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ORIGINAL RESEARCH

Organic and inorganic fertilizer application enhances the effectof Bradyrhizobium on nodulation and yield of peanut (Arachishypogea L.) in nutrient depleted and sandy soils of Ethiopia

Anteneh Argaw1

Received: 10 February 2017 / Accepted: 17 July 2017 / Published online: 8 August 2017

� The Author(s) 2017. This article is an open access publication

Abstract

Purpose An investigation was carried out to evaluate the

effect of the integrated application of organic and inorganic

fertilizer effect on Bradyrhizobium effectiveness on nodu-

lation and yield of peanut at the major growing areas of

Eastern Ethiopia, Babillae and Fedis sites.

Methods Systemic combination of compost, manure,

Bradyrhizobium inoculation and NP application was laid

out in Randomized Complete Block Design with three

replications.

Results The result showed that Bradyrhizobium integrated

with organic inputs significantly improved the nodule

number at Babillae while Bradyrhizobium when applied

with DAP resulted in a significant increase of nodulation at

Fedis site. The highest total biomass and total pods weight

at both sites were found to record when Bradyrhizobium

integrated with manure and compost. Integration of

Bradyrhizobium, manure and compost at Fedis and

Bradyrhizobium with manure at Babillae was found to

increase the kernel yield by 44 and 66.6% over the control

check, respectively. Integration of Bradyrhizobium, man-

ure and compost at Babillae and Bradyrhizobium with

starter N at Fedis significantly increased plant N accumu-

lation. The effect of organic and inorganic application on

soil N and organic carbon content was not significant at

Fedis, but the slight increase was observed in Babillae site.

A significant increase in the soil available P by organic

and/or DAP application was found in either of the exper-

imental sites.

Conclusion Organic fertilizer when integrated with Starter

N and DAP is better in improving the effectiveness of

Bradyrhizobium, nodulation and yield of peanut in either of

the sites.

Keywords Available P � Compost � Manure � Soilproperties � Soil N � Soil organic carbon

Introduction

Most of the research system in Africa emphasizes on

managing the three macronutrients nitrogen (N), phos-

phorus (P), and potassium (K) (Kang and Balasubramanian

1990; Smaling et al. 1993; Smaling and Braun 1996). In

this region, crop production is critically dependent on sub-

optimum nutrient application, especially N and P which are

very low in amount with less than 8 kg ha/year (Crawford

and Jayne 2010; Morris et al. 2007; Smaling 2006). Such

agricultural practice accelerates the depletion of other

macronutrients and micronutrients (Cobo et al. 2010;

Sanchez 2002; Smaling et al. 1997) and causes negative

soil nutrient balances. In Ethiopia, the nutrient depletion

has been 41, 6, and 26 kg/ha/year for N, P, and K,

respectively (Stoorvogel and Smaling 1990). This problem

is aggravated by the inherent poor fertility in most tropical

soils (Okalebo et al. 2003). These practices, consequently,

lead to the less responsive or non-responsive soil (Foli

2012; Vanlauwe et al. 2014). When farmers applied fer-

tilizers on this soil, they did not get benefit by increasing

crop productivity. Due to this reason, farmers became

reluctant to apply inputs, besides the cost of fertilizer is

increasing.

& Anteneh [email protected];

[email protected]

1 School of Natural Resources Management and

Environmental Sciences, College of Agriculture and

Environmental Sciences, Haramaya University, Haramaya,

Ethiopia

123

Int J Recycl Org Waste Agricult (2017) 6:219–231

DOI 10.1007/s40093-017-0169-3

http://crossmark.crossref.org/dialog/?doi=10.1007/s40093-017-0169-3&domain=pdfhttp://crossmark.crossref.org/dialog/?doi=10.1007/s40093-017-0169-3&domain=pdf

A study conducted across Ethiopia showed that most

sites are low in soil organic carbon (SOC), available N, and

available P, K and S contents and some micronutrients

(Hailu et al. 2015; Laekemariam et al. 2016). These

nutrient deficiencies can affect not only plants but also soil

microbes including rhizobia populations (O’Hara 2001)

and its activities such as N2 fixation (Giller 2001). To

lessen these problems, the use of chemical fertilizer has

been limited mainly because of little accessibility and lack

of buying ability of the poor farmers in the region (Morris

et al. 2007; Giller et al.1998; Mugwira and Murwira 1997;

Rufino et al. 2010). For instance, mineral fertilizers in

Africa cost at the farm gate, two to six times as much as in

Europe, North America, or Asia (Sanchez 2002). There-

fore, organic inputs are a viable alternative source of plant

nutrients for resource-poor farmers. Application of organic

input usually leads to increased crop yields (Ogundare

et al. 2012; Kimetu et al. 2004; Mugwira 1984; Vanlauwe

et al. 2001a, b). However, yield reduction by organic fer-

tilizer has also been reported (Mugwira and Murwira 1997;

Nhamo 2002). The negative effect of low-quality organic

fertilizer on the productivity of peanut has been resolved

when it has been applied it’s with chemical fertilizer and/or

fly ash (Burgos et al. 2006).

