ANNUAL DRAINAGE VOLUMES AND NITRATE-NITROGEN LEACHING UNDER SILAGE MAIZE IN WET AND DRY YEAR

The  quantity  of nitrate  in groundwater  is  affected by diffuse agricultural pollution and hence, it is strongly linked to the amount of applied nitrogen (in surplus) on agricultural land. In order to determine nitrate-nitrogen leaching in diverse precipitation conditions, lysimetric field experiment was set in 2011 in Varaždin County, Croatia. Leachate from three zero-tension pan lysimeters on agricultural plot (maize) was collected twice a month or after abundant rainfall. Research results show that 25% of total precipitation leached in 2012 and 13% in 2013. ANOVA results confirm there is a statistically significant difference in NO₃-N concentrations between  hydrological dry and wet years. In dry years NO₃-N concentrations vary from 36 to 56 mg/1 and in 2013 from 8 to 40 mg/I.