Typically, hydromulches contain paper, wood or straw in a slurry mixture with water and grass seed. The slurry, usually dyed green, helps the seeds stick and stay in place and provides a moist and nutritious mulch for germination.
The test hydromulches will have ryegrass seed in them and will be dyed red, green or brown to distinguish between those made with wastes from different cotton gin processes and regions. Agricultural engineers Greg Holt and Mike Buser, with the ARS Cotton Production and Processing Research Unit in Lubbock, Texas, and agricultural engineer Daren Harmel and soil scientist Ken Potter, with the ARS Grassland Soil and Water Research Laboratory in Temple, Texas, will do the testing. Summit Seed will provide equipment and supplies.
The researchers will compare the test hydromulches to three conventional ones, looking at factors such as seed germination, costs and erosion control.
The waste is held together by a low-cost process — COBY, for Cotton Byproducts — invented by the Lubbock scientists. It uses a hot, gelatinized starch solution that acts as a glue and as a lubricant to smooth the mixture's flow through extrusion equipment.
The scientists see this as another way to use waste material that cotton gins would otherwise have to pay to have removed. These costs are estimated at $4 million to $6 million annually.
The cotton-waste mixture has also been made into pellets and tested in pellet-burning stoves and as fertilizer and cattle feed. In a test with 162 heifers, cattle gained more weight on less feed. And Summit Seed is testing a dry mixture as a bedding mulch for landscaping use.
ARS is the U.S. Department of Agriculture's chief scientific research agency.