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Abstract:

The purpose of the present paper is to test the existence of significant differences concerning the effluent needed to remove the equivalent of an amount of 200 kg N ha^-1 applied fertilizer containing NO^₃- and to quantify the nitrate leached per mm of effluent for three different soil textures: sandy, sandy-loamy and loamy-clayey. The experiment was performed on undisturbed soils sampled in small-scale lysimeters, 0.3 m in diameter and 1.0 m height. NH_⁴NO_³ fertilizer granules were applied as a batch solution with a concentration of 6.26 g L^-1. Water was applied by a drip irrigation system in the lysimeters. Below the bottom outlets, glass containers were placed to periodically collect the effluent for chemical analyses and volume determinations. Soil texture and clay type determined the nitrate leaching pattern. Distinctly significantly more nitrates were leached out per mm of water from sandy- than from loamy soils. Swell-shrink clayey soils are almost impermeable and have a low risk in groundwater contamination with nitrate. If climate change continues and extreme rainfall events occur, nitrate leaching could be even greater within the region containing permeable sandy soils. To minimize nitrate leaching, sprinkling or drip irrigation, no-till cropping systems and split-fertilizer application should be applied.