青海东部地区地膜覆盖条件下土壤有机碳矿化对温度变化的响应

Responses of soil organic carbon mineralization to temperature change under the plastic film mulching in eastern Qinghai

本研究通过春玉米田间地膜覆盖试验,结合室内有机碳矿化速率培养实验,采用不同温度(10、15、20、25和30℃)进行室内培养,研究了青海东部地区无膜和覆膜两种栽培措施下土壤有机碳矿化对温度变化的响应规律。结果表明:在设定的温度范围内,无膜和覆膜处理条件下各土层土壤有机碳矿化速率均随着温度的升高呈指数增加,而随着土层深度的增加而减小;覆膜处理各土层土壤有机碳矿化速率、CO2释放量和分配比例均大于无膜处理;各土层土壤有机碳矿化速率温度敏感性(Q10)存在一定程度的变异,其中无膜处理Q10在1.564~1.817之间,覆膜处理Q10在1.465~1.790之间;土壤有机碳矿化速率随着土壤有机碳含量的增加而增大,但随着土壤全氮含量的增加土壤C/N比逐渐减小,土壤有机碳矿化速率也逐渐减小,由此推断土壤中氮素含量的增加可能会对土壤有机碳矿化速率产生抑制效应。

In this study,the responses of soil organic carbon mineralization to temperature change(10,15,20,25 and 30℃)were studied under two different cultivation methods of mulching and no mulching in the eastern part of Qinghai Province.The results showed that the mineralization rate of soil organic carbon increased exponentially with the increase of temperature,but decreased with the increase of soil depth.The mineralization rate,CO2 emission content and distribution ratio of soil organic carbon in different soil layers were higher than those in no mulching treatment.There was a certain degree of variation in the sensitivity of soil organic carbon mineralization rate of different treatments,among which the Q10 value of no mulching treatment was between 1.564 and 1.817,and that of film mulching treatment was between 1.465 and 1.790.The mineralization rate of soil organic carbon increased with the increase of soil organic carbon content,but with the increase of soil total nitrogen content,the C/N ratio of soil decreased gradually,and the mineralization rate of soil organic carbon also decreased gradually.So it was concluded that the increase of nitrogen content in soil may have an inhibitory effect on the mineralization rate of soil organic carbon.