The effect of various nitrogen fertilizer amounts on yield and nitrate accumulation in tubers of two potato cultivars in cold regions of Isfahan (Iran)

ABSTRACT: In order to study the effect of nitrogen fertilizer on tuber yield and also nitrate accumulation in potato cultivars this experiment was conducted in cold regions of Isfahan west (2010). Two potato cultivars (Agria and Marphona) and four amounts nitrogen fertilizer levels(350,525,700 and 875 kg/ha urea according to soil analysis) was studied as stripe plots in a randomized complete blocks design with three replications. Nitrogen fertilizer had highly significant effect on tuber yield but cultivar didn’t affect this trait. The highest tuber yield was obtained using 525 kg/ha of nitrogen (50% above soil analysis recommended amount) and higher amounts of fertilizer didn’t affect it. Both cultivar and fertilizer had very significant effect on nitrate accumulation in tubers. The highest nitrate concentration was observed in top level of fertilizer (875 kg/ha urea). On the whole, it seems that using nitrogen fertilizer according to soil requirements will cause good tuber yield and prevent nitrate storing in tubers