8 Cover story continued from page 6 through leaching, denitrification and volatilization. Some products also allow plants to receive a consistent nitrogen supply throughout all stages of growth, maximizing yields. Shaw reports that in 2023, the Holmes Agro Team made an increased effort to communicate the importance of using a nitrogen stabilizer on urea that is being broadcast and not incorporated into the soil, especially when considering the 4R principles. “This opened up great conversations of the potential economic benefits that come from protecting a high-cost input such as urea from unnecessary loss via volatilization, denitrification and leaching,” she explains. “Essentially the conversations are ‘we’re going to spend cents on the dollar to protect your investment of nitrogen while also meeting 4R principles, and achieving the overall goal of economically, agronomically and environmentally-sound fertilizer recommendations.’” TIMING Growers that follow the 4R principles also see many benefits from delaying some nitrogen application with side or top dressing or Y-dropping nitrogen into corn. This generally results in less nitrogen being applied to achieve the same yield. Ensure with Y-drop application that your nozzles are positioned accurately to achieve proper fertilizer placement and prevent crop damage. In addition, optimal moisture conditions help facilitate the movement of the nitgrogen applied through this method into the root zone. Johnston adds that some growers with 4R certified acres also benefit from splitting nitrogen application in a wheat crop. In addition, “many participants have also been able to reduce the amount of phosphorus applied in the fall,” he says. “Concentration of the phosphorus in a band reduces the amount of nutrient tied up in the soil. Use of soil amendments such as humic acid can help sequester phosphorus in the soil as well.” COVER CROPS Shaw adds that including cover crops in cropping systems in Ontario has been a great success story for 4R participants. “Talking to growers, there is usually great feedback on improved soil health, improved weed control for future years and improved fertilizer use and efficiency,” she says. “Cover crops also allow for those fall fertilizer programs to have nutrients applied to an active crop versus the bare ground. As part of 4R, it is important to minimize potential loss through surface erosion and having cover crops in place significantly reduces this risk.”• LAURA SHAW, CCA
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