Soil Eco-enzyme Stoichiometry And Evolutionary Characteristics Of Dominated Bological Taxa In Vegetation Succession

Due to the direct intervention of human activities,the ecological environment of the Loess Plateau has undergone unprecedented changes,making it one of the most vulnerable regions in China.Therefore,it is of great practical significance to study the vegetation restoration process in the Loess Plateau.In this study,six restoration stages in the restoration process of Ziwuling mountain:farmland,grassland,shrub,pioneer forest stage,mixed forest and top community stages were studied to simulate vegatation secondary succession process.By research soil enzyme activity measurement,soil nematode,soil AMF and nirH microbial communities and soil enzyme kinetic parameters,The main conclusions are as follows:?1?During the process of vegetation restoration,the soil enzyme activity in the later stage of vegetation restoration was significantly higher than that in the previous stage?P<0.05?,but the activities of soil enzyme BG,LAP and ALP decreased with the vegetation restoration process under the unit MBC.The microbial metabolic activity of vegetation restoration gradually decreased;all stages of vegetation restoration process had different degrees of N limitation,and the soil microbial N nutrient limitation became weaker and weaker,and P nutrient limitation became stronger.?2?During the process of vegetation restoration,the diversity index and pielou index of soil nematodes is slowly increasing,and the SR index is decreasing.The metabolic footprint of forest land in the later recovery stage of soil nematodes is greater than other recovery stages,in the top community.During the evolution,the fungal passages weakened and the bacterial passages became stronger.?3?Vegetation restoration significantly changed chao1 and phylogenetic diversity of soil arbuscular mycorrhizal fungi,but had no significant effect on soil nirH community?P<0.05?.Redundancy analysis showed that NO₃^--N is a common influencing factor for the diversity and abundance of arbuscular mycorrhizal fungi and nirH microbial communities.Vegetation restoration significantly changed the soil arbuscular mycorrhizal fungi and nirH microbial community structure.TP and NO₃^--N were the common driving factors for soil arbuscular mycorrhizal fungi and nirH microbial community structure changes.?4?The soil enzyme kinetic parameter Km decreased during the vegetation restoration process,and the sensitivity to temperature was enhanced.The affinity of soil enzymes to the substrate became stronger,which had little effect on the catalytic efficiency of soil enzymes.