不同耕作措施下旱作春小麦农田二氧化碳排放模拟及敏感性分析

Simulation and sensitivity analysis of carbon dioxide emissions under different tillage systems in dryland spring wheat fields

为探讨不同耕作措施下旱作春小麦农田CO_(2)排放以及气候条件、土壤性质和作物管理措施对CO_(2)排放影响的敏感性差异,本文基于DNDC模型,结合定西试验区旱作春小麦农田定点连续监测的CO_(2)排放通量等数据,检验该模型模拟不同耕作措施下CO_(2)排放的适宜性,并对其敏感性进行研究。结果表明:DNDC模型对不同处理下CO_(2)排放的模拟结果与实测结果较为一致,即传统耕作(R=0.836、n=48、P<0.01)、传统耕作+秸秆覆盖(R=0.791、n=48、P<0.01)、免耕(R=0.758、n=48、P<0.01)、免耕+覆盖秸秆(R=0.843、n=48、P<0.01),表明该模型可以用来模拟不同耕作措施下旱作春小麦农田CO_(2)排放;而模型敏感分析显示,年平均温度是模拟不同耕作措施下旱作春小麦农田CO_(2)排放的敏感参数,其变化程度对模拟结果影响最大。

We investigated the sensitivity differences of CO_(2) emission in dryland spring wheat fields under different tillage systems and the effects of climatic conditions,soil properties and crop management measures on CO_(2)emission.In this paper,based on the DNDC model and combined with data such as CO_(2) emission flux monitored continuously at the fixed points for dryland spring wheat fields in the Dingxi experimental area,the suitability of the model to simulate CO_(2) emission under different tillage systems was tested and its sensitivity was studied.The results showed that the simulation results of CO_(2) emissions under different treatments by the DNDC model were more consistent with the measured results,namely traditional tillage(R=0.836,n=48,P<0.01),traditional tillage+straw mulch(R=0.791,n=48,P<0.01),no-tillage(R=0.758,n=48,P<0.01),no-tillage+straw mulch(R=0.843,n=48,P<0.01),indicating that the model can be used to simulate different tillage emission of CO_(2) from spring wheat farmland under different measures.The model sensitivity analysis showed that the average annual temperature was the sensitive parameter to simulate the CO_(2) emission in dryland spring wheat fields under different tillage systems,and its variation degree had the greatest influence on the simulation results.