10 Research Building soil health over time LONG-TERM STUDY OF TILLAGE, FERTILITY, AND MORE Treena Hein CUTTING-EDGE RESEARCH INTO SOIL HEALTH continues in Ontario, led by a University of Guelph team. “Healthy, resilient soil is key to maintaining crop productivity,” notes Dr. Laura Van Eerd, professor of sustainable soil management at the University of Guelph. “This is particularly true in extreme weather years where drought or excessive moisture conditions are exacerbated in poor, degraded soils.” Van Eerd has been conducting a long-term soil health study with the help of a large, hardworking team. “My research program is only possible because of graduate students such as Yajun Peng, postdoctoral fellow Dr. Inderjot Chahal, and colleagues Dr. David Hooker and Sean Vink,” she explains. “Sean is our research technician who provides leadership through understanding how to farm and conduct research at the same time and is an outstanding resource.” This research was funded in part by the Ontario Agri-Food Innovation Alliance, a collaboration between the Government of Ontario and the University of Guelph. For years, Van Eerd’s team has been quantifying changes in soil health over time using indicators such as soil organic carbon (SOC) and total nitrogen (TN) storage level, which can vary in quantity due to tillage system, crop rotation, cover crop use and N application. It is important to understand the role of these management practices on SOC and TN (soil health) so that growers can make crop productivity gains and maximize profits. Also, SOC measurements may allow Ontario growers to trade in carbon credits in the future. “However, meaningful Ontario data is needed,” says Van Eerd, “and the long-term tillage system-crop rotation-nitrogen trial at Ridgetown is well suited to provide this information.” The trial was initiated in 1995 on clay loam soil in a split-split plot design with four replications. Using this experimental site, the team proposed to assess the differences in SOC and TN among crop rotations such as corn-corn, soybean-soybean, corn-soybean-wheat, or soybean-wheat, tillage system effects (zone-tillage versus conventional fall plow with spring secondary tillage), and the effect of N rate in the corn and wheat phases of the crop rotation. They also wanted to measure levels of SOC and TN by identifying sequestration rates and changes in storage from 2006 to 2019. Other questions were: How much carbon storage can we expect when we have a red clover cover crop after wheat, and from N fertilizer rate effects in the crop rotation? And how can we define the relationship between soil health and crop yield (and variability in yield over time, also called resiliency) under various management practices? PHOTOS COURTESY OF LAURA VAN EERD
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