Soybean Response to Management of Corn Residue Volumes Through Removal, Tillage, Planter Type and Nitrogen Application.

Recently, in the province of Ontario, many farmers have been observing an increasing yield lag associated with no-till soybeans (Glycine max) relative to conventionally tilled beans. It is suspected that rapid improvements in maize (Zea mays) yield is increasingly depositing more crop residue on the soil surface; and is reducing soil temperature and creating problems with soybean establishment and early development. The objective of this study is to evaluate soil moisture and temperature, soybean development and final grain yield under different residue management, tillage and planter or nitrogen combinations, under high maize residue scenarios. A split-split plot factorial experiment was established at two locations in Ontario for the 2011 and 2012 growing seasons. Maize residue was removed at one of 3 rates- no removal, intermediate or high. Each removal rate was subjected to 10 different tillage intensities or timings including no-till, moldboard plow, disk ripper, tandem disk, residue tillage specialist (RTS) and stalk chopping. Each removal x tillage plot was further split into either a row planter versus seed drill comparison, or a nitrogen comparison (56 kg/ha of nitrogen versus no nitrogen) sown with the planter. Results differed by year and location. In 2011, treatment effects had minimal impact on soil temperature, moisture and other measured variables; likely attributed to delaying planting until June 3^rd from wet weather conditions. In 2012 the trials were planted on April 19^th and May 14^th, and treatment effects and treatment interactions were much more pronounced. Although no yield measurements have been obtained for the 2012 season yet, potential indicators like lower soil temperature and slower plant development appear to be present in high residue plots such as NT, compared to residue removed or intensely tilled plots.