Spatial Distribution Characteristics and Correlation Analysis of Organic Matter, Total Nitrogen and Total Phosphorus in Topsoil Around Chaohu Lake
巢湖周边表土中有机质、全氮和全磷空间分布及其相关性

Sixty topsoil composite samples(0-20 cm) have been collected in 3 258 km2 surrounding area of Chaohu Lake.The concentrations of organic material(OM),total nitrogen(TN) and total phosphorus(TP) were determined,and their spatial distribution characteristics were studied by geo-statistics software named GS 7.0+,Surfer 8.0 and Mapinfo 8.5.The correlations of these 3 kinds of nutrient were analyzed by SPSS 17.0 at the same time.Results showed that the average ω(OM),ω(TN) and ω(TP) in topsoil around Chaohu Lake were 19 500 mg·kg-1,1 027 mg·kg-1 and 483 mg·kg-1.The ω(OM) and ω(TN) in topsoil in the east of Chaohu Lake were both higher than those in the west of the lake,while ω(TP) was reverse.The ω(TP) in topsoil around Hangbu-Fengle River and Baishitianhe River which located in the southwest of Chaohu Lake was higher than that in any other rivers and with the serious soil erosion.Hence,to control the TP released by nonpoint pollution,attention should be paid on these two rivers.Furthermore,the semivariogram models of ω(OM),ω(TN) and ω(TP) followed linear model and they all had a strong spatial autocorrelation,the ratios of nugget to sill were 0.015,0.202 and 0.128,respectively.The characteristics of spatial distribution of ω(OM),ω(TN) and ω(TP) were similar.Moreover,the Pearson correlation analysis showed that ω(OM),ω(TN) and ω(TP) were significantly correlated.The ω(TN) and ω(TP) can be calculated by two recommended formulas,and the results were acceptable in daily non-pint pollution management.