The current state of agricultural soils of the experimental field of the Omsk State Agrarian University

The aim of the study was to assess the current state and fertility of long-used arable soils of the educational and experimental field of the Omsk State Agrarian University. In 2012-2016 years sections were laid on the experimental plots and on the territory of the weather station with unplowed (virgin) soil. The morphology of the profiles was studied, the content of humus and exchange-absorbed cations, and the reaction of the environment in soil samples from genetic horizons were determined. The structural-aggregate composition and water resistance of macroaggregates in the 0-20 cm soil layer were analyzed. It has been established that the soil cover of the experimental field is represented by a combination of different genera and types of meadow-chernozem soil. According to generic characteristics, ordinary soil prevails, but there is also leached meadow-chernozem soil. In accordance with the classification of soils in Russia in 2004, it is proposed to classify them as quasi-gleyic agrochernozems, medium arable, loamy; eroded soils of the northern part of the field can be classified as abraded. According to the thickness of the Apakh or Apakh + AB (16-45 cm) horizons, the soils are moderately deep, thin and very thin, in terms of humus content (2.0-5.2%) soils can be low-humic and slightly humic. A decrease in the amount and reserves of humus in the 0-20 cm layer of agrosoils by an average of 33% relative to the virgin analogue was revealed, they are minimal in eroded soils. The physical and chemical properties of arable soils are generally favorable. They have a medium reaction close to neutral, a high content of exchange-absorbed calcium (20.1-32 mmol/100 g) and magnesium (5.7-8.0 mmol/100 g). Increased degradation of the humus layer during rainsheet leads to a decrease in the calcium content in it to 13.3-15.8 mmol/100 g. The structural state of the arable layer in terms of the content of aggregates with a size of 0.25-10 mm (43-65%), the coefficient of structure (0.64-1.86) and the number of water-stable macroaggregates (10-32%) is significantly inferior to the virgin soil, in which the data indicators were 84-86%; 4.6-5.9 and 91-98%, respectively.