Comprehensive evaluation and variation analysis of fertility of tobacco-growing soil in Eshan county of Yunnan province

Abstract

The soils in sampling sites of tobacco growing area in Eshan county of Yunnan Province were serially sampled respectively in 2008 and 2012,and comprehensive evaluation was conducted on the spatial and temporal variations of soil fertility.The results showed that the pH values of soil in Eshan,Yunnan were in a range of 4.03?8.29,the contents of organic matter in a range of 1.7?71.9 g/kg,available N in a range of 15?293 mg/kg,and the suitability proportion was 88.84%;the contents of available P and available K were lower than 70%,slightly less than the average.The average of comprehensive evaluation indexes of tobacco-growing soil was 0.63,the coefficient of variation was 1.4%,the fertility was evenly distributed and the spatial variation was small.The fertility of tobacco-growing soil in Eshan was divided into higher,high,medium,low and lower grades according to the IFI value.The proportion of area with soil fertility above the medium grade was 85.96%,the soil fertility in tobacco-growing area of Shuangjiangzhen and Fuliangpeng were higher compared to other towns.Compared to 2008,the pH value of tobacco-growing soil decreased by 0.22,the contents of organic matter reduced by 0.44 g/kg,the amount of available N increased by 4.21 mg/kg,the amount of available P decreased by 0.14 mg/kg,available K increased by 21.88 mg/kg,trace element Zn increased by 0.76 mg/kg and soil comprehensive fertility indexes increased by 0.08 in 2012.