Maintaining high corn yields on highly productive lands is essential for the sustainability of agricultural production in Wisconsin. Sustainability also relies on soil conservation practices and reduced energy inputs. Many growers have adopted no-till management practices to reduce energy costs, reduce soil erosion, and conserve soil organic carbon. However, no-till as a management practice remains an under-utilized conservation practice for corn-based production systems in Wisconsin. In Wisconsin, approximately 500,000 acres of corn is grown under no-till (Frazee et al., 2005), which ranks tenth among all states. More growers are likely to adopt no-till management practices if potential negative production implications can be overcome. Studies conducted on rainfed, Corn Belt soils have mixed results with studies showing positive yield effects of no-till (Olson and Ebelhar, 2009; Grandy et al., 2006; Hussain et al., 1999) and negative yield effects of no-till (Bakhsh and Kanwar, 2007; West et al., 1996). For Wisconsin soils, suppressed yields have been shown to be a result of lower soil temperatures (Andraski and Bundy, 2008). In an effort to combat this yield decrease, Andraski and Bundy (2008) further suggest that an additional 30 lb/ac of nitrogen (N) may be required to maintain corn yields when managed with no-till. Increasing the N fertilizer rate adds an additional expense to the operation and does not guarantee that this N will be used efficiently by the crop. Further adoption of no-till as a tillage practice is unlikely unless these yield and economic gaps can be overcome. There are currently several fertilizer technologies, such as polymer-coated urea (PCU) and urease and nitrification inhibitors (U! and NI) which may be viable alternatives to conventional N fertilizer for improving yields in no-till corn and would alleviate the need for supplemental N in these systems. The objectives of this study were to evaluate the effect of different N fertilizer products on corn yield in long-term tillage and crop rotation trials. The N products evaluated are a PCU, urea with UI, and a product with both a UI and NI. The PCU evaluated was ESN® (Agrium, Inc.), the UI evaluated was Agrotain® (Agrotain, Ltd.) added to urea, and the UI+NI product was SuperU® (Agrotain, Ltd) which has the UI and NI chemicals impregnated into the urea granule.
Soil Science Extension
University of Wisconsin Madison