Effect of simulated salinization on the properties of steppe chernozems of the Upper Volga Region

Abstract

The development of soil salinization processes in the steppe zone is a serious threat to food security in the country. This phenomenon has become one of the main environmental and socio-economic problems worldwide, and it is expected to worsen due to predicted climate changes. The territory of the Orenburg region is almost entirely located in the zone of fertile chernozems. The paper studies the effect of simulated soil salinization on the agronomic properties and biological activity of southern chernozems in the Orenburg region. The field experiment (2019–2022) was conducted on spring durum wheat variety “Orenburgskaya 10” during the periods of active vegetation of plants. Salt solutions were prepared by mixing salt with deionized water at NaCl (sodium chloride) concentrations of 1.1 and 11.7 g/l. The enzymatic activity indices of the chernozems demonstrated different sensitivity to the modeled salt stress and form the following series in terms of resistance to the introduction of toxic salt: urease> catalase> protease> polyphenol oxidase> peroxidase. During the course of the study, a decrease in organic matter and ammonium form of nitrogen in the soil was observed. Increasing the concentration of sodium chloride solution to 1,1 and 11,7 g/l promoted the development of peptization processes and a decrease in the aggregate composition of steppe chernozems. The presented results of the effect of salinization on the agronomic and biological properties of soils made it possible to assess the resistance of steppe chernozems to this type of degradation.