Dynamics of accumulation of 137CS, botanical composition and productivity of legume-cereal mixtures in the Tula region

Abstract

The purpose of the research is to select grass mixtures to improve hay and pasture lands on ravine - beam systems that have been exposed to radioactive contamination, to evaluate agrotechnical and agrochemical techniques to increase productivity and restore radioactively contaminated slope forage lands and reduce the accumulation of 137Cs in the grass. The work was carried out in 2003-2010 and 2019-2021 in the Plavsky district of the Tula region on medium loamy leached chernozem. In the first experiment, the yield and dynamics of accumulation of 137Cs by perennial grasses were studied. Perennial herbs were grown in variants without fertilizers and with annual application of N60P60K60. The objects of research were meadow clover, creeping clover, variable alfalfa, eastern goat, horned lyadvenets, boneless rump, meadow fescue, meadow timothy. The most productive in the experiments was a mixture of meadow clover, variable alfalfa and boneless stalk (10,5 t /ha of dry matter). The content of 137Cs in the air-dry mass of cereal-legume grass mixtures ranged from 8,3 to 40,1 Bq/kg. Perennial leguminous grasses bore 2...3 times more 137Cs than cereals. In the second experiment, the objects of the study were single-species crops of boneless stalk and its mixture with eastern goat with the use of mineral and microbiological fertilizers. As a result, it was found that the introduction of large doses of nitrogen fertilizers increased the accumulation of 137Cs in the herbage. With fractional fertilization, such an increase can be avoided. The complex application of nitrogen and microbiological fertilizers contributes to a 2-fold increase in the content of 137Cs in the herbage. In the experiments, the lowest values of the accumulation coefficients of 137Cs were noted in the variants with the addition of double superphosphate with potassium chloride and borofoski.