As residue quality influences the rate of decomposition,

the amount of nutrients immobilization–mineralization and

timing of nutrient release (Heal et al. 1997). Vanlauwe

et al. (2005) found that Class I residues caused net N

mineralization, Class II residues had no effect on mineral

N, and Class III and IV residues resulted in net N immo-

bilization. The addition of fertilizers with intermediate

quality organic inputs may increase organic matter

decomposition (Sakala et al. 2000; Zingore et al. 2003)

and, thus, enhances the crop production. Animal manures

and composts have shown in several trials to increase

nutrient availability and to partly substitute mineral fertil-

izers (Goyal et al. 1999). However, availability of manure

in smallholder farms was generally lower in Ethiopia

(Lupwayi et al. 2000). In this region, some crop by-prod-

ucts such as Khat leftover are available for use as soil

amendments because of fewer alternate uses.

Keeping the above in view, the present investigation

was undertaken with a major objective to make the influ-

ence towards growing peanut production by promoting the

use of integrated nutrient management that is capable of

increasing soil fertility status in the small plot based

farming systems in the Eastern Ethiopia using locally

available resources. The specific objectives of the study

were to compare the effect of combined application of

different organic input and inorganic fertilizer with

Bradyrhizobium inoculation on nodulation and yield of

peanut and to assess how these inputs influence selected

soil properties.

Materials and methods

Description of the study sites

Field experiments were initiated during the rainy season of

2014 cropping season at Fedis (09�06.9410N and042�04.8350E at an altitude of 5476 ft above sea level [asl])and Babillae (09�13.2340N and 042�19.4070E at 5478 ft asl)experimental sites, Eastern Hararghe, Ethiopia under Hara-

maya University. The study sites comprise lowland and

midland agroecological zones that obtain 400–800 mm of

annual rainfall in a bimodal pattern. In normal years,

60–70% of the rainfall occurs during the main rains season,

between May and October, while the rest falls during the

short rains between March and May. At Fedis site, the mean

maximum and minimum temperatures are 27.8 and 8.8 �C,respectively, with annual mean rainfall of 714.5 mm. The

climate of the Babillae is semi-arid tropical, with the mean

annual air maximum and minimum temperature for the

duration from 2000 to 2014 of 20 and 9 �C, respectively, andthe mean annual precipitation of about 566 mm.

The topography of Babillae is rolling with low SOC

concentration (0.56%) and total N (0.06%), available P

(2.22 mg/kg), cation exchangeable capacity of 6.26

cmol(?)/kg, exchangeable Ca?2, Mg?2, Na?1 and K?1 of

4.18, 3.5, 0.15 and 0.34 cmol(?)/kg and sand, silt, clay

contents of 76, 6 and 18%, respectively (Tekalign 1991).

The soil pH and electric conductivity are 6.66 and 0.04 mS/

cm, respectively.

The surface soil in the plot area in Fedis site before

commencing the experiment is a silty clay loam, containing

36% sand, 45% silt, and 19% clay. The soil (0–20 cm

depth) had a pH of 7.76, electric conductivity of 0.06 mS/

cm, ammonium acetate-extractable K of 1.09 cmol(?)/kg,

Mg of 12.87 cmol(?)/kg, Na of 0.12 cmol(?)/kg, Ca of

23.12 cmol(?)/kg with cation exchangeable capacity of

32.22 cmol(?)/kg. The soil had low organic carbon (1.32)

and Olsen extractable P (1.78 mg/kg) and medium total N

(0.12%) (Tekalign 1991).

Source of the test variety

Groundnut variety ‘‘Baha Jidu’’ which has been recently

approved as high yielder in this region was obtained from

groundnut improvement project, Haramaya University,

Ethiopia. BaHa-jidu variety is the runner type and medium

seeded (Kebede and Bushra 2012).

220 Int J Recycl Org Waste Agricult (2017) 6:219–231

123

Organic fertilizer sampling and analyses

The farmyard manure was prepared mainly from cow dung

and hay, which is normally used as a bedding material in

the cow shed. Compost was prepared following the con-

ventional method using locally available khat leftover

organic waste. The following properties were analyzed

according to the recommended testing methods: pH by

potentiometric; Ammonium acetate extraction, flame pho-

tometry for available K determination; organic C by loss of

weight on ignition; Olsen (available P); Kjeldahl (total N);

DTPA extraction(Zn); Azomethine-H method (available

B); KCl extract (NO3-) and KCl extract-Magnesium oxide

distillation (NH4?). The average nutrient composition of

FYM and compost applied in the experiment during this

period are given in Table 1.

