Optimizing Nitrogen Rates with Surfactant for Chipping Potato Production in Florida

Abstract

Nitrogen (N) fertilization is the major cost for fertilizers for commercial potato production. A field trial for chipping (var. ‘Atlantic’) potatoes was conducted to maximize N use efficiency in the Hastings area in the 2014 growing season. Triple superphosphate and muriate of potash were used at 100 lb/acre P₂O₅ and 260 lb/acre K₂O with four replicates. The trial had six different N rates: 0, 120, 160, 200, 240, and 280 lb/acre. In the treatments without applying a surfactant (SFT), N fertilizer as ammonium nitrate was applied: 1) preplant (30%); 2) at emergence (30%); and 3) 6- to 8-inch tall potato plants (40%), while those with the SFT were applied 100% N preplant. Marketable yields for 0, 120, 160, 200, 240, and 280 lb/acre N without applying the SFT were 10,817, 32,067, 34,959, 37,458, 36,527, and 37,688 lb/acre, respectively. The yields for 120, 160, 200, and 240 lb/acre N plus 30 lb/acre SFT were 22,144, 26,726, 30,563, and 30,831 lb/acre, respectively. The yields for 160 lb N plus 10 or 20 lb/acre SFT were 25,100 and 27,662 lb/acre, respectively. This growing season had heavy rain events in the early growing season. At the same N rate, three-split N applications without SFT were better than a single N application with SFT for tuber yields. The SFT did not increase tuber yields with heavy rains in the early growing season.