Effects Of N And P Additions On Vegetation And Soil In Degraded Alpine Steppe

Taked the slightly degraded alpine grassland in the Qinghai Lake Basin as the research object,through addition of N and P fertilizers,the plant community structure,productivity performance,plant leaf nutrients,soil nutrients were used to explore the ecological stoichiometry characteristics of plant leaves and soil between N and P in the alpine grassland,to study the effects of different N and P fertilizer additions on vegetation and soil of the alpine grassland.The results were as follows:1.N and P fertilizers can significantly increase the important value of gramineous plants,The effect of N fertilizer was higher,P fertilizer can significantly increase the important value of legumes(P<0.05).the species richness index decreased with increasing fertilization,Shannonwiener index and uniformity index have no significant effect.2.The addition of N and P fertilizers significantly increased the productivity of alpine grassland,The effect of N fertilizer was higher,The total biomass showed a parabolic increase first and then decreased(P<0.05).From 2017 to 2019,the total aboveground biomass of N and P application increased by 7.12%?34.67%,14.93%?45.83%,4.12%?26.45% respectively,the economic income in 2017 and 2018 first increased and then decreased,in 2019 it continued to increase.3.N fertilizer can increase the N: P ratio of plant leaves,and P fertilizer can reduce the N: P ratio of plant leaves;The explanation of the variation of N: P ratio of plant leaves was more than 50%,which indicated that the N: P ratio of plant leaves was mainly affected by P content.4.There were a significant correlations between total phosphorus and available phosphorus content,soil total nitrogen and ammonium and nitrate nitrogen in soil,The correlation coefficient between available P and total P was the highest(R2 = 0.628);N and P fertilizers did not affect the soil environment pollution.