Abstract:

【Objective】 This paper is aimed to create a macro model of fertilizer recommendations, so that obtain the most economical rice fertilization program specified for each district and the corresponding diagram of fertilization program by analyzing the distribution of soil nutrients, classifying the rice fields according to soil fertility, and drawing the map of soil fertility in Yiyang County. 【Method】Based on the fertility evaluation and soil testing data collected from 2006 to 2008 in Yiyang County, the relationship of soil nutrient content and topography in hilly area can be analyzed with GIS software by creating a nutrient thematic map, slope map and elevation chart. Then, combined with the soil fertility survey data, the different districts with integrated level of soil nutrient can be further classified. After that, the experiments with “3414” model are conducted, which represent the soil fertility grade of various districts. Finally, the experimental data were analyzed by SAS software for calculating the quotient for max productivity as well as the corresponding fertilizers rate and ratio needed.【Result】The high content of nitrogen, phosphorus and potassium are mainly distributed in plains and low slope areas, and low contents are in hilly, low mountains and hillock plain. The land of Yiyang County can be divided into nine districts. The best economic benefit obtained between RMB 8 313 yuan/hm2 to 13 500 yuan/hm2, and corresponding proportion of N, P and K fertilizer range in 1﹕0.18-0.49﹕0.48-0.85. 【Conclusion】 Distribution of soil nutrients at hilly areas varies greatly, resulting from the topography. GIS and modeling techniques combined with microscopic soil analysis and field test can solve the problems of fertilizer recommendations in such area, even propose area-specified fertilizer recommendations.

Key words: distribution map of soil, fertilizer recommendations, fertilizer effect equation, GIS