Litter decomposition rates and influencing factors of four typical plant communities in desert steppe

Abstract

Litter is the important components of grassland ecosystem, and plays an important role in grassland, influencing ecosystem structure, process and functioning. Litter accumulation can change the nutrient availability and modify local physical environmental conditions, and litter of grassland has gradually become one of the important issues in grassland ecology, but the factors related to the decomposition litter and litter decomposition rates in desert steppe is still unknown. In this study, four typical plant litters of desert steppe, Glycyrrhiza uralensis, Leymus secalinus, Agropyron crisatum and Artemisia desertorum communities were selected in Yanchi Country of Ningxia, and the loss rate of litter mass, the chemical composition, the water content of four typical plant communities were measured, and climatic factors and their partial http: / / www.ecologica.cn correlations were analyzed, and statistics and numerical taxonomy methods were used to identify the effects of litter accumulation. The results showed that the loss rate of litter mass was increased with decomposition time. However, the relationship between the loss rate of litter mass and decomposition time was not linear correlation. The loss rate of litter mass of four typical plant communities was Glycyrrhiza uralensis community > Leymus secalinus community > Agropyron crisatum community>Artemisia desertorum community. The litter decomposition rates of desert steppe was best represented by the he Olson model of single exponential decay, and the litter decomposition rate of Glycyrrhiza uralensis was the fastest, while the Artemisia desertorum was the slowest. The contents of N, P, K of litters of Agropyron crisatum, Leymus secalinus and Glycyrrhiza uralensis communities were significantly higher than Artemisia desertorum community, but contents of C, lignin, cellulose, and rates of C 颐 N and lignin 颐 N and cellulose 颐 N were significantly lower than litter of Artemisia desertorum community. The decomposition rates of four plant communities was positively correlated with the initial contents of N,P,K in litters,. Partial correlation analysis results showed the decomposition rates of four plant communities was significantly correlated with rainfall and the water content of litter. It was concluded that litter decomposition was complex physical and chemical and biological processes, which Influenced by many factors, and plant species was an major factor decisioned the rate of decomposition. The contents of 50% of litters decomposed in desert steppe was about 2-5 years, while 95% was about 8-24 years, which could provide scientific basis for the response and adaptation mechanism of grassland on the environmental factors and adaptation strategy.