Impact of multi-annual mineral fertilization with NPKCa on the content and uptake of magnesium by eastern galega

This paper presents the changes in the magnesium content in soil and plants and in the uptake of this element in yield under the influence of NPKCa fertilization. Eastern galega (Galega orientalis Lam.) was cultivated in 2005-2009. A field experiment was conducted on the experimental plots of the Siedlce University of Natural Sciences and Humanities. Thirteen levels of fertilization were included in the study: without fertilization, N20, P50, K150, N20P50K150, N20P50, N20K150, P50K150, N20P50K150Ca150, P50K150Ca150, Ca150, N20K150Ca150, N20P50Ca150. Three swaths of the test plants were harvested at budding in each year of the study. The total content of magnesium in soil and in plants was determined with the ICP-AES method on an emission spectrophotometer with inductively-coupled plasma. The applied mineral fertilization with NPKCa did not have any significant impact on the average magnesium content in soil. The highest (significantly) content of magnesium was determined in eastern galega biomass harvested from the plots fertilized with Ca150 as dolomite calcium in all years of the experiment (the mean for the years: 2.91 g kg-1 d.m.). The average content of Mg in the subsequent swaths was as follows (in g kg-1 d.m.): swath I (2.04) < swath II (3.23) > swath III (2.39). The determined content of magnesium in eastern galega in the subsequent years of the experiment ranged between 2.22 g kg-1 d.m. in 2006 and 2.83 g kg-1 d.m. in 2008. The highest uptake of magnesium in eastern galega yield (73.78 kg Mg ha-1) was recorded on a plot fertilized with N20P50Ca150 in 2008.