Agronomic considerations for reducing deoxynivalenol in wheat grain

Wheat fields under an array of agronomic practices were studied during harvest across southern and eastern Ontario. Mature wheat grain samples were harvested by hand and analyzed for deoxynivalenol (DON). DON levels from wheat grain samples harvested by hand were likely more representative of levels in the field than samples that are typically harvested by machine. The amount of variation in DON levels associated with year and agronomic effects were calculated from simple linear models. As expected, the largest factor associated with variation in DON levels was the year. Year effects accounted for 48% of the variation in DON levels across all fields during 4 years of the survey, followed by cultivar (27%), and the crop 1 year previous to wheat (14-28% depending on the year). No effect on DON could be detected from other agronomic factors including tillage system, crops planted 3 years before wheat, or type of nitrogen fertilizer applied in the spring.