The aim of research was determination of the content of selected constituents (dry matter, ash, α-aminonitrogen, reducing sugars, Mg, Ca, K), of sugar beet roots grown under conservation tillage using mulch from straw, winter rye and winter vetch, as well as two levels of nitrogen fertilization. This experiment was conducted between 2007–2010 at the Experimental Station of University of Environmental and Life Sciences in Wroclaw. From among conservation tillage systems of sugar beet, the highest amount of ash was found in roots grown under rye mulch and the lowest one was found in roots collected from plots under fore-crop straw mixed with harrow. Sugar beet roots under mustard mulch had the best technological quality (the lowest amount of α-amino-nitrogen) while the worst quality was observed under winter vetch mulch.