Cotton and Cover Crop Nitrogen Efficiency in High-Residue Conservation Tillage Systems. (S06-reiter249573-poster)
Authors:
M.S. Reiter* - Auburn University
D.W. Reeves - USDA-ARS-NRCC, Watkinsville, GA C.H. Burmester - Auburn University
H.A. Torbert - USDA-ARS-NSDL, Auburn, AL
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-1) and subsequent cotton N rates as vertical treatments (0, 45, 90, 134 kg N ha-1). Averaged over cotton N rates and years, 67 kg N ha-1 applied to rye produced the most biomass (5116 kg residue ha-1) compared to 0 and 34 kg N ha-1 (2798 and 3877 kg residue ha-1). For maximum lint yield, if 0 kg N ha-1 was applied to the cover crop then 90 kg N ha-1 was needed on the cotton (1120 kg lint ha-1), while both 34 kg N ha-1 and 67 kg N ha-1 on rye required 45 kg N ha-1 on cotton (1091 and 1140 kg lint ha-1). To reach sufficient levels of leaf blade N (35 g N kg-1), 90 kg N ha-1 was needed by the cotton following 0 and 34 kg N ha-1 applied to rye (35.9 and 37.0 g N kg-1), but only 45 kg N ha-1 was needed by cotton following 67 kg N ha-1 applied to the cover crop (34.9 g N kg-1). We recommend applying 67 kg N ha-1 to rye and 45 kg N ha-1 to cotton to obtain maximum rye residue for soil protection and sufficient leaf N for maximum lint yields.
Speaker Information: Mark Reiter, Auburn University, National Soil Dynamics Laboratory411 South Donah, Auburn, AL 36832; Phone: 334-844-4741 ext. 174; E-mail: [email protected]
Session Information: Monday, November 3, 2003, 2:00 PM-4:00 PM Presentation Start: 2:00 PM (Poster Board Number: 1027) Keywords: N Management; rye; biomass; leaf N
