The Influence of Irrigation on Nitrates Movement in Soil and Risk of Subsoil Contamination

This paper presents the results of the nitrates movement monitoring under the conditions of field experiment, with different fertilisation doses applications, with and without irrigation and, for different crops. The experiments were conducted at the experimental station of the Hydromelioracie, state entp., at Most pri Bratislave site, south slovakia. The soil at the site is mainly clay loam with a high retention capacity and a relatively low hydraulic conductivity. The results of the nitrates measurements in the soil profile during the vegetation period and those of lysimetric water analysis have shown that the movements of nitrates in irrigated and non-irrigated fields differed significanty during the early stages of the vegetation period, but at the end of this period the differences between the irrigated/non-irrigated and fertilised/non-fertilised soils were small, probably due to an increased uptake of water and nutrients during the vegetation period at the irrigated field. Properly applied irrigation was not the reason for nitrates penetration below the root zone under the soil and meteorological conditions of Most pri Bratislave site.