The nitrate concentration in groundwater is increasing in the major part of intensive agriculture areas in Europe. In order to assess the effective impact of agriculture on the environment it is required to better understand the nitrogen balance and the biophysical processes involved, which are site specific and influenced by soil type, climate and cropping systems. To this purpose a set of monitoring sites representative of different soils and cropping systems has been supplied in the Lombardy plain, where a high intensive agriculture and livestock breeding as well as water pollution by nitrogen compounds occur. Ten monitoring sites have been equipped with a meteorological station and TDR probes, tensiometers, microlysimeters and soil temperature probes at different depths in the soils. Furthermore soil profiles description, hydrological and micromorphological characterization and analysis of soil horizons have bee provided. In this paper the data collected from 2003 to 2005 in two monitoring sites are presented. In the first site a coarse loamy (with more than 70% of sand in the subsoil), moderately acid and well drained soil (Ultic Haplustalf coarse loamy, S.T. USDA, 2003) occurs; the crop was maize, minimum tillage, surface irrigation (700 mm/ha/year) and fertilization with sewage sludge and with inorganic fertilizers (280 kg N/ha/year) were adopted. The average rainfall was 800 mm/year. The second site is characterized by a fine, rich in calcium carbonate and alkaline soil, with a calcic horizon and some vertic features (Typic Calciustept fine, S.T. USDA, 2003); even there the crop was maize, while the soil was ploughed at 35-40 cm depth, sprinkler irrigation (350 mm/ha/year) and fertilization with both cattle and pig manure and with inorganic fertilizers (480 kg N/ha/year) were used. The average rainfall was 760 mm/year. The soil water content is higher in the second site, mainly in the surface and sub-surface horizons, where an higher clay content increases the water retention capacity. As expected, the surface layers (<50 cm) show the highest variations mainly during the growing season, when also the maximum evapotranspiration and irrigation supply occur. Deeper soil horizons show much more uniformity, even if, it can be still observed the effect of irrigation. In the second site, this behaviour is much more evident, probably because of occurrence of preferential flows leading to a more uniform redistribution of water in depth. As observed, the nitrate content in the water circulating in the soils decreases very quickly during the irrigation periods. This decrease occurs in both the surface and bottom layers, suggesting leaching can occur, even if nitrogen plant uptake has to be also considered. The very high nitrate contents in the soil water in autumn after harvesting seem to be related to the late organic matter mineralization and lack of nitrogen plant uptake; however the nitrate content always and rapidly decreases after the following high rainfall events. In the first site the average nitrate leaching can be preliminary estimated as ranging around 150 kg N/ha/year, in the second site around 215 kg N/ha/year. More reliable estimations will be carried out using deterministic models simulating the N-cycle (ANIMO, CROPSYST, DAISY). The two sites show different nitrogen and water dynamics: in the coarse textured soil the water and nitrate movement seem mainly affected by high hydraulic conductivity (water decreases in the whole soil profile very quickly); in the fine textured soil water movement is in part reduced by lower hydraulic conductivity, even if the occurrence of preferential flow allow to get a deep transport of water and nutrients.