中文摘要：

采用动态密闭气室分析法,对荒漠草原4种典型植物群落（蒙古冰草群落、赖草群落、甘草群落、沙蒿群落）土壤呼吸进行了测定,运用数理统计的方法得到了枯落物输入对土壤呼吸的贡献量及其与环境因子的关系。结果表明：土壤呼吸日变化呈＂单峰＂曲线,有枯落物输入的土壤呼吸速率显著高于无枯落物输入的土壤呼吸;4种群落枯落物对土壤呼吸CO2的贡献量依次为：甘草群落（0.095g/（m2·h））〉蒙古冰草群落（0.083g/（m2·h））〉赖草群落（0.076g/（m2·h））〉沙蒿群落（0.041g/（m2·h））,枯落物呼吸日贡献量与地表温度呈线性正相关。枯落物呼吸贡献量的季节变化规律呈＂双峰＂曲线,2次峰值分别出现在7月与9月,9月枯落物呼吸贡献量最大,分别为0.13、0.14、0.12、0.12g/（m2·h）;枯落物呼吸季节贡献量与土壤含水量呈线性相关,与土壤表层温度呈对数相关。

英文摘要：

The dynamic closed chamber method, daily and seasonal respiration rates of litters and soil respiration rate before and after the input of litters were measured for four typical plant communities （ Agropyron crisatum,Glycyrrhiza uralensis,Leymus secalinus and Artemisia desertorum） in desert steppe. Contribution of litters’ input to soil respiration and its relationship with environmental factors were obtained statistically. The results showed that the daily soil respiration rate displayed ＂single-peak ＂ curve. The soil respiration rate with input of litters was higher than without. The rank of contribution of litters to soil respiration rate for four plant communities was G. uralensis（ 0. 095 g / （ m 2 ·h） ） 〉 A. crisatum （ 0. 083 g/（ m 2 ·h） ） 〉 L. secalinus（ 0. 076 g/（ m 2 ·h） ） 〉 A. desertorum（ 0. 041 g/（ m 2 ·h） ） . Contribution rate of litter inputting to soil respiration rate correlated positively with temperature on ground surface. The seasonal contribution rate of litters on soil respiration rate for four plant communities exhibited ＂doublepeak＂curve with peak appearing in July and September and highest value recorded in September,i. e. 0. 13,0. 14,0. 12,0. 12 g / （ m 2 ·h） . The seasonal contribution rate of litters on soil respiration rate is positively related with soil water content and logarithmically with temperature on ground surface.