Submitted to: Western Society of Weed Science
Publication Type: Research notes
Publication Acceptance Date: 11/15/2006
Publication Date: 3/12/2007
Citation: Anderson, R.L. 2007. Cultural tactics that reduce common sunflower seedling emergence in following years. West. Soc. Weed Sci. Res. Rep. p. 95-96. Interpretive Summary: Producers in the western Corn Belt are interested in alternative rotations, in part because of rising input costs associated with weed management. This study examined impact of cultural tactics on common sunflower seedling emergence in following years. A cropping system that included cool-season crops and no-till management reduced seeding emergence 86% compared to the conventional system of tillage with soybean. The cool-season crops apparently enhanced the natural loss of live seeds in the soil seedbank. We encourage producers to consider diversifying their corn-soybean rotation to include cool-season crops; weed management may be improved with less herbicide inputs in diverse rotations.
Technical Abstract: Weed management is expensive for producers in the western Corn Belt. Costs are high because the corn-soybean rotation favors population growth of weed species that are crop mimics. One prominent weed in this rotation is common sunflower. Producers may improve weed management by adding crops with different life cycles to the corn-soybean rotation. This study quantified seed survival of common sunflower in the soil seedbank as affected by cultural tactics related to tillage management and crop sequencing. Seedling emergence in the third and fourth year after initiating the study was 50% less with a no-till system compared with tillage. Adding the cool-season crops, canola and winter wheat, to the no-till rotation reduced seedling emergence 86% compare with the tilled sequence. Not tilling leaves weed seeds on the soil surface, which favors rapid death of seeds due to environmental exposure. Winter wheat and canola apparently enhance the natural loss of live weed seeds in soil due to microbial factors. Developing weed management systems based on crop diversity and no-till can help reduce input costs. Index words: cultural tactics, seedling emergence, crop sequencing