土地利用方式转变后灰色森林土有机碳矿化的温度响应特征

通过室内培育试验，分析了土地利用方式转变后灰色森林土有机碳矿化过程及其对温度变化的响应特征.结果表明：原始林转变为农田后，0～10 cm、10～20 cm的土壤有机碳和全氮含量分别下降了68.5%、76.8%和40.5%、44.4%;而农田土壤有机碳的平均矿化速率和累积矿化量仅分别为原始林的24.4%～43.2%和9.20％～13.7％.低温条件下（<25 ℃）土壤有机碳矿化的温度敏感性显著高于高温条件下（>25 ℃）.低温条件下（<25 ℃）两种利用方式的土壤有机碳矿化对温度变化的敏感性没有显著差异;但高温条件下（>25 ℃），农田0～10 cm土壤有机碳矿化的温度敏感性高于原始林，而农田10～20 cm土壤有机碳矿化的温度敏感性明显较低.

Temperature sensitivity of organic C mineralization in gray forest soils after land use conversion.

A laboratory incubation test was conducted to study the organic C mineralization in gray forest soils after land use conversion and the temperature sensitivity of the mineralization. It was shown that after the conversion from wildwood land to farmland, the organic C and total N contents in 0〖KG-*2〗-〖KG-*7〗10 cm and 10〖KG-*2〗-〖KG-*7〗20 cm soil layers decreased by 685% and 768%, and 405% and 444%, and the average mineralization rate and cumulative mineralization of soil organic C in farmland were 244%〖KG-*2〗-〖KG-*7〗432% and 920%〖KG-*2〗-〖KG-*7〗137% of those in wildwood land, respectively. At lower temperature (<25 ℃), there was no significant difference in the temperature sensitivity of soil organic C mineralization between the two land use types; while at higher temperature (>25 ℃), this temperature sensitivity in farmland soil was higher in 0〖KG-*2〗-〖KG-*7〗10 cm layer but significantly lower in 10〖KG-*2〗-〖KG-*7〗20 cm layer, compared with that in wildwood land soil.