Abstract
In field experiment conducted in 2005-2007 there was evaluated the suitability of Entec 26 - a new concept nitrogen fertilizer containing DMPP nitrification inhibitor (3,4-dimethylpyrazole phosphate) and ammonium nitrate as a source of this nutrient for white cabbage. Ammonium nitrate was supplied in split doses of 75 (1/2 + 1/2), 150 (1/2 + 1/2), 225 (1/3 + 1/3 + 1/3) and 300 (1/4 + 1/4 + 1/2) kg N per hectar, as preplant and one or two top dressings. Entec 26 was used in the same amounts and terms of application as ammonium nitrate or in one preplant dose.
Results of the study showed that Entec 26 was a better source of nitrogen than ammonium nitrate, providing higher yield of marketable heads and lower nitrate contents in plants at harvest. Plants supplied with a single preplant dose of N produced similar marketable yield with lower nitrates accumulation in comparison to split application of the fertilizer. Irrespective of nitrogen form, enhancement of its dose from 75 kg·ha-1 to 300 kg·ha-1 resulted in the decrease of sugars and vitamin C contents, while the increment of total N and nitrates level in cabbage heads.