The newest integrative methods of research of soil organic carbon stabilization at different tillage

Abstract

In agriculture, one of the technologies for the recovery of lost organic carbon is the minimum and no-till methods, which contribute to the increase of organic matter and the global stabilization of carbon dioxide. But the effectiveness of carbon sequestration in soil by such methods is limited by the fact that organic carbon is quickly released from the soil, which is returned to plowing. Therefore, this necessitates an urgent need to study the response processes of humus molecules, leading to the structuring of soil organic matter to manage carbon sequestration and integrative monitoring of CO 2 emissions. The purpose of the work was to identify and establish the processes of response of humic molecules as a complete supramolecular system by integrative spectroscopic aproach that determine the stabilization of soil carbon and determine the dynamics of CO 2 emissions from the soil.. The studies were aimed at detecting changes in the integral characteristics of the spectra in complex molecular spectroscopic analysis of all humic acid (HA) extract of chernozem typical and to determine the impact of different tillage methods on soil CO 2 emissions. Complex spectroscopic analysis was performed in the advanced laboratories of KNU named after V. N. Karazin and the Scientific and Technological Complex "Institute of Single Crystals". Instrumental control of the carbon dioxide release rate from the soil surface was performed using a portable gas analyzer testo 535. With using modern spectroscopic methods of unfractionated chernozem typical humic acid extracts, there were established processes of reorganization of humic superstructure, characterized by the restructuring of intermolecular forces, which causes a change in the reactivity and stability of HA. It is revealed that humic superstructure of arable chernozem typical is characterized by high molecular mobility, due to hydrophilic positive hydration and good solubility, high sorption and complexing properties, but with poor ability to attach, due to migratory "scattering", deep into the soil profile. It is proved that the largest total volumes of CO 2 emissions from typical chernozem are characterized by the technology of direct sowing (no - tillage), this is facilitated by better water regime and fuller mineralization of plant residues on the soil surface. During basic tillage by disking of 10-12 cm, the annual carbon losses are the lowest. In addition, systematic plowing over 6 years led to a decrease in the content of labile organic matter and fulvic acids. and a reduction in the potential for CO 2 production in the topsoil compared to surface tillage and direct sowing technology.