New Project Underway Demonstrating Biodegradable Mulch

Posted: May 25, 2011

Penn State Extension Educators across the state are collaborating with local growers to look at biodegradable mulch. We all know the benefits of plastic mulch. Not only does it keep the weeds down, it warms up the soil giving us earlier (and more) tomatoes, peppers, eggplants and other heat loving veggies. But it costs us. Farmers estimate it costs $25-100 an acre for labor and disposal of plastic mulch. A possible alternative to black plastic mulch is biodegradable film mulches that look and act much like black plastic, but instead of ripping them up in the fall, you till them into the soil and the microbes degrade the material, leaving you a clean field (hopefully) in the spring.
Little Peace Farm, Schuylkill Haven PA

Little Peace Farm, Schuylkill Haven PA

To look at the possible labor and resource savings Penn State Extension educators, working with growers, laid biodegradable mulch at 5 sites in Northampton, Berks, Schuylkill, Snyder, and Bucks Counties. Two more sites should go in this week. Growers will tell us how easy biodegradables were to use, how they compare to plastic and whether they broke down by the next spring. Dr Orzolek, Penn State Department of Horticulture, is testing biodegradable mulches in replicated plots in State College to provide data to compliment grower feedback.

What is biodegradable mulch?  Good biodegradables are made from plant starches such as corn and wheat. Soil microbes break down the starch into CO2 and water. Warm, moist conditions that favor the microbes speed up biodegradation. Sticky starches help them adhere to soil, keeping them from blowing away/ littering. The technology has changed from the old degradable films made from polyethylene which degrades slowly and sometimes become dry and brittle, blowing into the neighbor’s yards and hanging from the trees.

How do biodegradable mulches perform? Demonstrations this year will tell us more. At a demonstration site last year at Trauger Farms, Bucks County, PA two of the newer mulches performed very well. Research by Dr. Orzoleck (2008) found that “Biodegradable performed as good or better than plastic for yields in pepper, cantaloupe.”

Aren’t biodegradable mulches more expensive? The cost of biodegradable mulch has come down recently. We estimate comparable costs of $349/A for biodegradable mulch compared to $310/A for plastic mulch plus removal and disposal with a resource savings of 400 lbs of plastic/ A.

For more information visit see the biodegradable mulch factsheet. Keep a look out for the results of this year’s demonstrations.