Transformation of soil fertility indicators of agricultural land in the northern forest-steppe of the Omsk region

The article presents the results of research on the transformation of soil fertility indicators in the northern forest-steppe of the Omsk region when used in agriculture (on the example of the territory of the Krasnopolyansky rural settlement of the Gorky district). According to the agrochemical survey, due to the active use of organic and mineral fertilizers, the weighted average phosphorus content increased from 100 mg/kg of soil in 1983 to 117 mg/kg of soil by 1991. In the future, the use of organic fertilizers decreased, which led to the transformation of soils with high and increased phosphorus content into the group with an average content (51-100 mg/kg): in 2000 it decreased to 104 mg/kg of soil, and by 2015 - to 94 mg/kg of soil. In 1991, the humus content was 6.6%. The use of organic fertilizers by 2000 decreased, and the humus content decreased to 6.0%, by 2015 it slightly increased to 6.3% due to changes in the structure of the use of arable land and the expansion of the area of perennial grasses. Over all the years of observations, the content of exchangeable potassium in arable soils was consistently high from 192 mg/kg to 215 mg/kg of soil. Weighted average acidity - close to neutral, at 6.0 pH. In connection with the negative changes in a number of indicators of soil fertility in part of the land-use territory, measures for their stabilization are proposed.