Iowa State University University agricultural engineers Jeff Lorimor and Brad Woerner list several alternative methods for reducing nutrient runoff from feedyards.

The first step in any control system should be solids settling. Research has shown settling basins below earthen beef feedlots removed 64 percent of the solids from the raw runoff, 84 percent of the nitrogen, 80 percent the phosphorus and 34 percent of potassium .

Vegetative filter strips provide an opportunity for runoff and pollutants to infiltrate into the soil profile; and allow deposition of suspended solids. These can reduce solids by up to 98 percent, with most reductions in the 70-90 percent range. TKN removal averaged 71.5 percent, and P removal averaged 68.7 percent. Critical design factors are length and/or the ratio of the vegetated area to the feedlot runoff area.

Constructed wetlands can provide 50 percent or more reduction of nitrogen, phosphorus and solids, and 60 percent or greater reductions of BOD.

Finally, soil infiltration areas are very effective in removing pollutants. The researchers note that using various combinations of the technologies, reductions of over 90 percent could be attainable. For more information, go to