Effects of litter input of four typical plant communities on soil respiration in desert steppe

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/(m2•h)）A.crisatum（0.083 g/(m2•h)）L.secalinus（0.076 g/(m2•h)）A.desertorum（0.041 g/(m2•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 “doublepeak” 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/（m2•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.