Numerous studies have demonstrated that biochar application can increase crop yield by improving soil properties and health. Yet, these studies, however, neglected how biochar alters yield variability across years – reflecting the yield stability. This study aimed to investigate the effects of biochar application on crop yield variability. Published data from 38 experimental sites were collected from the Web-of-Science. Two-thirds of the data were originated from three main staple crops: maize, wheat, and rice. The remaining were from rapeseed, soybean, sweet potato, and peppermint. Biochar effects on crop yield and its variability as well as their driving factors were analyzed by linear mixed models depending on soil conditions, field management practices, and climate types. Biochar increased the crop yield globally by 14 %, especially in soils with low pH (< 5.5), low nitrogen (N) and phosphorus (P) inputs (≤ 120 kg N ha, < 35 kg P ha), with high biochar inputs (≥ 20 Mg ha), and under crop rotation. Biochar increased crop yields by 12 % in short-term (≤ 5 years) and 21 % in long-term (> 5 years) experiments. Biochar increased yield variability by 42 % in acidic soils (pH < 5.5) and by 24 % with low N inputs (≤ 120 kg N ha), mainly because its liming and fertilization effects were short-lasting within the first few years. The yield variability after biochar application decreased with the increase in mean annual temperature, inter-annual variabilities of temperature and precipitation, but with the decrease in mean annual precipitation in the growing season. Yield variability under biochar increased in short-term experiments by 27 %, but there was no change (0 %) in long-term experiments because of the higher yield gains and resistance to fluctuating weather conditions. Therefore, crop yield variability decreased with increasing yield in long-term experiments. Biochar application increased short-term variability of crop yields, but its long-term variability remained unaffected. This study highlights that biochar can support steadily future crop production in the long run.

中文翻译：

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生物炭对作物产量变异性的影响


大量研究表明，生物炭的应用可以通过改善土壤性质和健康来提高作物产量。然而，这些研究忽略了生物炭如何改变多年来的产量变异性——反映了产量的稳定性。本研究旨在探讨生物炭施用对作物产量变异性的影响。来自 38 个实验站点的已发布数据是从科学网络收集的。三分之二的数据来自三种主要农作物：玉米、小麦和水稻。其余的来自油菜籽、大豆、甘薯和薄荷。根据土壤条件、田间管理实践和气候类型，通过线性混合模型分析了生物炭对作物产量及其变异性及其驱动因素的影响。生物炭使全球作物产量提高了 14%，特别是在 pH 值低 (< 5.5)、氮 (N) 和磷 (P) 投入低（≤ 120 kg N ha，< 35 kg P ha）且生物炭投入量高的土壤中(≥ 20 毫克·公顷)，并进行轮作。生物炭在短期（≤ 5 年）实验中使作物产量提高了 12%，在长期（> 5 年）实验中提高了 21%。生物炭在酸性土壤（pH < 5.5）中使产量变异性增加了 42%，在低氮输入（≤ 120 kg N ha）时产量变异性增加了 24%，这主要是因为其施灰和施肥作用在最初几年内持续时间较短。施用生物炭后的产量变异性随着年平均气温、气温和降水量的年际变化的增加而减小，但随着生长季年平均降水量的减少而减小。在短期实验中，生物炭下的产量变异性增加了 27%，但在长期实验中没有变化 (0%)，因为产量增益更高并且对天气条件波动的抵抗力更高。 因此，在长期实验中，作物产量变异性随着产量的增加而降低。生物炭的施用增加了作物产量的短期变异性，但其长期变异性不受影响。这项研究强调，从长远来看，生物炭可以稳定支持未来的农作物生产。