Treatments and crop management

The experiment consisted of eleven treatments: (1) 2 ton

manure/ha ? 4 ton compost/ha ? no inoculation; (2) 2 ton

manure/ha ? 4 ton compost/ha ? Bradyrhizobium inocu-

lation; (3) 2 ton manure/ha ? no inoculation; (4) 2 ton

manure/ha ? Bradyrhizobium inoculation; (5) 4 ton com-

post/ha ? no inoculation; (6) 4 ton compost/

ha ? Bradyrhizobium inoculation; (7) DAP—(46 P2O5 kg/

ha ? 19 kg N/ha); (8) (46 P2O5 kg/ha ? 19 kg N/

ha) ? Bradyrhizobium inoculation; (9) 20 kg N/ha; (10)

20 kg N/ha ? Bradyrhizobium inoculation and (11) the

control check. The rates of organic inputs were developed

based on its inorganic N (NO3- and NH4

?) concentration.

The treatments were replicated three times, and laid out

according to a Randomized Complete Block (RBD) design,

with plot dimension of 3 m 9 3 m.

The experimental plots preparation involved one plow-

ing immediately after getting the first rainfall in June fol-

lowed by blade harrowing. The organic inputs are surface

applied and incorporated minimally with a hoe to a depth

of approximately 10 cm. Inorganic N and P fertilizers were

applied in the form of urea and triphosphate, respectively.

The entire dose of inorganic and organic fertilizers was

applied as basal at the beginning of growing season as per

the treatment.

Soil sampling and analysis

After the peanut harvest in November 2014, soil samples

were taken from 0 to 20 cm soil layers from each plot of

two experimental sites. In each plot, the soil samples were

collected from four points and were mixed to get a com-

posite sample. Soil samples were air dried, gently ground

and passed through a 2-mm sieve. The major chemical

composition of the manure and compost was then analyzed

using standard laboratory methods of soil and plant

analysis.

Agronomic data collection

At the R2 stage of peanut, five plants from the central three

rows were uprooted. The nodulation status (nodule number

dry eight) and shoot dry weight were recorded. At harvest,

the pod weight, the total biomass yield, and the kernel

weight were measured. The yield was calculated by har-

vesting central three rows of peanut (3.6 m2).

Plant samples and analysis

At late flowering stage (R2), three plant samples were

uprooted for plant N tissue analysis. The oven dried plant

sub-samples were then ground and analyzed for N by the

micro-Kjeldahl procedure.

Statistical analysis

Statistical analyses of the data were done using the SAS

version 9.2 to analyze variance and to determine the sta-

tistical significance of the treatment effects. Analysis of

variance (ANOVA) was performed on a fully randomized

Table 1 The selected chemicalproperties of khat leftover and

manure compost

Parameters Khat leftover compost Manure compost

pHH2O (1:2.5) 6.82 7.21

EC (mS/cm) 7.46 7.50

Total N (%) 2.48 1.30

Organic carbon (%) 33.02 18.91

NH4–N (mg/kg) 43.22 57.59

NO3–N (mg/kg) 9860.79 5557.60

Available K (cmol(?)/kg soil) 12.36 25.59

Available P (mg/kg) 524.13 763.14

Zn (mg/kg) 26.81 4.49

B (mg/kg) 7.91 3.49

Int J Recycl Org Waste Agricult (2017) 6:219–231 221

123

plot design to test for significance of treatments and means

were compared by least significance difference (LSD) at

the 5% level (SAS, 1996).

Results

The nodulation and yield of peanut showed a significant

response to organic (compost and manure) and inorganic

fertilizer (Urea and DAP) integrated with Bradyrhizobium

inoculation (Tables 2, 3, 4). At Fedis, the nodule number

was found to be increased by 141, 142.8 and 143.6% due to

the applied compost (C) ? Bradyrhizobium, Manure

(M) ? Bradyrhizobium, and DAP ? Bradyrhizobium,

respectively, compared to the control check (Table 2).

Only DAP ? Bradyrhizobium application resulted in a

significant increase in the nodule number of peanut at

Babillae. However, the treatments did not affect the pooled

NN peanut. Likewise, the nodule dry weight of peanut at

Babillae was enhanced significantly by

M ? C ? Bradyrhizobium and C ? Bradyrhizobium

application (Table 2). At Fedis, an increase in nodule dry

weight of peanut by starter N (20 kg N/ha) application was

found. Application of M ? C ? Bradyrhizobium and

C ? Bradyrhizobium resulted in a significant increase in

the pooled nodule dry weight.

Excluding C ? M, the other organic and inorganic

combination of fertilizer improved the effectiveness of

Bradyrhizobium inoculation on nodulation at Babillae site

(Figs. 1a, 2a). At Fedis site, manure and compost appli-

cation enhanced the effectiveness inoculation on nodule

number and dry weight at Fedis site (Figs. 1b, 2b).

However, starter N and DAP application did not improve

the effectiveness of Bradyrhizobium inoculation at Fedis

site.

