Fertiliser use efficiency, production risks and profitability of maize on smallholder farms in East Africa

IF 1.6 4区农林科学 Q1 Agricultural and Biological Sciences

Experimental Agriculture Pub Date : 2022-07-13 DOI:10.1017/S001447972200014X

A. Kiwia, D. Kimani, Rebbie Harawa, B. Jama, G. Sileshi

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引用次数: 1

Abstract

Abstract The use of fertilisers in maize production has been the focus for many years of agronomic studies on research stations in East Africa. However, information on production risks and profitability of fertiliser use on smallholder farms is generally lacking because most of the early studies have focused on mean yields and yield components on research stations. This study applied rigorous analyses to determine conditions under which (1) production risks are low; (2) the recommended nitrogen (N) and phosphorus (P) fertiliser rates achieve a yield target of ≥3 t ha−1 believed to be a necessary condition to kick start a smallholder-led ‘green revolution’ in Africa and (3) N and P fertiliser use is profitable on smallholder farms in East Africa. Analysis of data from 464 on-farm trials in Kenya, Rwanda, Tanzania and Uganda revealed significant variations in production risks and nutrient use efficiency with season and soil type. On most sites, except in Uganda, production risks were lower with the recommended N and P fertilisers than the control during both the short and long rains. Production risks were three to four times higher with N and P fertiliser relative to the control on Lixisols and Ferralsols, but such risks were much lower on Nitisols, Leptosols, Vertisols, Plinthosols and Cambisols. The probability of exceeding grain yields of 3 t ha−1 with the recommended N and P rates was over 0.60 on Nitisols and Leptosols, but less than 0.20 on Lixisols and Plinthosols. The agronomic use efficiencies of N (AEN), P (AEP) and value cost ratios (VCR) were highest on Cambisols and lowest on Plinthosols. The VCR increased linearly with increase in AEN (R2 = 0.92) and AEP (R2 = 0.87) and less so with increase in grain yields (R2 = 0.47–0.60). Net present values indicated profitably of N and P fertiliser over the long term in only 30% of the site by season combinations in Uganda compared with 69% in Kenya, 81% in Rwanda and 84% in Tanzania. Patterns of N use efficiencies were different from P use efficiencies across soil types. Therefore, we recommend that N and P fertilisers should be appropriately targeted to soils where applied nutrients are used efficiently by maize crops.

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东非小农玉米的肥料使用效率、生产风险和盈利能力

玉米生产中肥料的使用一直是东非研究站多年来农艺研究的焦点。但是，关于小农农场使用化肥的生产风险和盈利能力的资料普遍缺乏，因为大多数早期研究集中在研究站的平均产量和产量组成部分。本研究采用严格的分析来确定以下条件:(1)生产风险低;(2)推荐的氮肥和磷肥施用量达到≥3 t ha的产量目标，这被认为是启动非洲小农主导的“绿色革命”的必要条件;(3)东非小农使用氮肥和磷肥是有利可图的。对肯尼亚、卢旺达、坦桑尼亚和乌干达464个农场试验数据的分析显示，不同季节和土壤类型在生产风险和养分利用效率方面存在显著差异。除乌干达外，在短雨和长雨期间，在大多数地点，使用推荐的氮肥和磷肥的生产风险都低于对照。氮肥和磷肥的生产风险是利索醇和Ferralsols对照的三到四倍，但硝硝醇、瘦硝醇、垂硝醇、Plinthosols和cambisol对照的风险要低得多。在推荐施氮磷条件下，硝硝土和细硝土产量超过3 tha - 1的概率大于0.60，而利索土和细硝土产量超过0.20。氮(AEN)、磷(AEP)和价值成本比(VCR)的农艺利用效率在cambisol上最高，在plinthosol上最低。VCR随AEN和AEP的增加呈线性增加(R2 = 0.92)，随产量的增加呈线性增加(R2 = 0.87)，但随产量的增加呈线性增加(R2 = 0.47 ~ 0.60)。净现值表明，在乌干达，按季节组合，只有30%的场地长期使用氮磷肥是有利可图的，而肯尼亚为69%，卢旺达为81%，坦桑尼亚为84%。不同土壤类型的氮利用效率与磷利用效率存在差异。因此，我们建议氮肥和磷肥应适当地施用于玉米作物有效利用所施养分的土壤。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experimental Agriculture 农林科学-农艺学

CiteScore

2.50

自引率

6.20%

发文量

审稿时长

24 months

期刊介绍： With a focus on the tropical and sub-tropical regions of the world, Experimental Agriculture publishes the results of original research on field, plantation and herbage crops grown for food or feed, or for industrial purposes, and on farming systems, including livestock and people. It reports experimental work designed to explain how crops respond to the environment in biological and physical terms, and on the social and economic issues that may influence the uptake of the results of research by policy makers and farmers, including the role of institutions and partnerships in delivering impact. The journal also publishes accounts and critical discussions of new quantitative and qualitative methods in agricultural and ecosystems research, and of contemporary issues arising in countries where agricultural production needs to develop rapidly. There is a regular book review section and occasional, often invited, reviews of research.