【摘要】 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。更多还原

【Abstract】 Land use changes may have great impacts on dryland agriculture in the Loess Plateau of China, one of the most fragile agro-ecosystems in the world. Here we investigated the variation of soil organic carbon(SOC)and crop yields in dryland under long-term different fertilization in Guanzhong plain area during 20 years using DNDC model. There were five treatments including no fertilization control(CK),inorganic fertilizers(NPK), NPK combined with straw(SNPK), NPK combined with low manure(M1NPK), and NPK combined with high manure(M2NPK). In the CK treatment, SOC and crop yields were significantly reduced. The NPK treatment promoted crop production, but had little effect on SOC, which was similar to that in CK. However, both SOC and crop yields were increased in the SNPK, M1 NPK and M2 NPK treatments, with the greatest effect observed in the M2 NPK. These observed data were used to calibrate and verify DNDC model.The model showed good fitting to measured SOC and crop yields, and thus could be used to predict SOC and crop yields dynamics. The prediction by the model indicated that combination of inorganic fertilizers and manure could not only enhance crop aboveground and underground biomass and heterotrophic respiration, but also increase soil carbon storage. This result would shed light on fertilization practices in this region.更多还原