Jump to Main Content
Nitrification Inhibitor Evaluation on Cotton. II. Inhibitor Incorporation Depth and N Placement
- York, A. C., Tucker, M. R.
- Agronomy journal 1985 v.77 no.3 pp. 407-411
- Gossypium hirsutum, nitrogen fertilizers, nitrification inhibitors, North Carolina
- The use of nitrification inhibitors (NIs) in the Southeast has given inconsistent results. Because application techniques may afTect the efficacy of NIs, a 3-year experiment with cotton (Gossypium hirsutum L.) was conducted on a sandy, low organic matter soil (Arenic Paleudults) to evaluate the efficacy of etridiazol [5-ethoxy-3-(trichloromethyl)-1,2,4-thiadiazole] and nitrapyrin [2-chloro-6-(trichlorometlyl) pyridine] when N was broadcast and deeply incorporated or applied as a 36-cm band over the row surface. The NIs, tankmixed with trifluralin (α,α,α-trifluor0-2,6-dinitro-N,N-dipropyl-p-to-luidine) herbicide, were deeply incorporated with a disk prior to bed formation or shallowly incorporated with a rolling cultivar after bed formation. Regardless of N placement method or NI incorporation depth, neither inhibitor affected cotton yield, percent lint, fiber quality, or leaf N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, or B contents. Split N applications, with one-third at planting and the remainder sidedressed at the early square stage, increased N-use efficiency in 2 of 3 years. Nitrogen placement did not affect cotton yield, fiber quality, or leaf nutrient content. Surface-banding the N reduced stands by 9 to 20%. As compared to shallow incorporation, deep incorporation of trifluralin reduced cotton yield 6 to 17% and leaf K content at the peak flowering stage 7 to 24%, but did not affect fiber quality. Deep incorporation of trifluralin, combined with either surface-banded N or application of all N at planting, reduced cotton stands in 2 of 3 years.