The Relationship Between Topographic And Soil Organic Matter,Total Nitrogen,Phosphorus,Potassium In The Xianshuihe Valley

According to the data of 48 sampling points and the general investigation for soil in 1981 in theXianshuihe valley, the change characteristic of soil organic carbon(SOM),soil total nitrogen(TN),soiltotal phosphorus(TP),soil available phosphorus(AP),soil total potassium(TK) and soil availablepotassium(AK) alone the altitude,aspect and slope were studied by coupling RS, GIS, GPS with themethod of Bivariate Correlation, and the relativity among the above indexes and the landform factorwere discussed. The main results were as follows:The average contents of SOM were 37.5g kg^-1,24.2g kg^-1 and 17.6g kg^-1 in the soil layers of A, B1 andB2. Altitude had a certain influence on the content of SOM. The results of correlation analysis showedthat there were significant positive correlation between the altitude and SOM in the layers of A and B2(n=47,r=0.461 ,r0.05=0.181,r＞r0.05; n=36,r=0.404,r0.05=0.181,r＞r0.05). The results of correlationanalysis also showed that there were no significant correlation between the slope and SOM.The average contents of TN were 1.69 g kg^-1,1.18g kg^-1 and 0.89g kg^-1 in the soil layers of A, B1 andB2. The results of correlation analysis showed that there were positive correlation between the altitudeand TN in the layers Of A(r=0.351), B1(r=0.256)and B2(r=0.429);And there were negative correlationbetween the aspect and TN in the layers of A(r=-0.011) and B1(r=-0.024),while there were positivecorrelation between aspect and TN in the layers of B2(r=0.423); while there were negative correlationbetween slope and TN in the layers of B2(r=-0.387).The average contents of TP were 2.10 g kg^-1,1.83 g kg^-1 and 1.80 g kg^-1 in the soil layers of A ,B1 andB2. And The average contents of AP were 4.47 mg kg^-1,2.33 mg kg^-1和2.46 mg kg^-1.The results ofcorrelation analysis showed that aspect had a certain influence on TP and AP in the layers of A, B1 andB2. There were positive correlation between altitude and TP in the layers of B2(r=0.382), and Therewere positive correlation between altitude and TP in the layers of A ,B1 and B2(r=0.382) ;And therewere negative correlation between the aspect and AP in the layers of A(r=0.252), Bl(r=0.028)andB2(r=0.146).The average contents of TK were 25.28 g kg^-1,24.24 g kg^-1和22.27g kg^-1 in the soil layers of AB1 and B2. And the average contents of AK were 120.4 mg kg^-1,76.10 m g kg^-1和68.90 mg kg^-1 in thesoil layers of A ,B1 and B2. The results of correlation analysis showed that aspect had a certain influenceon TK and AK in the layers of A, B1 and B2. There were positive correlation between the aspect and TKin the layers of A(r=0.266) and B1 (r=0.139).And there were positive correlation between the aspect andTK in the layers of A(r=0.016).