By Edwin L. Aguirre
The U.S. Department of Agriculture (USDA) recently awarded a four-year, $744,000 grant to a team of researchers to develop new mulch films for agricultural crops that are not only sustainable and biodegradable but will also help nourish and improve the health of soils and reduce plastic pollution.
Lehigh University Chemical and Biomolecular Engineering Assoc. Prof. Jonas Baltrusaitis and UMass Lowell Plastics Engineering Prof. Meg Sobkowicz Kline are working together to create polymers that would stop weeds and other invasive plants from taking hold in farms while providing nutrients to crops, retaining soil moisture and regulating soil temperature, thereby increasing crop yield.
“Our goal is to create mulch films that will completely biodegrade while also slowly releasing fertilizer, such as urea, to the soil and plants,” says Sobkowicz-Kline, who is the team’s co-principal investigator.
Baltrusaitisis is the project’s lead investigator, with the biopolymer manufacturing company CJ Biomaterials, based in Woburn, Massachusetts, as industry partner.
“We will also study the effects of our polymer-nutrient composite materials on the overall soil and plant health over time, compared to conventional plastic mulch films widely used by farmers today,” says Sobkowicz-Kline.
The team aims to make biodegradable mulch films that are able to maintain their durability, performance and effectiveness throughout the planting-to-harvest cycle. The materials would also have to be affordable, practical and cost-effective to make them competitive against traditional, inexpensive plastic films on the market, so they would get adopted by farmers across the country.
A Collaborative Research and Development Effort
Baltrusaitisis and his team are exploring various biopolymers, including polylactic acid (PLA) and polyhydroxyalkanoates (PHA), which are derived from renewable resources and can decompose into nontoxic components under specific environmental conditions. They are also developing the “cocrystals,” or multicomponent crystals, of agricultural nutrients for the soil and plants.
Sobkowicz-Kline’s team will create the composites by compounding the biopolymers and nutrient cocrystals supplied by Lehigh and then using a manufacturing technique called blown film extrusion to produce the film for field testing.
“Our role is to extrude the biopolymers with and without the cocrystals,” she says. “We will also prepare the films so they can be studied in soil models and, eventually, actual field growth experiments to evaluate their physical and chemical properties.”
CJ Biomaterials is providing the biopolymers for testing and advice on processing the films.
A Sustainability Advocate
According to Sobkowicz-Kline, the biodegradable mulch films will avoid excessive application of fertilizers in farms and help to conserve freshwater resources.
“Excessive fertilizing contributes to global warming through the eutrophication of waterways and aquatic ecosystems,” she says.
Eutrophication is a process in which a body of water becomes overloaded with plant nutrients from farm runoff, leading to algal blooms. When the excess algae and plant matter die and eventually decompose, they produce large amounts of carbon dioxide, which can lower the pH of seawater and lead to ocean acidification.
“As the climate changes, more droughts occur, so retaining soil moisture is increasingly important, especially in arid areas,” she says. “Our project will address these aspects of environmental sustainability.”
Since joining the Plastics Engineering Department in 2011, Sobkowicz-Kline has been active in the fields of renewable polymers, plastics recycling and sustainability, and climate change. She is a member of UMass Lowell’s Climate Change Initiative and is the university’s representative to the REMADE (Reducing Embodied Energy And Decreasing Emissions) Institute, which is one of the U.S. Department of Energy’s Clean Energy Manufacturing Innovation Institutes and is a part of the Manufacturing USA network.
In 2021, Sobkowicz-Kline was awarded a $3 million grant by the National Science Foundation (NSF) to create the Sustainable Water Innovations in Materials – Mentoring, Education and Research (SWIMMER) program at UML. The program trains graduate students to develop sustainable materials and chemicals to protect water resources.
In 2022, she received a $500,000 NSF grant to help advance the development of a new manufacturing process to ease the recycling of plastic film packaging – the ubiquitous thin, flexible material used in grocery bags, produce wrappers, zip-top storage bags and many other consumer products.
Source : uml.edu