Study On The Change Of Land Use And Land Cover And Variability Of Soil Nutrients In The Southern Slope Of The Daxiangling Mountains

With reference to the remote sensing images of MSS in 1982 and ASTER in 2006 on ArcGIS9.0 technology support,the study took the southern slope of the Daxiangling Mountains as an example,use the mixed methods of eye-interpretion,supervision and un-supervision to interpret the change of land use and the cover,and then compute the correlation indexes of land use dynamic change and land use conversion matrix.According to the geography data,analyzed the characteristics of land use and land cover on different terrain factors.Meanwhile,using the date of soil census in 1982 and sample chemical analysis in 2006,obtained the overall variable characteristics of soil SOM,SAN,STP,SAP, SAK.In unison,focal subjects are exploring the variability of soil nutrient in two typical ways of dry land changing into orchard and woodland.The main results were as follows.During the 24-year reign,the notable change of land use and land cover have taken in the study area.Every land types have translated frequently between each other,then the results leaded to the rising of plaque fragmentation.The basic characteristics of land use and land cover showed that the area of orchard,woodland,paddy field and residential area have increased,respectively being 6415.41 hm²,3580.72 hm²,1154.14 hm²,556.00 hm², 30.78 hm².Meantime,the area of dry land,shrubbery and bare land have decreased, respectively being 5403.76 hm²,3886.26 hm²,2447.02 hm².The computing results of the land-use dynamic change indexes showing that the singleness land-use dynamic changes were all in better classification except river and dry land;The general land-use dynamic changes was 17.99,attributing to the type of intraday variation;The compressive index of the degree of land use in 1982 and 2006 were 244.43 and 253.81,belong to mediate using level.According to land use conversion matrix,the area holding the line was 35246.49hm², being 57.61 percentage of the whole study.The land use types of rolling-out and rolling-in frequently were paddy field,dry land,bare land.While,orchard and woodland were the rolling-in largely types,rolling-in category being complex;shrubbery land and residential area were the rolling-in and rolling-out largely types,rolling-out category being complex. The river was changing slightly,and changing types being simple.The different characters of terrain factor showed that the characteristic of LUCC responding to altitude was consentaneous in different era.Meanwhile,the area percentage of slope classes for LUCC had minor differences,but single land use and land cover had a great correlation with slope class.When it comes to slope exposures,the diversion in 24 years was fewer,and due to the small area of sunny slope,all area percentage of land use types distributed in mid-sunny slope and shade slope in the gross.The results of the samples statistical analysis in 1982 and 2006 showed that the average content of SOM has displayed increasing trend,being increasing from 23.79±16.93g kg^-1 to 27.83±19.68g kg^-1,generally higher in northeast and southwest.The content of STN and SAN have varied unextraordinary and being consistently in trend of geographical distribution.The content of STN in orchard,woodland,shrubbery have increased to a greater extent,the content of SAN changed slightly in all land use types. While,STP has diversified slightly,only 0.02 g kg^-1,SAP has diversified extraordinary, being 4.09 mg kg^-1.The SAP and STP have varied identically in geographical trend, un-obviously in study region.The SAK has increased significantly,the incremental reaching to 36.31 mg kg^-1,varied consistently with the SAP in north and south geographical trend.In the course of dry land changing into orchard,the average content of SOM has increased from 23.4 g kg^-1 to 28.0 g kg^-1,while,the STN has weakened in decreasing degree when the resuming year increasing,the SAN has all descended except the sample of 69,being 20.41%averagely.The STP and SAP all increased,being 0.050 g kg^-1 and 9.0 mg kg^-1 respectively.The SAK has responded distinctly to the course,increasing 56.84% as a whole.Contemporarily,in the course of dry land changing into woodland,the content of SOM,STN and SAN increased 57.09%,57.13%and 70.36%respectively.The SAK varied inconspicuously,the course of resuming and rebuilding was complex,but being ascending in the mass.