Characteristics Of Large Soil Animals Communities And Soil Quality Evaluation In Shenmu Sabina Vulgaris (Ant.) Nature Reserve

In this study,soil animals communities and soil physical and chemical properties under the Sabina vulgaris(Ant.)community in Shenmu County Nature Reserve in Shaanxi were selected as the research object.Nine typical plots were selected to collect soil samples and soil large soil animals.Based on the determination of soil physical and chemical properties,identification of large soil animals community composition,and analysis of the interaction between the two indicators,the membership value of soil animals and soil physical and chemical properties were calculated.Using the principal component method to comprehensively evaluate the soil quality of the sample plot.This research aims to clarify the improvement effect of Sabina vulgaris(Ant.)community on sandy land restoration,in order to provide data support and theoretical basis for ecological restoration and reconstruction of windy sand areas in the future.The main results are as follows:(1)A total of 182 individual soil animals were collected and captured in 9 sample plots in the study area,which were identified as belonging to 6 orders and 14 branches.Among them,Coleoptera,Lepidoptera and Hymenoptera are the dominant groups;Diptera,Hemiptera and Arachnid are common groups;there are no rare groups of soil animals captured.And the captured animals showed surface aggregation.(2)The LSD analysis shows that the soil mechanical composition of different soil layers is significantly different in the 0-60 cm soil layer(P<0.05),and it is mainly composed of particles <0.5 mm;the physical and chemical indicators of the soil are different.The difference between land and different soil layers is significant(P<0.05).As the thickness of the soil layer increases,the bulk density of the soil increases,and the capillary porosity and total porosity gradually decrease.The soil is weakly alkaline,and the pH value varies between 7.25 and 8.51;the overall conductivity of the soil fluctuates greatly,and the variation value is between 8.13 and 88.70.The analysis of soil organic matter and available nutrients in various plots found that: the soil nutrients of various plots have obvious vertical distribution characteristics,especially the soil chemical indicators,the surface accumulation phenomenon is obvious,and it decreases with the increase of soil depth.Under the influence of slope position,the overall water content and water storage capacity of each sample plot are as follows: lower dune> middle dune> inter-dune lowland> sand ridge,middle dune> lower dune> low dune> sand ridge.Under the influence of slope aspect,except for saturated water content,non-capillary porosity and total porosity,windward slope> leeward slope of each plot;the rest are leeward slope> windward slope.Under the influence of vegetation inside and outside the forest,the soil water content and water storage capacity of each plot showed the order of grassland> Sabina vulgaris> sandy land;except for available phosphorus,the soil layer of 20~100 cm was the smallest of Sabina vulgaris.(3)Redundant correlation analysis(RDA)shows that soil saturated water content,soil porosity(total porosity,capillary porosity,non-capillary porosity),available potassium,organic matter,alkaline nitrogen and capillary water holding capacity are the influences An important factor in the distribution of soil animals.Environmental factors have a greater impact on Coleoptera,Hymenoptera,Hemiptera,Arachnid,and Diptera.(4)The cumulative contribution rate of 5 principal component variables extracted by principal component analysis is 85.91%.The comprehensive evaluation value of the soil was further calculated,and the Sabina vulgaris community as a whole ranked first;from the comprehensive evaluation value of the soil at different slope positions,it is in the middle of the dune(0.659)>the lower part of the dune(0.555)>the upper part of the dune(0.502)>lowland between the dunes(0.161).The comprehensive evaluation value of soil in different slope directions is leeward slope(0.648)>windward slope(0.405);the comprehensive evaluation value of soil inside and outside forest is grassland(0.648)>sandy(0.368)>Sabina vulgaris(0.161).