Submitted to: Weed Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/18/2013
Publication Date: 7/1/2013
Citation: Williams, M.M. II, Boydston, R.A. 2013. Crop seeding level: implications for weed management in sweet corn. Weed Science. 61(3):437-442. Interpretive Summary: Weeds escape control in nearly all sweet corn fields, and how well those surviving plants grow and persist is influenced in large part by the crop. This work was conducted to determine how sensitive the growth and seed production of wild-proso millet, a difficult-to-control weed, was to sweet corn plant populations. Wild-proso millet was grown in sweet corn seeded at different levels and measured for plant size, seed production, and how readily the weed seeds germinated. In general, wild-proso millet did poorer as sweet corn seeding levels were increased from very low to exceptionally high. This response appears to be the result of how the higher crop seeding levels improved the crop’s ability to compete for limited resources. The impact of this research is that it quantifies the risk of greater weed seed production with major loss of crop plants, such as the result of severe weather. In addition, small gains in crop population density in the near-future may offer minimal improvements to weed suppression.
Technical Abstract: Sweet corn is seeded under a wide range of population densities; however, the extent to which variable population density influences weed fitness is unknown. Therefore, field studies were undertaken to quantify the influence of sweet corn seeding level on growth, seed production, and post-harvest seed germination of wild-proso millet, one of the most problematic weeds in the crop. As crop seeding level decreased from high populations (>100,000 seed ha-1) to low (<50,000 seed ha-1), across site-years the crop canopy became shorter and thinner, resulting in greater wild-proso millet biomass, seed production, and germinability. However, at the level of individual fields, reductions in wild-proso millet fitness were modest, at best, between a crop population currently used by growers and a higher crop population known to optimize yield of certain hybrids. These results indicate near-future increases in sweet corn seeding levels may play a minor role in improving weed management in individual sweet corn fields. Nonetheless, a reduction in crop populations, via weather- or management-driven phenomenon, increases risk of greater wild-proso millet seed production.