未来气候条件下秸秆还田和氮肥种类对夏玉米产量及土壤氨挥发的影响

Effects of Straw Returning and Nitrogen Fertilizer Types on Summer Maize Yield and Soil Ammonia Volatilization Under Future Climate Change

【目的】秸秆还田配施氮肥可以提高作物生产力,但在气候变化条件下,不同管理措施对夏玉米农田氮素利用存在很大的不确定性。明确在未来气候条件下秸秆还田与氮肥种类对夏玉米产量和土壤氨挥发的影响,以应对气候变化。【方法】利用DNDC模型预测未来不同情景下,秸秆还田和不同氮肥种类对关中地区夏玉米产量和土壤氨挥发的影响。通过田间土壤温度、水分、产量和土壤氨挥发累积量试验数据的验证,DNDC模型可以很好地模拟未来气候条件下不同处理的作物产量和土壤氨挥发累积量。【结果】模拟和实测结果均表明,在当前气候条件下秸秆还田会提高作物产量并促进土壤氨挥发,稳定性氮肥与普通尿素相比对产量无显著影响但会显著减少土壤氨挥发累积量。敏感性分析表明,作物产量与土壤氨挥发累积量均对施氮量最敏感。在RCP4.5排放情景下,单施稳定性氮肥(NF1)和单施尿素(NF2)分别在2050s-2090s和2070s-2090s产量显著降低,秸秆配施稳定性氮肥(SF1)和秸秆配施尿素(SF2)均在2050s-2090s产量显著升高;在RCP8.5排放情景下,单施稳定性氮肥(NF1)在2070s-2090s产量显著降低,单施尿素(NF2)产量无显著变化,秸秆配施稳定性氮肥(SF1)和秸秆配施尿素(SF2)均在2050s-2090s产量显著升高。单施稳定性氮肥(NF1)在RCP4.5排放情景下的2050s-2090s和在RCP8.5排放情景下2030s-2090s土壤氨挥发累积量与当前气候条件相比显著提高,其余各处理在不同排放情景下未来各时期土壤氨挥发累积量与当前气候条件相比均显著降低。【结论】DNDC预测结果表明,在关中地区未来气温和CO_(2)浓度升高以及降水变化的气候条件下,秸秆还田配施稳定性氮肥会显著提高夏玉米产量并降低土壤氨挥发累积量,是最佳的高产减排农田管理方案,可为应对气候变化及合理使用秸秆和氮肥提供理论基础。

【Objective】 Returning straw to the field and applying nitrogen fertilizer can increase crop productivity. However, under the conditions of climate change, the different management measures have great uncertainty in the nitrogen utilization of summer maize farmland. It is very important to clarify the impact of straw returning and nitrogen fertilizer types on summer maize yield and soil ammonia volatilization under future climate conditions. 【Method】 This study used the DNDC model to predict the impact of returning straw to the field and different types of nitrogen fertilizers on summer maize yield and soil ammonia volatilization accumulation in Guanzhong area under different scenarios in the future. Through the verification of field soil temperature, moisture,yield and soil ammonia volatilization test data, the DNDC model could simulate crop yields and soil ammonia volatilization accumulations under different treatments under the future climate conditions well.【Result】Both simulation and actual measurement results showed that returning straw to the field increased summer maize yields and promoted soil ammonia volatilization under the current climate conditions. Compared with ordinary urea, slow-release fertilizers had no significant effect on summer maize yield but would significantly reduce soil ammonia volatilization accumulation. Sensitivity analysis showed that both crop yield and soil ammonia volatilization accumulation were the most sensitive to nitrogen application. Under the RCP4.5 emission scenario, the single application of stable nitrogen fertilizer(NF1) treatment and single application of urea(NF2) treatment significantly reduced the summer maize yield in 2050s-2090s and 2070s-2090s, respectively. Both the treatment of straw combined with stable nitrogen fertilizer(SF1) and the treatment of straw combined with urea(SF2) significant increased summer maize yield in 2050s-2090s;under the RCP8.5 emission scenario, NF1 significantly reduced the summer maize yield from 2070s to 2090s, and NF2 showed no significant change. The summer maize yields under SF1 and SF2 were increased significantly from 2050s to 2090s. For NF1 under the RCP4.5 emission scenario in 2050s-2090s and under the RCP8.5 emission scenario 2030s-2090s, the soil ammonia volatilization accumulation significantly increased compared with current climate conditions;for the remaining treatments, the cumulative amount of soil ammonia volatilization in future periods under different emission scenarios would be significantly reduce compared with current climatic conditions.【Conclusion】The DNDC forecast results showed that under the climate conditions of rising temperature and CO_(2) concentration and changing precipitation in the Guanzhong area in the future, the returning straw to the field and applying stable nitrogen fertilizer would significantly increase the summer maize yield and reduce the accumulation of ammonia volatilization in the soil, and it was the best high-yield and emission-reducing farmland management plan. This research provided a theoretical basis for coping with climate change and the rational use of straw and nitrogen fertilizer.