|Kamanian, Armen - WASHINGTON ST UNIVERSITY|
|Stockle, Claudio - WASHINGTON ST UNIVERSITY|
Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2005
Publication Date: January 1, 2006
Citation: Nitrogen Fertilizer Recovery in No-Tillage Wheat: Influence of Previous Crop, Terrain and Application Method. Huggins, D.R., Kemanian, A.R., Smith J.L., Stockle, C.O. Abstracts 2005 International Annual Meetings American Society of Agronomy, Nov. 6-10, Salt Lake City, UT Technical Abstract: Nitrogen use efficiency depends on the synchronization between nitrogen supply and demand by the crop. The objective of this research is to quantify the influence of application method, landscape position, and preceding crop on nitrogen use efficiency of no-till spring wheat. Nitrogen fertilizer labeled with 5% enriched 15N was banded or broadcast at seeding in no-till spring wheat at a rate of 200 kg ha-1 in two landscape positions (south and north facing slopes) and in different residues (peas or spring barley). The experiment has three replications and includes a treatment without fertilizer application. Biomass production ranged from 14.5 (north slope, barley and pea residue) to 7.3 Mg ha-1 (no nitrogen, north slope, barley residue). Yields, however, were higher in pea ground due to a lower harvest index in the barley compared with the pea residue. In the barley (pea)residue, nitrogen uptake in the banded treatment was 16% (10%) higher than in the broadcast, and more than doubled the total nitrogen uptake in the non-fertilized plots (80 kg N ha-1). Fertilizer recovery was 50 and 36% for the banded and broadcast treatments, and 41 and 46% for the pea and barley residue. Fertilizer recovery in the north facing aspect position was slightly higher than in the south aspect. Overall the banded grain N concentration was higher that in the broadcast (2.35 vs. 2.04%). The grain N concentration was higher in the barley residue (2.30 vs 2.05%), due to the lower yields.