Barnyardgrass control in conventional and Clearfield rice grown under intermittent flooding

Authors: ATWILL, LEE - Hills Lake Farms, Llc; BOND, JASON - Mississippi State University; GORE, JEFFREY - Mississippi State University; GHOLSON, DREW - Mississippi State University; WALKER, TIM - Horizon Ag, Llc; SPENCER, DAVE - Mississippi State University; OAKLEY, GRAHAM - Mississippi State University; REYNOLDS, ZACH - Mississippi State University; KRUTZ, JASON - Mississippi State University

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2023
Publication Date: 5/11/2023
Citation: Bond, J.A., Gore, J., Gholson, D.M., Spencer, D.G., Oakley, G.R., Reynolds, Z.D., Krutz, J.L. 2023. Barnyardgrass control in conventional and Clearfield rice grown under intermittent flooding. Crop, Forage & Turfgrass Management. 284;108347. https://doi.org/10.1002/cft2.20246.
DOI: https://doi.org/10.1002/cft2.20246

Interpretive Summary: In the mid-southern United States, rice (Oryza sativa L.) is typically grown using flooding to suppress weed germination and growth. In order to determine if herbicide performance was affected by intermittent flooding two experiments were conducted in conventional and Clearfield rice weed control programs. The studies examined the effects of flooding and herbicide program on the control of barnyardgrass, ricegrain yield, and total water applied. The experiments were conducted at the Delta Research and Extension Center in Stoneville, MS on Sharkey clay soils. Intermittent flooding was found to have no adverse effect on the control of barnyardgrass compared to continuous flooding in either conventional or Clearfield rice weed control programs. Initiating irrigation when the perched water table drops to 8 inches below the soil (intermittent flooding) was found to have no impact on rice grain yield but reduced the water applied by 51%. This work demonstrates that mid-southern US rice producers can capture the water-saving benefits of intermittent flooding while having no adverse effects on herbicide activity or crop productivity in conventional and Clearfield systems.

Technical Abstract: In the mid-southern United States, rice (Oryza sativa L.) is flooded primarily to suppress weed germination and growth. Two experiments were conducted to determine whether herbicide performance in conventional or Clearfield rice weed control programs was affected by intermittent flooding. The effects of flooding and herbicide program on barnyardgrass [Echinochloa crus-galli(L.) P. Beauv] control, ricegrain yield, and water applied were investigated at the Delta Research and Extension Center in Stoneville, MS, on Sharkey clay (very fine, smectitic, thermic ChromicEpiaquert). For herbicides commonly applied in conventional (clomazone, quinclo-rac, pendimethalin, thiobencarb, fenoxaprop-ethyl, cyhalofop-butyl, and bisypriboacsodium) or Clearfield rice weed control programs (imazethapyr plus bispyribac-sodium followed by imazethapyr, imazamox or bispyribac-sodium), intermittent flooding had no adverse effect on barnyardgrass control relative to a continuous flood. Moreover, initiating irrigation when the perched water table drops to 8 inches below the soil surface had no effect on rice grain yield and reduced water applied by 51%. Mid-southern US rice producers can capture the water-saving benefits of intermittent flooding while having no adverse effects on herbicide activity or crop productivity in conventional and Clearfield systems.