Researchers Aim to ‘Upcycle’ Nutrient Waste on Farms Using Duckweed
by Tim Schley (Penn State News) New approach to nutrient management could make money for farmers and land managers; Best management practices for reducing runoff and other nutrient losses in agriculture have been difficult to implement, according to Penn State researchers. The team is hoping that duckweed could help make money for farmers and land managers while limiting nutrient pollution into the environment.
With a $1.7 million grant from the National Science Foundation, Penn State researchers will investigate how duckweed could be grown on Pennsylvania farms to limit nutrient pollution into the Chesapeake Bay.
Duckweed, a tiny plant resembling a lily pad, grows rapidly in water with elevated levels of nitrogen and phosphorus, often the result of fertilizer and manure runoff. While many consider the plant a pest, farmers may find duckweed doubly beneficial, according to Rachel Brennan, associate professor of environmental engineering and lead investigator of the project.
“Not only can duckweed capture the nutrients before they cause problems like algal blooms and dead zones, but it can also ‘upcycle’ those nutrients into something that farmers can use again,” Brennan said. “It can be harvested multiple times per week and used as a feed supplement for farm animals. We have also demonstrated that it can be used as a soil amendment to support crop growth with much less runoff than conventional fertilizer. Duckweed has enormous potential for taking a waste product and giving it greater value.”
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“For this to work, it needs to be economically advantageous for farmers,” Brennan said. “They should not have to buy as much chemical fertilizer or feed because they can take their own waste nutrients, convert them to duckweed and then use them again.”
Some of the experiments in the project focus on duckweed’s performance as a feed supplement, including how well cows digest the plant and its impact on milk production, as well as ways to improve both.
Others will investigate duckweed’s effects as a fertilizer. According to McPhillips, there are indications it might not only reduce the amount of nutrients in runoff but could also reduce the emission of nitrous oxide, the third most abundant greenhouse gas.
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The team also plans to examine the proposal from a holistic perspective, brainstorming ways a duckweed-based “circular bioeconomy” could sustainably scale beyond local farms.
“Collecting biomass from fields to make ethanol in central processing plants is a well-established practice, and maybe a similar approach could be used for collecting manure from farms to produce duckweed,” Brennan said. “It could be vertically farmed in large warehouses because it only needs about an inch of water to grow. It would be a big change, but any major transformation to agriculture is going to seem radical at first.” READ MORE
Researchers say cultivated seaweed can soak up excess nutrients plaguing human health and marine life (Phys.Org/University of California – Santa Barbara)
