关键词: 酶学特性, 酶学特性

Abstract: In order to manage and use vegetation resources more scientifically and rationally, the author based on the typical region of Shiyang River in Minqin County cultivated land as the research object, by analyzing the different restoration of distribution and the change of soil nutrient of recovery process of vegetation land in lower reaches of Shiyang River. The results showed that: (1) the content of N fertilizer in the soil with the increasing length of grain for the rising trend in a fluctuant way, but along with the deepening of the soil in the same duration of woodland decreased gradually, 1-10 years after the farmland, mostly for one year from the raw herbs and plants perennial root, the root shallow, the soil N content changed smaller; 15-30 years, 1 year raw herbs was gradually replaced by perennial herbs and shrubs, plant root depth up to 20-40 cm N content change relatively large amplitude; stabilised in 50 years, (2) P content in soil level five different stages were A>B>C>D distribution regularity, the characteristics of 1-10 years after the farmland, the differences of the content of A, B layers P, C, D layers were affected by conversion of time smaller; grain for 15-50 years later, A, B, C, D amplitude phases soil P content changed. (3) In different fixed number of year at all levels, the content of K showed the same regularity as P, namely the general rule of A>B>C>D, 1-30 years after returning farmland, the content of K C D layer increased with fluctuation decreased as the fixed number of year, and A, B layer regularity was not obvious. After farmland 50 years, content of the K tended to be stable.