Status and comprehensive evaluation of soil fertility in Neixiang tobacco-growing areas

To malce clear the soil fertility status,10 indexes of the soil nutrient contents of 601 soil samples from Neixiang tobacco-growing areas were analyzed. Based on methods of factor analysis and principal component analysis,the comprehensive evaluation of soil fertility was conducted. The results of comprehensive evaluation indicated that there existed significant variation for the soil fertility of Neixiang tobacco-growing areas. The soil fertility could be classified into four ranks by cluster analysis.Rank 1 was of the highest soil fertility with comprehensive scores≥0. 5,including 48 soil samples;Rank 2 was of higher soil fertility with comprehensive scores 0. 0 ~ 0. 5,including 212 soil samples;Rank 3 was of the medium soil fertility with comprehensive scores- 0. 5 ~ 0. 0,including 312 soil samples; Rank 4 was of low soil fertility with comprehensive scores≤- 0. 5,including 29 soil samples.The contents of total N was high in general,and the contents of organic matter,available P were medium; The contents of slowly available K was adequate,but the contents of available K was obviously deficient; It was suggested that N be controlled,P be added,and K be adjusted; to promote the conversion of slowly available K to available K,organic fertilizer with higher C /N shoud be added to the soil;according to different plots with larger nutrient change,classification fertilization program was needed to develop.