engleski

The effect of nitrogen fertilization on nitrate leaching under potato production

The aim of this study was to determine the effect of different fertilization by nitrogen on nitrate leaching from the soil during potato production. The study was conducted in Belica, north-west region of Croatia, in the period 2009-2010 on Fluvisol. Fied trial was designed as a completely randomized block design with four levels of nitrogen fertilization (50, 100, 150, 200 kg N/ha), with three replications. Water samples were taken monthly by lysimeters during the growing period of potato and soil samples three times a year. Nitrates in soil and water were determined spectrophotometrically, using a complex yellow phenolsulphonic acid (USDA- SCC-NSCS, 1992). Increase in applied fertilizer rates (50–200 kg N/ha) led to an expected increase in the nitrate concentration in the arable soil layer (0.04–9.51 mg NO3-/100 g soil) with significantly highest concentrations on variant fertilized with 200 kg N/ha. Nitrate concentrations in percolating water varied in wide range, 4.1–283.5 mg NO3-/l, in dependance of nitrogen fertilization, precipitation, soil moisture regime and stage of growth of potato. Increased nitrogen fertilization of potato was accompanied by an increase in nitrogen leaching (1.1 to 13.9+kg NO3-N/ha) as well as increase in yields of fresh mass of potato tubers from 8.2 to 37.7 t/ha.

nitrogen fertilization; nitrate leaching; potato

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