Author
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Forcella, Frank |
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Submitted to: Weed Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/3/2009 Publication Date: 7/6/2009 Citation: Forcella, F. 2009. Potential Use of Abrasive Air-Propelled Agricultural Residues for Weed Control. Weed Research. 49:314-345. Interpretive Summary: Few tactics exist for organic farmers to control weeds, especially without the use of soil tillage. A new tactic is proposed that results in plant abrasion and death upon treatment with grits propelled by compressed air. Walnut shell grit was delivered by a sand blaster at 75 psi at distances of 1 to 2 feet from seedlings of common lambsquarters in greenhouse pots. Control was influenced by size of plants at time of treatment. Small seedlings (1-leaf growth stage) were controlled easily with a single split-second blast of grit, but as seedling size at the time of treatment increased, so did the number of blasts needed to affect control. Seedlings at the 2-, 4-, and 6-leaf stages were destroyed completely by 2, 4, and 10 blasts of grit, respectively. These results indicate that small weed seedlings potentially may be controlled non-chemically by abrasion from air-propelled grit derived from agricultural residues. The efficacy of the technique requires field verification, but if it is successful organic farmers will benefit from a new weed control tactic. Technical Abstract: A new postemergence weed control tactic is proposed for organic production systems that results in plant abrasion and death upon assault from abrasive grits propelled by compressed air. Grit derived from granulated walnut shells was delivered by a sand blaster at 517 kPa at distances of 30 to 60 cm from seedlings of Chenopodium album in glasshouse pots. Control was influenced by size of plants at time of treatment. Seedlings at the 1-leaf stage of growth were destroyed entirely with a single split-second blast of grit, but were unaltered by compressed air alone. As seedling size at the time of treatment increased, so did the number of blasts needed to affect control. For seedlings at the 2- and 4-leaf growth stages, a single split-second blast of grit resulted in 73% and 23% reductions in fresh weight, respectively. Seedlings at the 6-leaf growth stage required five blasts for 65% fresh weight reduction. Seedlings at the 2-, 4-, and 6-leaf stages were destroyed completely by 2, 4, and 10 blasts of grit, respectively. These results indicate that small weed seedlings potentially may be controlled non-chemically by abrasion from air-propelled grit derived from agricultural residues. |
