EFFECTS OF APPLIED NITROGEN ON YIELDS, TUBER SIZES, AND SPECIFIC GRAVITIES OF TWO POTATO CULTIVARS

Abstract

Potatoes (Solanum tuberosum L. cv. Sebago and Netted Gem) were grown at several locations on Prince Edward Island over a 5-yr period with rates of applied N from zero to 336 kg/ha. Significant yield responses to applied N occurred at all locations each year with each cultivar. At most locations, 112–134 kg N/ha was adequate for maximum yields. The response of the two cultivars to applied N was similar. Applied N up to 134 kg/ha increased the percentage yields of A-size tubers. Tuber specific gravity was affected by N application at only 8 of the 15 locations. Generally, excessive rates of applied N reduced specific gravity but rates sufficient for maximum yields were not deterimental.