Structural state of migrational-mycelial (typical) agrochernozems of the Kamennaya Steppe on plowed fields of different ages

Resumo

Changes in the structural state of migrational-mycelial (typical) chernozems (Haplic Chernozems (Clayic, Aric, Pachic)) as dependent on the duration of their cultivation (from 20 to 120 years) are considered. Field studies were performed in 2013 on the fields of the Dokuchaev Research Institute of Agriculture in the Central Chernozemic Region of Russia (the Kamennaya Steppe area) used for growing cereals and row crops in rotation. The study showed that the most intensive degradation of the structure of chernozems takes place during the first two decades of their agricultural use. The maximum transformation of the soil structure is observed in the upper 10 cm, as this layer is subjected to the most frequent and intense mechanical impacts. The rate of structural degradation decreases with time until the equilibrium between disaggregation and aggregation processes is reached. The time required for this largely depends on the applied crop rotation systems and agrotechnologies. In this context, flexible assessment scales for the structural state of agrochernozems under conditions of different farming systems should be developed in order to perform monitoring of the physical properties of cultivated chernozems for their long-term efficient and ecologically sustainable use. Despite general disintegration and destruction of granular aggregates, the structural state of agrochernozems in the Kamennaya Steppe area remains sufficiently good even on the old-cultivated (120 yrs.) fields.