|Reiter, M - AUBURN UNIVERSITY|
|Burmester, C - AUBURN UNIVERSITY|
Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2003
Publication Date: February 11, 2003
Citation: Reiter, M.A., Reeves, D.W., Burmester, C.H., Torbert Iii, H.A. Cotton and cover crop nitrogen efficiency in high-residue conservation tillage systems. American Society of Agronomy Abstracts. 2003. CD ROM. (S06-reiter249573-poster). Technical Abstract: Producers utilizing conservation tillage in cotton (Gossypium hirsutum L.) raised the question of whether N applied to cover crops to increase residue was available to the following cotton crop. A 3-year field study was initiated in 1999 on a Decatur silt loam (clayey, kaolinitic, thermic Rhodic Paleudult) to test a strip plot design of 4 replications with rye (Secale cereale L.) cover crop N rates as horizontal treatments (0, 34, 67 kg N/ha) and subsequent cotton N rates as vertical treatments (0, 45, 90, 134 kg N/ha). Averaged over cotton N rates and years, 67 kg N/ha applied to rye produced the most biomass (5116 kg residue/ha) compared to 0 and 34 kg N/ha (2798 and 3877 kg residue/ha). For maximum lint yield, if 0 kg N/ha was applied to the cover crop then 90 kg N/ha was needed on the cotton (1120 kg lint/ha), while both 34 kg N/ha and 67 kg N/ha on rye required 45 kg/N ha on cotton (1091 and 1140 kg lint/ha). To reach sufficient levels of leaf blade N (35 g N/kg), 90 kg N/ha was needed by the cotton following 0 and 34 kg N/ha applied to rye (35.9 and 37.0 g N/kg), but only 45 kg N/ha was needed by cotton following 67 kg N/ha applied to the cover crop (34.9 g N/kg). We recommend applying 67 kg N/ha to rye and 45 kg N/ha to cotton to obtain maximum rye residue for soil protection and sufficient leaf N for maximum lint yields.