Content of soil organic matter and its relationships with main nutrients on degraded alpine meadow in Eastern Qilian Mountains

The content of soil organic matter (SOM) of alpine meadow with different degraded degrees in Jinqiang River area of Eastern Qilian Mountains was measured and its relationships with the contents of soil total phosphorus (TP), total nitrogen (TN), available phosphorus (AP) and available nitrogen (AN) were studied. The results indicated that the contents of OM, TN and AP decreased along with the degradation degree within 0 to 20 cm. However, the content of TP showed an increasing and then decreasing trend along with the degradation degree. And the content of AN showed an increasing trend. The change of each nutrient was significant at 0.01 level. Under light degradation, the content of soil OM had no significant correlation with other four nutrients. Same results were obtained with mediate degradation and heavy degradation. But took the three degraded alpine meadow as a whole, OM was significant (P0.01) respectively correlated with TN, AN and AP except TP. Under a relatively large scale, OM could be used as the indicator of soil nutrition status. When studying and estimating soil nutrient condition of alpine meadow, temporal and spatial heterogeneity and scale should be addressed.