Effect of tillage and cultivar on sudden death syndrome and yield of soybean in Iowa Yuba Kandel: Iowa State University; Daren Mueller: Iowa State University; Leonor Leandro: Iowa State University<div>Reduced-tillage has become a common practice of soybean farming in the Midwestern U.S. Field trials were established in a field with a history of sudden death syndrome (SDS; caused by <i>Fusarium virguliforme</i>) in Iowa in 2011, and evaluated for five consecutive years, to determine the impact of long-term tillage on SDS and yield. The study site contains mainly webster clay loam, bemis moraine, and nicollet loam soil, with 1 to 3% slopes that are poorly drained. The experiment was laid out in a split split-plot design with four replicates. The main plot factor was tillage (no till both crops, no till corn and chisel plow soybean, and disc corn and chisel plow soybean, respectively), and each main plot was divided into subplots of corn or soybeans (in a 2-year rotation). Each subplot was again divided into sub-subplots where two soybean cultivars, susceptible and moderately resistant to SDS, were planted each year. Root rot and SDS disease index (FDX) differed among years, as some years were more favorable for the disease than the others. However, tillage did not affect any parameters, including yield, in any year (P > 0.05). Cultivar effect was significant for each parameter occasionally. Compared to the susceptible cultivar, the moderately resistant cultivar had 61% less root rot in 2015; 61 and 62% less FDX in 2014 and 2015, respectively, and 21% greater yield in 2015. These data suggest planting resistant cultivars can be an effective management tactic but tillage is not an effective option for SDS management.</div> View Presentation |