Abstract: The objective of the current study is to reveal the changes of soil microbial functional diversity in the artificial grassland with different cultivation periods in the ThreeRiver Headwater Region, so as to provide evidence to ameliorate the degraded alpine meadow based on the efforts of planting artificial grassland. Three artificial grasslands with cultivation durations of 4, 8 and 12 years were selected. Soil nutrients and microbial functional diversity were determined using conventional laboratory analysis and the BiologECO microplate method. In the 0-10 cm soil layer, soil pH and total nitrogen (TN) content were significantly greater with 4 cultivation years than with the other cultivation years, while total potassium (TK) and available nutrients increased with increasing cultivation years (P<0.05). In the 10-20 cm soil layer, soil pH was significantly higher in 4-year grassland than in the other grasslands, while TK in 12-year grassland was significantly lower than in the other grasslands (P<0.05). Additionally, available nitrogen (AN) and available potassium (AK) showed the following pattern: 8 years > 12 years > 4 years. In the 0-10 cm soil layer, average well color development (AWCD) value showed 8 years > 12 years > 4 years. But AWCD value increased with increasing cultivation years in the 10-20 cm soil layer. Soil microbial functional diversity showed that Shannon and Pielou index in 0-10 cm soil layer of the 12-year grassland were lowest, while in the 10-20 cm soil layer the least values were found in the 4-year grassland. McIntosh index increased with increasing cultivation years in the 10-20 cm soil layer. Principal component analysis (PCA) showed that amino acids were the main carbon source for maintaining soil microbial community. Redundancy analysis (RDA) indicated that soil organic carbon (SOC), TK, AN, AK and pH were the main factors influencing the metabolic rate of soil microbial community and microbial functional diversity. In summary, there were differences among soil microbial functional diversity in the artificial grasslands of different cultivation durations. Soil nutrient content, soil microbial community stability and ecological environment improved with increasing cultivation years.

Key words: habitat, litter, Horqin Sandy Land