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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION SYSTEMS RESEARCH FOR IMPROVING ENVIRONMENTAL QUALITY AND PRODUCER PROFITABILITY Title: Optimize nitrogen for Alabama wheat yields with and without fall tillage.

Authors
item Balkcom, Kipling
item Burmester, Charles -

Submitted to: Better Crops
Publication Type: Popular Publication
Publication Acceptance Date: June 15, 2011
Publication Date: July 1, 2011
Citation: Balkcom, K.S., Burmester, C.H. 2011. Optimize nitrogen for Alabama wheat yields with and without fall tillage. Better Crops. 95(3):8-11.

Interpretive Summary: Alabama wheat farmers are changing management practices to maximize yields and reduce trips across their fields, which includes using higher nitrogen (N) fertilizer and wheat seeding rates, and planting wheat in no-till or reduced tillage systems. Different tillage practices have prompted questions about N fertilizer rates and application timings according to tillage practices used at planting. ARS researchers located in Auburn, AL with Auburn Univ. scientists used four locations across Alabama during the 2008, 2009, and 2010 wheat growing seasons to examine tillage practices and rates and times of N fertilizer application for Alabama wheat. No differences were observed between wheat yields for conventional and non-inversion tillage systems at six of the eight site-year locations in Alabama. At the remaining two site-years, non-inversion tillage wheat yields were 33% and 64% greater compared to conventional tillage. These results indicate that concerns about slow wheat development associated with surface residue and subsequently cooler soils are not warranted in Alabama with cotton as the preceding crop. Non-inversion tillage on Coastal Plain soils and no-till on Limestone Valley soils, produced comparable or superior wheat yields across Alabama compared to conventional tillage. Fall-applied N was not necessary to optimize yields on Limestone Valley soils, but necessary for Coastal Plain soils. The N application window was wider for Limestone Valley soils, while Coastal Plain soils required all N applied by growth stage 25.

Technical Abstract: Alabama wheat farmers are changing management practices to maximize yields and reduce trips across their fields, which includes using higher nitrogen (N) fertilizer and wheat seeding rates, and planting wheat in no-till or reduced tillage systems. Different tillage practices have prompted questions about N fertilizer rates and application timings according to tillage practices used at planting. Four locations were used across Alabama during the 2008, 2009, and 2010 wheat growing seasons resulting in eight site-year comparisons. These locations were at the Tennessee Valley Research and Extension Center (TVS) in Northern Alabama, the E.V. Smith Research Center (EVS) in Central Alabama, the Wiregrass Research and Extension Center (WGS) in Southeast Alabama and the Gulf Coast Research and Extension Center (GCS) in Southwest Alabama. No differences were observed between wheat yields for conventional and non-inversion tillage systems at six of the eight site-year locations in Alabama. At the remaining two site-years, non-inversion tillage wheat yields were 33% and 64% greater compared to conventional tillage. These results indicate that concerns about slow wheat development associated with surface residue and subsequently cooler soils are not warranted in Alabama with cotton as the preceding crop. Non-inversion tillage on Coastal Plain soils and no-till on Limestone Valley soils, produced comparable or superior wheat yields across Alabama compared to conventional tillage. Fall-applied N was not necessary to optimize yields on Limestone Valley soils, but necessary for Coastal Plain soils. The N application window was wider for Limestone Valley soils, while Coastal Plain soils required all N applied by growth stage 25.

Last Modified: 11/22/2014
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