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Seed of Research

The Alabama Agricultural Experiment Station’s Agricultural Enhancement & Seed Funding Program is designed to foster innovation, enhance research capabilities, and support emerging and established scholars through targeted research opportunities. And, for the first time this year, post-doctoral and graduate students are eligible for these grants. Seeds of Research is an occasional series of articles that will take a unique look at these research projects in their infancy and the scientists behind them.

Rarely do we read or listen to a news report that doesn’t mention the dangers of microplastics in the environment. These tiny particles are apparently turning up everywhere, from the depths of the ocean to the human body. And yes, even in farmers’ fields.

“Agricultural soil is considered a ‘sink’ for plastics because it receives plastic inputs faster than they are removed, leading to particle accumulation over time,” said Rakesh Kumar, a post-doctoral fellow in the Auburn University College of Agriculture’s Department of Biosystems Engineering.

“Agricultural soil receives plastic from mulch films, irrigation materials, seed coatings, sludge-based fertilizers, runoff and airborne deposition,” he said. “Once these plastics break down into microplastics, they persist in the soil for long periods,” he said.

Kumar’s research into microplastic pollution recently received a $10,000 grant through the Alabama Agricultural Experiment Station’s Agricultural Enhancement & Seed Funding Program. It’s the first year post-doctoral and graduate students have been eligible for such grants.

Kumar, who is originally from India, said it “feels incredibly encouraging” to be a first-time recipient of an AAES internal grant.

“It shows that early-career researchers are being recognized and supported at Auburn, and it gives me confidence to develop my project and pursue larger opportunities in the future,” he said.

Kumar said he was drawn to Auburn University because of its strong academic reputation, supportive community and the values reflected in the Auburn Creed.

“After learning more about the campus culture and opportunities, I felt it was the right place for me,” he said. “Initially, I had the opportunity to begin my post-doctoral research on broader topics relating to the fate and transport of contaminants in the environment, nutrient management and biochar application under the supervision of Dr. Jasmeet Lamba.”

Kumar has been working on microplastic pollution research across different ecosystems since completing his PhD in India.

“Terrestrial ecosystems — including sediments and agricultural soils — are sinks for microplastic deposition,” he said. “Here in Biosystems Engineering, I am exploring nutrient management in agricultural soils. My research project began with a general interest in the topic, which grew into a specific question after background reading and refinement. From there, I shaped the idea into a focused study designed to address a research gap for Alabama.”

Plastic pollution requires urgent action, Kumar said, because it is already moving through soil, water, food chains and other natural ecosystems.

“When plastics degrade into tiny particles, called microplastics—smaller than 5 millimeters—they can damage soil structure, reduce water retention, disrupt microbial communities, and affect plants, animals and food safety.

“Microplastic particles have been observed to adsorb and transport nutrients and essential trace metals, potentially restricting plant uptake,” he said.

Plastic mulch is commonly used in vegetable production in Alabama, and it contributes greatly to microplastic pollution, Kumar said.

“Additionally, there are several polymer-based fertilizers, such as controlled-release fertilizers, urea, potassium chloride and ammonium nitrate, as well as seed units, which, when applied in agriculture, can lead to long-term sources of microplastic pollution in soils.”

In Alabama, he added, major sources of microplastics include the degradation and weathering of large plastic particles into smaller sizes by plastic permeable paving, plastic reinforcement grids and cisterns, from which microplastic particles leach into stormwater and soils.

Plastic materials in agriculture break down into microplastics that persist in the environment and are difficult to remove once they enter soils and water, Kumar said.

“Microplastics can affect nearly every major part of agriculture, from soil function to crop production and food safety. The most important impacts are on soil health, plant growth, nutrient cycling, water retention and soil organisms.”

A practical response to plastic mitigation starts with using less plastic, reusing more, recycling properly, pushing for policies that hold producers accountable, and implementing effective plastic waste management, Kumar said.

“The most effective solutions are preventive, because once plastic is exposed to the environment, it is very difficult to remove,” he said. “In addition, we can reduce single-use plastics, especially bags, bottles, cutlery and straws, as well as excessive packaging.”

The primary aim of Kumar’s research is to understand how microplastics behave in soil with respect to phosphorus sorption, as a function of microplastic type and soil type, and how this may be hindered by competition for active sites on soils where phosphorus can bind.

“This research aims to produce information on the implications of plastic mulch and plastic-based material applications in soil and their potential impacts on phosphorus cycling in Alabama soils,” he said. “The knowledge gained from this study will be made available to the scientific community, stakeholders, the public, and the agricultural community.”

Results will help optimize the use of plastic-based materials, such as plastic mulch, in agricultural practices, focusing on nutrient management while considering both agricultural and environmental sustainability, he said.

“I will be able to convey our messages to statewide stakeholders, including the Alabama Department of Environmental Management (ADEM), the Alabama Cooperative Extension System (ACES), and other state and federal organizations, to raise public awareness regarding effective plastic use and management,” Kumar said.

Kumar’s co-principal investigator and mentor, Jasmeet Lamba, said Kumar’s research is vital because, while the environmental risks of microplastics are well documented, their effects on nutrient cycling in agricultural soils remain poorly understood.

“This research addresses that gap by examining how microplastics influence phosphorus cycling in soils, an essential nutrient for plants,” said Lamba, associate professor in Biosystems Engineering.

“Through this seed grant, the team will generate preliminary data to better understand microplastic–soil nutrient interactions,” he said. “These findings will support future field-based research and help guide sustainable agricultural practices that protect soil health and crop productivity.”

Lamba sees his role as mentor and co-PI to support Kumar’s growth as an independent researcher while ensuring the successful completion of the proposed research.

“I will provide guidance on the overall research direction,” he said. “At the same time, I will encourage Rakesh to lead in day-to-day project activities, manuscript preparation, conference presentations, and work with him on the development of follow-up extramural proposals.”