土壤CO_2浓度变化及其影响因素的研究

STUDY OF CO_2 CONCENTRATION CHANGES IN SOIL PROFILE AND ITS AFFECTING FACTORS

以无锡地区典型水稻土稻麦轮作田为对象,研究和讨论了农田不同层次和时间土壤空气中CO2浓度变化规律,以及温度、降水、环境CO2浓度升高和作物生长对土壤CO2浓度变化的影响。结果表明:农田土壤空气CO2浓度变化与土壤温度变化密切相关,土壤温度升高会导致土壤CO2浓度上升;较大的降雨会闭塞土壤直接向大气排放CO2的通道,导致短期内在土壤浅层出现较高的CO2浓度分布;作物生长会导致CO2在土壤中累积,在小麦生长季内,0～30cm土壤CO2浓度廓线跟小麦根系生长密切相关;大气CO2浓度升高200±40μmol/mol使15cm土层的土壤CO2浓度提高12%±3%。

The dynamics of the concentration of soil CO_2 in different layers of a rice-wheat rotation field in Wuxi and at different time was monitored and the influences of temperature, precipitation, environmental CO_2 concentration and crop growth on soil CO_2 were studied. The results showed that the diurnal changes of CO_2 concentration in soil air followed a sinusoidal pattern similar to that of soil temperature. Soil CO_2 concentration rose with soil temperature. Heavy rainfall tended to close the air voids open to the atmosphere, resulting in a short-term increase in CO_2 concentrations in the shallow layer of the soil. Crop growth induced CO_2 accumulation in the soil. During the season of wheat growth, the concentration of soil CO_2 in the 0～30 cm layer was closely related to wheat growth. An increase in atmospheric CO_2 concentration by 200±40 μmol/mol enhanced CO_2 concentration in the 0～15 cm soil layer by 12%±3%.