INFLUENCE OF SYSTEMIC APPLICATION OF FERTILIZERS ON THE HUMUS CONTENT IN THE ORDINARY CHERNOZEM
The article presents data showing that the use of arable land without the use of fertilizers with straw incorporation into the soil and root-crop residues in the central agro-climatic zone of Samara Volga leads to an annual reduction of humus content in the ordinary chernozem up to 1,075 tons per 1 ha. The application of mineral fertilizers from minimal to intense levels can reduce the loss of humus on 4,8-30,3% and reduce its deficit to 1.2 - 3.6 times, but does not, it totally made up the balance. In order to maintain the equilibrium of balance of humus (in the layer 0-30 cm) at the level of 4.11% in zernoparovyh rotation is additionally required to contribute annually to the soil 8-12 t / ha of manure.