Changes Of Soil Nutrients In Different Degradation Stages Of Alpine Steppe In Bayanbulak

In this study is based on the alpine steppe in different degraded stages including non-degradation(ND),Light degradation(LD),mid-degradation(MD),and heavy-degradation(HD)of Bayanbulak.Though using the combinative method of field investigation and indoor analysis,organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorous,available potassium,soil moisture and bulk density of degraded grassland were analyzed.And to discuss the change rule of biochemical metrological characteristic of organic matter(C),total nitrogen(N),total phosphorus(P)in degraded grassland.The PCA method was used to screen soil indicators reflected soil fertility and quality,providing a theoretical basis for rational utilization of grassland degradation.The main results are showed as follows:(1)The results showed that the soil organic carbon content in light degradation,mid-degradation and heavy-degradation were decreased by 16.82%?29.14% than non-degradation grassland with the aggravation of grassland degradation.The total N was gradually reduced in non-degradation,light degradation and mid-degradation while increased in heavy-degradation.The contents of total P,available P,available K and available N rose differently while no significant difference in the content of total K.(2)In the degradation process of alpine steppe,the C / N ratio,C / P ratio and N / P ratio of soil 0?10 cm,10?20 cm,20?30 cm decreased.The 0?30 cm soil layer never returned to mild degradation.The carbon and nitrogen ratio,the carbon to phosphorus ratio and the nitrogen and phosphorus ratio of moderate and severe degraded soils were reduced by 1.38%?13.49%,32.90%?38.14% and 38.84%?49.11% respectively.(3)Results showed that organic carbon density and total nitrogen density were significantly reduced with the degradation aggravation and soil layer deepen,and there were obvious differences between degradation degrees(P<0.05).The soil organic carbon and nitrogen density of different soil layers with different degradation degree were higher than alpine grassland.Organic carbon density and nitrogen density declined by52.16%?70.63% in soil layers(0?10 cm?10?20 cm and 10?20 cm)of light degradation,mid-degradation,and heavy-degradation compared to non-degradation grassland.(4)The soil moisture presented increased volatility,but soil bulk density was decreased volatility.All soil nutritive ingredients tested were screened by PCA the correlation analysis method and the stability of the soil factor corresponding to the external variation law are combined.Finally,the soil total nitrogen,available potassium,Soil bulk density as the soil monitor index of Bayanbulak alpine grassland.By PCA the nutrient values of the grassland plant were synthetically evaluated,the results showed that with the Intensity of grassland degradation,the soil nutrient content of decresed gradually.