Agro-ecological characteristics of soils, economic efficiency of the use of chemicals and new complex fertilizers in the Bryansk region
The study aimed to analyse the state and dynamics of changes in agrochemical indicators of soil fertility for agricultural purposes in the Bryansk region and develop measures to optimise it, including in the zone of radioactive contamination. The maximum level of most indicators of soil fertility in the Bryansk region was reached in 1991-1995 due to the use of high doses of ameliorants, mineral and organic fertilizers. After that, they began to decline. Weighted mean soil acidity (pH) of arable land as of 01.01. 2022 amounted to 5.57 units, which is significantly higher than the initial (5.11) in the first survey cycle in 1970. Acidic soils (pH 4.1-5.5) in the Bryansk region occupy 507.5 thousand hectares, or 51% of the surveyed arable land, including strongly acidic soils account for 85.3 thousand hectares, or 9%. The content of organic matter (humus) in the soils of arable land averaged 1.95%, which is lower than in 1991-1995 by 0.21%. The weighted average content of phosphorus in the region is 211 mg/kg. Soils with a low supply of this mineral element occupy an area of 215.8 thousand hectares, or 22% of arable land. The arable land of the region on an area of 711.1 thousand hectares, or 71%, is characterised by a reduced supply of mobile potassium, which is 5% more than in 2011. For the 2021 crop an average of 156.3 kg/ ha of a.i. of mineral fertilizers was applied, including 79.7 kg of nitrogen, 27.3 kg of phosphate and 49.2 kg of potassic. The payback of 1 kg of applied nutrients was 5.3 feed units (103% of the norm), against 5.7 feed units in 2020. The use of humic organomineral preparations in areas contaminated as a result of the accident at the Chernobyl nuclear power plant makes it possible to reduce the flow of cesium-137 into plants, in comparison with the traditional technology used in the economy by 3.3-4.3 times.