Research on definition of management zones based on GIS and soil properties in tobacco-planted field
基于GIS和多种土壤属性的烟田养分分区管理研究

This research was to define management zones of tobacco planting field in Pingdingshan. The variables of pH, total nitrogen, organic matter, alkalytic nitrogen, available phosphorous, available potassium, active soil organic matter and cation exchange capacity data determined in 111 topsoil (0-20 cm) samples were selected as data sources. Principal components analysis (PCA) and fuzzy cluster algorithm were then performed to delineate management zones (MZs); fuzzy performance index (FPI) and normalized classification entropy (NCE) were used to determine the optimum cluster number. The results showed that the optimum number of MZs for this study area was three and the fuzziness exponent was 1.5. The analysis of variance indicated the heterogeneity of soil fertility among different MZs, while the variation coefficient of soil nutrients decreased. The average confusion index was 0.37 in this area. The overlapping of fuzzy classes at points was low and the spatial distribution of membership grades was unambiguous. The results indicated that fuzzy c-means clustering algorithm could be used to delineate management zones. The defined MZs provide a basis of information for site-specific fertilizer management in the tobacco-planted field.