Agriculture: Farming, Ranching playlist: https://www.youtube.com/playlist?list... more at http://quickfound.net/links/agricultu... "Shows new herbicides incorporating 2,4-D." Reupload of a previously uploaded film with improved video & sound. Public domain film from the Library of Congress Prelinger Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original). http://creativecommons.org/licenses/b... https://en.wikipedia.org/wiki/2,4-Dichlorophenoxyacetic_acid 2,4-Dichlorophenoxyacetic acid (usually referred to by its abbreviation, 2,4-D) is a common systemic pesticide/herbicide used in the control of broadleaf weeds. It is one of the most widely used herbicides in the world, and the third most commonly used in North America. 2,4-D is a synthetic auxin (plant hormone), and as such it is often used in laboratories for plant research and as a supplement in plant cell culture media such as MS medium. It was a major ingredient in Agent Orange alongside its chemically similar relative, 2,4,5-T (2,4,5-trichlorophenoxyacetic acid). History 2,4-D was developed during World War II by a British team at Rothamsted Experimental Station, under the leadership of Judah Hirsch Quastel, aiming to increase crop yields for a nation at war. When it was commercially released in 1946, it became the first successful selective herbicide and allowed for greatly enhanced weed control in wheat, maize (corn), rice, and similar cereal grass crops, because it only kills dicots (broadleaf plants), leaving behind monocots (grasses). Genetically modified crops Dow has demonstrated soybean resistance to 2,4-D due to insertion of a bacterial aryloxyalkanoate dioxygenase gene. This is intended as an alternative to Roundup Ready crops due to the increasing prevalence of glyphosate resistant weeds. Department of Agriculture approval is pending for a 2,4-D resistant corn. Mode of action 2,4-D is a synthetic auxin, which is a class of plant hormones. It is absorbed through the leaves and is translocated to the meristems of the plant. Uncontrolled, unsustainable growth ensues, causing stem curl-over, leaf withering, and eventual plant death. 2,4-D is typically applied as an amine salt, but more potent ester versions exist as well. Manufacture 2,4-D is a member of the phenoxy family of herbicides, which include: - 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) - 2-Methyl-4-chlorophenoxyacetic acid (MCPA) - 2-(2-Methyl-4-chlorophenoxy)propionic acids (mecoprop, MCPP) - 2-(2,4-Dichlorophenoxy)propionic acid (dichlorprop, 2,4-DP) - (2,4-Dichlorophenoxy)butyric acid (2,4-DB) 2,4-D is manufactured from chloroacetic acid and 2,4-dichlorophenol, which is itself produced by chlorination of phenol. Alternatively, it may be produced by the chlorination of phenoxyacetic acid. The production processes creates several contaminants including isomers, monochlorophenol, and other polychlorophenols and their acids... Despite its short half-life in soil and in aquatic environments, the compound has been detected in groundwater supplies in at least five States and in Canada. It has also been detected in surface waters throughout the United States at very low concentrations... 2,4-D has been evaluated by the European Union and included on its list of approved herbicides, stating inter alia that "the review [of 2,4-D] has established that the residues arising from the proposed uses, consequent on application consistent with good plant protection practice, have no harmful effects on human or animal health." Concern over 2,4-D is such that it is currently not approved for use on lawns and gardens in Sweden, Denmark, Norway, Kuwait and the Canadian provinces of Québec and Ontario. 2,4-D use is severely restricted in the country of Belize. In 2005, the United States Environmental Protection Agency approved the continued use of 2,4-D...

• published: 17 Mar 2016
• views: 1274