The research was conducted in the years 2006/2007-2008/2009 on the basis of an experiment set up in 2005 on the Experimental Farm in Bezek (51^o19’ N; 23^o25’ E), belonging to the University of Life Sciences in Lublin. The evaluation included the effect of tillage systems (plough tillage and conservation tillage with autumn and spring disking of catch crops) and of using various catch crops in spring wheat monoculture on chosen chemical properties of rendzina soil. Conservation tillage, compared with plough tillage, affected the increase of the content of organic carbon, nitrogen and potassium and the decrease of phosphorus content in the topsoil (0-20 cm). The highest content of magnesium and sulphate sulphur was determined in the soil with conservation tillage where catch crops were disked in spring. Stubble catch crop of white mustard influenced the increase of S-SO₄ content in the soil, compared with control and other plots where the catch crops were sown. Organic carbon content in the soil where red clover, Westerwolds ryegrass and white mustard were sown as catch crops, was greater than on plots after lacy phacelia or without catch crops. The highest phosphorus content in the soil was determined in the combination with undersown catch crop of red clover, in control and with lacy phacelia. The highest potassium content in the soil was found on plots with Westerwolds ryegrass and white mustard. In autumn, the content of P, K, and S-SO₄ in the soil was significantly lower than in spring. Similar tendency was observed for nitrogen and magnesium. The content of organic carbon, potassium, magnesium and sulphate sulphur in the soil increased in successive years of research. The highest phosphorus content was found in the first, and of nitrogen in the second year of research.

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