Data from: Wheat nutrient response functions for the East Africa highlands

Wheat (Triticum æstivum L.) is an important East Africa highland crop but yields are low. Information is scarce for optimization of fertilizer use. Research was conducted to determine yield response functions for N, P and K, and to diagnose Mg–S–Zn–B deficiencies. The average grain yield increase in Rwanda due to N application was 1.5 Mg ha−1 with a mean economically optimal rate (EOR) of 68 kg ha−1 N. In Kenya and Tanzania, yield was increased by 29% with EOR N for two SY but unaffected by N rate for four other SY which on average had 50% of the soil organic C (SOC) as the N-responsive SY. Yield was increased, on average, with application of P and K by 0.47 and 0.23 Mg ha−1, respectively, at EOR in Rwanda but effects were inconsistent for other SY where soil test K was higher than in Rwanda. Application of Mg–S–Zn–B resulted in 0.46 Mg ha−1 more yield in Rwanda but did not affect yield at other SY where the average soil test values for these nutrients was 35% higher than in Rwanda. If the financially constrained farmer opts to apply the affordable fertilizer to twice as much land at 50% EOR compared with 100% EOR, the mean yield increase is reduced by 27% but production and PCR are increased by 43 and 72%, respectively. Nutrient effects were relatively consistent and positive in Rwanda, but less and less inconsistent elsewhere with generally less SOC, more K–Mg–S–Zn–B availability, and often lower yields.

普通小麦（Triticum aestivum L.）是东非地区重要的高地作物，但当前其籽粒产量偏低，且关于肥料施用优化的相关研究信息较为匮乏。本研究旨在明确氮（N）、磷（P）、钾（K）的产量响应函数，并诊断镁-硫-锌-硼（Mg–S–Zn–B）的养分缺素状况。在卢旺达，施用氮肥带来的平均籽粒增产幅度为1.5 Mg·ha⁻¹，经济最佳施用量（EOR）下的氮肥用量为68 kg·ha⁻¹。在肯尼亚与坦桑尼亚，两类试验体系（SY）在采用经济最佳施用量氮肥后，籽粒产量提升29%；而其余4类试验体系的产量不受氮肥施用量影响，且其平均土壤有机碳（SOC）含量仅为对氮肥响应敏感的试验体系的50%。在卢旺达，采用经济最佳施用量时，施用磷肥和钾肥可分别使平均产量提升0.47 Mg·ha⁻¹和0.23 Mg·ha⁻¹；但在其他试验体系中，由于其土壤钾素测试值高于卢旺达，磷钾肥的施用效果并不一致。在卢旺达，施用镁-硫-锌-硼复配肥料可使产量提升0.46 Mg·ha⁻¹；但在其他试验体系中，由于其上述养分的平均土壤测试值较卢旺达高出35%，该类肥料的施用对产量无显著影响。若资金受限的农户选择按50%经济最佳施用量施肥，并将施肥面积扩大至原按100%经济最佳施用量施肥的2倍，则平均增产幅度将降低27%，但总产量与成本收益率（PCR）将分别提升43%和72%。在卢旺达，各类养分的施用效果相对一致且均为正向效应；而在其他试验区域，由于土壤有机碳含量普遍偏低、钾-镁-硫-锌-硼的养分有效性更高，且产量通常更低，养分施用效果的一致性逐渐降低。