EFFECT OF NITROGEN FORMS ON GROWTH, YIELD AND NITRATE ACCUMULATION OF CULTIVATED PURSLANE (PORTULACA OLERACEA L.)

The present investigation was carried out to determine not only the most appropriate nitrogen form but also the effect of these forms on growth, yield, element content and nitrate accumulation of cultivated purslane (Portulaca oleracea L.) when the usual N dose was applied. The experiment was conducted under field conditions during 2009 and 2010. The nitrogen forms used in this work were ammonium nitrate, urea, ammonium sulfate, calcium ammonium nitrate. While the highest yield was being determined in urea (2889 g plot-1) in 2009, in ammonium nitrate (3022.5 g plot-1) in 2010. The macro and microelements in purslane are N, Ca, K, Mg, Na, P, S and B, Cu, Fe, Mn, Zn, respectively. In spite of the fact that the lowest nitrate accumulation was determined in control and ammonium sulfate application as 1247.75 mg kg -1 and 1232.25 mg kg -1 respectively, the highest nitrate accumulation was in calcium ammonium nitrate (1435.00 mg kg-1). Considering the nitrate accumulation in leafy vegetables is harmful for human health, therefore, the usual dose of ammonium sulfate is firstly suggested that it should be applied to not only have better yield and agronomic traits but also produce healthy crops for human nutrition in cultivated purslane. However, when the highest yield was taken into consideration, ammonium nitrate was also suggested as a fertilizer for purslane.