Quantitative and qualitative changes of humus at application of organic fertilizer systems in grey forest soil

Abstract

The purpose. To determine influence of organic fertilizer systems on quantitative and qualitative changes of humus in 10-field grain-tilling crop rotation in grey wood large-silty sandy loam soil of the Northern part of Forest-steppe of Ukraine. Methods. Field, laboratory, mathematical. Results. Use of soil without fertilization has led to greater losses of humus and aggravation of quality due to mineralization processes predominating above immobilization ones. Amount of fulvic acids was increased and content of humic acids was decreased. Type of formation of humus — fulvate-humate. Under condition of importation of dung in dose of 12 t/hectare the content of humus was close to reference value, but it was not possible to achieve its positive balance. Amount of humic acids was increased and of fulvic acids was decreased, especially in arable layer of soil. Type of formation of humus in arable layer — humate-fulvate, and in sob-arable — fulvate-humate. At importation of dung in dose of 24 t/hectare the content of humus has reached positive balance with substantial improvement of quality indicators, concerning 12 t/hectare of dung — amount of humic was considerably augmented and the amount of fulvic acids in tillable and sub-arable layers of soil was diminished. Ratio Sga:Sfa in arable layer — 1,90, in sub-arable — 1,22. Type of formation of humus — humate-fulvate. Conclusions. It is fixed that importation of dung in dose of 12 t/hectare in grain-tilling crop rotation is insufficient for maintenance of sufficient balance of humus, but quality indicators of humus have considerably improved in comparison with the supervisory control. More efficient is the dose of dung of 24 t/hectare, it ensures positive balance of humus and improves its quality contents in tillable and sub-arable layers of soil.