- Author: Bob Johnson
- Posted by: Gale Perez
From the weekly newspaper for California Agriculture, Ag Alert • Dec. 2, 2020 • California Farm Bureau Federation
Advisors seek practical use of steam in weed control
By Bob Johnson
Steam-treating a shallow band of soil within the seed line before planting may offer, when combined with advanced cultivators, an economical weed control option for organic farmers and conventional growers looking to reduce herbicide use.
University of California specialists said their research in Salinas Valley vegetable fields this year showed the technique can significantly reduce weed pressure.../h2>
Despite the tremendous need, there are currently no preemergence herbicides that are organic-compliant. Steam injected into the soil such that the soil temperatures reach >140°F for 15-20 minutes will kill weed seed in the soil. The effect of this reduction in the seedbank viability results weed control in the treated area that persists for several weeks or months, similar to the effects of a preemergence herbicide.
Two studies were conducted at the USDA Hartnell Farm at Salinas, CA during July to September 2020. Steam was applied to raised beds using a custom-built steam injector. Prior to seeding lettuce, steam was applied in a 4-inch wide band to a depth of 3 inches deep. The steam was supplied by a SF-20 Sioux steam...