In order to explore the effects of different grazing intensities on soil nitrogen conversion rate and nitro-gen use in alpine meadow in spring(March to June),the vegetation characteristics,soil physicochemical prop-erties and soil nitrogen content change characteristics of alpine meadow under five grazing intensities,namely forbidden grazing(CK),light grazing(LG),moderate grazing(MG),heavy grazing(HG)and Severely degraded grazing(SG),were investigated and analyzed by alternating grazing methods of yak and Tibetan sheep.The results showed that with the increase of grazing intensity,vegetation coverage,height,aboveg-round biomass and soil water content decreased,while belowground biomass,soil bulk density,compactness and soil temperature increased.The contents of total nitrogen and ammonium nitrogen in soil were the highest under LG treatment,and the nitrate nitrogen showed a decreasing trend as a whole.The net nitrogen mineral-ization rate,ammonization rate and nitrification rate of soil with different grazing intensities were the highest under LG treatment.The redundancy analysis of soil nitrogen use and vegetation characteristics and soil traits showed that soil factors were the main driving factors of nitrogen use.The results of entropy weight-TOPSIS ranking showed that soil nitrogen use was LG>MG>HG>CK>SG.In conclusion,soil nitrogen use was the highest under the light grazing treatment of alpine meadow in spring.
关键词
春季放牧/放牧强度/转化速率/土壤氮利用
Key words
Spring grazing/Grazing intensity/Conversion rate/Soil nitrogen utilization
维普
万方数据