[Comprehensive evaluation of cultivated black soil fertility]

Black soil is one of the main soil types in northeastern China, and is a valuable soil resource of this country. Based on the analysis of the physical and chemical properties of soil samples collected from the north-south transaction of black soil, the index system of black soil fertility was established, the fertility level was evaluated and classified by Fuzzy and Factor Analysis, and the fertility map of black soil zone was drawn with GIS software ArcInfo. It was found that the humus layer in black soil region was thick in north and thin in south, which was due to the climatic condition and soil-forming process. The soil fertility level was high in east and low in west. From north to south, it was decreased in the order of central part > northern part > south part. In most part of this region, soil fertility level was medium, and the area accounted for 73.6% of the black soil area.