Effect of Regional Different N-Fertilizer Applications on Nitrate Accumulation in Winter Vegetables Grown on Tokat Region

Authors: M. RÜŞTÜ KARAMAN, ABDÜLREŞİT BRAHİ, AYDIN GÜNEŞ, ALİ İNAL, MEHMET ALPASLAN

Abstract: The main object of this study was to observe the effect of regional N-fertilizer applications on the nitrate accumulation of some winter vegetables grown on farmer's fields located at different parts of the Tokat region. For this reason, leaf samples of some winter vegetables, namely spinach, cabbage, leek and lettuce collected from each field were analysed for nitrate, and the soil samples taken from a depth of 0-20 cm depth of each sampling field were analysed for nitrate content and texture. According to the results of this study, different nitrate levels (910-2360 mg/kg in spinach, 945-1785 mg/kg in cabbage, 750-1947 mg/kg in leek, 1401-2202 mg/kg in lettuce) were determined depending on soil texture and nitrogen fertilizer used by farmers. It was also found that the nitrate content of vegetables was increased with increasing regional nitrogen use, especially in the form of nitrate. The nitrate contents of many vegetables were usually found to be less than the critical levels (FAO and WHO reports have recommended a level of less than 2000 mg nitrate for per 60 kg body weight of humanbeigns). The nitrate values of 2059, 2230, 2250, 2255 and 2360 mg/kg in spinach and 2155, 2156, 2178 and 2202 mg/kg in lettuce were found to be higher than the critical levels reccomended by WHO and FAO. The findings obtained from this study generally showed that there were no significant nitrate accumulation problems in the winter vegetables grown in this region.

Keywords: Nitrogen fertilizer applications, nitrate, winter vegetables

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