There was no significant effect of organic and inorganic

fertilizers’ combination with Bradyrhizobium on shoot dry

weight measured at late flowering and a number of pods

per plant at Babillae site (Table 2). In contrary, M, C, and

DAP applied with Bradyrhizobium caused a significant

positive influence on the shoot dry weight at Fedis site. The

pooled shoot dry weight significantly increased by DAP

applied with Bradyrhizobium inoculation. The plants

receiving DAP ? Bradyrhizobium and M ? Bradyrhizo-

bium were found to record significantly higher number of

seed per plant than the control at Babillae and Fedis sites,

Table 2 Nodule number, nodule dry weight and shoot dry weight of peanut as affected by combined application of organic and inorganicfertilizer application at Babillae and Fedis sites, eastern Ethiopia

Treatments Nodule number Nodule dry weight Shoot dry weight

Babillae Fedis Mean Babillae Fedis Mean Babillae Fedis Mean

M ? C 70.0abc 21.0c 5.1a 0.080bc 0.060abc 0.070abc 63.4a 46.0d 54.7bc

M ? C ? B 63.3abc 35.7abc 49.5a 0.188a 0.082abc 0.135a 53.8a 49.4 cd 51.6c

M 69.3abc 47.3abc 58.3a 0.028c 0.048bc 0.038bc 52.9a 64.6bcd 58.8bc

M ? B 94.7a 50.0abc 72.3a 0.056c 0.094ab 0.075abc 61.4a 77.1abc 69.2abc

C 52.7bc 37.7abc 45.2a 0.636c 0.043bc 0bc.053 63.2a 51.7 cd 57.4bc

C ? B 94.0a 47.7abc 70.8a 0.142ab 0.053bc 0.0ab98 79.1a 81.9ab 80.5ab

DAP 42.3c 50.3c 46.3a 0.048c 0.080abc 0.064bc 81.4a 65.9bcd 73.6abc

DAP ? B 95.0a 31.7a 63.3a 0.097bc 0.062abc 0.079abc 89.9a 95.7a 92.8a

Urea 45.0bc 64.0ab 54.5a 0.039c 0.111a 0.075abc 53.6a 54.8bcd 54.2c

Urea ? B 83.3ab 59.3bc 71.3a 0.087c 0.078abc 0.083abc 63.2a 58.2bcd 60.7bc

No amendment 39.0c 30.3 34.7a 0.023c 0.033c 0.028c 72.1a 45.1d 58.6bc

Mean 68.1 43.2 55.6 0.077 0.068 0.073 66.7 62.8 64.7

Significance *** ** ns *** *** *** ns *** ***

LSD (P\ 0.05) 39.0 31.6 42.3 0.078 0.053 0.068 44.3 29.4 15.2CV (%) 19.63 25.04 39.20 34.34 26.92 48.18 22.72 16.07 20.94

M ? C—2 ton manure/ha ? 4 ton compost/ha ? no inoculation; M ? C ? B—2 ton manure/ha ? 4 ton compost/ha ? Bradyrhizobium

inoculation; M—2 ton manure/ha ? no inoculation; M ? B—2 ton manure/ha ? Bradyrhizobium inoculation; C—4 ton compost/ha ? no

inoculation; C ? B—4 ton compost/ha ? Bradyrhizobium inoculation; DAP—(46 P2O5 kg/ha ? 19 kg N/ha); DAP ? B—(46 P2O5 kg/

ha ? 19 kg N/ha) ? Bradyrhizobium inoculation; Urea—20 kg N/ha; Urea ? B—20 kg N/ha ? Bradyrhizobium inoculation

Means within the same factor and column followed by the same letter are not significantly different at 5% level of significance

ns non significant

** Significant at 0.01

*** Significant at 0.001


123

respectively. The pooled number of seeds per pod was not

affected by the treatments.

The highest total biomass yield (kg/ha) of peanut at

Babillae and Fedis was recorded by combined application

of manure, compost and Bradyrhizobium (Table 3). This

treatment increased the total biomass yield by 46.3 and

35.1% over the control check at Babillae and Fedis

site, respectively. The total pod’s weight (kg/ha) under

application of M ? C ? Bradyrhizobium and Urea ?

Bradyrhizobium was significantly (P\ 0.05) superior tothat of control check at Babillae site (Table 4). Similarly,

the total pod’s weight at Fedis and pooled total pods weight

were found to be significantly increased due to combined

application of manure, compost and Bradyrhizobium.

The shelling % was not influenced by the treatment at

Babillae site (Table 4). However, most of the organic and

inorganic fertilizers applied with Bradyrhizobium inocula-

tion encouraged the pooled shelling % at Fedis site. A

significant increase in plant N accumulation at Babillae site

was found in combined application of manure, compost

and Bradyrhizobium. Most of the organic and inorganic

fertilizer combination increased the accumulation of N in

plant tissue at Fedis site and the pooled plant N accumu-

lation (Table 4).

At Babillae site, manure and compost applied with

Bradyrhizobium inoculation significantly increased the

plant N accumulation compared to sole application of

manure and compost (Fig. 3a). Bradyrhizobium inocu-

lation did not increase the plant N accumulation when

integrated with manure and compost, and manure at

Fedis site (Fig. 3b), but inoculation improved the

plant N accumulation when integrated with DAP and

Urea.

