摘要
根据静态气室法对大针茅（ＳｔｉｐａｇｒａｎｄｉｓＳｍｉｒｎ）草原整个生长季土壤呼吸和地表凋落物分解释放ＣＯ２量的测定结果，分析了大针茅草原土壤呼吸和凋落物分解速率的季节动态，并探讨了其与地上、地下生物量及环境因子的关系。结果表明：（１）在整个观测期内，大针茅草原由土壤呼吸和地表凋落物分解所释放ＣＯ２速率的季节动态呈梯形曲线，８月下旬达到最大值２．５１ｇＣ·ｍ－２·ｄ－１；（２）ＣＯ２排放速率的季节变化趋势与地上生物量，尤其是地上绿色生物量部分的季节动态有一定同步性，而与地下生物量的季节变化趋势不同步，甚至相反；（３）地表凋落物层有减缓土壤向大气排放ＣＯ２的作用；（４）土壤呼吸和地表凋落物分解释放ＣＯ２的速率（ｙ）与土壤湿度（ｘ）显著相关，其对数回归模型为：ｙ＝３．４６９ｌｏｇ１０ｘ－２．０５３（ｒ＝０．９２，Ｐ＜０．０１）。
Based on the measurement of the CO 2_release rate of soil respiration and litter decomposition in Stipa grandis Smirn steppe in Xilin River Basin, Inner Mongolia, the authors analyzed the seasonal dynamic pattern of soil respiration and litter decomposition and their relation to the aboveground biomass, belowground biomass and environmental factors. The results were as follows: (1) The seasonal dynamic pattern fit nearly a trapezoidal curve and the highest CO 2_release rate appearing in the late August was 2.51 gC·m -2 ·d -1 ; (2) The seasonal dynamic pattern of CO 2_release rate was generally consistent with that of the aboveground biomass, especially with the green aboveground biomass, but was not consistent with or even contrary to that of the belowground biomass; (3) The litter layer on the soil surface could slow down the emission of CO 2 from soil to atmosphere; (4) The soil moisture ( x ) was highly correlated with the CO 2_release rate ( y) , which could be described by a logarithmic regression model: y =3.469log10 x -2.053 ( r =0.92, P <0.01).
基金
国家自然科学基金重大项目
关键词
大针茅草原
土壤呼吸
凋落物分解
生物量
Stipa grandis steppe, Soil respiration, Litter decomposition, Aboveground biomass, Belowground biomass
