基于DNDC模型模拟的冬小麦田土壤有机碳和作物产量对地表覆盖的响应

依托前期长期定位试验,基于DNDC过程模型,对秸秆和地膜覆盖条件下冬小麦田土壤有机碳和小麦产量的长期变化规律进行了模拟研究.结果表明,DNDC模拟的有机碳含量和冬小麦产量变化与田间观测结果较一致,能较理想地模拟两种覆盖措施对土壤有机碳和作物产量的长期影响.模拟结果显示,在50 a时间尺度上,不覆盖与地膜覆盖处理下0～5...

Responses of soil organic carbon and crop yield to surface mulching with straw and plastic film in winter wheat field using DNDC model

The long|term trends of winter wheat field soil organic carbon (SOC) and crop yield to straw mulching and plastic film mulching were modelled using the Denitrification|decomposition (DNDC) model based on a winter wheat mulching field experiment on the Loess Plateau of China. Strong consistence was found between the modelled values with field observations for both SOC and yield, indicating that DNDC was a useful tool to test the long|term effects of surface mulching on these two indicators. At a 50-year scale, the SOC content at 0~50 cm depth showed a downward trend under no mulching and plastic film mulching, with an average annual change of -11.3 kg·hm^-2 and -25.2 kg·hm^-2, respectively. On the contrary, the SOC content presented an increasing trend under straw mulching at rates of 4 500 kg·hm^-2 and 9 000 kg·hm^-2, with an average annual change of 116.3 kg·hm^-2 and 256.9 kg·hm^-2, respectively. It was manifested as a trend of more increments in the first 5 years, and a decrease in later increments and reaching equilibrium in the 40~50 years. The simulated wheat yield ranged from 5 713.3 kg·hm^-2 to 7 046.7 kg·hm^-2. Compared with no mulching, wheat yield increased by 2.7%, 9.8% and 13.4% with plastic film mulching, and straw mulching at 4 500 kg·hm^-2 and 9 000 kg·hm^-2 averaged across 50 years, respectively. There was a significant positive correlation between the modelled SOC content and wheat yield. In general, compared with no mulching, plastic film mulching and straw mulching could be a reliable management practice for long|term carbon sequestration and yield increase in the dryland agricultural systems on the Loess Plateau.