模拟增温对农田土壤有机碳矿化及腐殖质组成的影响

Effects of Experimental Warming on Organic Carbon Mineralization and Humus Composition in Farmland Soils

在特定气候变化条件下,揭示农田土壤有机碳分解转化规律,对东北粮食主产区研发适应气候变化的农业技术具有重要意义。通过室内培养试验,以吉林省6种主要类型农田土壤为试材,探讨了土壤有机碳矿化及腐殖质组成对温度(10℃、30℃和50℃)变化的响应。结果表明:6种类型农田土壤有机碳累积矿化量和有机碳矿化速率均随培养温度的升高而增加;冲积土和草甸土在低温(10~30 t)的温度敏感性系数(Q10)低于高温(30℃~50℃),而暗棕壤、白浆土、风沙土和黑土则相反;水溶性有机碳(WSOC)含量表现为50℃>10℃>30℃,土壤腐殖质组分的含碳量以及胡敏酸碳/富里酸碳(H AC/FAC)比值随培养温度的升高通常呈降低趋势。这说明,高温(50 ℃)有利于WSOC的积累,但温度升高不利于腐殖质组分碳(HEC)的积累。

Under the conditions of specific climate change,revealing the trend of organic carbon composition and transformation of farmland soils is of great significance to the development of agricultural technology adapting to climate change in the major grain-producing area of Northeast China.With laboratory incubation experiment,we studied the effects of different temperatures(10 ℃,30℃ and 50℃)on organic carbon mineralization and humus composition in six farmland soils of Jilin province.The results indicated that the soil organic carbon accumulative mineralization amount and mineralization rate increased with the increasing incubation temperature in six farmland soils.The temperature sensitivity coefficient(Q10)of alluvial soil and meadow soil in the low temperature ranges(10-30℃)was lower than the high temperature range(30-50℃),but that of dark brown soil,albic soil,sandy soil and black soil was the opposite.Water soluble organic carbon(WSOC)content was in the order of 50℃>10℃>30℃.The carbon contents of humus fractions and the ratios of humic acid carbon and fulvic acid carbon(HAC/FAC)usually tended to decrease with the rise of incubation temperature.These results indicated that high temperature(50℃)is beneficial to the accumulation of WSOC content,but the rise of temperature is not conducive to the accumulation of humus fractions carbon(HEC).