Flattened stands of rye could give soybean crops
the competitive edge over weeds so little or no herbicide is needed. Image
courtesy
Adam
Davis, ARS. |
|
Researchers Roll Out the Rye to Rein In
Weeds
By Jan
Suszkiw July 27, 2007
Rather than till crop fields to disrupt weedsand risk losing
soil to erosionorganic soybean growers should take note of Agricultural
Research Service (ARS) studies in Urbana,
Illinois.
There, ARS ecologist
Adam
Davis is experimenting with a no-till system that calls for flattening
seven-foot-tall stands of cereal rye into dense vegetative mats that secure the
soil and curtail weeds like giant foxtail so that soybean plants can grow
uncontested. Davis envisions soy growers using the rolled-rye cover in an
integrated approach to weed control.
In two years of field studies conducted by Davis near the ARS
Invasive
Weeds Management Research Unit in Urbana, soybeans grown in rolled-rye
fields averaged 40 bushels (2005) and 33 bushels (2006) of seed per acre.
No-till soybean controls treated with glyphosate at half or full strength
produced nearly 50 bushels per acre.
Organic soybean growers forgo herbicide use and instead rely on
tillage and other cultivation measures to control weeds. But such measures can
necessitate making up to 10 trips into the crop field, which increases fuel and
labor costs. By establishing a stand of rye in the fall and rolling it flat in
late May, growers need only make one trip. That's because weeds are suppressed
both before and after the stand is rolled.
The key to the approach is a specialized, multi-bladed roller that
attaches to a tractor's front or back end. As the tractor moves through a
field, the roller crimps the rye plants' stems and flattens them into a
two-inch-thick matted mulch. A planter accompanying the roller then deposits
soybean seeds into the soil beneath, eliminating the need for tillage.
Davis learned of the rollers, designed by scientists at
The Rodale Institute in Kutztown,
Pa., while doing postdoctoral research with Dale Mutch in 2004 at
Michigan State University's
Kellogg Biological Station in Hickory
Corners. There, organic soybeans grown in rolled-rye or hairy vetch mulches
yielded 58 to 62 bushels per acre on sandy loam soils.
Davis joined the ARS Urbana unit in 2005 and expanded on the Michigan
work to include conventionally grown soybeans.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.