Abiotic and Biotic Factors in Litter Decomposition in a Sermiarid Grassland

Decomposition of grass leaf litter was studied on a shortgrass prairie using chemicals (HgCl 2 and CuSO 4 ) to prevent microbial activity (abiotic treatment), 53—μm nylon mesh to exclude mesofauna (microbial treatment), and l—mm nylon mesh to allow the access of mesofauna. After 9 months, 15.2% of the blue grama grass litter was decomposed in the microbial treatment, and 29.4% was decomposed in the microbial plus mesofaunal treatment. After 7 months, 6.2% of the litter had disappeared from the abiotic treatment. There was a general decrease in C:N ratios with the microbial treatment lowest at the end of the experiment. Total available carbohydrates generally decreased with time. Certain mite families fluctuated with seasons. The tydeids were most active in winter and tetranychids were most active in summer. A correlation between abiotic factors and mite families was also observed.