Influence of Permanent Crops and Fallow on the Thermal and Optical Properties of Typical Chernozem

Abstract

Using the thermal method and IR spectroscopy, a typical chernozem (Haplic Chernozem (Loamic, Pachic)) of various land uses was studied. According to the data obtained, the organic matter of the chernozem mainly consists of weakly thermally stable aliphatic compounds such as polysaccharides. This is evidenced by the mass loss in the low-temperature region, which varies within 68.15–71.54%, and the intense absorption band at 1083 cm-1, which determines the shape of the IR spectra of the chernozem. Under the influence of extensive agricultural use, the mineralization of labile aliphatic compounds and an increase in stable cyclic structures in the composition of the organic matter of chernozem occurred. This is indicated by a decrease in the Chernikov–Konchits Z coefficient from 3.16 to 2.47–2.73 and the intensity of most absorption bands in the IR spectra. The most noticeable negative impact on the organic matter of a typical chernozem was caused by bare fallow.