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为探讨长期不同施肥条件下土壤有机碳和作物产量的变化规律及DNDC模型在关中地区的适用性,利用在陕西杨凌设置的长期定位施肥试验数据,选取不施肥(CK)、单施氮磷钾无机肥(NPK)、无机肥配施秸秆(SNPK)、无机肥配施低量有机肥(M1NPK)及无机肥配施高量有机肥(M2NPK)5个处理,分析了20年来土壤有机碳(SOC)含量、碳循环以及农作物产量的变化趋势等基本特征。分析数据表明:CK使得土壤肥力持续下降,显著地降低了SOC含量和作物产量;NPK处理虽可促进作物产量,但对表层土壤肥力的增加不明显,与CK处理无显著差异;而SNPK、M1NPK与M2NPK处理既增加了作物产量,同时也显著提高了土壤肥力,且以M2NPK的增产增肥效果最佳。在此基础上,利用实测数据标定和验证了DNDC模型,通过均方根误差(RMSE),标准化的均方根误差(N-RMSE)以及符合度指数(d)对模型适用性分析,模型预测精度较好,可用于预测该地区作物产量和土壤有机碳动态。从模型输出20年来土壤碳含量的变化看,施肥能提高作物地上部、地下部生物量以及土壤异氧呼吸作用,即同时提高了外源碳携入量和内源碳消耗量,但各施肥处理均在碳储量上表现为盈余状态。因此,在关中地区,为提高土壤肥力、碳储量以及作物产量,可推广无机肥配施有机肥的措施。
In order to explore the variation regularity of soil organic carbon and crop yield under long-term different fertilization conditions and the applicability of DNDC model in Guanzhong area, long-term fertilization experiment data were set up in Yangling, Shaanxi Province. Five treatments of NPK, SNPK, M1NPK and M2NPK combined with inorganic fertilizers were applied to analyze the effects of soil organic carbon SOC) content, carbon cycle and crop yield trends and other basic characteristics. The results showed that CK decreased soil fertility and decreased SOC content and crop yield significantly. Although NPK treatment could promote crop yield, soil fertility did not increase obviously, and no significant difference was found between CK and CK. However, SNPK, M1NPK The treatment with M2NPK not only increased crop yield, but also significantly increased soil fertility, and the best yield was M2NPK. Based on this, the DNDC model was calibrated and validated with the measured data. The model applicability was analyzed by root mean square error (RMSE), normalized root mean square error (N-RMSE) and coincidence index (d) Accurate, can be used to predict the crop yield and soil organic carbon dynamics in the area. According to the changes of soil carbon content in the past 20 years since the model was put out, fertilization can improve the above-ground and underground biomass of crops and the respiration of soil in respiration. That is to say, both the amount of exogenous carbon and the amount of endogenous carbon were increased. Disposal shows a surplus on carbon stocks. Therefore, in the Guanzhong area, measures to increase the use of organic fertilizers by inorganic fertilizers may be promoted to increase soil fertility, carbon stocks and crop yields.