Integrated Evaluation of Soil Fertility in Nanping Tobacco Planting Areas

soil nutrient data derived from field sampling was used to evaluate soil fertility of tobacco planting areas in Nanping. The evaluation could provide basic information for soil diagnosis and management. The soil fertility indexes of all sampling plots were evaluated by Fuzzy integrated fertility index (IFI) method, and then were interpolated to a raster dataset by ANUSplin interpolation method. The dataset was graded to six levels(from high to low: I to VI) by quantile method. The results showed that soil organic matter and nitrogen content exerted as crucial factors affecting the soil IFI index, due to their important roles in the biogeochemical cycle. Spatial pattern of the soil IFI showed a decreasing trend from west to northeast with a highly spatial variation in the studied areas. The highest index was found in the west part including Shaowu City and Guangze County, which accounted for 84.54% of total I-level soil areas. The soil IFI of the entire Shaowu City exceeded II-level, while the soil IFI of the entire Guangze County exceeded III-level. The Fuzzy IFI method provides an efficient approach to quantify soil fertility, and could detect spatial patterns of regional soil fertility when coupled with the interpolation method.