Agricultural Research,Education and Extension Organization Iranian Journal of Soil Research 2228-7124 22 2 2009 03 05 Effect of Water and N Fertilizer on the Yield and Nitrate Concentration of Potato Tubers Effect of Water and N Fertilizer on the Yield and Nitrate Concentration of Potato Tubers 243 250 127007 10.22092/ijsr.2009.127007 FA S. H. Mousavi Fazl Researcher, Agricultural Research Center of Semnan F. Faeznia Researcher, Agricultural Research Center of Semnan Journal Article 2006 10 03 Eeffects of water and nitrogen levels on the yield and nitrate concentration in potato tubers was studied in a field experiment in Agricultural Research Center of Semnan (Shahrood), during 2000 and 2001. In this research a split –plot design was used with two factors. The factors included water (main plot) at four levels (50, 75, 100 and 125 percent of water requirement) and N in subplots at four levels (50,75,100 and 125percent of recommended value based on soil testing). Irrigation requirement was determined using data of class–A evaporation pan. Plants were irrigated in furrows. Irrigation amounts at the aforementioned levels were, respectively, 4000, 6000, 8000, 10000 m³.ha^-1  and nitration treatments used were 200,300,400 and 500 kg.ha^-1, respectively .The results showed that the effects of water and nitrogen levels and their interaction had significant effects (a=1%) on the yield, such that the maximum yield was obtained with treatments of W₁₂₅N₇₅, W₁₂₅N₁₂₅, W₁₂₅N₁₀₀, W₇₅N₁₂₅ and W₇₅N₇₅ corresponding to tuber yields of 27.8, 27.7, 25.8, 23.7 and 23.5 tons per hectare, respectively. The effects of water and nitrogen on the quality characteristics, such as tubers N content, dry matter and protein percent of potatoes were significant. Maximum concentration of N in tubers was obtained for W ₅₀, while W₁₂₅ gave the minimum protein percent. Highest water use efficiencies were observed in W₇₅N₁₂₅ and W₇₅N₇₅, corresponding to 3.97 and 3.90 kg.m^-3.ha^-1 respectively. The W₇₅N₇₅ treatment was superior to other treatments in terms of higher WUE and lower N concentration. Eeffects of water and nitrogen levels on the yield and nitrate concentration in potato tubers was studied in a field experiment in Agricultural Research Center of Semnan (Shahrood), during 2000 and 2001. In this research a split –plot design was used with two factors. The factors included water (main plot) at four levels (50, 75, 100 and 125 percent of water requirement) and N in subplots at four levels (50,75,100 and 125percent of recommended value based on soil testing). Irrigation requirement was determined using data of class–A evaporation pan. Plants were irrigated in furrows. Irrigation amounts at the aforementioned levels were, respectively, 4000, 6000, 8000, 10000 m³.ha^-1  and nitration treatments used were 200,300,400 and 500 kg.ha^-1, respectively .The results showed that the effects of water and nitrogen levels and their interaction had significant effects (a=1%) on the yield, such that the maximum yield was obtained with treatments of W₁₂₅N₇₅, W₁₂₅N₁₂₅, W₁₂₅N₁₀₀, W₇₅N₁₂₅ and W₇₅N₇₅ corresponding to tuber yields of 27.8, 27.7, 25.8, 23.7 and 23.5 tons per hectare, respectively. The effects of water and nitrogen on the quality characteristics, such as tubers N content, dry matter and protein percent of potatoes were significant. Maximum concentration of N in tubers was obtained for W ₅₀, while W₁₂₅ gave the minimum protein percent. Highest water use efficiencies were observed in W₇₅N₁₂₅ and W₇₅N₇₅, corresponding to 3.97 and 3.90 kg.m^-3.ha^-1 respectively. The W₇₅N₇₅ treatment was superior to other treatments in terms of higher WUE and lower N concentration. https://srjournal.areeo.ac.ir/article_127007_950bd46dceeced1bae43f3af09e52ad6.pdf