The Effects of Nitrogenous Fertilizer Forms and Application Times on Tuber Yield and Tuber Size of Potato

This research was carried out to determine the effects of application time, amount and forms of nitrogenous fertilizer to total and different sized of tuber yields of potato in Erzurum conditions during year 2000-2001. The experiment was designed as of split plots with three replication of two factors in completely randomized bloc design which were 3 nitrogenous fertilizer form and 11 application time. As factor, nitrogenous fertilizer forms were taken up ammonium sulphate, ammonium nitrate and urea. This fertilizer forms was applied in different amount on three development stages which are before planting, during hoeing and neck filling up. In this research, large tuber yield per decare (diameter over 5.0 cm), medium tuber yield per decare (diameter 3.5-5.0 cm), small tuber yield per decare (diameter lower than 3.5 cm) and total tuber yield per decare were determined. Application time and amounts of nitrogenous fertilizer affected significantly all parameters except medium tuber yield. On the other hand, forms of nitrogenous fertilizer did not affected the other parameters except the large tuber yield. As result, to get more tuber yield and reduce the labor and time consumption, nitrogenous fertilizer should be applied as ammonium sulphate form and all of the fertilizer should be applied before planting.