Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2004
Publication Date: 7/24/2004
Citation: Russelle, M.P., Kelley, D.W., Trojan, M.D., Iverson, S.P., Schmidt, K.M., Quinonez, L. 2004. Phytofiltration shows promise to reduce ground water nitrate [abstract]. 59th Annual Soil and Water Conservation Society Conference, July 24-28, 2004, St. Paul, MN. p. 26. Interpretive Summary:
Technical Abstract: Treatment of drinking water to remove excess nitrate is expensive and the commonly used process, reverse osmosis, generates a wastewater stream containing very high nitrate concentrations. We hypothesized that ground water nitrate concentrations could be reduced by over-irrigating perennial forages to remove nitrate from irrigation water and produce cleaner recharge water. Field experiments at two sites in Minnesota and a greenhouse experiment were conducted for 2 years. In the field, nitrate-spiked water was applied to three or four species (alfalfa, smooth bromegrass, orchardgrass, and soybean) at irrigation water concentrations ranging from approximately 15 to 50 ppm nitrate-N. Highest yield and N removal were obtained with alfalfa, lowest with smooth bromegrass. Soil solution nitrate concentrations were generally very low under the perennial forages and considerably higher under soybean. Removal of nitrate appears to involve both N uptake and denitrification. We tested alfalfa, reed canarygrass, bermudagrass, and switchgrass in coarse sand in the greenhouse with different water application rates. All species removed nitrate effectively when water did not move too quickly through the root zone. This remediation approach has potential in areas where ground water can be readily influenced by leaching.