The effects of plant density and nitrogen fertilizer amounts as top dressing on yield of potato at Damavand region

This study was carried out in 2004 in Damavand region to evaluate the effect of plant density and nitrogen fertilizer amounts as top dressing on yield and yield components of potato (Agria cultivar) on a split plot design of the study comprised of randomized complete blocks design with four replications. In this experiment, plant densities (7.97, 5.29 and 3.32 plant /m) and nitrogen fertilizer amounts (0, 100, 200 and 300 kg urea/ha) were levels of main plot and sub plot respectively. Characteristics such as number of tuber per plant, average tuber weight, weight of tubers per plant, tuber yield (t/ha) and dry matter percentage after harvesting were recorded and statistically analyzed. The results showed that there were significant differences between plant densities and nitrogen fertilizer levels for all traits(Duncan 1%). Means comparison showed that density of 5.29 plants per square meter and fertilizer levels (200 and 300 kg urea/ ha) from the point of view of all traits were superior to the others. Also interaction effects of plant density and nitrogen fertilizer statistically were significant for all characteristics.