Study On Soil Ecological Stoichiometey Of Enclosing Life In Typical Steppe

A research conducted on the topical steppe in Taibusi country of theInner Mongolia. It took the neighboring plots principles to study soil organiccarbon, total nitrogen, total phosphorus content and density the13differentenclosed years of natural grass, witch choose the free-grazing as control. Theobjective of the experiment is the ecological stoichiometry in differentenclose years, reveal the instructions significance of characteristics ofecological stoichiometry on grassland degradation and recovery. It canprovide scientific evidences for controlling recovering and boostingproductivity of grassland, and seek the optimal way for recovering ofdegraded grassland.1. The content of SOC, TN, TP in the enclose sample were significantlyhigher than free grazing after severe degradation of the enclosed measures,and have an upward trend with the increase of the enclosed. On14yearsenclose sample, it has the maximum, decreasing trend was cured after theenclosed years continue to increase. By the surface to the underlyingdownward trend, it with different enclosed years of grassland was highlysignificant correlation.2. The density of SOC, TN, TP in the enclose sample were significantlyhigher than free grazing land, and have an upward trend with the increase ofthe enclosed. On14years enclose sample, it has the maximum, respectively,78.02g cm^-2,6.20g cm^-2,1.21g cm^-2, decreasing trend was cured after theenclosed years continue to increase.It were highly significant correlation.Before enclosed14years, they increased after enclosed14years the densityof them are varying degrees of reduction.3. The enclosure14years ago, with the increase of the enclosed life soil wasC/N decreases; after enclosed14years was to rise, until the enclosure22isgreater than the free grazing land. The soil N/P and C/P in Enclosed samplesis less than the free grazing land, with the increase of years of the enclosure.The soil N/P and C/P is reduced. In Free grazing land the N and N/P correlation coefficient was greater than the P and N/P, in enclosed plots it isless than the P and N/P, which can be judged relatively nitrogen-poor, freegrazing land enclosed plots relative P deficiency.4. With the enclosed lifing, the grass and root biomass and its C content isincreased, the maximum is in the14enclosed, after that were decreased；TheN and P content is decreasing, the enclosed14years occurred the minimumvalue, after they increasing. With the increase of the enclosed life the densityof vegetation C, N andP were increased, the maximum respectively in14,25and11year sample of the enclosed, after it reduce trend. Aboveground andunderground root C/N, C/P in enclosed is greater than the free grazing andincreased with the enclosed, the maximum were in enclosed14year sample,and then with the enclosed life increase would have a decreasing trend. Freegrazing land the N/P were less than14indicating that free grazing land by theN limit in nitrogen-poor state, in the enclosed it greater than16, indicatingthat free grazing land by the P limit in phosphorus-poor state.The growing season enclosed recovery measures have a significant impacton soil C, N, P content and its density. Enclosed the density significantquantitative relationship. Instructions enclosed restoration measures ondegraded grassland has a significant role in the recovery. In14yearsenclosed,they reach its maximum, after they have reduce trend, indicating thatthe grass enclosure not be for an indefinite period, should be based ongrassland community growing, the annual climatic conditions and economicdevelopment, ecological protection, and social needs flexibility. Free grazingrelative to nitrogen deficiency, the same conclusion through the analysis onplant ecological stoichiometry has also been obtained through the analysis ofthe soil ecological stoichiometry, enclosed plots relative P deficiency,indicating characteristics of soil ecological stoichiometry grasslanddegradation and recovery also has certain significance.