The paper is based on the researches carried out in a long term trial placed in 1995. The most unfavourable values of the bulk density, total porosity, and penetration resistance were determined in the variant with disk roller; it is followed by variant with plough land of 12 cm depth and chisel; the most favourable values were registered in the variant with summer plough land of 20 cm depth. In the last 3 years, in comparison with the variant of summer plough land of 20 cm, in the others variant the lost yield were of 27,2-49,2% in the variant with disk roller,, of 19,1-25,4% in the variant with chisel and of 11,8-32,1% in the variant with plough land of 12 cm. The results emphasized the importance of summer plough land in the conditions of the soil with 31.5% colloid clay.

bulk density; total porosity; penetration resistance; hydraulic conductivity; plough land; and yield

Presentation: oral