Nitrogen migration and modern approaches to planning effective nitrogen nutrition when growing winter rapeseed in the conditions of the Western Forest Steppe

Abstract

Purpose. The purpose of the research was to establish the patterns of vertical and seasonal migration of nitrate and ammonium forms of nitrogen in the soil depending on the phases of winter rapeseed development, as well as to evaluate the effectiveness of using different forms of nitrogen fertilizers.
Methods. In the process of conducting the work, generally accepted scientific agrochemical methods and special research methods were used to determine the content of mineral forms of nitrogen in the key phases of organogenesis of winter rapeseed culture.
Results. It was established that the highest concentration of nitrate nitrogen was formed in the upper layer of the soil (0–20 cm) in the spring period of intensive growth of rapeseed, which is due to the active mineralization of nitrate forms and the introduction of nitrogen fertilizers. In the later phases of vegetation, there was a tendency to move nitrates into deeper soil horizons, especially under conditions of increased moisture, which indicates an increased risk of their leaching beyond the root layer. The ammonium form of nitrogen was characterized by lower mobility and was mainly accumulated in the upper layers of the soil. During the cultivation of rapeseed of the winter variety of DSV selection hybrids (in particular, Dominator), it was established that it showed a high ability to assimilate mineral nitrogen, which contributed to the reduction of its losses under optimized nitrogen fertilization rates. The research results demonstrate a comprehensive assessment of nitrogen migration processes in the soil, taking into account the varietal characteristics of the winter rapeseed hybrid.The article substantiates the introduction of environmentally safe standards of nitrogen fertilization, aimed at increasing the efficiency of nitrogen use and preserving soil fertility.
Conclusions. The article highlights the peculiarities of the migration of nitrogen compounds in the soil profile for the technology of growing rapeseed of the winter variety of hybrids of DSV selection (in particular, Dominator) in the conditions of the "Victoria 92" farm in the Western Forest Steppe zone. The migration of nitrogen in the soil is a complex process that depends on water, microorganisms and chemical transformations. Observations of soil nitrate content showed that the use of mineral fertilizers contributed to the accumulation of nitrates in the soil only in the second half of the growing season of the crop. But the amount of nitrates in the seedling phase of winter rape in 60 cm vertical of the soil decreased by 1.0-1.3 mg/kg, compared to controls without fertilizers. A significant decrease in nitrates was noted in the upper 0-20 cm soil layer – by 5.5-6.3 mg/kg.