Understanding dynamics of soil organic carbon (SOC) stock in agroecosystems under climate change is imperative for maintaining soil productivity and offsetting greenhouse gas emissions. Simulations with the SPACSYS model were conducted to assess the effects of future climate scenarios (RCP2.6, RCP4.5 and RCP8.5) and fertilisation practices on crop yield and SOC stock by 2100 for a continuous winter wheat cropping system in southeast England. Weather data between 1921 and 2000 was considered as the baseline. SPACSYS was first calibrated and validated with the data of the Broadbalk continuous winter wheat experiment for over a century. Six treatments were used: no fertiliser, a combination of chemical nitrogen, phosphorus and potassium with three nitrogen application rates (N1PK, N3PK and N5PK), manure only (FYM, close N application rate to N5PK) and a combination of manure and chemical nitrogen application (FYMN, the same chemical N application rate as N3PK). Compared with the observations, SPACSYS was able to simulate grain yields and dynamics of SOC and TN stocks. Our predications showed that wheat yield would increase by 5.8–13.5% for all the fertiliser application treatments under future climate scenarios compared to that under the baseline because of a gradual increase in atmospheric CO concentration. Meanwhile, the SOC stock can increase for the practices under the scenarios except the NPK fertiliser practices under RCP2.6. Increased C input through “CO-fertilisation effects” can compensate C losses by soil respiration under the RCP scenarios. We concluded that manure application practices can be considered as a sustainable strategy for enhancing wheat yield and soil C sequestration under the future climate scenarios.

中文翻译：

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气候变化对英格兰东南部小麦连作制度作物产量和土壤碳储量的影响

了解气候变化下农业生态系统土壤有机碳（SOC）存量的动态对于维持土壤生产力和抵消温室气体排放至关重要。使用 SPACSYS 模型进行模拟，以评估未来气候情景（RCP2.6、RCP4.5 和 RCP8.5）和施肥实践对 2100 年英格兰东南部冬小麦连作制度的作物产量和 SOC 储量的影响。1921 年至 2000 年之间的天气数据被视为基线。SPACSYS 首次使用一个多世纪以来 Broadbalk 连续冬小麦实验的数据进行校准和验证。采用六种处理：不施肥、化学氮、磷、钾组合，三种氮肥施用量（N1PK、N3PK和N5PK）、仅施肥（FYM，施氮量接近N5PK）以及粪肥和化学氮肥组合施用（FYMN，与 N3PK 相同的化学施氮量）。与观测结果相比，SPACSYS 能够模拟粮食产量以及 SOC 和 TN 储量的动态。我们的预测表明，由于大气二氧化碳浓度逐渐增加，未来气候情景下所有施肥处理的小麦产量将比基线增加5.8-13.5%。同时，除了 RCP2.6 下的 NPK 施肥实践之外，其他情景下的实践中 SOC 存量都会增加。通过“二氧化碳施肥效应”增加碳输入可以补偿 RCP 情景下土壤呼吸造成的碳损失。我们的结论是，粪肥施用实践可以被视为在未来气候情景下提高小麦产量和土壤碳固存的可持续策略。