Агроэкологическая характеристика черноземов Каменной степи: влияние растительных сообществ и распашки

Abstract

Changes in soil carbon stocks have a significant impact on atmospheric CO2 concentrations and the global carbon balance. Despite the proven effectiveness of agroforestry in erosion control and prevention of soil fertility loss, there are many controversial data suggesting that the impact of afforestation on Chernozem soils should be further investigated. The Kamennaya Steppe site (arable land surrounded by shelterbelt forests) is a reference site for monitoring studies at the Voronezh Carbon Test Site, where the carbon balance of agro-ecosystems is being studied and the ecological role of shelterbelt forests in changing soil properties and carbon sequestration is being evaluated. The study was focused on the evaluation of agro-ecological characteristics and the impact of tillage on Chernozems of Kamennaya Steppe under different vegetation types. The study of the chemical properties of chernozems was carried out using classical chemical methods; the analysis of heavy metals was carried out using the voltampermetric method. Comprehensive agro-ecological evaluation showed that the studied Vorony-Calcic Chernozems had a high content of humus, which reached 7-8% in the upper horizons, enriched with mineral nutrition elements, and had favorable physical and chemical properties. Forest and grassland vegetation contribute to enrichment of the soil with organic residues, while tillage and mineralization of organic matter on arable land led to a decrease in humus content. Data analysis suggested that the study area did not suffer from contamination. Furthermore, it was found that the organic matter of the studied chernozems was able to bind the studied metals and retain them in an unavailable state. This phenomenon was supported by rather high correlations between humus and total heavy metal content (r = 0.946 for Pb and r = 0.975 for Cd at p < 0.00001). It should be emphasized that shelterbelt forests could act as a biogeochemical barrier to the lateral migration of heavy metals. Cadmium is a rather mobile element potentially capable to migrate to adjacent environments. Therefore, regular monitoring of the agro-ecological condition of the Chernozems of the Kamennaya Steppe is required.