Floating Plants Reduce Nutrient Levels in Manure Lagoons

August 1, 2006 — 

Scientists at the USDA's Agricultural Research Service (ARS) lab in Tifton, Georgia have been experimenting with using floating mats of plants to reduce nitrogen and phosphorus levels in hog lagoons.

The research, conducted thus far only in small tanks containing various concentrations of wastewater, have shown that cattails, grown on floating rafts constructed of PVC pipe and chicken wire covered with jute erosion-control matting, grew the best on full-strength wastewater. The cattails produced 15,240 grams of dry biomass, and removed an average of 493 grams of nitrogen and 73 grams of phosphorus, per square meter per year.

A follow-up project is currently being conducted on lagoon on a commercial hog farm in Tifton using a new type of floating mat covered with the coarse fibers from the outer shell of coconuts. According to the research published in ARS's Agriculture Research magazine, several different plant species seem to be good candidates, including St. Augustine grass, coastal Bermudagrass, and giant reed, which have potential as a source of bioenergy fuel. The vegetation can then be harvested and composted and used as a soil amendment. If grass is grown, it can be removed intact and transplanted as sod.

Source:
Agriculture Research, August, 2006