Effect of fertilization on soil fertility under different types of meadow agrophytocenoses

Goal. To determine the amount of accumulation of root mass, symbiotic nitrogen, parameters of soil fertility indicators, and the balance of the main nutrients for growing Lucerne sowing and Lucerne-cereal mixtures under the influence of lime and fertilizers. Methods. Field (conducting an experiment in the field, determining the amount of above-ground mass and roots), laboratory (determining soil fertility indicators), and mathematical and statistical (mathematical processing of research results). Results. According to the results of studies conducted during 2019–2021 in the zone of the Forest-Steppe of Ukraine on dark gray podzolized coarse-pollinated light-clay soil, the value was determined of the accumulation of root mass and symbiotic nitrogen by perennial grasses, indicators of cellulase activity, anti-erosion resistance and changes in soil fertility indicators, as well as the balance of the main nutrient elements for growing Lucerne, cereal and Lucerne-cereals agrophytocenoses for feed under the influence of lime and fertilizers. Conclusions. Under the action of symbiotic nitrogen of Lucerne in single-species sowing and Lucerne-cereals mixtures, and mineral nitrogen, the dose of N90 on the cereal grass cover increased the accumulation of dry mass of roots by 0,99–1.90 t/ha, productive action of roots — by 0.19–0.64 units, cellulase activity of soil — by 3–4%. Anti-erosion resistance of meadow agrophytocenoses (by the duration of erosion of the soil monolith by a uniform stream of water) increased by 1:04–1:42 min/s. The amount of alkaline hydrolyzed nitrogen in the soil was also increased. Different types of meadow grass stands with a harvest of above-ground biomass produce 56–307 kg/ha of nitrogen, 12–45 kg/ha of phosphorus, and 87–263 kg/ha of potassium. Nitrogen balance on Lucerne and Lucerne-cereals stands on the background without nitrogen fertilizers was positive in the range of 15–28 kg/ha, on cereal grass stand with N90 — close to neutral, on cereal grass stand without nitrogen — negative (–18…–28 kg/ha). The balance of phosphorus in the case of entering R45K90 on the cereak grass stand was positive — 24–32 kg/ha, on Lucerne and Lucerne-cereals — close to neutral, without the use of fertilizers — negative (–12…–40 kg/ha). The balance of potassium was negative with a deficit (–56…–241 kg/ha), except for its value on the cereals grass stand with entering R45K90, where it was close to neutral.