Impact of Land Cover on Temperature and Moisture Sensitivity of Soil Organic Matter Mineralization in Subtropical Southeastern China

土地利用方式对中国东南部亚热带地区土壤有机质矿化的温度和湿度敏感性的影响(英文)

Understanding the temperature and moisture sensitivity of soil organic matter （SOM） mineralization variations with changes in land cover is critical for assessing soil carbon （C） storage under global change scenarios We determined the differences in the amount of SOM mineralization and the temperature and moisture sensitivity of soils collected from six land-cover types, including an orchard, a cropland, and four forests, in subtropical south- eastern China. The responses of SOM mineralization to temperature （5, 10, 15, 20, and 25~C） and moisture （30%, 60%, and 90% of water-holding capacity [WHC]） were investigated by placing soil samples in incubators. Soil C mineralization rate and cumulative C mineralization were higher in orchard and cropland soils than in other forest soils. With increasing temperature, soil C mineralization rates and cumulative C mineralization increased with the rise of WHCo The temperature sensitivity of soil C mineralization was not affected by land-cover type and incubation moisture. All soil temperature treatments showed a similar response to moisture. Cropland soil was more respon- sive to soil moisture than other soils. Our findings indicate that cropland and orchard soils have a higher ability to emit CO2 than forest soils in subtropical southeastern China.

理解不同土地利用方式下土壤有机质矿化的温度和湿度敏感性的变化对于估计全球变化背景下土壤碳贮存是十分重要的。我们采集了位于中国东南部亚热带地区的果园、农田和四个不同森林类型的土壤,测定了土壤有机质的矿化量及其对温度和湿度的敏感性。通过室内培养的方法,我们获得了土壤有机质对不同温度(5、10、15、20和25°C)和湿度(土壤持水量的30%、60%和90%)的响应。结果表明,果园和农田土壤的碳矿化速率和累积量高于森林土壤。随着培养温度的增加,土壤碳矿化速率和累积量显著增加,随着土壤持水量的降低而减小。土壤碳矿化的温度敏感性不受土地利用类型和培养湿度的影响。在所有的温度处理下,土壤都表现出相似的湿度响应。相比于其它土壤,农田土壤对土壤湿度更加敏感。我们的发现表明,在中国东南部亚热带地区农田和果园土壤比森林土壤有较高的CO2释放的能力。