锡林河流域一个放牧草原群落中根系呼吸占土壤总呼吸比例的初步估计

SEPARATING ROOT AND SOIL MICROBIAL CONTRIBUTIONS TO TOTAL SOIL RESPIRATION IN A GRAZED GRASSLAND IN THE XILIN RIVER BASIN

采取根系生物量梯度上土壤呼吸变化趋势线外推法对锡林河流域一个放牧羊草 (Leymuschinensis)群落中根系呼吸占土壤总呼吸的比例进行了估计。结果表明 :在测定年度整个生长季的不同月份 ,该群落中根系呼吸量占土壤呼吸总量的比例在 15 %～ 37%之间 ,平均为 2 4%;根系呼吸所占比例较高的月份与根系生长的高峰期基本一致 ,均出现在 6月中旬和 8月上旬 ;上述结果与国外同类研究结果相比 ,具有很好的一致性。

The contribution of root respiration to total soil respiration was examined in a grazed steppe grassland in Inner Mongolia. From respiration data based on CO 2 uptake by NaOH and corresponding root biomass values for each of 10 plots, a linear regression of CO 2 rates on root dry weights was calculated for every ten days. By extrapolating the regressive line to zero root biomass, the proportion of the total soil respiration flux that is attributable to live root respiration was estimated to be 24% on average, ranging from 15% to 37% in the growing season. The larger proportional values appeared in the same period of the season as that of the peak values of root growth, both of which occurred in mid_June and early_August respectively.