The author is is an assistant professor and extension specialist in the department of biological and agricultural engineering at North Carolina State University, Raleigh, N.C.

When carefully managed, manure is a low-cost source of nutrients and organic matter that improves soil fertility and crop yields

Sludge is a nutrient-rich by-product of manure storage and treatment. Sludge accumulates at the bottom of the lagoon as a result of two processes: the biological treatment by microbial communities and...