WINTER OILSEED RAPE YIELD DEPENDING ON FOLIAR FERTILIZATION
Background. An insufficient amount of nutrients in plants results in the disturbance of basic physiological processes, weakens the growth and development of plants, and consequently contributes to a reduction in yield. The aim of this study was to determine the effect of foliar fertilizers containing sulphur, boron and amino acids on the seed yield of three winter oilseed rape morphotypes (Monolit, PX115, PT248).
Material and methods. The study was carried out in 2016-2019 at the Zawady Agricultural Experimental Station (52o03' N; 22o33' E) belonging to the University of Natural Sciences and Humanities in Siedlce, in Poland. The field experiment was established in a split-plot design with three replicates. The studied factors were: I – three winter oilseed rape morphotypes: population (cv. Monolit), restored with the traditional growth type (cv. PT248), and restored with the semi-dwarf growth type (cv. PX115); II – types of foliar feeding: 1. The control variant – without foliar feeding and amino acids applied, 2. biostimulant Aminoplant, 3. foliar fertilizer Siarkomag + foliar fertilizer Bormax, 4. foliar fertilizer Siarkomag + foliar fertilizer Bormax + biostimulant Aminoplant.
Results. Foliar fertilizers used in the experiment increased the thousand seed weight (on average in the range from 0.9% to 3.4%), seed yield (on average in the range from 2.5% to 18.5%), straw yield (on average in the range from 2.1% to 5.4%) and the harvest index (on average in the range from 4.4% to 7.5%). Of the compared cultivars the semi-dwarf cultivar (PX115) was characterized by the highest yield, while the lowest was from the population cultivar (Monolit). The highest thousand seed weight, main and secondary yields were obtained in the first year of the study which was characterized by a higher total rainfall during seed development and maturation of pods periods compared to the multi-year period, while the lowest levels of these factors was in the vegetation season of 2017–2018 with a humid autumn season and dry period during the flowering and maturation of pods.
Conclusion. The most significant increase in the thousand seed weight and seed yield was obtained after applying mixed fertilizers containing sulphur, boron and amino acids. Additional foliar application of the biostimulant Aminoplant on plots with the population and semi-dwarf cultivars did not significantly increase the seed yield as compared to the control. A significant effect of the genetic factor and climatic conditions on the discussed traits has been demonstrated.