The effect of different grazing systems on soil nutrient contents in dessert steppe

The effect of different grazing systems,including continuous grazing system,rotational grazing system and banning grazing system,on soil nutrient content was discussed in the paper,based on 7 years grazing experiments in desert steppe.The results showed that soil nutrient contents were affected by different grazing systems obviously.The ratio of carbon to nitrogen was decreased.The contents of organic matter,N,total K and available K were increased by rotational grazing and banning grazing.At the same time,different grazing systems also affected the change trend of soil nutrient contents with soil depth.The available N,available K decreased with soil depth in different grazing systems.With the increase of soil depth,the total N content increased in banning grazing system,the total P content increased in continuous grazing system,and the available P,total K decrease in rotational grazing system.The fitting curve was quadratic power function between soil nutrient contents and soil depth.The results implied that rotational and banning grazing would increase soil nutrient contents and restrained the degradation of soil in desert steppe.