集约农作条件下土壤有机碳动态模拟及其在黄淮海平原区的应用

Modeling and Applications of Soil Organic Matter in Intensive Cropping in China’s Huang-Huai-Hai Plain

集约农田土壤有机碳动态对作物可持续生产有重要意义。本研究基于碳固持CQESTR模型,在国内短期、中长期物料填埋试验资料基础上进行修正,将CQESTR模型按照物料降解与累积积温关系划分4个阶段,确定了不同降解阶段的物料类型因子。通过对黄淮海平原集约化农区7个独立肥料长期定位点1151组耕层土壤有机质观测值与模拟值进行验证,模型模拟95%置信区间为1.91g·kg-1,r2=0.91。修正的CQESTR模型可以预测不同种植和管理措施下作物残体、外源有机物料及土壤有机质的矿化,从而对集约耕作条件下土壤有机碳矿化和固持进行评价。

Organic carbon dynamics in intensive agricultural soils is significant for sustainable crop production. Based on the short-, mid-term buried organic material experiments in China’s Huang-Huai-Hai Plain, the CQESTR model is modified with the division of 4 decomposition stages according to the relation between biomass decomposition and cumulative degree days and the biomass type factors in different stages are determined. Through the validation of soil organic matter (OM) by 7 independent long-term soil fertility and fertilizer efficiency experiments in China’s Huang-Huai-Hai Plain, the modified CQESTR model can be used to predict the mineralization of residue, added organic amendment and native soil OM based on cropping and management practices, thus predicting the effect of tillage and crop rotation on organic carbon decomposition and storage in agricultural soils. The modified model provides estimates with a 95% confidence interval of 1.91 g·kg-1 OM and regression coefficient r2 of 0.91 on 1 151 pairs of fitted and observed soil OM from 7 independent fertility experiments in the plough layer. The modified model performs better than the original one.