Abstract: As one of the most important ecosystem processes, litter decomposition is closely related to plant nutrients, ecosystem productivity and carbon and nutrient cycling, particularly to soil organic carbon pool-size and its stabilization. During last decades, numerous studies on litter decomposition in moist environment was conducted. However, there was few information about litter decomposition in arid area. Litter decomposition in arid area is different from that in moist environment owing to severe natural climate, such as sporadic rainfall, intense solar radiation, long-term drought and serious water loss and soil erosion. In recent studies, it was found that there is a discrepancy between simulated decomposition rates and measured ones in arid area. It is considered that ephemeral plants are important for net primary productivity in some deserts, and particularly for soil carbon input. The aims of this study are to investigate the dynamic status of litter decomposition of three typical desert species. Litter bag method was used to investigate the decomposition rate and nutrient release of roots, stems and leaves of Eremurus inderiensis, Erodium oxyrrhynchum and Seriphidium santolinum. Mass loss curves of leaves, stems and roots of these species were well described by an exponential decay model. Mass loss rates of leaves and roots of E. inderiensis, leaves, stems and roots of E. oxyrrhynchum, stems and roots of S. santolinum were 41.96%, 81.94%, 42.18%, 29.32%, 47.02%, 20.66% and 20.71% respectively. During the 364day decomposition in field, the decomposition rates were different from different species litters, and they were in an order of roots > leaves of E. inderiensis, roots > leaves > stems of E. oxyrrhynchum and roots > stems of S. santolinum. N and P release was observed throughout the decomposition process, N and P contents in litters were negatively correlated with mass loss. In addition, decomposition rate was significantly different at different decomposition stages. In conclusion, the decomposition rates of litters of desert ephemeral plants were high, and the decomposition time and litter types are the important factors of decomposition in arid area.

Key words: desert ecosystem, ephemeral plant, litter, decomposition, nutrient, Gurbantunggut Desert