Flame Cultivation in CottonRecently, several issues have forced some producers to reconsider the merits of flame cultivation. Increasing herbicide prices, government regulations regarding worker protection, restricted-use pesticide records, public fear of herbicide damage to the environment, lack of acceptable chemical control of certain problem-weed species, and herbicide-resistant weeds are among current factors. These issues, combined with LP gas prices, make this old technology attractive.Using flame cultivation to control weeds works by destroying cambium cells in seedling plants. The critical temperature to achieve cambium cell destruction is 130 degrees Fahrenheit, and weeds less than 2 inches tall are the ideal size for control. Flame cultivation without a water shield can safely be used in cotton after plants develop a main stem 3/16 inch in diameter at the soil surface. This stem size correlates with a plant height of approximately 8 to 10 inches. The design of the water-shielded burner in the early 1970's improved cotton tolerance, thereby allowing use of flame cultivation in cotton 5 to 6 inches tall. The water-shielded burner uses a single flat-fan nozzle positioned above the burner to deliver 7 to 10 gallons of water per acre, as a barrier to prevent heat movement into the cotton canopy. To control weeds effectively in the cotton row, have the burner perpendicular to the row. Position the burner 8 to 10 inches above the soil surface, angled 30 degrees to 45 degrees to the ground, and spaced approximately 8 to 10 inches from the row. This positions the flame to strike the soil 2 inches from the cotton plant. Set in this manner, the flames strike the soil and move horizontally along the surface across the cotton row, killing small weeds in its path. A burner on each side of the row controls weeds on either side. Burners must be off-set (or tandem to each other) to avoid a plume of heat's rising into the cotton canopy. Liquid-pressure-type burners should be operated in the 15- to 30-psi range to develop the optimal flame pattern and to prevent flame out. Low pressures are best suited for small cotton or sparse weed populations, while high pressures are best used in large cotton and dense weed infestations. Keep the tractor speed in the 3 to 5 mph range. Like pressure, use slower speeds in dense weed populations or large cotton, and use higher speeds in sparse weed populations or small cotton. Operation at these pressures and speeds consumes approximately 5 to 6 gallons propane per acre. Some of the advantages of flame cultivation include:
By John D. Byrd, Jr., Ph.D, assistant Extension weed specialist, and Charles E. Snipes, Ph.D., plant physiologist, Delta Research and Extension Center. Mississippi State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status. Information Sheet
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