The research goal was to determine the influence of drainpipe spacing onthe quantity of nitrogen leached, under standard agricultural practices, in the ecological conditions of eastern Slavonija. The field trial was set up at the agroecological station Kapelna-Donji Miholjac in the period 1993-1994, on amphigley soil, drained through an open channel network and drainpipes spaced 10, 20 and 40 m, according to the split-plot method with three replications. Winter wheat, cultivar Marija, served as test crop. Research results revealed differences in the concentration of nitrate and ammonium nitrogen in soil, depending on drainpipe spacing, plot location and sampling time. Significantly lower concentrations of nitrate nitrogen were recorded on plots overlying drainpipes compared to the plots situated between drainpipes, regardless of drainpipe spacing. Nitrogen in drainage water and groundwater was mainly present in the nitrate form. The highest average concentration of nitrate nitrogen in drainage water of 25.9 mg NO3-N / l and in groundwater of 16.7 mg NO3-N / l were recorded at the drainpipe spacing of 10 m, and the lowest at the drainpipe spacing of 40 m. The significantly highest quantity of leached nitrogen of 11.2 kg N/ha was recorded at the drainpipe spacing of 10 m, whereas differences in the leached nitrogen quantities between drainpipe spacing of 20 and 40 m were not significant. The relatively small quantities of nitrogen leached, despite high nitrate concentrations in drainage water, resulted from the low drainage discharge during the trial period.

drainage water and groundwater; nitrate and ammonium nitrogen; leaching

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia