The response of different kinds of rapeseed cultivars to foliar application of nitrogen, sulphur and boron

The study was based on in 2016–2017, 2017–2018, 2018–2019 field experiment conducted at the University of Natural Sciences and Humanities in Siedlce (Zawady Agricultural Experimental Station), eastern Poland. The studied factors were: I. winter rape cultivars: Monolit—open pollinated cultivar; PT248-F1 hybrid cultivars with traditional growth type; PX115-F1 hybrid cultivars with a semi-dwarf growth type and types of foliar nutrition: (1) control variant without foliar nutrition and amino acids; (2) amino acid; (3) foliar fertilizer sulphur and boron; (4) foliar fertilizer sulphur with foliar fertilizer boron and amino acid. The aim of the study was to determine the effect of foliar application of sulphur, boron, amino acids on the use and feed value of seeds of three winter rape morphotypes. The highest content of crude fat in seeds of the studied morphotypes was found after foliar fertilization with sulphur and boron and amino acids, while the lowest under the influence of amino acids. The highest concentration of total protein was obtained after the application of amino acids, and regardless of the morphotype studied on this object, the same value of this trait was demonstrated. In restored morphotypes, the use of additional foliar fertilization S and B in combination with amino acids did not significantly increase this characteristic compared to the amino acid variant. As a result of the application of amino acids and foliar feeding of S and B, and amino acids, the largest increase in crude fibre content in rapeseeds was obtained, while the application of S and B did not significantly increase this characteristic compared to the control variant. The best feed and use value of seeds were noted in restored morphotypes, with the semi-dwarf variety having the highest fat and crude fibre content. Climatic conditions in the years of research significantly determined the value of seeds. The highest values of the examined traits were obtained in the last year of the study, and the lowest in the growing season 2016–2017.