Extraction and Integration of Different Soil Nutrient Grading Systems for Soil Nutrient Mapping

These works present a model to integrate and harmonize different nutrient grading indexes originating from various existing soil polygon maps. The soil nutrient grading indexes might be different from one national soil survey to another and even be different for the different counties in the same national soil survey in China. Soil nutrients mapping in large regions, such as national or provincial regions, had to be done after the integration of those grading indexes. The hardcopy of the soil nutrient maps for most of the counties of China was collected and vectorized. These maps were mostly scaled at 1:50,000–1:500,000 and could be used as the input data for the integration of the grading index. Next, a model named Soil Nutrient grading system Integration Model (SNI-Model) was established using ARCGIS10.0 and was written in C#. The SNI-Model did not change or revise the properties of the spatial soil nutrient maps and saved the original grading index for every soil polygons. Also, it was designed in a two color systems for more easy reading. SNI-Model consisted of five modules and could be easily used to intelligent integrate the soil grading indexes for soil nutrient mapping. The SNI-Model is a general model and may also be applicable to the environment, ecology, and other research areas to resolve the similar problems.