Research on the field-specific nutrient management
of flue-cured tobacco in condition of decentralized operation

【Objectives】The study aimed to research the method of soil nutrient interpolation and management zone based on soil nutrient variability and nature operation unit, which is on condition of decentralized operations and hilly-sloppy lands for planting tobacco in southwest China. 【Methods】 Soil nutrient interpolation and management zone was established by the empirical study. On condition of diversified management, the basic steps of soil nutrient precise management and partition were put forward without the support of variable machine equipment, which included soil nutrition interpolation, soil nutrient statistics taking the separate plot as a unit, fertilizer formula recommended according to the fertilizer model, and plot nutrient management based on cluster analysis of fertilizer nutrient. In Yiliang county of Yunnan Province, soil samples were collected every 50×50 m on farmland with typical production organization and topography. Data were analyzed by geographic statistics for spatial variability of soil nutrients and by Kriging for spatial interpolation and by spatial overlay analysis statistics for fertilization and by clustering analysis method for nutrient management zone establishment. Effect of regionalized nutrient management method was verified through the field trial. 【Results】 The experimental field belongs to medium fertility, and soil nutrients have regional distribution characteristics and suitable for the partition of nutrient management. Soil nutrient variations are mainly from the structural factors, which can carry out statistical analysis and spatial interpolation to meet the requirements of precision nutrient management. The effective range of inorganic nitrogen is the minimum, which controls the sampling density, and the grid sampling spacing is about 50 m of precision nutrient management under the condition of slope farmland and decentralized management. According to the spatial analysis results, combined with the index system for fertilization, the fertilization rates of the 111 fields are proposed, and the fields are divided into 8 management areas through the method of clustering analysis. The application steps in gentle slope fields show that compares with the farmers’ conventional fertilization, the application amounts of N and P fertilizers through the precise nutrient management could be decreased by 10.7%, 10.3%, and the fertilization costs of nitrogen, phosphorus and potassium nutrients are saved by 43.2 yuan/hm2, 50 yuan/hm2 and -6.9 yuan/hm2, with the total saved cost of 86.3 yuan/hm2. The yield, output value, average price and high class leaf proportion are increased. The yield is increased by 6.7%-14.5% with an average increase of 10.6%, the proportion of superior leaves is increased by 4.2% to 13% with an average increase of 7.3%, the price is increased by 0.13-0.54 yuan/kg with an average increase of 0.48 yuan/kg, and the output value is increased by 7.50%-18.3%, with an average increase of 14%. The production is increased by 5454.63 yuan/hm2, and the net benefit is increased by 5140.9 yuan/hm2. 【Conclusions】 The method of nutrient management zones established by the operation unit can not only save fertilizer and increase farm income, but also is conducive to the spread of farmers organization, which has theoretical and practical significance to the application of precision fertilization technology.