Influence of Weeds on Soybean Harvesting Losses with a Combine

Various soybean [Glycine max(L.) Merr. ‘Amsoy’] losses during harvesting with a combine were studied in relation to different weed densities, weed species, and growing weeds (early harvest) versus desiccated weeds (late harvest). Average soybean losses from shattering and stubble, stalk, and threshing losses were 7.8, 0.9, 2.0, and 1.4% of total yields, respectively. All harvest losses except threshing losses were significantly greater on late as compared with early harvested soybeans. The major loss from weeds in soybeans was reduced yields due to competition; whereas, harvesting losses were associated with high soybean yields and low weed yields. Soybean harvesting losses were 19% greater on plots containing a predominance of broadleaf compared with grass weeds. Average harvesting losses of 12.1% of total soybean yields ranged with treatments from 8.8 to 15.5%. Average gathering losses were 10.7% and threshing losses 1.4% of total soybean yields.