Research On Land Use Of Shennongjia National Park Based On Soil Health

With development of society and increase of population,people's unreasonable use of land resources has brought a series of problems,such as soil acidification,soil pollution and soil fertility decline,then soil health has begun to receive extensive attention.Shennongjia National Park is located in the southwest of Shennongjia Forest Area,Hubei Province,which located in the east of the Daba Mountains.It is not only an important habitat for golden monkeys and golden sculptures,but also an important water conservation area for the Yangtze River and the Hanjiang River,the South-to-North Water Transfer Project and the largest green natural screen in the Three Gorges Reservoir Area.As a key area in the transition zone between North and south of China,the study of soil distribution and health status of Shennongjia National Park is a realistic need to promote harmonious coexistence between man and nature,and a powerful measure to speed up the construction of ecological civilization.It can not only make the rational use of land resources and the protection of ecological environment possible,but also provide a reasonable basis for the land management measures formulate in Shennongjia National Park.Based on relevant researches in the world,established the index system and evaluation model of soil health by using the method of analytic hierarchy process(AHP)and principal component analys is(PCA).Soil morphological indexes of Shennongjia National Park are obtained by field observation and record: litter layer thickness,humus layer thickness,soil layer thickness;physical and chemical properties of soil are obtained by National Standard Method: bulk density,mechanical composition,pH,organic matter,total nitrogen,total phosphorus,total potassium,alkali hydrolyzed nitrogen,cation exchange capacity;investigate 20 *20 m or 10 *40 m vegetation,obtained plant diversity index.Systematically analys is single factor and comprehensive evaluation results of soil characteristics in Shennongjia National Park on the altitudegradient.In order to provide data support for the establishment of land management and land health evaluation index system in Shennongjia National Park.Expect toprovide data suppor t for the land management and theestablishment of index system of land health evaluation in Shennongjia National Park.The main conclusions are as follows:(1)The thickness of litter layer was mainly 2-5 cm,humus layer was mainly 10-24 cm,and soil layer was mainly over 30 cm,all of which are in the middle-thick layer.The bulk density value is small and in loose level.Among the mechanical components,the content of silt is the most,followed by sand and clay.Organic matter,total nitrogen,alkali-hydrolyzed nitrogen and cation exchange capacity are in a rich level,total potassium content is in the upper and middle level,total phosphorus content is extremely deficient,and species diversity of trees is not high.(2)From the different soil layers,except bulk density,pH and total potassium,the other indicators show that layer A is larger than layer B;from the different slope,layer A soil: sand content,organic matter content,total nitrogen,alkali-hydrolyzed nitrogen,the south slope is higher than the north slope;bulk density,silt content,clay content,pH value,total phosphorus,total potassium,cation exchange capacity,the south slope is smaller than the north slope.Layer B soil: sand content,pH value,total nitrogen,the southern slope is larger than the northern slope;bulk density,silt content,clay content,organic matter content,alkali-hydrolyzed nitrogen,total phosphorus,total potassium,cation exchange capacity of the southern slope is smaller than the northern slope.The diversity coefficient of shrub layer on thesouth slopeis higher than the north,and the diversity coefficient of arbor layer was on thesouth slopeis lower than the north.Elevation was positively correlated with organic matter,total nitrogen,alkali-hydrolyzed nitrogen and CEC,negatively correlated with bulk density,pH and diversity coefficient of arbor layer.(3)The MSD of soil health assessment in layer A isorganic matter,alkali-hydrolyzed nitrogen,total phosphorus,CEC,pH,bulk density,clay content,humus layer thickness,soil layer thickness,litter layer thickness,diversity coefficient of shrub layer,diversity coefficient of arbor layer.The MSD of soil health assessment in layer B is organic matter,alkali-hydrolyzed nitrogen,total potassium,pH,humus layer thickness,soil layer thickness,litter layer thickness,diversity coefficient of shrub layer,diversity coefficient of arbor layer..Among them,litter layer thickness,plant diversity index,species richness index,humus layer thickness,soil layer thickness,soil organic matter,cation exchange capacity,total nitrogen,hydrolytic nitrogen,total phosphorus,total potassium use ring function,pH and clay content use trapezoidal function.(4)From the evaluation results,the soil health index of layer A is in the middle and high level,layer B is in the middle and low level,and that of the north slope is higher than the south slope.From the variation degree,the layer of B is higher than the layer of A,the south slope is higher than the north.From the trend of change,inthe south slope is "N" type,which increases first,then decreases and then increases,while that in the north slope is "V" type,which increases first and then decreases.(5)Bulk density,total phosphorus,total nitrogen and species diversity are the limiting factors affecting the level of soil health.Strengthening the protection of spec ies diversity,speeding up the legislative construction of land management,coordinating land planning,strict approval process,actively building the early warning mechanism of land protection,and strengthening the awareness of land security of the whole people are the important means to maintain the current soil health,land ecological security and sustainable land use.