Study On Process Of Ecological Stoichiometry In Hilly Area Of Loess Slope In Abandoned Arable Land

Plant-soil-microbiological characteristics in the process of ecological restoration with different years of leaving uncultivated in typical hilly region of the loess plateau is studied in this project,selecting abandoned farmland,7 years,12 years,17 years,22 years,32 years,total six age limits.There are several analysis indexes,which include plant biomass and diversity,soil plant nutrients,characteristic of microbial diversity and enzyme activity.The main conclusions are as follows:1.Plant diversity increases initially and decreases afterwards in the succession of land abandonment.Meanwhile,biomass and biomass carbon is accumulating,biomass nitrogen and phosphorus decreases initially and increases afterwards.Plant nitrogen and phosphorus contents are deficiency at this stage.2.Soil nutrient decreases initially and increases afterwards in the medium of succession of land abandonment.When nutrient content is in the minimum,and corrosion resistance of soil is the worst accordingly,soil and water loss and soil erosion need be paid special attention in this period.3.Soil water soluble organic matter is different from hot water soluble organic matter in the succession of land abandonment.Insoluble components of hot water soluble organic matter replace ecological function of water soluble organic matter under a certain degree and condition.4 Based on the analysis of ecological stoichiometric enzyme,in the reaction system of 37?.After 30 years of ecological recovery of nitrogen and phosphorus cycles,enzyme activity will be stable to a certain proportion.However,enzyme activity of carbon cycle is still searched for the optimal solution.Catalyst of ecosystem material circulation process does not reach steady state.In addition,to a certain extent,stoichiometric features of enzymes can show resistance of ecosystem.