Impact of foliar fertilizing on the white mustard productivity in the northeastern Forest-Steppe of Ukaraine

The experimental studies were carried out on the fields of the Sumy NAU Training Research and Production Complex (TRPC) during 2016–2018.The soil of the experimental plot is typical deep-medium humus, large-dusty and medium-loam black soil on forest trees. The subject of the research was a white mustard variety of Oslava created at the Institute of Feed and Agriculture of the Podillya NAASU, entered in the Register of varieties suitable for cultivation in Ukraine in 2010. The aim of the research is to optimize the nutrition of the white mustard variety of Oslava through the complex application of mineral fertilizers and foliar fertilization under the conditions of the northeastern forest-steppe of Ukraine. The analysis of weather conditions, in particular the hydrothermal coefficient of Selyaninov (HTC), established that 2016 season was wet (HTC = 1.60), 2017 and 2018 were dry (HTC = 0.59 and 0.46). During the research, the cultivation technology was generally accepted in the experimental area, except for the elements studied. The results of the three-year study on the influence of foliar fertilizing under different mineral nutrition backgrounds on the yield of the white mustard variety Oslava are presented. It was found that the application of mineral fertilizers and complex fertilizers for the foliar feeding had a positive effect on the morphometric parameters of the white mustard, in particular, increased the plant height and the number of branches of the first order. The use of mineral fertilizers at the rate of N30P30K30 provided an increase in the yield by 0.34 t/ha, N60P60K60 – by 0.55 t/ha, N90P90K90 – by 0.61 t/ha on an average compared to the control. Therefore, for the maximum yield (2.14–2.21 t/ha) with a mass of 1000 seeds (5.39–5.54 g) of the white mustard under the conditions of the Northeastern Forest-Steppe of Ukraine, foliar fertilizing of Vuxal boron (3.0 l/ha) + Vuxal bioaminoplant 3.0 l/ha) and Spectrum B + Mo (2.0 l/ha) + Spectrum Ascorist (3.0 l/ha) should be applied on the background of N60-90P60-90K60-90, what provided an increase in the yield compared to the control of 0.58-0.65 t/ha.