FIELD: agriculture; crop farming. SUBSTANCE: method involves taking samples from the soil-forming horizon for lithologic assay to identify the soil type and aggregate composition and chemical assay for pH of the weathering medium. A topographic plotting board is used to determine the absolute altitude of sampling points by the relief isolines, and for each type of rock values of the weathering medium pH are plotted as dependent on the absolute altitudes. Then a lithologic map of types of soil-forming rock is constructed with the relief horizons. The values of pH are used to identify the mapped areas with acid, neutral and alkaline environments. Soils on areas with acid values of pH are regarded as soils low in available potassium and rich in phosphorus. Soils with neutral pH are regarded as soils with high availability of all nutrients, and alkaline pH soils are regarded as rich in available potassium compounds and low in phosphorus. EFFECT: more accurate identification of soil zones for optimal fertilization. 2 dwg, 1 tbl
