Changes in Agrochemical and Agrophysical Properties of Drained Meadow Soils with Bleached Horizons (Podbels) during Fallow Succession

The study examines the agrochemical and agrophysical properties of meadow podbels (haplic gleysols) in fallow drained soils of different ages located in the Daurskii Massif drainage system in the Jewish autonomous oblast. The soil structure was analyzed using dry sieving, and the density was determined using a drive cylinder method. The results show that drained arable lands that were removed from active production require an extended period of time to regenerate. In the absence of soil cultivation, vegetation growth and root development are observed. A 6- to 7-cm-thick sod is formed on a 10-year fallow and an up to 12- to 13-cm-thick one on a 25-year fallow, which contributes to soil loosening. Plots with a 25-year fallow demonstrate an increase in the humus level (Ctotal 5.1%) compared to arable land (Ctotal 2.8%). The level of mobile forms of phosphorus and potassium in fields sown with soybeans is determined as medium for P2O5 and very high for K2O. Removal of land from agricultural rotation gradually improves its structure, where the coefficient of structure increases from 0.9 on arable land to 1.9 after 25 years without cultivation.