engleski

INFLUENCE OF NITROGEN FERTILIZATION TO NO3-N CONCENTRATION IN SUBSURFACE DRAINAGE WATER

In a field trial with different mineral nitrogen doses (0, 100, 150, 200, 250 and 300 kg Nha-1) nitrate nitrogen losses in drainage water are quantified for the period from October 1997. The trail was set up so that the area of each fertilizing treatment embedded two drainpipes, in their full length. Water samples were collected on a daily basis during the periods of outflow. NO3-N concentration in drainage water varied in dependence on the crop type and development stage, on the fertilization, on the quantity and intensity of precipitation and on the drainage volume. Crop sequence at test field included corn, winter wheat, oilseed rape and soybean. Obtained results can be used for prediction of nitrogen losses with drainpipe water in regions with similar agro-ecological conditions. Increased rates of applied mineral nitrogen led to higher average values of NO3- N concentration in drainage water. At the treatments with 100 and 150 kg ha-1 N, average nitrate nitrogen concentration was lower than 15 mgL-1. At the treatments with higher doses of nitrogen, concentrations of NO3- N in drainage water were also higher, and they were in relation with quantities of applied nitrogen. Maximum average concentrations went up to 27, 2 mgL-1 NO3- N at treatment with 300 kg ha-1 N. Scientific research results are used for assessment of water contamination with nitrogen. According to the applicable EU regulations, continuous groundwater quality monitoring, particularly for nitrogen from agriculture is required for compliance with the water quality monitoring provisions of the Nitrate Directive (91/676/EEC).

Subsurface drainage water, Nitrate-nitrogen losses

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