Author
 |
Webster, Theodore |
|
Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 7/1/2007 Publication Date: 8/1/2008 Citation: Webster, T.M. 2008. Cultural practices in cotton (Gossypium hirsutum) affect weed seed production. Weed Management. 1665:1-21. Interpretive Summary: Billions of dollars are lost annually due to weeds or weed control, but weeds persist. Weed management emphasizes preventing weed reproduction, reducing weed emergence after crop planting, and minimizing weed interference with crop yield. One of the challenges for effective IPM for weeds will be to develop cropping systems that minimize the opportunity for weed growth and reproduction. The objectives of this research were to 1) determine if cotton row spacing has an impact on weed growth and seed production and 2) evaluate the influence of cotton density in conventional row spacing on weed growth and seed production. Ultra-narrow row (UNR) cotton grown in 25 cm rows reduced sicklepod plant biomass and seed production by 80% compared to conventional row spacing (91 cm). At the maximum cotton density, the predicted sicklepod biomass, sicklepod seed production, and smallflower morningglory seed production was reduced 70%, 72%, and 82%, respectively. Increased cotton seeding rates (in both conventional row patterns or UNR) reduced weed seed production. There is a cost associated with this benefit. Cotton seed price likely prohibits this use as a means to reduce weed populations. Weeds that tolerate or are resistant to the most commonly used herbicides will become a greater challenge. Alternative systems that integrate cultural practices into management systems that include the remaining herbicide tools will become of greater importance. Technical Abstract: Billions of dollars are lost annually due to weeds or weed control, but weeds persist. Successful weed management systems must reduce weed populations. The objectives of this research were to 1) determine if cotton row spacing has an impact on weed growth and seed production and 2) evaluate the influence of cotton density in conventional row spacing on weed growth and seed production. Ultra-narrow row (UNR) cotton grown in 25 cm rows reduced sicklepod plant biomass and seed production by 80% compared to conventional row spacing (91 cm). There was an inverse hyberbolic correlation between cotton yield and sicklepod seed production, with the highest yield and least sicklepod seed production in UNR cotton. In the second study, cotton was seeded at four rates: 49,000; 99,000; 118,000; and 148,000 plants/ha. There were inverse linear relationships between cotton plant population density and sicklepod plant biomass, sicklepod seed production, and smallflower morningglory seed production; at the maximum cotton density, the predicted sicklepod biomass, sicklepod seed production, and smallflower morningglory seed production was reduced 70%, 72%, and 82%, respectively. Increased cotton seeding rates can reduce weed seed production. However, cotton seed price likely prohibits this use. As herbicide resistance continues to increase, alternative systems that integrate cultural practices into management systems that include the remaining herbicide tools will become of greater importance. |
