The yield and chemical composition of winter oilseed rape seeds depending on different nitrogen fertilization rates and the preceding crop

The aim of this study was to determine the influence of nitrogen fertilization and the preceding crop on the yield and chemical composition of winter oilseed rape. The yield of winter oilseed rape increased significantly in response to a fertilizer dose of 180 kg N ha-1. In our study, significant interactions were observed between the preceding crop and dose of nitrogen fertilizer. The optimal N fertilizer dose for winter oilseed rape grown after peas, narrow-leaved lupine and traditional (indeterminate) faba beans is 120 kg N ha-1. The recommended N fertilizer dose for winter oilseed rape is 60 kg N∙ha-1 after determinate faba beans and 180 kg N ha-1 after spring wheat. Winter oilseed rape was characterized by the highest seed yield when grown after determinate faba beans, and its yield was slightly lower after peas and narrow-leaved lupine. The lowest seed yield was noted when spring wheat was the preceding crop. The micronutrient content (Mn, Zn, Cu and Fe) of winter oilseed rape increased significantly in response to an increase in nitrogen fertilization doses. The seeds of winter oilseed rape were characterized by the highest phosphorus and magnesium content when grown after peas, the highest potassium content was achieved after determinate faba beans, and the highest calcium content occurrd in oilseed ape when grown after spring wheat. A linear regression analysis revealed a significant relationship between total nitrogen concentrations in the seeds of winter oilseed rape growth after spring wheat and nitrogen fertilization dose. An increase in fertilization levels enhanced nitrogen accumulation in seeds. A similar trend was noted when winter oilseed rape was grown after indeterminate faba beans and peas.