Alfalfa may be the answer farmers everywhere are looking for to clean up the pollution in their soil and water supply.
An innovative alfalfa variety developed in the Agricultural Research Service within the St. Paul campus’ Plant Science Research Unit has proven to be useful in removing nitrate pollutants from soil and ground water. The variety’s seed, which only the St. Paul scientists possess, is not yet patented. However, the product is already being targeted for marketing.
“We would like to develop a marketing agreement with a seed company,” said Agronomy Professor Carroll P. Vance. “The big issue now is to get enough seed so we can let people use it at other sites or to have a seed company become interested in it. Right now we are just giving it away,” Vance said.
Nitrate soil contamination comes from over-fertilization, fertilizer spills, livestock manure and food-processing wastes. Once in the soil, the nitrate can move into ground water and contaminate drinking water supplies.
Normal alfalfa plants obtain nitrogen from the air in a symbiotic process called nitrogen fixation. They can also get nitrogen from fertilizer in the soil. As the plants use the soil’s nitrogen, they remove the excess nitrate polluting the ground water.
Vance and Assistant Professor JoAnn Lamb, along with Michael P. Russelle, professor in the Department of Soil, Water and Climate, worked together to develop an unusual alfalfa that only uses nitrogen from the soil. Research shows that because it can’t get its nitrogen from the air, the plant takes up more nitrate from the soil and water.
After discovering this, Vance, Lamb and Russelle realized alfalfa would be a useful tool in phytoremediation, a process of using plants for cleaning pollutants from the soil and water.
The new alfalfa is able to remove 30 percent more nitrate pollutants from the soil and water than normal alfalfa plants.
In addition to its enhanced ability to absorb nitrate, the new alfalfa is also a visual indicator, as the plant turns yellow when the soil runs out of nitrogen. When the plant turns color, it’s apparent that it has removed all the nitrate from the soil.
To test the new alfalfa, a test site was set up in Bordulac, N.D., where a derailment of rail cars leaked nitrogen fertilizer. After conducting tests at the site, which showed very high levels of nitrate in the soil and ground water, the new alfalfa was planted to test how well it removes the nitrate from the area. Each acre of alfalfa at this test site will remove several hundred pounds of nitrate nitrogen each year. The alfalfa will also be a valuable source of animal feed.
The scientists have established an agreement with Canadian Pacific Railroad Company, which is funding the upkeep of the site, to demonstrate how well alfalfa removes nitrate from ground water.
Success of the new alfalfa will be an advancement for agriculturists in environmental cleanup. “Phytoremediation is a new concept in environmental management and it has a lot of potential,” said Vance.
Vance said phytoremediation is important to agriculturists because concentration of nitrate pollution in one area is a big problem in agriculture today.
“When nitrate gets into the ground water or streams, it causes eutrophication, which causes the growth of algae and stimulates the growth of unwanted organisms. Thus it chokes out the diversity that might naturally occur,” said Vance.
Presently, the most pressing concern with the development of the new alfalfa is producing enough seed. Vance said the scientists receive many seed requests from people all over the country and Canada who own and manage feed lots, railroad companies and mining corporations.
The scientists are the only people who have the seed; however they do not have a patent on it.
Vance estimates that cleaning up contaminated sites in the United States would cost billions of dollars through mechanical means. “Using a phytoremediation system would reduce the cost by tenfold,” Vance said.
Scientists are now researching to phytoremediate other types of contamination and to produce more seed of the new alfalfa. “We’re very excited about the possibility of this and the consultants who have heard about it are very excited about using it,” Vance said.