Carrot Yield and Quality as Influenced by Nitrogen Application in Cut-and-Peel Carrots

Abstract

Root bulking, quality, and uniformity in cut-and-peel carrots (Daucus carota) are paramount for optimizing marketable yield and quality. Root bulking is an ecophysiological manifestation in response to inputs such as fertilizers. Understanding this ecophysioloical interaction will help to optimize yield, quality, and amount of inputs used. Three years of field trials were conducted in Kings County, Nova Scotia, to investigate the effects of varying levels of nitrogen (N) fertilizer on yield, recovery, and root and tissue N of two cut-and-peel varieties, Sugarsnax and TopCut. Seven levels of ammonium nitrate (34–0–0; 0, 50, 100, 150, 200, 300, and 400 kg N h−1) were hand broadcast in a split (60% pre-emergence and 40% 8 weeks after emergence) application. No significant interactive effects of N and variety in terms of gross yield or recovery were observed, though Sugarsnax total yields were 12.7% greater than those of TopCut. Overall, optimum yields were achieved at N rates of 150 kg N h−1 and further addition did not significantly improve yield or quality. Increased N significantly increased root and tissue N, but N concentration in both tissues peaked at the 300 kg N h−1 rate. However, neither root nor leaf tissue N had any effect on marketable or total yield. These results show that root bulking is not modulated by altering N applications, and the results also suggest that carrots may have high N-use efficiency or harness N from deeper zones.