Identifying management zones in tobacco-planted fields based on tobacco quality

The objective of this study was to explore the key quality-limiting factors of tobacco, and to provide a solid foundation for scientifically formulated management zone (MZ). One hundred and eleven soil samples were collected from top 20cm soil layers based on an approximately 20m grid of the study area, and eight soil properties were analyzed for stepwise multiple regression analysis and fuzzy clustering algorithm. The results show that the contents of soil organic matter (OM), total nitrogen (TN), alkalytic nitrogen (AN) and available phosphorous (AP) are low, while the content of available potassium (AK) is high in this study area. All of the soil nutrients are best simulated by using spherical models, and they have the considerable spatial variabilities. The results of stepwise multiple regression analysis show that OM, AK, AP, and CEC are the key tobacco quality-limiting factors. The four factors are taken as the variables for delineating MZs, and the study area is classified into four MZs. The soil OM, AP, AK, and CEC are the key quality-limiting factors of tobacco in the study area. The study area is clearly defined into four MZs based on the four key soil nutrients, it is concluded that tobacco-planted fields could be managed in a site-specific way.