Extension Ag Update
September/October 2004
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Curbing What Goes Down the Drain
Don Comis, (301) 504-1625, comis@ars.usda.gov, USDA ARS News Service

The underground drainage systems that criss-cross much of the U.S. Corn Belt are about to get a major overhaul to improve both farm efficiency and the environment.   The upgrade is important because the same pipes that deserve a lot of credit for America's agricultural bounty bear some of the blame for carrying nitrates, phosphorus and other pollutants to waterways such as the Gulf of Mexico.  Norm Fausey leads the Agricultural Research Service's Drainage Research Unit at Columbus, Ohio. He and ARS agricultural engineers Kevin King and Barry Allred, along with Ohio State University-Columbus scientist Larry Brown, are now in the sixth year of running drainage management studies in northwest Ohio.

Drainage management is a new system of draining water only as needed for planting and growing crops. Currently, most drainpipes just drain continuously year-round. With drainage management, control structures allow farmers to raise or lower the water table in various fields as conditions warrant. This even gives farmers the option of letting farm fields provide wetland functions and wildlife habitat for birds and ducks during the non-growing season.
ARS serves on a task force called ADMS, for Agricultural Drainage Management Systems, that is promoting the field drainage upgrade. The task force's members are banking on the concept of drainage management to reduce nitrate losses by at least 30 percent while draining 40 to 60 percent less water. Those numbers, recently reported by the ADMS task force, come from research findings in Illinois, North Carolina and Ohio.

ADMS is also considering the idea of creating new wetlands alongside crop fields to filter contaminants from drainage water. Farmers could store the filtered water in a reservoir for later reuse during drier parts of the growing season. Fausey has designed such a system, called a Wetland Reservoir Subirrigation System. He has seen these reuse systems raise corn yields by more than 45 percent and soybeans by about 40 percent in dry years.

Future Fashions Made of Silky Smooth Wool?
Jim Core, (301) 504-1619, jcore@ars.usda.gov, USDA ARS News Service

Forget the "itch factor." A new "biopolishing" process developed by the Agricultural Research Service (ARS) makes scratchy wool feel silky and look whiter. Not only does it change the texture and appearance of wool, it also modifies the surface to make it shrink-proof.  Besides comfort and form, the method improves aesthetics, according to Jeanette Cardamone, a textile chemist at the ARS Eastern Regional Research Center in Wyndmoor, Pa.   The process results in an increased shine on the fabric's surface from the removal of projecting fiber yarn ends. This contributes to a smooth feel, which increases wool's appeal in women's fashions.

In biopolishing, the wool is pre-treated with a stable, activated peroxide, followed by a treatment with either serine or cysteine protease cellular enzymes.  The hydrogen peroxide step bleaches the wool at lower temperatures and in half the time as conventional techniques, which results in reduced processing costs, according to Cardamone. The bleaching technique also makes it easier to dye the wool.

Shrinkage in conventional wool occurs during machine washing because the resulting heat and pressure lock wool's scales in place. The wool is shrink-proofed by another step that uses enzymes to modify wool's surface by degrading its proteins with enzymes called proteases, so its scales no longer get tangled-up. Shrinkage is controlled without loss in strength or elastic recovery.   Wool scales are usually resistant to enzyme attack, but in biopolishing, enzymes "digest" the scales, resulting in a smoother surface.

Biopolishing can be applied to multiple surfaces--everything from loose fibers to yarn, fabric or completed garments. The American Wool Council, a division of the American Sheep Industry (ASI) Association, provided partial funding for the research.   The biopolishing process is being tested in woolen mills. There is already interest from the U.S. military in wool treated with the biopolishing process, especially for the manufacture of underwear for troops.

Reduce Root-Knot and Lesion Nematodes with Crop Rotation
Robert J. Kratochvil, Sandra Sardanelli, Kathryne Everts, and Elizabeth Gallagher, University of Maryland

Sorghum sudangrass can suppress lesion nematode in vegetables and soybeans according to researchers at the University of Maryland as reported in the Agronomy Journal.  Sorghum sudangrass was grown as a green manure crop following nematode susceptible crops.   Annually growing this grass reduced the root-knot nematode population as well as the control treatment of growing a soybean variety with no known RKN resistance with a nematicide application.

Fingerprinting Dust with Enzymes
V. Acosta-Martinez and T. M. Zobeck, Wind Erosion and Water Cons. Research Unit, ARS- USDA, Texas

Enzyme activities from soils can be used to track wind erosion of soils from the source to the locations where low visibility can threaten human health and safety.  Using enzymes, scientists reported in the Agronomy Journal, soil characteristics affecting the potential for soil to erode by wind can be evaluated with the enzymes serving as biochemical fingerprints.   The impact of the eroded soil on soil and air quality many miles away can be studied.

Bacteria Propel Gains in Ammonia Removal
Luis Pons, USDA ARS News, (301) 504-1628, lpons@ars.usda.gov

Using an innovative bacterial process, Agricultural Research Service (ARS) scientists are paving the way for new, cost-efficient and large-scale methods of removing ammonia from livestock wastewater.  In tests with anammox--a technology that uses rare anaerobic bacteria to convert nitrite and ammonium to harmless dinitrogen gas--soil scientists Matias Vanotti and Ariel Szogi at ARS' Coastal Plains Soil, Water and Plant Research Center in Florence, S.C., have scored noteworthy results.

They're the first researchers to isolate from animal wastewater the planctomycetes bacteria used in the anammox process. They've also highlighted anammox's commercial potential by removing nitrogen from wastewater at rates similar to those obtained using conventional methods.  Short for "anaerobic ammonium oxidation," anammox was discovered in the Netherlands during the 1990s. The process is more energy-efficient than traditional biological nitrogen-removal systems because only part of the ammonium in wastewater needs to be nitrified, and it removes ammonium without needing costly aeration or additives.

In tests in Florence and at a swine farm near Kenansville, N.C., Vanotti and Szogi achieved the high nitrogen-removal rates by improving the bacteria's environment for reproduction. The bacteria's slow multiplication makes their cultivation difficult. The scientists' isolation of the bacteria from wastewater during these tests may make possible economical treatments for high-ammonia effluents, because it shows that it may not be necessary to cultivate the bacteria off-site. Vanotti added that although the researchers have used anammox to remove up to 500 grams of nitrogen per cubic meter daily from wastewater, their goal is to triple this rate within the next year.