Effects of different phosphorus and potassium fertilization on contents and uptake of macronutrients (N, P, K, Ca, Mg) in winter wheat II Uptake of macronutrients

Sa？etak The aim of this study was the assessment of macronutrient (N, P, K, Ca, Mg) accumulation in wheat at the critical phases of yield shaping as well as at the full ripening stage when judged at optimal P and K fertilizer rates applied as well as at reduced levels of fertilization with these elements. Four-year-long investigation on winter wheat was carried out in 2007-2010 within an agricultural holding located in vicinity of Srem city (western Poland). The experiment was conducted under field conditions and based on the randomized-block design with four replications for each treatment. The factors investigated were differentiated P and K rates applied at constant N and Mg levels. Macronutrient accumulation in wheat differed depending on the element studied, plant development stage as well as P and K fertilization levels. The highest differentiation in macronutrient accumulation was observed at wheat flowering stage. At the full ripening stage, there were observed attributable to mineral fertilization significant differences in accumulation of K and Mg. Regression analysis proved that wheat grain yield was determined to the biggest extent by accumulation of K at BBCH 31 stage and that of N at BBCH 92 stage