The kernel yield of peanut was significantly influenced

by Bradyrhizobium inoculation integrated with organic and

inorganic fertilizer at Babillae site (Table 4). At this site,

the highest kernel yield was recorded at Bradyrhizobium

integrated with manure, followed by manure applied with

compost. However, Kernel yield at Fedis site and pooled

kernel yield were not significantly affected by the treat-

ments. The highest kernel yield (1562.1 and 1818.8 kg/ha)

of peanut at Babillae and Fedis site was 66.6 and 44.1%

increase over unamended control of respective sites,

respectively.

Table 3 Number of pegs per plant, hundred seed weight and total biomass yield of peanut as affected by combined application of organic andinorganic fertilizer application at Babillae and Fedis sites, eastern Ethiopia

Treatment Number of peg per plant Hundred seeds weight Total biomass yield (kg/ha)


M ? C 10.7a 23.2ab 16.9a 61.0ab 41.9ab 51.5a 6296.3b 5759.3b 6027.8c

M ? C ? B 11.2a 28.4a 19.8a 59.5ab 41.5ab 50.5a 8833.3a 8933.3a 8883.3a

M 11.9a 26.1ab 19.0a 63.7ab 41.0b 52.3a 6666.7b 5703.7b 6185.2bc

M ? B 9.8a 23.4ab 16.6a 61.8ab 54.6a 58.2a 7092.6ab 8600.0a 7846.3ab

C 11.0a 22.1ab 16.6a 54.6b 40.0b 47.3a 5796.6b 5648.1b 5722.4c

C ? B 9.2a 27.2a 18.2a 60.2ab 42.8ab 51.5a 5592.6b 7394.4ab 6493.5bc

DAP 10.6a 17.4b 14.0a 64.2ab 41.5ab 52.8a 6666.7b 5277.8b 5972.2c

DAP ? B 9.8a 24.8ab 17.3a 69.9a 41.2b 55.6a 6925.9ab 6903.7ab 6914.8bc

Urea 10.2a 22.6ab 16.4a 61.2ab 43.5ab 52.4a 5870.4b 5869.2b 5869.8c

Urea ? B 11.0a 26.3ab 18.7a 60.7ab 41.0b 50.9a 6851.9ab 5666.7b 6259.3bc

No amendment 9.0a 20.0ab 14.5a 58.3ab 41.1b 49.7a 6037.0b 6611.1ab 6324.1bc

Mean 10.4 23.8 17.1 61.4 42.7 52.1a 6602.72 6578.85 6560.78

Significance ns * ns * * ns ** *** ***

LSD (P\ 0.05) 4.0 9.3 26.3 12.8 13.3 22.0 2108.9 2570.7 1737.7CV (%) 13.13 13.35 45.8 7.15 10.68 21.75 10.94 13.39 13.60

M ? C—2 ton manure/ha ? 4 ton compost/ha ? no inoculation; M ?C ? B—2 ton manure/ha ? 4 ton compost/ha ? Bradyrhizobium

inoculation; M—2 ton manure/ha ? no inoculation; M ? B—2 ton manure/ha ? Bradyrhizobium inoculation; C—4 ton compost/ha ? no

inoculation; C ? B—4 ton compost/ha ? Bradyrhizobium inoculation; DAP—(46 P2O5 kg/ha ? 19 kg N/ha); DAP ? B—(46 P2O5 kg/

ha ? 19 kg N/ha) ? Bradyrhizobium inoculation; Urea—20 kg N/ha; Urea ? B—20 kg N/ha ? Bradyrhizobium

Means within the same factor and column followed by the same letter are not significantly different at 5% level of significance

ns non significant

* Significant at 0.05

** Significant at 0.01

*** Significant at 0.001


123

Table

4Totalweightofpodsper

hectare,shellingpercentage,

grain

yield

andplanttissueN

accumulationofpeanutas

affected

bycombined

applicationoforganic

andinorganic

fertilizer

applicationat

BabillaeandFedissites,easternEthiopia

Treatment

Pod(kg/ha)

Shelling%

Kernel

yield

(kg/ha)

PlanttissueN

accumulation

Babillae

Fedis

Mean

Babillae

Fedis

Mean

Babillae

Fedis

Mean

Babillae

Fedis

Overall

M?

C2588.6abcd

2189.2b

2388.9abcd

53.6abc

67.4a

60.5a

1388.1ab

1466.8ab

1427.4ab

2.717bc

2.990ab

2.853ab

M?

C?

B3420.9ab

3222.2a

3321.6a

35.3d

56.8ab

46.0ab

1182.0abc

1818.8a

1500.4a

3.050a

2.937abc

2.993a

M2586.8abcd

1691.8b

2139.3bcd

48.0abcd

68.9a

58.5a

1217.2abc

1166.1abc

1191.7abc

2.657bc

2.743bcd

2.700bcde

M?

B3342.1abc

2244.7b

2793.4ab

47.2abcd

62.1ab

54.6ab

1562.1a

1397.5ab

1479.8a

2.607bc

2.567de

2.587cde

C2061.9bcd

2027.0b

2044.4bcd

41.2

cd58.3ab

49.7ab

854.0c

1170.2abc

1012.1bc

2.523c

2.610de

2.567de

C?

