Recycled Waste May Meet U.S. Nitrogen and Phosphorus Needs

By Blake Jackson

A new Cornell University study suggests that nutrients recovered from animal and human waste could significantly reduce the United States’ reliance on synthetic fertilizers, even when accounting for practical challenges such as processing and transportation.

Researchers estimate that these waste sources could theoretically supply 102% of the nation’s nitrogen needs and 50% of its phosphorus requirements valued at more than $5.7 billion annually.

Despite this potential, a key obstacle remains: the geographic mismatch between where waste is generated and where nutrients are most needed.

Waste tends to accumulate in densely populated or livestock-heavy areas, while regions with high agricultural demand such as the Midwest and southern Great Plains often face nutrient shortages.

Still, the study found that 37% of nitrogen and 46% of phosphorus could be used locally, while more than half of the surplus could be redistributed to nearby areas at relatively low cost.

“This is a coordination problem, not a resource problem,” said corresponding author Chuan Liao, assistant professor in the Cornell CALS Ashley School in the College of Agriculture and Life Sciences.

“Even considering the real-world constraints, there’s still a substantial amount of nutrients that can be economically redistributed to meet crop needs.”

Using publicly available data, the research team mapped waste sources and nutrient demands across 15 major crops, identifying overlaps with economically vulnerable regions.

Pollution risks were also noted, as excess waste can contaminate water systems, while heavy reliance on synthetic fertilizers may degrade soil and water quality.

“The nutrient inequality seems to mirror social inequality in a large sense,” Liao said. “So potentially fixing the nutrient flow can promote environmental justice.”

Liao advocates for decentralized systems that process waste locally, emphasizing collaboration across agriculture, waste management, and energy sectors to fully realize this opportunity.

Photo Credit: pexels-jan-kroon