Ecological Assessment of Sulfur Content in Agroecosystems of the Central Black Earth Region of Russia

Abstract

Studies were carried out on the territory of the steppe and forest-steppe zones of the Central Black Earth Region of the Russian Federation. The objects of research were the soil of nature reserves and arable chernozems that were not touched by agricultural activity, typical and common, the vegetation cover of natural biocenoses and agroecosystems, and organic fertilizers. The studies found that the background content of mobile sulfur in virgin soils is at a low level: 2.31 mg/kg - in a typical chernozem and 1.83 mg/kg - in an ordinary chernozem. According to agrochemical monitoring of arable soils carried out during 2015-2018, an increase in the weighted average content of mobile sulfur by 0.7 mg/kg to 3.3 mg/kg was established, compared to 2005-2009. However, the proportion of soils low on this element remains quite high - 90.3%. The main source of sulfur supply to the soils of agroecosystems (7.52 kg/ha) are organic fertilizers, the doses of which in 2015-2018 increased to 8.1 tons/ha. The average sulfur content in the steppe mixture of herbs of reserves is 0.3-0.4 mg/kg. The highest sulfur content among perennial legumes is clover (0.61%) and alfalfa (0.60%), and among legumes - soybeans, containing 0.34% of the element in grain and 0.21% - in straw.