放牧制度对荒漠草原生态系统土壤养分状况的影响

从土壤N,P,K及土壤有机质等方面研究了在连续进行了7 a的放牧制度试验对荒漠草原生态系统土壤养分含量的影响。研究结果表明:放牧制度对土壤的养分状况有明显的影响。划区轮牧区和禁牧提高了土壤有机质、土壤氮素、土壤全钾和土壤速效钾含量。土壤表层磷含量划区轮牧区最高。放牧导致碳氮比减少。同时,土壤养分含量随土壤深度的变化在不同处理没有表现出较为一致的变化趋势。禁牧区土壤全氮含量随土壤深度的增加而增加;不同处理土壤速效氮、土壤速效钾含量均随土壤深度的增加逐渐降低;土壤全磷在自由放牧区随土壤深度的增加逐渐升高;土壤速效磷、全钾含量在划区轮牧区随土壤深度的增加逐渐降低;土壤养分含量与土壤深度的拟合曲线为二次幂函数。研究表明,禁牧和划区轮牧较自由放牧可以提高荒漠草原土壤养分元素的含量,有利于遏制草原土壤的退化。

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.