Nitrification Inhibitor Influences on Potato

AbstractNitrification inhibitors may reduce loss of fertilizer N from the root zone by reducing leaching and denitrification. This reduced N loss should be reflected in increased crop yields. These studies were conducted to determine if potato yield, specific gravity, or leaf N at flowering would be increased by use of nitrification inhibitors. Nitrification inhibitors dicyandiamide (DCD) and 2‐chloro‐6‐(trichloromethyl)‐ pyridine (nitrapyrin) were evaluated in five studies on potato (Solanum tuberosum L. cv. Atlantic) in Northeast Florida on an Arenic Ochraqualf, a Grossarenic Paleudult, and a Grossarenic Paleaquult. Treatments were combinations of N at 67, 134, and 202 kg ha−1; DCD at 0, 5.6, and 11.2 kg ha−1; nitrapyrin at 0.56 and 1.12 kg ha−l; and isobutylidene diurea (IBDU) applied as one‐third of the N. Tuber yields were not affected by nitrification inhibitors in four of five tests but were increased 14% in one test. Nitrification inhibitors increased leaf N concentration at flowering in three of four tests. Tuber yields were higher with DCD than with nitrapyrin in three of five tests. In several year‐location combinations, use of IBDU resulted in greater tuber yield and leaf N concentration at flowering than did nitrification inhibitors. Based on these results, nitrification inhibitors can not be recommended for potato production on hyperthermic, sandy, irrigated soils.