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Optimizing interaction between crop residues and inorganic N under zero tillage systems in sub-humid region of Kenya

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Title Optimizing interaction between crop residues and inorganic N under zero tillage systems in sub-humid region of Kenya
 
Creator Kinyua, Michael
Mucheru-Muna, Monicah
Bolo, Peter
Kihara, Job Maguta
 
Subject soil structural units
tillage
inorganic fertilizers
carbon
stocks
crop residues
Nitosols
unidades estructurales de suelos
labranza
abonos inorgánicos
 
Description Conservation agriculture practices involving zero tillage and residue retention are promising nutrient management strategies for soil health restoration. Despite their potential positive impact on soil fertility, improved crop yields and increased revenues for smallholder farmers; their effect on nitrogen inputs and crop growth is not clearly understood. This may limit their potential as a nutrient management strategy that may remedy soil degradation and boost crop yields for farmers. This study investigated how different tillage practices, crop residues and inorganic nitrogen (N) options affect maize production, soil fertility and economics of smallholder farming systems. The study was conducted in a short-term (2 years) on-station trial, under randomized complete block design with three replications in a maize monocrop system. Six treatments, involving three different rates of maize stover residue (0, 3 and 5 t ha−1) and inorganic N (0, 3 and 5 t ha−1) inputs, respectively, were assessed under conventional and zero tillage systems. Mineral N and organic C were assessed at four depths (0–10 cm, 10–30 cm, 30–60 cm and 60–90 cm) whereas soil aggregate distribution was assessed at 0–5 cm, 5–10 cm, 10–15 cm and 15–20 cm depths. Application of inorganic N as the only input increased (p ≤ 0.05) grain yield (with the yields doubling in the short rains (SR) of 2015 and increasing by 1.4 times in long rains (LR) of 2016) compared to unfertilized control treatment. Treatment, soil depth and the time of sampling significantly affected soil mineral N concentration (p ≤ 0.05). Soil organic C reduced significantly (p ≤ 0.05) with sampling depths, but no differences were observed across treatments. At 0–5 cm depth, the proportion of large macroaggregates in zero tillage increased (48%; p ≤ 0.05) after application of crop residues at 5 t ha−1 relative to 3 t ha−1. Zero tillage treatment with application of 5 t ha−1 of residue and 80 kg N ha−1 was the most dominant and most profitable compared to the other treatments. This treatment had a benefit cost ratio (BCR) of 2.9 (in the short rains season of 2015) and 3.0 (long rains of 2016 seasons). Its marginal rate of return (MRR) was 368% (in the 2015 short rains season) and 416% (in the 2016 long rains season). This makes it a good nutrient management strategy with potential of optimizing maize yields.
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Date 2021-09
2022-02-15T08:54:03Z
2022-02-15T08:54:03Z
 
Type Journal Article
 
Identifier Kinyua, M.; Mucheru-Muna, M.; Bolo, P.; Kihara, J. (2021) Optimizing interaction between crop residues and inorganic N under zero tillage systems in sub-humid region of Kenya. Heliyon 7(9): e07908. ISSN: 2405-8440
2405-8440
https://hdl.handle.net/10568/118127
https://doi.org/10.1016/j.heliyon.2021.e07908
 
Language en
 
Rights CC-BY-NC-ND-4.0
Open Access
 
Format application/pdf
 
Publisher Elsevier
 
Source Heliyon