About
  PDF
Full Text
(86 K)

Managing Nitrogen for Cotton in a High-Residue Conservation Tillage System

M.S. Reiter, C.H. Burmester, and D.W. Reeves

ABSTRACT

Over 70% of the cotton (Gossypium hirsutum L.) in the Tennessee Valley of northern Alabama is currently raised using conservation tillage techniques. High-residue small grain cover crops are becoming a common tool in these systems, but N immobilization may occurr causing previous N recommendations to be obsolete. A replicated 3-year field study was initiated in 1999 in the Tennessee Valley of Alabama on a Decatur silt loam (clayey, kaolinitic, thermic Rhodic Paleudult) to test a factorial arrangement of N source (ammonium nitrate and urea-ammonium nitrate), N rates (0, 40, 80, 120, 160 lb N/A), N application timing (all at-planting and 50-50 split between at-planting and first square), and N application method (banded or broadcast) for cotton grown in a high-residue rye (Secale cereale L.) conservation system. Preliminary results suggest that 120 lb N/A may be needed to optimize yields (781 lb lint/A in 2000, 1026 lb lint/A in 2001, and 875 lb lint/A in 2002). Generally, highest yields were obtained when N was applied at-planting (803 lb lint/A in 2000, 957 lb lint/A in 2001, and 863 lb lint/A in 2002). Ammonium nitrate applications resulted in greater yields when broadcast at-planting while UAN applications resulted in greater yields when banded, regardless of application timing. At current prices for AN and UAN, the pre-liminary data suggest the most efficient and economical practice for cotton grown in high-residue conservation systems would be to apply 120 lb N/A as UAN in a banded application at-planting.





[Main TOC] | [TOC] | [TOC by Section] | [Search] | [Help]
Previous Page [Previous] [Next] Next Page

Document last modified April 16, 2003