The effect of soil cultivation on changes of its physical and chemical properties

The aim of this work was to determine the effect of soil tillage and fertilization of soil physical and chemical topsoil properties of Eutric fluvisol. Treatments were carried out in 1999-2001 in Vysoka nad Uhom. This experimental place is situated in central part of the East-Slovakian Lowland, approximately 105 m above sea level. For this locality the continental climate is a typical one. An average annual air temperature is 9.1 degree C, during vegetation period 15.2 degree C. A long-time average of rainfall is 591 mm, during vegetation period 397 mm. From soil characteristics of treatment locality influence than this soil is characterised as loamy soil, middle heavy soil with content of clay particle more than 30%. This soil is depth and good permeable in whole profile. The topsoil has light brown colour and cloddy till bean-shaped structure. The field treatments were realised without irrigation in natural conditions. Two soil tillage technologies were examined: konv. - conventional tillage, i.e. current way of soil by ploughing; bez. - no-tillage technology, i.e. direct sowing without tillage. Crop rotation in 1999-2001 was as follows: grain maize - field pea - winter wheat. In before experimental year 1998 alfalfa in the third crop year was cultivated. Two variants of fertilization were also examined: Frac - rational fertilization and Fo - without fertilization. Doses of fertilizers on variant Frac were followed: grain maize - 120 kg nitrogen (dose divided on base and further fertilising, 22 kg phosphorus, 93 kg potassium per hectare, field pea - 20 kg nitrogen, 30 kg phosphorus, 80 kg potassium per hectares ,winter wheat - 90 kg nitrogen (dose divided on base, regeneration and quantitative fertilizing), 30 kg phosphorus, 100 kg potassium per hectare. Nitrogen fertilizers were applied in form of ammonium sulphate and ammonium nitrate, phosphorus fertilizers as superphosphate and potassium fertilizers in form of potassium chloride. Soil samples were taken in autumn after harvest of field crop. On taken samples were ascertained physical soil parameters (bulk density, total porosity, maximum capillary water capacity) and chemical parameters, i.e. quantitative and qualitative parameters of humus (humus content, composition of humus substances). Obtained data were compared with before experimental year 1998. Data were tested by mathematics-statistical methods. Variance analysis and simple regression linear analysis were used. Increase of bulk density for no-tillage variant in comparison with conventional tillage variant was determined. With this result corresponded decrease of total porosity. Maximum capillary water capacity was enough variable and its value was statistical significantly influenced by soil tillage technology, fertilization and experimental year. On no-tillage variant higher humus content in soil was ascertained. On the contrary the qualitative parameters of humus were positively influenced by conventional soil tillage system. The rational fertilization had also positively influence on content and composition of humus. Optimum content of organic matter and its good quality effected physical and chemical soil properties, too. Statistically significant relations between selected physical soil properties and humus composition were determined. Statistically significant negative correlation between bulk density and carbon content of humic acids was ascertained (r = -0.38). Between total porosity and carbon content of humic acids positive significant relation was observed (r = 0.44)