C A L I F O R N I A
Vegetables A SPECIAL GROWERS’ REPORT OF AG ALERT ®
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A work crew lays biodegradable plastic in a strawberry field. Research on the material shows economic advantages to using the biodegradable plastic mulch, which can be incorporated into the soil at the end of the year.
Strawberry fields test biodegradable plastic mulch ByKathyCoatney Soil-biodegradableplasticmulchhas real potential, according toresearchersevaluating thematerial.
In tests of some of the older products, the plastic just broke apart, but never actually broke down all theway, Bolda said. Thesewere not true biodegradablemulches because they did notmeet the standards for biodegradability, he said. The BDMs Bolda is workingwithnowactually break down all theway. “It’s composedof different things, so it’snot just plasticsbreakingdown intosmaller and smaller pieces. They actually get decomposed once they are incorporated in the soil,” he said, and they’re consumed bymicroorganisms. Working with four to five strawberry growers, Bolda is testing two different kinds of BDMswith three different thicknesses. TheBDMswere placed in the ground in the fall of 2020 alongside regular plastic. “We’ve beenmonitoring it through the year,” Bolda said, adding the results so far are encouraging. But researchers are keeping closewatch. Krone said, “The second hurdle is when they till it in. We know that it will biodegrade eventually, but we don’t know inCalifornia climate how long that will be.” She said that’s because there tends tobemoremicrobial activitywhen it’swarm, but alsowhen it’smoist. “Sobothwarmth and soilmoisturewouldplay a part in the speedof biodegradation in the soil,” Krone said.
Mark Bolda, a University of California Cooperative Extension farm advisor for Santa Cruz, Monterey and San Benito counties, said there are economic advantages to biode- gradablemulch, or BDM. It can be incorporated into the soil at the end of the year rather than sending crews out to pull it up and gather pieces of plastic, which is labor intensive. “Biodegradablemulch has been around for awhile,” Bolda said. Bolda is doing a collaborative project with Lisa DeVetter, associate professor at Washington State University, and PamKrone, agriculture water quality coordinator for CaliforniaMarine Sanctuary Foundation. The research looks at ways to improve plastic mulch so that it sustains itself long enough to support plant growth, but then efficiently degrades into the soil to prevent plastic pollution. Krone has also beenworkingwithBolda on the research. “I knowit’s kindof a strangeconnection,” she said. “But agricultural plastic cannot only end up polluting rivers and streams but also the ocean.” However, sheadded, “There’sacoupleof big finds that thegrowersare interested in:One is that theydon’twant it tobiodegrade toosoon, because theydon’twant their strawberries to be resting on the dirt.”
See MULCH, Page 8
August 4, 2021 Ag Alert 7
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