Wednesday, November 15, 2006

Nitrogen Use Efficiency and Yield Effects Using a Slow Release Nitrogen Fertilizer in Winter Wheat and Maize.

Sheri L. Cahill1, Deanna Osmond1, Carl Crozier1, Daniel W. Israel2, and Randy Weisz1. (1) NCSU, Dept of Soil Science, College of Agriculture and Life Sciences, Campus Box 7619, 100 Derieux Street, Williams Hall, Raleigh, NC 27695, (2) Dept of Soil Science, North Carolina State Univ, Box 7619, Raleigh, NC 27695

The potential for improved fertilizer N use efficiency (NUE) and yield in winter wheat (Triticum aestivum L.) and maize (Zea mays L.) was tested using a new, controlled release urea formaldehyde polymer (UFP) fertilizer. This polymer was compared with conventional aqueous urea-ammonium nitrate (UAN) [(NH2)2CO–NH4NO3] fertilizer during a two-year field experiment in North Carolina from 2004 to 2006. The crops were grown on three soils: Candor (sandy, siliceous, thermic Grossarenic Kandiudult), Portsmouth (fine-loamy over sandy or sandy-skeletal, mixed, semiactive, thermic Typic Umbraquults) and Cape Fear (fine, mixed, semiactive, thermic Typic Umbraquult). The sandy soil was irrigated as needed to avoid drought stress. Treatments were N source (UAN and UFP) and N rate (0, 42, 84, 126, 168, 210, 252 kg N ha-1 for maize and 0, 54, 84, 114, 144, 174, 204 kg N ha-1 for wheat) arranged as randomized complete blocks with four replications. The UAN and UFP were applied as a split application for wheat, while maize received UFP at planting and split UAN. Timing of the materials was determined either by label (UFP) or prior experimental experience (UAN). There was no apparent difference in grain yield, stover yield, or NUE between UAN and UFP during either year. Soil samples were collected from 0 to 20-cm and 20 to 40-cm depths from the control and highest N rate plots for each fertilizer type and crop at 2 and 6 wk after the last fertilization. Nitrate-N ranged from 1 to 8 mg kg-1. Until statistical analyses are performed, it is unclear whether there was a difference between UAN and UFP in yield, NUE or NO3-N in the soil profile. Since the cost of UFP is substantially greater than UAN and form did not affect yield, UFP was not economically viable.

Handout (.pdf format, 183.0 kb)