The changes of clay-loamy soil properties at its different tillage

The aim of this work was to show the development of physical properties of clay-loamy soil at various tillage practices. Treatments were carried out in 1998-2006 in Milhostov on heavy Gleyic Fluvisol (FMG). This experimental locality is situated in central part of the East-Slovakian Lowland, approximately at an altitude of 101 m. For this locality the continental climate is typical. Gleyic Fluvisol is characterized as a clay-loamy soil, heavy soil with the average content of clay elements higher than 53%. This soil is slightly leaching in the whole profile. The topsoil has a lump aggregate structure with a high binding ability. A coherent layer of grey clay is usually in the depth of 0.8 m. The field treatments were realized without irrigation. Two soil tillage technologies were examined (PS - no-tillage technology, i.e. direct sowing without tillage, KA - conventional tillage, i.e. current way of soil tillage by ploughing). Field plants were arranged into a crop rotation as follows: clover-grass mixtures 2nd crop year - clover-grass mixture 3rd crop year - grain maize - field bean - winter wheat - soya bean - winter wheat - grain maize -spring barley. Soil samples were taken in spring since April to May. Physical soil parameters (bulk density, total porosity, maximum capillary capacity, available water capacity, non-capillary porosity, point of decreased availability) were determined in these soil samples. Obtained data were tested by statistical methods, especially by variance analysis. An increase in bulk density at no-tillage variant in comparison with conventional tillage variant was determined. With this result the decrease of total porosity in variant with direct sowing without ploughing corresponds. Tillage system, mainly conventional tillage, affected maximum capillary capacity significantly. Available water capacity did not show any differences between variants with different soil preparation and its values 7.07-25.88% suggest a significant dependence of this soil parameter on the content of clay particles. In the average during the nine-year experimental period the less non-capillary pores were determined on variant with conventional tillage (D = 0.25%) and the decrease in total porosity at no-tillage systems was not found out. Tillage practice of clay-loamy soil had statistically significant effect on bulk density and total porosity. All studied soil parameters were statistically significantly affected by experimental year, i.e. by rotation of field crops on a trial plot.