植被恢复过程中土壤养分的变化

在纸坊沟流域不同退耕年限的区域采集表层0~20 cm土样274个,分析了不同植被及其退耕年限下的土壤养分变化规律。结果表明,退耕后林草覆盖下的土壤有机质和全氮含量有所增加,特别是刺槐林地增加幅度较大,全磷含量变化不显著,草地覆盖下土壤的速效氮含量低于农田速效氮含量;土壤有机质、全氮、全磷、硝态氮和铵态氮随退耕年限增加呈现出先减少后增加的趋势;退耕年限与土壤有机质和全氮存在显著的正相关性。

Influence of the Vegetation Restoration Process on Nutrient in Zhifanggou Watershed

In order to understand the nutrients change after vegetation restoration process and provide the scientific and technical support for the comprehensive treatment of vegetation in Loess Plateau,we took 274 soil samples with different vegetation restoration times in Zhifanggou Watershed and analyzed the nutrients of these samples.The result was that after vegetation restoration the content of organic matter and total nitrogen kept increasing along the increment of vegetation restoration time,especially for those covered with Robinia pseudoacacia.The change of the content of total phosphorus was not very prominent.Because of the influence of people the rapidly available nitrogen of grass was less than farmland.In the first year,the changes of organic matter,total nitrogen,nitrate nitrogen and ammonium nitrogen along the increment of vegetation restoration time kept reducing and then kept increasing.The result of the correlation between the nutrient and vegetation restoration time was that the vegetation restoration time and soil organic matter,total nitrogen had prominent correlation.The organic matter and total nitrogen had significant correlation.The nitrate nitrogen and total nitrogen,ammonium nitrogen had prominent correlation.The correlation between the total phosphorus and other nutrients was not very prominent.