Anaerobic Soil Incubation to Determine Residual Nitrogen Availability to Corn. (S04-crozier630339-poster)
Authors:
C.R. Crozier* - North Carolina State Univ.
R.W. Heiniger - North Carolina State Univ.
J.D. Williams - North Carolina State Univ.
Abstract:
This study evaluates the usefulness of anaerobic soil incubation in characterizing residual soil N available to corn (Zea mays L.). During 2001 and 2002, a total of 21 site-years were investigated, including 7 irrigated sites. Yield response to N fertilizer and soil N status (ammonium, nitrate, mineralizable during anaerobic incubation) were determined. Crop N responses were highly variable, linear-plateau regression determined optimum N rates ranging from 0 to 310 kg N/ha (mean 162 kg N/ha) and apparent N-use efficiencies ranging from 0 to 42.3 kg N/Mg grain (mean 17.7 kg N/Mg grain).
Anaerobic incubation released an average of 4 times the amount of N present as residual inorganic N (46 kg N/ha and 12 kg N/ha, respectively). All yield response correlations were substantially poorer for non-irrigated fields. For the irrigated sites, simple linear correlations between yield with no fertilizer N and soil N were 0.69 (mineralizable plus inorganic N) and 0.54 (residual nitrate); and between
magnitude of yield response to added fertilizer N and soil N were 0.85 (mineralizable plus inorganic N) and 0.68 (residual nitrate). Soil assays were not good predictors of the optimum fertilizer rate. Ongoing research attempts to combine a soil assay for an early-season N recommendation with a plant assay for a mid-season sidedress recommendation.
Speaker Information: Carl Crozier, North Carolina State Univ., V.G. James Res. Ext. Center207 Research Sta. Rd., Plymouth, NC 27962; Phone: 252 793-4428 x 134; E-mail: [email protected]
Session Information: Tuesday, November 4, 2003, 2:00 PM-4:00 PM Presentation Start: 2:00 PM (Poster Board Number: 931)
Keywords: nitrogen availability; soil incubation; corn; residual nitrogen
