Tillage and Nitrogen Application Methodology Impacts on Corn Grain Yield

Increased fuels costs have prompted many producers to consider conservation tillage techniques and single pass applications of nitrogen (N) fertilizer and herbicide to reduce fuel expenses. The objective of this study was to determine the impacts of tillage and nitrogen application methodology on corn grain yield. The experiment was conducted from 2002–2005 at the Northwest Research Station of the Ohio Agricultural Research and Development Center (OARDC) near Hoytville, OH. Six different tillage regimes were established as main plots: no-till, fall disc-field cultivator, Aerway tool tillage, early planted strip-till, late planted strip-till, and zone deep-till. Subplots consisted of either a single-pass application of broadcast, surface applied urea-ammonoium nitrate (UAN) representing a weed ‘n’ feed application, a split application of nitrogen between planter applied and sidedress N (subsurface injected N), or an unfertilized control. The rate of N for the different application methodologies was 168 kg ha−1. Dry conditions during the 2002 growing season resulted in very poor corn yield and thus little response to tillage or N application. In 2003, the split treatment maximized corn yield likely due to minimized ammonia volatilization independent of tillage regime. Surface broadcast applications of UAN resulted in lower grain yields in conservation tillage treatments compared to split nitrogen applications in 2004. No statistical differences were noted between the two application methods in the conventional tillage treatments. In 2005, no yield differences could be attributed to N application methodology across tillage treatments. From this study it was concluded that surface broadcast application of UAN can result in yield loss, especially in conservation tillage systems.