USDA and university researchers work to prevent U.S. cotton contamination

Authors: Whitelock, Derek

Submitted to: Cotton Farming
Publication Type: Popular Publication
Publication Acceptance Date: 12/1/2017
Publication Date: 12/1/2017
Citation: Whitelock, D.P. 2017. USDA and university researchers work to prevent U.S. cotton contamination. Cotton Farming. 23-25.

Interpretive Summary:

Technical Abstract: U.S. cotton is considered to have some of the lowest levels of contamination in the world. However, that reputation is in jeopardy as complaints of contamination from domestic and foreign mills are on the rise. Cotton contamination is classified by the International Textile Manufacturers Federation in major categories including fabrics and strings from plastics and natural fibers, oils and chemicals, organic matter, and inorganic matter. Of particular concern for the U.S. are plastic contaminants – plastic trash that collects in cotton fields, black plastic film used as mulch, plastic twine typically used for hay baling, and yellow plastic film used for round module wrap. So, what is the cotton industry doing to keep plastic contamination out of U.S. cotton? The answer to that question has two parts: education and research. First, there is a nation-wide campaign led by the National Cotton Council to educate the cotton industry about plastic contamination and how to prevent it. This effort targets producers, ginners, and warehousers using a variety of approaches including local, state and national cotton industry meetings, magazine articles, mailings, and a website specifically created for contamination prevention (www.cotton.org/tech/quality/contamfree.cfm). Second, there are Cotton Incorporated supported collaborative research efforts at the USDA ginning laboratories in Texas, New Mexico, and Mississippi, the USDA cotton quality lab in New Orleans, and at Texas A&M University, Oklahoma State University, and the University of North Texas. These efforts target different points in the cotton production scheme from the field, to the harvester, and to the gin and focus on detection using imaging/optical techniques and separation using physical/electrostatic methods. The best way to keep plastics out of U.S. cotton is to prevent it from entering the cotton stream in the first place. One ongoing research project is investigating harvester-mounted cameras to detect contamination in the field and warn the operator before it enters the harvester and ends up in the module. Next year, another research effort will look into unmanned aerial vehicles or drones mounted with cameras to fly over the cotton field and detect and record the location of contaminants. These coordinates can then be transmitted to the cotton producer’s smart phone and located manually, or an autonomous land vehicle can be dispatched to retrieve the plastics prior to harvesting. For the occasion when plastic contaminants do slip into the module or in the case where round module wrap is not completely removed, research efforts on detection methods at the cotton gin are underway. A color camera system for viewing the backside of the module feeder cylinders to detect plastics wrapped on the spikes or pieces that slip through is being developed. For contaminants that make their way into the gin machinery, a prototype system is being evaluated and refined to detect colored contaminants in seed cotton in places where the flow is slower and more spread out, like in rectangular ducts between cylinder cleaners and stick machines. For neutral colored or transparent plastics that are much more difficult to detect, researchers are investigating infrared detectors and light sources that sense differences in chemical composition rather than color. Assuming these detection methods are successful, what can be done to extract the plastic contaminants from the cotton? Previous research showed that with current gin machinery about 17% of plastics that enter the gin end up in the bale. Research on modifying current machinery to more effectively remove plastics are underway. In addition, extraction methods using jets of air to fluff the cotton and float lighter contaminants away are under investigation. Another concept being explored exploits the differences in the static electric c