Bu çalışma, artan miktarlarda uygulanan bazı azotlu gübreler (amonyum nitrat-AN, amonyum sülfat-AS ve Üre-Ü) ile ahır gübresinin (AO) farklı mevsim (kış, İlkbahar) ve değişik tekstüre sahip topraklarda (killi Ün, kumlu tin) yetiştirilen ıspanak bitkisinin [Spl-nacia oleracea L.) yaprak, yaprak sapı ve köklerinin nitrat içeriği Üzerine olan etkilerini be¬lirlemek amacıyla yapılmıştır. Araştırma sonuçlarına göre, bitkide nitrat birikimi üzerine mevsim, tekstür, gübre çeşidi ve gübre dozlarının etkileri önemli (P

This pot experiment was conducted to determine the effects of some nitrogeneous fertilizers such as ammonium nitrate-AN, ammonium sulphate-AS, urea-U and barnyard manure and their levels on the nitrate content of leaf, leaf stems and roots of the spinach plant [Spinacta oleracea L.) grown in various soils (clay loam, sandy loam) and under different seasonal (spring and winter) conditions. According to results, the effects of the factors such as seasons, soil texture, rate and kind of the fertilizers used on the nitrate accumulation in the plants were found significant (P<0.05). In other words, the winter season, the clay loam, the urea and the fertilizer rate of 60 kg N/da gave higher values than their own controls in terms of the nitrate accumulation in the plants. Amount of the nitrate accumulated in plants which has been obtained with the fertilizer rate of 20 kg N/da was found to be above the permitted (safety) level (300 mg NO3/kg) at the harvest.