B1966.0bcd

2143.5b

2054.7bcd

59.3ab

60.3ab

59.8a

1160.9abc

1288.0abc

1224.4abc

2.787abc

2.757bcd

2.772abcd

DAP

1881.4

cd1546.4b

1713.9d

61.9ab

64.3ab

63.1a

1173.0abc

656.9c

914.9c

2.683bc

2.700cd

2.692bcde

DAP?

B2747.6abcd

2118.2b

2432.9abcd

45.4bcd

52.8ab

49.1ab

1247.9abc

1120.8bc

1184.3abc

2.737abc

2.817bcd

2.777abcd

Urea

1598.4d

2076.1b

1837.3

cd63.2a

56.3ab

59.7a

997.1bc

1169.8abc

1083.4abc

2.750abc

2.897abc

2.823abc

Urea?

B3839.5a

2307.7b

3073.6ab

30.6d

48.5b

39.5b

1118.7abc

1090.7bc

1104.7abc

2.873ab

3.143a

3.008a

Noam

endment

1982.2bcd

2068.0b

2025.1

cd47.5abcd

61.2ab

54.3ab

937.7bc

1261.9abc

1099.8abc

2.653bc

2.387e

2.520e

Mean

2546.9

2148.6

2347.7

48.0

59.7

54.1

1167.15

1237.04

1202.09

2.731

2.777

2.754

Significance

**

***

***

***

***

***

***

***

***

***

LSD

(P\

0.05)

1528.8

780.28

1032.4

17.6

18.8

18.6

470.56

658.56

464.31

0.315

0.264

0.241

CV

(%)

20.57

12.44

22.68

12.4

10.8

17.7

13.81

18.24

19.93

3.95

3.25

4.52

M?

C—

2tonmanure/ha?

4toncompost/ha?

noinoculation;M

?C?

B—

2tonmanure/ha?

4toncompost/ha?

Bradyrhizobium

inoculation;M—

2tonmanure/ha?

noinoculation;

M?

B—

2ton

manure/ha?

Bradyrhizobium

inoculation;C—

4ton

compost/ha?

no

inoculation;C?

B—

4ton

compost/ha?

Bradyrhizobium

inoculation;DAP—

(46

P2O5kg/

ha?

19kgN/ha);DAP?

B—

(46P2O5kg/ha?

19kgN/ha)

?Bradyrhizobium

inoculation;Urea—

20kgN/ha;

Urea?

B—

20kgN/ha?

Bradyrhizobium

inoculation

Meanswithin

thesamefactorandcolumnfollowed

bythesameletter

arenotsignificantlydifferentat

5%

level

ofsignificance


123

Inoculating Bradyrhizobium integrated with compost

and manure recorded the higher kernel yield than those

organic fertilizers without inoculation at Babillae (Fig. 4a).

However, compost and manure application together did not

enhance the effect of Bradyrhizobium on kernel yield. At

Fedis site, Bradyrhizobium in combination with organic

and DAP application produced higher kernel yield than

those obtained from fertilizer without inoculation (Fig. 4b).

The effect of organic and inorganic fertilizers on soil N

and organic carbon was not significant at Fedis site

(Table 5). The treatments did not also significantly influ-

ence the pooled soil N and organic C content. Slight

increase in soil N and organic C by the organic and inor-

ganic application was found at Babilale site. However,

organic and inorganic application significantly improved

the soil available P in both experimental sites. The pooled

available P significantly increased when applied DAP

alone and in combination with Bradyrhizobium over the

control check.

Discussion

The result from this experiment showed that Bradyrhi-

zobium inoculation in conjunction with organic (Compost

and manure) and inorganic fertilizer (NP) significantly

increased the nodulation and yield of peanut at both

experimental sites. Inoculating Bradyrhizobium integrated

with organic fertilizer and DAP at both sites were found

to increase significantly the nodulation when compared to

the corresponding sites control check. This finding is

similar to those reported by Panda et al. (2012) who found

that poultry manure boosts the effectiveness of Rhizobium

in cowpea. With the present study, all fertilizer

020406080

100120

2 tonmanure/ha + 4ton compost

/ha

2 tonmanure/ha

4 ton compost/ha

DAP(100kg/ha)

Urea(20Kg/ha)

Nod

ule

num

ber

per

plan

t

Organic and Inorganic fertilizer rates of application

Babillae site

Uninoculated Inoculated

a

01020304050607080

2 tonmanure/ha +

4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)

Nod

ule

num

ber

per

plan

t

Organic and inorganic fertilizer application

Fedis site


b

Fig. 1 Effect ofBradyrhizobium inoculation on

nodule number of peanut at

a Babillae and b Fedisexperimental sites


123

combination improved the effectiveness of Bradyrhizo-

bium inoculation on the NN and NDW at Babillae site.

However, an increase in NN and NDW due to inoculation

was recorded only with the sole and combined application

of manure and compost at Fedis. These difference results

could have been attributed to the correction of the defi-

ciencies of essential macronutrients and micronutrients on

top of NP in Babillae soil. Previous work on organic

fertilization effect on the soil has found to buildup of

essential plant nutrients (i.e., N, P, K, S, Ca, Mg, Zn, Fe,

Mn, and B) in the soil (Dotaniya et al. 2016; Ogundare

et al. 2012; Rezig et al. 2012). Organic manure applica-

tion enhanced the native rhizobia population nodulating

cowpea by 23% above control (Kimiti and Odee 2010).

