[Effects of regulation measure on soil and microbial biomass of moderately degraded alpine meadow in Qilian Mountain, China].

We examined the effects of different regulation measures (spring rest grazing, spring rest grazing-cutting turf, spring rest grazing-cutting turf-fertilization, spring rest grazing-cutting turf-sowing, spring rest grazing-cutting turf-fertilization-sowing) on vegetation, soil physical and chemical properties, and soil microbial biomass in mode-rately degraded alpine meadow in Qilian Mountain. The results showed that all the regulation measures significantly increased plant coverage and aboveground and underground biomass of degraded alpine meadows. Plant species richness increased significantly under the two measures of spring rest grazing-cutting turf-fertilization and spring rest grazing-cutting turf-fertilization-sowing. The dominant species of spring rest grazing-cutting turf-sowing and spring rest grazing-cutting turf-fertilization-sowing was cv. Qinghai. Soil pH and bulk density in moderately degraded alpine meadow (control) were significantly higher than those of all regulation measures. Soil water content, soil organic carbon, total nitrogen and total potassium, carbon-nitrogen ratio and nitrogen-phosphorus ratio of spring rest grazing-cutting turf-fertilization-sowing measures were the highest, which were 21.3%, 22.30 g·kg, 2.77 g·kg, 19.93 g·kg, 8.3 and 3.5, respectively. Soil microbial biomass nitrogen and phosphorus (104.98 and 40.74 mg·kg) of degraded meadows under spring rest grazing-cutting turf-fertilization-sowing measures were significantly higher than those of other measures, while soil microbial biomass carbon (240.72 mg·kg) of degraded meadows under spring rest grazing-cutting turf-fertilization measures was significantly higher than that of other measures. The results of radar map showed that the regulation measures affected the characteristics of degra-ded meadow vegetation (aboveground and underground biomass), soil physical and chemical properties (water content, organic carbon, total nitrogen, total phosphorus, and total potassium) and soil microbial biomass (carbon, nitrogen and phosphorus). Spring rest grazing-cutting turf-fertilization-sowing measures had the best performance in restoraing degraded meadows in the study area.