اثر منابع (كود اوره و نيترات آمونيوم) و سطوح مختلف كود نيتروژنه بر صفات كمي، كيفي و تجمع نيترات در تره ايراني Allium ampeloprasum

Effect of Sources (Urea and Ammonium Nitrate) and Level of N Fertilizer on Quantitative and Qualitative Characteristics and Nitrate Accumulation in Tareh Irani (Allium ampeloprasum Tareh Group)

Due to the effective role of nitrogen fertilizer on growth, yield and quality of a crop, farmers nowadays apply too much of them to their crops. Excessive use of nitrogen fertilizers in agriculture not only causes surface and underground water pollution but it also can lead to nitrate accumulation in plants, causing various diseases such as mcthaemoglobinemia in infants and gastrointestinal cancer in adults. Tareh Irani is one of the important leafy vegetables in Iran. In spite of its high cultivation and use, there has been little fundamental research carried out specially on its fertilization. In the present study, the effects of different sources (urea and ammonium nitrate) and levels (50, 125, 200, 275, 350 and 425 kgHaʹ1) of nitrogen fertilizers were investigated on yield, nitrate accumulation and some of the quality characteristics of various clippings of Tareh Irani. The results showed that by increasing the amounts of nitrogen fertilizers, yield, number, length and width of leaf as well a nitrate accumulation in leaf increased. The highest yield was obtained in either of the 425 kgNHa"1 as urea or 200 kgNHa"1 as ammonium nitrate but nitrate accumulation was less in the later case. Ammonium nitrate lead to more nitrate accumulation. In spite of an increase in nitrate accumulation from 3rd clip to the last one, yield decreased. This can be due to the effects of unfavorable environmental factors such as lower temperatures and shorter days at the end of the growing season that can also lead to high of nitrate accumulation. Total soluble solids were not observed to be affected by different treatments.