Environmental aspects of mineral fertilizing of perennial grass mixtures on drained organic soils

Environmental protection and effective use of floodplain organic soils of river valleys in the humid zone is associated with the development of sustainable agrosystems, in which 65–75% of the sown area is allocated to perennial grasses. The main measure in the technology of growing perennial grass mixtures is the introduction of mineral fertilizers. The conducted studies show that the highest yield of perennial grass mixtures on average for 2016–2019 was obtained with the introduction of recommended doses of fertilizers obtained on the basis of perennial studies (N45P45K120) — 8.9 t/ha, and with the addition of 2 l/ha Organic Balance — 9.4 t/ha of dry mass; for the yield of 8.5 t/ha for the calculated dose of fertilizers to increase the yield of herbs N45P84K150 and 8.3 t/ha for the calculated dose for the planned yield taking into account the content of nutrients in the soil N45P138K293. Therefore, the most economically profitable and scientifically justified application of mineral fertilizers to crops of perennial grasses obtained on the basis of long-term scientific data, taking into account soil, climatic and weather conditions. In addition, the introduction of different doses of mineral fertilizers led to their corresponding leaching into the drainage waters, the leaching of NO3 during the growing season in the version with the recommended dose of fertilizers was 12.3 mg/l, and in the version with the introduction of mineral fertilizers for crop growth (N45P84K150) increased leaching into groundwater up to 17.2 mg/l of water. Thus, the economic and ecological evaluation of determination of doses of mineral fertilizers calculated by various methods showed that it is most expedient to determine calculations based on data obtained in long-term studies on crops of perennial grasses.