长期施肥对冬小麦/夏玉米轮作下土壤呼吸及其组分的影响

为阐明施肥对农田土壤呼吸的影响,于2002年6月至2003年6月在河南封丘潮土上进行的长期试验地上测定了玉米/冬小麦轮作系统下的土壤呼吸,分析了土壤呼吸与土壤水分和温度的关系,并利用统计分析方法研究了土壤呼吸各组分的贡献。土壤呼吸变化与作物生长发育规律一致,施肥通过影响作物的生长发育而对土壤呼吸产生影响。不同作物生长期,根际呼吸、土壤原有机质以及前作根茬和有机肥中碳对土壤呼吸的贡献不同。玉米期土壤有机质、根际呼吸、前作根茬和有机肥中的碳对土壤呼吸的平均贡献率分别为70.19%、19.43%和10.37%;而小麦生长期则分别为23.75%、62.26%和14.11%。由于不同施肥处理的作物生长量、土壤有机质含量以及前作根茬和有机肥施入而进入的有机碳量不同,造成土壤呼吸个体上存在着较大差异。土壤有机质的消耗主要发生在玉米生长阶段。

Effect of long-term fertilization on soil respiration flux and its components under winter wheat/summer maize rotation

To understand the influence of fertilization on soil respiration,a long-term experiment,in a fluvo-aquic soil in Fengqiu County,Henan Province,was conducted to monitor soil respiration under the rotation system of winter wheat/summer maize from June 2002 to June 2003.The relationship between soil respiration and soil water and temperature,and the contributions of soil respiration components were analyzed by statistic method.Fertilization influenced crop growth and caused the differences in soil respiration among the plots under different fertilization treatments,but the seasonal variation of soil respiration nearly coincided with crop growth.Contributions to soil respiration from rhizosphere respiration,heterotrophic respiration of intrinsic organic matter and decomposition of organic carbon in stubble of pre-crop and manure were different in different crop growth periods.The average contributions during maize growth season from the rhizosphere respiration,heterotrophic respiration of intrinsic organic matter and decomposition of organic carbon in stubble of pre-crop and manure were 19.43%,70.19% and 10.37%,respectively,whereas 62.26%,23.75% and 14.11% during wheat growth season,respectively.There were enormous differences in soil respiration among different fertilization treatments.Consumption of soil organic matter occurred mainly in maize growth period.