Agriculture 2011, 1(1), 22-37; doi:10.3390/agriculture1010022
Article

Effects of Tillage and Crop Residue Application on Soybean Nitrogen Fixation in a Tropical Ferralsol

1,2,* email, 2email, 3email and 2email
Received: 25 October 2011; in revised form: 6 December 2011 / Accepted: 8 December 2011 / Published: 20 December 2011
(This article belongs to the Special Issue Soil Biology and Its Importance in Soil Fertility)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: This study was aimed at quantifying soybean (Glycine max) nitrogen fixation under reduced tillage (RT) and conventional tillage (CT) in a tropical Ferralsol of the sub-humid zone of western Kenya, using the isotope 15N dilution method. Crop residue (CR) management was a superimposed treatment in soybean-maize rotation and intercropping systems. This study quantified N in abscised soybean leaves. Soybean-N derived from the atmosphere (%NDfA) ranged between 41–65%; it was higher (P < 0.05) in RT (55.6%) than in CT (46.6%). Total fixed-N under ‘RT + CR’ was more than in the other treatments by at least 55% in intercropping and 34% in rotation system. Nitrogen fixed in soybean aboveground parts was 26–48 kg N ha−1 with intercropping and 53–82 kg N ha−1 with rotation. Seasonal litter fall contained about 15 kg N ha−1, with 54% NDfA. Annual nitrogen balances with soybean and maize grain removed were better in RT (−9 to −32 kg N ha−1) than in CT (−40 to −60 kg N ha−1). Application of P increased nodule weight (P < 0.05) by 3 to 16 times over the control. Soybean residues should be returned to the field after harvest to reduce soil N mining. We conclude that ‘RT + CR’ increases biological nitrogen fixation in soybean, over CT, and that phosphorus application is needed for better soybean nodulation in western Kenya.
Keywords: intercropping; litter fall; N balance; %NDFA; 15N dilution
PDF Full-text Download PDF Full-Text [296 KB, uploaded 20 December 2011 08:30 CET]

Export to BibTeX |
EndNote


MDPI and ACS Style

Kihara, J.; Martius, C.; Bationo, A.; Vlek, P.L.G. Effects of Tillage and Crop Residue Application on Soybean Nitrogen Fixation in a Tropical Ferralsol. Agriculture 2011, 1, 22-37.

AMA Style

Kihara J, Martius C, Bationo A, Vlek PLG. Effects of Tillage and Crop Residue Application on Soybean Nitrogen Fixation in a Tropical Ferralsol. Agriculture. 2011; 1(1):22-37.

Chicago/Turabian Style

Kihara, Job; Martius, Christopher; Bationo, Andre; Vlek, Paul L. G. 2011. "Effects of Tillage and Crop Residue Application on Soybean Nitrogen Fixation in a Tropical Ferralsol." Agriculture 1, no. 1: 22-37.

Agriculture EISSN 2077-0472 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert