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Phosphorus use effiiency and productivity of pigeonpea (Cajanus cajan (l.) millsp.) and soybean (glycine max (l.) merrill) on smallholder farms in different agro-ecological zones of central Malawi

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Title Phosphorus use effiiency and productivity of pigeonpea (Cajanus cajan (l.) millsp.) and soybean (glycine max (l.) merrill) on smallholder farms in different agro-ecological zones of central Malawi
 
Creator Mzumara, Edward
 
Subject soil fertility
nitrogen fixation
intercropping
 
Description Low soil fertility especially nitrogen (N) is one of the major constraints to increased maize productivity on smallholder farms in Malawi. Integration of grain legumes in maize based systems is one of the strategies to improve soil fertility and yields as legumes fix atmospheric nitrogen through a symbiotic relationship with Rhizobium bacteria. A study was conducted in the 2013/2014 growing season in Linthipe and Golomoti Extension Planning Areas (EPAs) in Dedza District, and Nsipe EPA in Ntcheu District. The objectives of the study were to evaluate the grain yields and biological nitrogen fixation (BNF) of the sole and intercropped pigeonpea and soybean under two levels of inorganic P fertilizer (0 and 14 kg P ha-1) and to determine the Phosphorus use efficiency (PUE). BNF was assessed using the N difference method. The experiment was laid out in a randomized complete block design (RCBD). Soils were sandy clay loams, loamy sand and sandy loams to sandy clay loams for Linthipe, Golomoti and Nsipe respectively. Soil pH was moderately acidic to acidic, pH 4.9 to 5.8 in the three sites. Available soil P (Mehlich-3) averaged 44, 84 and 39mg kg-1; and the mean soil organic matter (OM) were 2.55, 1.63 and 2.39% for Linthipe, Golomoti and Nsipe EPAs, respectively.

Soybean grain yields were not affected by cropping system. However, intercropping significantly reduced pigeonpea grain yield by 47%. Similarly, BNF of soybean was not affected by cropping system while that of pigeonpea was reduced by 41% on per crop basis, with intercropping. Overall, intercropping of pigeonpea and soybean was efficient in resource utilization than sole cropping with land equivalent ratio (LER) of 1.44. On area basis, total BNF of the soybean+pigeonpea intercrop system was 90 kg ha-1 which was 67 and 38% higher than the BNF of the sole crops of soybean and pigeonpea, respectively. Site and P fertilizer interaction effects were significant on grain yield and N fixed by soybean. P fertilization increased grain yields of both the sole and intercropped soybean in the mid altitude areas of Linthipe, p=0.002 and Nsipe, p=0.037. Similarly, P fertilizer increased BNF in both sole and intercropped stands of soybean in Linthipe, p=0.039 and Nsipe, p=0.002 over unfertilized. However, P fertilization had no significant effect on soybean grain yields and BNF in the low altitude area, Golomoti. Pigeonpea grain yields and BNF were not affected by P fertilizer at Nsipe and Golomoti EPAs. The PUE values for soybean were 56.9, 25.7 and 41.6 for Linthipe, Golomoti and Nsipe EPAs, respectively and those for pigeonpea were 20.1 and 23 for Golomoti and Nsipe EPAs, respectively. The overall PUE of the soybean + pigeonpea intercrop was 38 and 75% higher than sole cropping of soybean and pigeonpea, respectively. This study showed that intercropping of soybean with pigeonpea and application of inorganic P in mid altitude areas, offer good option for increasing grain yields of the legumes and improves soil fertility through biological nitrogen fixation that consequently lower smallholder farmers‘ cost of production.
 
Date 2016-07
2022-11-15T18:44:26Z
2022-11-15T18:44:26Z
 
Type Thesis
 
Identifier Mzumara, E. 2016. Phosphorus use effiiency and productivity of pigeonpea (Cajanus cajan (l.) millsp.) and soybean (glycine max (l.) merrill) on smallholder farms in different agro-ecological zones of central Malawi. MSc thesis in Agronomy. Lilongwe, Malawi. Lilongwe University of Agriculture and Natural Resources.
https://hdl.handle.net/10568/125473
NATURAL RESOURCE MANAGEMENT
 
Language en
 
Rights Copyrighted; all rights reserved
Open Access
 
Format 138 p.
application/pdf
 
Publisher Lilongwe University of Agriculture and Natural Resources