Abstract: Environment and biota are two dominant factors to affect litter decomposition, and changes in microenvironment and microbial community can influence the process of litter decomposition. Biological Soil Crusts (BSCs) are common in arid land, and are important biological cover on desert surface. BSCs can deeply affect the soil physicochemical characteristics. However, whether BSCs presence affects litter decomposition need to be further studied. In this study, 8 widespread plant species in Gurbantunggut Desert were selected, such as Haloxylon persicum, Haloxylon ammondendron, Artemisia ordosica, Chondrilla piptocoma, Aristida pennata, Salsola ruthenica, Salsola affinis and Bassia hyssopifolia. We examined the effects of soil surface with and without BSCs on mass loss rates and decopomsition rates of 8 species with litter bag methods. We put litters of the 8 species on desert surface (with and without BSCs) for 280 days. Our results show that both BSCs and species had significant effects (P<0.01) on litter decomposition. The litter mass loss rate was 13.67%-64.56% for soil surface covered by BSCs and 13.58%-54.13% for removing BSCs. The presence of BSCs on soil surface reduced the time period of decomposition (semi and 95% decomposition time) and the magnitudes were different among species. The effects of BSCs on litter decomposition were mediated by initial contents in litters. Our results indicate that BSCs can accelerate litter decomposition and the effects were different with changes in species.

Key words: biological soil crusts, desert plants, litter decomposition, Gurbantunggut Desert