Understanding the long-term responses of crop yield and soil organic carbon to fertilization is necessary to sustain food supply in a context of global change. The time-course of winter wheat yield and soil organic carbon were established in a 31-year long experiment with four fertilization regimes: unfertilized control; fertilized with mineral nitrogen and phosphorus, NP; fertilized with mineral N, P and K, NPK; and fertilized with manure and mineral NPK, MNPK. Over the time series, mean temperature increased at 0.054 ℃ year (i.e. 1.67 degrees over the course of the experiment) and annual precipitation increased at 8.9 mm year. Yield did not show trends in unfertilized controls, increased at 210 kg ha year in the first 20 years and decreased slightly afterwards in the NP and NPK treatments, and increased at 310 kg ha in the MNPK treatment until 2006, and leveled off afterwards. Soil organic carbon increased linearly with rates from 0.05 g kg year in unfertilized controls to 0.24 g kg year in MNPK. In fertilized crops, yield correlated nonlinearly with annual precipitation, and linearly with average temperature during the growing season. Across fertilizer treatments, yield correlated nonlinearly with soil organic carbon and the thresholds of soil organic carbon for peak yield increased with water supply. It is concluded that the combination of organic and inorganic fertilizers contributed to yield and soil organic carbon against the background of a warmer and wetter climate.

中文翻译：

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黄土高原年际天气变化下冬小麦产量和土壤有机碳对长期（1990—2021）施肥制度的响应

了解作物产量和土壤有机碳对施肥的长期反应对于在全球变化的背景下维持粮食供应是必要的。冬小麦产量和土壤有机碳的时间过程是在一项为期 31 年的实验中建立的，实验采用四种施肥方式：不施肥控制；施用矿物氮和磷、NP；施氮肥、磷肥、钾肥、氮磷钾肥；并施有机肥和矿物质NPK、MNPK。在时间序列中，年平均气温增加了0.054℃（即实验过程中增加了1.67度），年降水量增加了8.9毫米。未施肥对照的产量没有表现出趋势，在前20年，NP和NPK处理的产量增加了210公斤公顷，之后略有下降，而MNPK处理的产量在2006年之前增加了310公斤公顷，之后趋于平稳。土壤有机碳呈线性增加，从未施肥对照的每年 0.05 克/公斤到 MNPK 的每年 0.24 克/公斤。在施肥作物中，产量与年降水量呈非线性相关，与生长季节的平均温度呈线性相关。在施肥处理中，产量与土壤有机碳呈非线性相关，并且峰值产量的土壤有机碳阈值随着供水量的增加而增加。结论是，在气候变暖和湿润的背景下，有机和无机肥料的组合有助于提高产量和土壤有机碳。