P and K Accumulation by Rapeseed as Affected by Biostimulant under Different NPK and S Fertilization Doses

Biostimulants are gaining growing importance among preparations used for plant production. They may cause increasing the effectiveness of nutrient uptake. The aim of the study was to assess P and K accumulation by winter rapeseed after the application of a biostimulant under conditions of varied NPK and S fertilization levels. The field experiment was established on Alfisol, and the factors were: Two levels of NPK fertilization (high 180 N, 70 P, 132 K (kg ha(-1)) or low 144 N, 35 P, 66 K (kg ha(-1))); elementary S fertilization (36 or 0 kg ha(-1)) and application of seaweed biostimulant or without that treatment. Biostimulant caused an increase in P and K accumulation in the shoots of rapeseed during generative development. Application of biostimulant in rapeseed fertilized with lower NPK rates or not fertilized with S increased P and K accumulation in shoots to the level obtained at higher NPK and S rates without that treatment. Increased level of NPK fertilization caused an increase in P and K accumulation in both shoots and roots at flowering and ripening stages. At the fruit development stage, under higher NPK fertilization there was higher uptake of P and K in rapeseed shoots after presowing fertilization with S.