Characteristics And Evaluation Of Land Natural Quality In Baotianman Nature Reserve Based On Soil

The Baotianman nature reserve in the western mountainous area of henan province is located in the transition zone between the north and the south of China.It has typical characteristics of transition zone and rich species diversity.It has unique advantages in the study of soil quality characteristics in middle and high mountainous areas,the enhancement of the development and sustainable utilization of mountainous land resources,and the prevention and control of soil degradation.So far,little work has been done in the evaluation of soil properties and quality in Baotianman.This study takes the north and south slope of Baotianman as the research object,and combines field survey sampling,indoor analysis,mathematical model and computer technology to analyze the statistical and spatial distribution characteristics of soil physical and chemical indexes.Using fuzzy mathematics comprehensive evaluation method to analyze the overall situation of soil quality in the study area,further from two aspects of slope and soil layer to vertical differentiation regularity of soil quality are discussed,as the north-south transition zone other mountainous areas to carry out the spatial heterogeneity of soil quality research,prevention and control of soil degradation,soil resource management to provide some reference and data support.The main conclusions are as follows:(1)physical index characteristics of soil quality:The soil texture in the study area was dominated by sand and fine powder.With the elevation rising,the contents of coarse powder,fine powder and clay increased linearly,while the contents of gravel decreased linearly and the water content increased linearly.There is A great difference in the differentiation law of soil bulk density in different vertical sample zones on the north and south slopes.With the increase of altitude,the soil bulk density of the north slope first rises and then falls,while the soil bulk density of layer A in the south slope declines linearly,and there is no obvious change law in layer B.From the perspective of profile,the content of coarse powder and soil water content in layer A is greater than that in layer B,the content of fine powder and soil bulk density in layer B is greater than that in layer A,and the content of sand grains in layer A and B is relatively close.From the perspective of coefficient of variation,the contents of gravel and clay have strong variability,the bulk density of sand,fine powder and soil tends to be stable,and the moisture content of the south slope is higher than that of the north slope,but the overall level is still at an appropriate level.Generally speaking,the soil physical properties in the study area are better.(2)chemical index characteristics of soil quality:The pH value of the studied soil ranged from 4.40 to 6.49.The soil was acidic,rich in organic matter and nitrogen,suitable in potassium,and deficient in phosphorus.The CEC was distributed between 4.43 and 38.73coml/kg.The average content of trace elements manganese and copper exceeded the national standard,and the average content of zinc and iron was in the state of enrichment.From the vertical sample belt,the distribution rules of organic matter,total nitrogen and total phosphorus in different vertical sample belts on the north and south slopes are relatively consistent.As the elevation gradient increases,the organic matter decreases linearly in the low elevation areas of 900 ~ 1200 m,and first rises and then falls in the middle elevation areas of 1200 ~ 1500 m,and rises linearly in the high elevation areas above 1500 m.The distribution law of pH,total potassium and CEC in different vertical sample belts on the north and south slopes has its own characteristics.As the elevation of the north slope increases,the pH and total potassium are bounded by the elevation at 1,200 m.The fluctuation range of CEC is large,and the correlation with the elevation change is not obvious.In the vertical sample belt of the south slope,pH and CEC maintained a fluctuating upward trend with the increase of elevation,while the relationship between total potassium and elevation phase was poor.From the perspective of profile,all soil chemical indexes are in weak and moderate variability,except for pH and total potassium content,which is higher in layer B than in layer A,and most index contents are higher in layer A than in layer B.On the whole,the contents of soil organic matter,nitrogen and potassium are suitable for vegetation growth,and phosphorus is relatively deficient.The vertical differentiation rules of soil chemical quality indexes are relatively complex,and the content differences are relatively small.The north slope is slightly higher than the south slope,and the soil layer A is higher than the soil layer B.(3)comprehensive evaluation of soil qualityPrincipal component analysis(PCA)was used to select the minimum data set from 20 soil physical and chemical indexes by calculating the Norm value,combining sensitivity analysis and correlation analysis.The MDS of soil layer A were clay,water content,bulk density,total phosphorus,nickel,organic matter and total nitrogen.MDS of soil layer B were: manganese,organic matter,water content,total nitrogen,total phosphorus,fine powder,zinc,carbon nitrogen ratio.Fuzzy mathematical model was used to calculate soil quality comprehensive index SQI.Generally,the SQI of soil layer A in the research area was on the high side,while that of layer B was on the low side.Generally,the SQI of the north slope was higher than that of the south slope,and that of layer A was higher than that of layer B.The further analysis of SQI according to different slope directions and different soil occurrence layers shows that the vertical differentiation of SQI is obvious in different vertical sample belts of the north and south slopes.The vertical differentiation rules of different soil layers were similar,and all SQI showed that layer A was larger than layer B,and A higher value appeared in the middle altitude area.(4)measures and Suggestions to improve the natural quality of land and realize the sustainable development of landThe overall soil quality of baotianman is on the high side,but due to historical reasons,there are some problems in management,protection,planning,development and land use,resulting in low land quality in some areas.Distribution characteristic is based on the land natural quality,targeted put forward sound reserve land laws and regulations,strengthen supervision and improve the public accomplishment,strict examination and approval process,functional zoning of land resources,combined with the regional soil quality adjust measures to local conditions the arrangement of the management strategy,reasonable for protection,development,utilization,land quality space dynamic evaluation and prediction work.