Diagnosis of crop secondary and micro-nutrient deficiencies in sub-Saharan Africa

Crop production in sub-Saharan Africa has numerous biotic and abiotic constraints, including nutrient deficiencies. Information on crop response to macronutrients is relatively abundant compared with secondary and micronutrients (SMN). Data from 1339 trial replicates of 280 field trials conducted from 2013 to 2016 in 11 countries were analyzed for the diagnosis of SMN deficiencies. The diagnostic data included relative yield response (RYR) and soil and foliar test results. The RYR to application of a combination of Mg, S, Zn, and B (Mg-S-Zn-B) relative to a comparable N-P-K treatment was a >5% increase for 35% of the legume blocks and 60% of the non-legume blocks. The frequencies of soil test Zn, Cu, and B being below their critical level were 28, 2 and 10% for eastern and southern Africa, respectively, and 55, 58 and 89% for western Africa, while low levels for other SMN were less frequent. The frequency of foliar results indicating low availability were 58% for Zn, 16% for S and le...撒哈拉以南非洲的作物生产面临诸多生物与非生物限制因子，养分亏缺便是其中之一。相较于中量元素与微量元素（secondary and micronutrients, SMN），有关作物对大量养分响应的研究数据相对充足。本研究对2013至2016年间于11个国家开展的280项田间试验、总计1339个试验重复的相关数据进行分析，以诊断中量元素与微量元素（SMN）亏缺状况。诊断所用数据涵盖相对产量响应（relative yield response, RYR）以及土壤、叶片测试结果。相较于等量氮-磷-钾（N-P-K）处理，施加镁-硫-锌-硼（Mg-S-Zn-B）复合养分的相对产量响应，在35%的豆科地块与60%的非豆科地块中提升幅度超过5%。东非与南部非洲的土壤锌、铜、硼测试值低于临界值的频率分别为28%、2%和10%；西非该三项指标的对应频率则分别为55%、58%和89%，其余中量元素与微量元素亏缺的发生频率相对更低。叶片测试结果显示养分有效性偏低的频率分别为：锌58%、硫16%，以及[原文未完整呈现的剩余内容]