THE EFFECT OF A MICRO-GRANULAR STARTER FERTILIZER ON THE BIOMASS QUALITY OF WINTER OILSEED RAPE

The effectiveness of mineral fertilization can be improved through starter or band application. This technique reduces fertilizer doses (costs) and minimizes environmental risks (decreased nutrient stratification, reduced nutrient emissions to surface water, groundwater and the ambience). This paper presents the results of a 3-year study investigating the effects of a micro-granular starter fertilizer (MSF) applied in the seed zone on the macronutrient content in autumn and after the harvest of winter oilseed rape (Brassica napus L.). The study was carried out at the Agricultural Experimental Station in Balcyny (northeastern Poland) in 2012-2015. The application of MSF, in addition to NPK applied pre-sowing (NPK + MSF), contributed to an increase in the macronutrient content of leaf rosettes (N, P, K and Ca) and roots (N, P and K) of winter oilseed rape before the end of the growing season. The application of MSF in treatments with NPK fertilization significantly decreased the content of P and Mg in the seeds of winter oilseed rape. The application of MSF increased the macronutrient content of straw, but the magnitude of this effect was determined by the NPK dose applied pre-sowing. The application of MSF (regardless of NPK doses) increased the content of N, P, Mg and Ca, and decreased the content of K in the roots of winter oilseed rape. In treatments where MSF was combined with a standard dose of NPK applied pre-sowing, the nutrient uptake increased by 12-24% N, 14-22% P. 13-26% K, 11-24% Mg and 18-24% Ca (75-90 days after sowing (DAS). The application of MSF increased the macronutrient uptake by straw, but decreasedthe macronutrient uptake by roots (318-332 DAS).