(12-61-00) MOP MgSo4 CaNo3Micronutrien

ts (g/a)

0-8 8 12 5 89-15 7 20 5 8

16-50 35 40 5 17 10 5 10051-80 30 10 25 5 25 10 5 100

81-110 30 10 25 25 10 5 100111-140 30 25 25 10 5 100141-180 40 17 5

Total 180 92 75 20 125 45 20 400

Fertilizer N P K S Mgo CaoSSP 0 40 0 28

Urea 42AS 15 18

MAP 2 12MOP 75

MgSo4 4CaNo3 3 5

Total nutrients k/a

63 52 75 46 4 5

Fertilizer TypeQty (kg)

Price (Rs/kg)

Total cost Rs

Cost RsCategor

y% of Total

costFYM Basal 6000 1 6000

8250 Basal 56SSP Basal 250 8 2000Micronutrients Basal 5 50 250

Urea Traditional 92 6.34 5832986

Traditional

20AS Traditional 75 12.7 953MOP Traditional 125 11.6 1450MAP WSF 20 85 1700

3570 WSF 24MgSo4 WSF 45 14 630CaNo3 WSF 20 42 840

Micronutrients EDTA 0.4 1000 400Total Cost 14806 14806 100