Effect of planting date,nitrogen rate,and plant spacing on potatoes grown for processing in Prince Edward Island

Russet Burbank and Kennebec potatoes were evaluated over 5 years at 3 planting dates, 3 plant spacings, and 3 nitrogen rates. Delayed planting significantly reduced Russet Burbank yield, but did not effect Kennebec yield. Both varieties exhibited reduced specific gravity of tubers with delayed planting. Spacings between 38 and 56 cm for Russet Burbank and 20 and 38 cm for Kennebec had no significant effect on yields of “A” size tubers, but wider spacing reduced specific gravity of tubers. No yield advantage occurred with nitrogen application greater than 134 kg N/ha. Increased nitrogen application reduced specific gravity of tubers. Significant differences in the N, P, and K levels of leaves, petioles, and tubers were observed due to some treatments.