This positive influence leads to enhance the root growth

and the uptake of nutrients (Ibrahim et al. 2011) and thus

improve the nodulation (Basu et al. 2007; Mohammadi

et al. 2011; Tsai et al. 1993). This observation is in

agreement with other studies where organic matter has

been shown to increase the viable number of rhizobia and

nodulation of peanut (Basu et al. 2008). These authors

found a significant increase in native rhizobia population

and nodule formation.

The application of organic fertilizer rich in nitrate did

not suppress nodulation in both experimental sites though

this N-rich material with C: N ratio less than 17:1 enhanced

mineralization by microorganisms. However, the negative

effect of N on nodulation did not observe. Lack of inhi-

bition effect of N might be because of the attenuated effect

of other essential nutrients found in the organic input

(Burgos et al. 2006). Wu and Arima (1992) reported that N

applied with other nutrients had increased nodulation

whereas N applied alone reduced the nodule formation.

This result suggests that application of medium quality

00.050.1

0.150.2

0.25

2 tonmanure/ha +

4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)N

odul

e dr

y w

eigh

t per

pla

nt


Babillae site


a

00.020.040.060.080.1

0.120.14

2 tonmanure/ha +

4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)

Nod

ule

dry

wei

ght p

er p

lant


Fedis siteUninoculated Inoculated

b


nodule dry weight of peanut at



123

organic fertilizer is essential to enhance nodulation in

degraded and low fertile sand soils of Ethiopia.

Organic and inorganic fertilizer application did not

increase significantly the shoot dry weight measured at the

late flowering stage at Babillae site but it was increased

significantly at Fedis site. The effect of organic fertilizer

with Bradyrhizobium inoculation at Babillae site did not

improve the number of pod per plant and hundred seeds

weight. However, the treatment where Bradyrhizobium was

combined with DAP significantly increased the hundred-

seed weight at Babillae site. Insufficient nutrient supply at

flowering stage of the plants due to immobilization

(Petersen et al. 2005) might have been the reason, which

limited the remarkable effect of organic inputs. Limitation

in plant growth due to nutrients immobilization particularly

N and P had also been stated by Herencia et al. (2011).

In contrary, there was an increase in a number of pods

per plant, hundred seeds weight, and shoot dry weight of

peanut by Bradyrhizobium when integrated with organic

fertilizer (manure and/or compost) at Fedis site. This result

indicates the need of organic fertilizer application at Fedis

site beside Bradyrhizobium inoculation. This increase in

pod number might be through reducing bulk density

besides supplying adequate nutrients (Mittra et al. 2005),

thereby increasing pegging and pods formation.

The highest total biomass yield, kernel yield and plant N

accumulation of peanut at either of the experimental sites

were found where Bradyrhizobium in conjunction with

organic fertilizer was applied. This shows the importance

of organic fertilizer application in increasing yield of

peanut. This pronounced effect of organic inputs on final

yield of peanut could be associated with the mineralization

and releasing of nutrients from the organic inputs at a late

stage of the plants. It has been known that organic fertilizer

is the major source of mineral nutrients (Eghball et al.

2002). These responses of grain yields to organic fertilizer

0200400600800

10001200140016001800

2 tonmanure/ha

+ 4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)

Ker

nel y

ield

(kg/

ha)


Babillae site UninoculatedInoculated

a

0

500

1000

1500

2000

2500

2 tonmanure/ha +

4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)

Ker

nel y

ield

(kg/

ha)


Fedis siteUninoculated Inoculated

b


grain yield of peanut at



123

are consistent with other studies on peanut such that there

was a significant increase in peanut production by organic

input enriched by fly ash (Burgos et al. 2006). The benefits

of organic fertilizer and inorganic fertilizer application in

combination with rhizobia on the agronomic productivity

of food legumes have been previously reported in chickpea

(Namvar et al. 2013; Shahzad et al. 2013). The present

results are also in accordance with the findings of Shahzad

et al. (2013) who demonstrated a significant increase in soil

nutrients including available P by organic matter

application.

The effect of organic and inorganic fertilizer on soil N

and organic C was not significant at both sites indicating

that one year application organic fertilizer did not affect the

soil N and soil organic matter. However, the results showed

that DAP and organic inputs increased the available P in

both soils. The increase in P due to organic fertilizer

application could be organic acids production as a result of

microbial decomposition of organic matter, which can

solubilize the native unavailable inorganic P beside serve

as source of inorganic P (Ramesh et al. 2009).

