The aim of this study was to estimate the effect of the catch crop used as green manure on magnesium content in soil and in the grain and straw of spring barley cultivated afterward in different soil conditions. The field study was carried out in 2008-11 in two different soils: lessive soil (location 1) and typical black earth (location 2). The experimental factor was the catch crop (field pea) used as green manure for spring barley cultivated in the following year. Three treatments were assessed: I) catch crop ploughed in autumn, II) catch crop left over winter as mulch (uncut), and III) control – without the catch crop.
Mg content in spring barley grain and straw was determined using the colorimetric method with titanium yellow. Mg content in spring barley grain was not dependent on the catch crop used as green manure. This factor had a better effect on Mg concentration in straw. In both locations it was significantly higher in the control than after the catch crop. Ploughing in the catch crop resulted in a significant decrease in Mg content in straw of barley cultivated in lessive soil as compared with mulch. The content of this element in straw of barley cultivated in the typical black earth was significantly higher in the treatment with ploughed-in catch crop than with mulch. Mg content in spring barley grain was not correlated or negatively correlated with soil abundance in this element. However, a positive correlation between Mg content in soil before spring barley sowing and in straw of this plant was found.