Giant Soybeans Suck Up Phosphorus from the Soil

Besides providing forage for livestock, three new giant soybeans may pull more phosphorus out of soils than conventional soybeans grown for grain.

The exceptional growth of these giant soybeans could make them useful in areas such as parts of Maryland's Eastern Shore, where excess phosphorus in the soil is suspected of contributing to water pollution problems. On these soils, the new soybeans could be grown to produce forage that could be baled or cubed for shipping to other areas.

The new trio--Derry, Donegal and Tyrone--are the first improved forage-type soybean varieties bred for use as animal feed, according to geneticist Thomas Devine. He developed the new varieties at the Agricultural Research Service in Beltsville, Md.

In tests Devine led and coordinated in several states through 1996, forage soybeans produced more than 6 tons of dry matter per acre--about 75 percent more than conventional soybeans. Assuming the percentage of phosphorus in a giant soybean plant is the same as that for a normal-size soybean, the new varieties would take up more of the nutrient.

The new varieties differ in maturity dates, disease resistance and geographic areas where they will grow best. Donegal is suited to the Northeast. Derry is ideal for the Midwest and Tyrone is best for the South.

An article about the new soybeans appears in the May 1998 issue of ARS' Agricultural Research magazine. The article is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/may98/gian0598.htm

Scientific contact: Thomas E. Devine, ARS Weed Science Laboratory, Beltsville, Md., phone (301) 504-6375, fax (301) 504-6491, tdevine@asrr.arsusda.gov.