Conclusion

In general, organic fertilizer applications are relevant to

boost the effectiveness of Bradyrhizobium on nodulation

and yield of peanut in degraded and sand soil of eastern

Ethiopia. Compost and farmyard manure prepared from

locally available materials and inoculation of elite

Bradyrhizobium isolate are needed to increase the pro-

ductivity of peanut sustainably in sandy and degraded soil

of eastern Ethiopia. Although this study finds a handful of

beneficial effects of organic amendments with Bradyrhi-

zobium on the yield of peanut, its effect on selected soil

properties has been negligible. Therefore, further study on

00.5

11.5

22.5

33.5

2 tonmanure/ha +

4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)

Plan

t N a

ccum

ulat

ion


Babillae siteUninoculated Inoculateda

00.5

11.5

22.5

33.5

2 tonmanure/ha +

4 toncompost /ha

2 tonmanure/ha

4 toncompost /ha

DAP(100kg/ha)

Urea(20Kg/ha)

Plan

t N a

ccum

ulat

ion


Fedis siteUinoculated Inoculated

b


plant N accumulation of peanut

at a Babillae and b Fedisexperimental sites


123

the long-term application of organic inputs effect on soil

fertility and peanut production would be suggested.

Acknowledgements The author is grateful to Mr. Berhanu Mengistuand Girmay Mekonnen for their assistance in the field and laboratory

experiments. My appreciation also goes to Ms. Rahel Berhanu for

providing laboratory facilities.

Compliance with ethical standards

Conflict of interest The authors declare that there is no conflict ofinterest.

Open Access This article is distributed under the terms of theCreative Commons Attribution 4.0 International License (http://crea

tivecommons.org/licenses/by/4.0/), which permits unrestricted use,

distribution, and reproduction in any medium, provided you give

appropriate credit to the original author(s) and the source, provide a

link to the Creative Commons license, and indicate if changes were

made.

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Table 5 Total N, organicmatter and available P of

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affected by combined

application of organic and

inorganic fertilizer application

Treatment Soil total N Soil organic carbon Available P concentration


M ? C 0.037ab 0.125a 0.081a 0.433ab 1.304a 0.868a 3.78bc 3.95ab 3.87c

M ? C ? B 0.042ab 0.124a 0.083a 0.487ab 1.270a 0.879a 7.31b 5.25ab 6.28bc

M 0.047ab 0.098a 0.072a 0.541ab 1.137a 0.839a 1.53c 5.20ab 3.37c

M ? B 0.028b 0.084a 0.056a 0.325b 1.141a 0.733a 7.19b 6.28a 6.73bc

C 0.047ab 0.093a 0.070a 0.541ab 1.083a 0.812a 5.76bc 2.87b 4.32c

C ? B 0.051ab 0.098a 0.075a 0.596ab 1.137a 0.866a 5.11bc 3.58ab 4.35c

DAP 0.700a 0.087a 0.078a 0.812a 1.083a 0.947a 20.46a 5.91ab 13.18a

DAP ? B 0.042ab 0.095a 0.068a 0.487ab 1.137a 0.812a 15.42a 6.23a 10.83ab

Urea 0.037ab 0.096a 0.067a 0.433ab 1.124a 0.779a 2.69bc 3.10b 2.89c

Urea ? B 0.053ab 0.098a 0.076a 0.575ab 1.104a 0.839a 4.77bc 3.58ab 4.18c

No amendment 0.029b 0.094a 0.062a 0.346b 1.179a 0.762a 3.40bc 3.01b 3.20c

Mean 0.044 0.099 0.072 0.507 1.154 0.83 7.04 4.45 5.74

Significance * ns ns * ns ns * ** ***

LSD (P\ 0.05) 0.037 0.046 0.066 0.437 0.479 0.76 5.60 3.09 6.38CV (%) 28.46 15.78 47.82 29.55 14.21 47.25 27.24 23.76 57.31

M ? C—2 ton manure/ha ? 4 ton compost/ha ? no inoculation; M ? C ? B—2 ton manure/ha ? 4 ton

compost/ha ? Bradyrhizobium inoculation; M—2 ton manure/ha ? no inoculation; M ? B—2 ton man-

ure/ha ? Bradyrhizobium inoculation; C—4 ton compost/ha ? no inoculation; C ? B—4 ton compost/

ha ? Bradyrhizobium inoculation; DAP—(46 P2O5 kg/ha ? 19 kg N/ha); DAP ? B—(46 P2O5 kg/

ha ? 19 kg N/ha) ? Bradyrhizobium inoculation; Urea—20 kg N/ha; Urea ? B—20 kg N/

ha ? Bradyrhizobium inoculation

Means within the same factor and column followed by the same letter are not significantly different at 5%

level of significance


123

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Organic and inorganic fertilizer application enhances the effect of Bradyrhizobium on nodulation and yield of peanut (Arachis hypogea L.) in nutrient depleted and sandy soils of EthiopiaAbstractPurposeMethodsResultsConclusion

IntroductionMaterials and methodsDescription of the study sitesSource of the test varietyOrganic fertilizer sampling and analysesTreatments and crop managementSoil sampling and analysisAgronomic data collectionPlant samples and analysisStatistical analysis

ResultsDiscussionConclusionAcknowledgementsReferences

organic and inorganic fertilizer application enhances the ... · ruﬁno et al. 2010). for...

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