Wetland buffers remove phosphorus (P) and nitrogen (N). Restored riparian wetland buffers retained or removed at least 60% of N and 65% P that entered from an adjacent site where manure was applied, according to results of a nine-year study by Agricultural Research Service (ARS) scientists in Tifton, GA, and cooperators at the University of Georgia.

Ecologist Richard Lowrance of the ARS Southeast Watershed Research Unit and Engineer George Vellidis of the University of Georgia, found that a particular type of buffer — called a restored Zone 3 Conservation Buffer — is especially effective in removing excess nutrients from water that runs off agricultural fields where manure has been applied. A Zone 3 buffer is a grassy edge placed next to the field.

During the study, the amount of water and concentrations of N and P in water entering and leaving the riparian wetland were monitored. The stream flow concentrations of N and P leaving the conservation wetland buffer were ½ N and ¼ P of the incoming concentrations in surface runoff from adjacent fields.

Other Tifton scientists are conducting various conservation buffer research studies that examine several different scenarios farmers encounter. Ultimately, this research should help growers develop a way to lower nutrients that make it to streams and waterways.