Reducing Nutrient Losses in the Environment

By Marco Furlanis (Environmental Management and Protection, ’23)

Miguel Ramos (Environmental Earth and Soil Science, ’23)
records data on each sample and rehydrates experimental units
as part of weekly monitoring procedures.

Sarah Milad, environmental earth and soil science senior,
collects soil solution samples to submit to a lab for weekly testing.

Can algae be beneficial as a fertilizer? Can it be a natural source in boosting sustainable crop production?

Those questions are at the root of a research study underway by Assistant Professor Charlotte Decock, who focuses on fertilizer management and sustainable agriculture at Cal Poly, and environmental earth and soil sciences major Miguel Ramos.

Nitrogen and phosphorus limit food production across the globe, but when those nutrients are present in excess quantities, they can leak out of the soil and pollute waterways and ground water. It turns out that a major source of potential nutrient contamination comes from municipal wastewater treatment facilities, and often, these excessive nutrients are dumped into landfills, which is expensive, potentially harmful to the environment and not a good use of these scarce nutriments. 

To address this issue, Decock and Ramos teamed up to examine how algae sludge produced from municipal wastewater treatment facilities could be used as a fertilizer for crops. Support for this work comes from the Cal Poly BEACoN program, which aims to connect underrepresented students with professors to work together on a common interest. As a BEACoN research scholar, Ramos is conducting laboratory experiments to analyze the performance of algae sludge in soil. 

A primary focus of this research is to investigate the efficiency of using algae sludge as a fertilizer and to study the behavior of phosphorus and nitrogen cycling in soil treated with algae-based fertilizers compared to inorganic fertilizers. “Currently, wastewater treatment plants landfill their sludge, which is really expensive,” Decock said. “This project aims to assess what the potential fertilizer value is of algae and whether algae behaves differently in soil compared to other commercialized fertilizer products.” 

Overall, tightening global nutrient cycles will be critical to sustaining agriculture in the future. “Eventually the phosphorus in the world is going to run out,” Decock said. “The more we mine phosphorus, the more it’s going to dissipate in our environment, causing us to have less for future food securities. This project will promote a more circular economy by recovering that phosphorus in a meaningful way to keep it cycling.”

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Read more stories in the Summer 2023 Newsletter