EFFECT OF DIFFERENTIATED PHOSPHORUS AND POTASSIUM FERTILIZATION ON WINTER WHEAT YIELD AND QUALITY

This study was conducted in 2007-2010, on a farm near rem (south of Poznan., Poland). A field experiment was set up in a randomized block design with four replications for each combination tested. The effects of differentiated rates of phosphorous and potassium applied together with a fixed level of nitrogen and magnesium fertilization were investigated. During the experiment, the winter wheat grain yields were high and significantly different between both between fertilizer treatments and when compared with the control. Correlation analysis on relationships between grain yield and nutrient content in wheat leaves at the beginning of stem elongation stage (BBCH31) showed significant relationships for phosphorous, calcium, magnesium, zinc and manganese. Regression analysis proved that the content of zinc in leaves at the BBCH31 stage was the main factor which determined winter wheat grain yield. Furthermore, mineral fertilization significantly increased the content of protein and gluten when compared with the control objects, whereas no significant differences were observed among the fertilized objects. Statistically significant relationships were found between leaf content of N, P, Mg, Zn and Mn at BBCH31 and the accumulation of protein and gluten in wheat grain. Protein and gluten in grain depended on the content of magnesium in leaves at the beginning of stem elongation stage. Weather conditions as a factor significantly influenced grain size uniformity while mineral fertilization had no influence on this trait.