稻田土壤理化特性对CH4排放的影响

通过对8个稻田土壤的培养实验，研究了土壤特性在水分和小麦秸杆两因子两水平处理下对甲烷排放的影响。相关分析结果表明，各处理下的甲烷排放量均与土壤砂粒含量成正比（p<0.01）。逐步回归分析表明，在淹水条件下，无论施加小麦秸杆与否，甲烷排放量均可通过土壤砂粒含量和C/N比的线性组合得以定量表述，其决定系数（R

Influence of paddy soilproperties on CH4 emissions

Under the flooded and saturated conditions, eight paddy soil samples were incubated at 25 ℃ for 20 days to identify the key parameters influencing methane emission in terms of soil properties. Two treatments of no organic matter input and with additional winter wheat straw input were set up for each water regime. Correlation analysis indicated that CH4 emission rate is positively related to soil sand content for all cases（p<0.01）. Results from a stepwise regression analysis suggested that CH4 emission could be quantitatively described by a linear combination of soil sand content and the ratio of soil C/N under the flooded condition. Values of the determination coefficient (R 2) are 0.991*** and 0.985*** for the control and with additional winter wheat straw input, respectively. Under the saturated condition, CH4 emission from the control could be also quantitatively described by a linear combination of these two soil parameters （R 2=0.898**）, while that from the treatment of wheat straw input was only found to be positively correlated with the soil sand content（R 2=0.776**）