Newest Soil Erosion Formula "Goes
The Revised Universal Soil Loss Equation can be used to
calculate erosion potential on a wide range of croplands.
After nearly a decade of work at more than 10 locations across the country,
scientists have completed an erosion-stopping computer program known as
RUSLERevised Universal Soil Loss Equation.
This program is a more accurate version of one developed in the early 1960's
to estimate and help control soil erosion by water.
"Farmers often need advice on what they can do to keep erosion under
control on their land," says hydraulic engineer Kenneth G. Renard.
"The new program will show them how they can best reduce erosion with the
Renard served as the agency's team leader to revise the program, in
cooperation with scientists from USDA's Natural Resources Conservation Service
(NRCS). He recently retired from the ARS Southwest Watershed Research
Laboratory in Tucson, Arizona.
The new team leader is ARS hydraulic engineer George R. Foster, director of
the National Sedimentation Laboratory at Oxford, Mississippi.
RUSLE requires descriptive information on plants and tillage operations that
significantly affect erosion. This includes coverage of the soil by plant
canopy, height that waterdrops fall from the canopy, amount of roots in the
upper 4 inches of soil, surface roughness, amount of residue on soil surface,
and depth that residue is buried by a tillage operation.
Besides incorporating advances in computer technology, RUSLE has been
improved with new rainfall/runoff erosivity values for the western United
States and new ways to calculate factors such as prior land use and slope
length and steepness.
One of the major advantages of the new program is that it is now possible to
calculate soil loss for vegetables and alternative crops where experimental
data are not available. It can quickly evaluate a wide range of untested
A set of baseline values was created by ARS scientists and NRCS technical
specialists. These serve as a guide for estimating values for crops and tillage
operations not represented in the baseline data.
ARS scientists also came up with procedures for varying these data as yield
and tillage operation change from the typical conditions represented by the
core data. RUSLE was validated against both the original Universal Soil Loss
Equation data and extensive new data on conservation tillage that were not
available when the original program was developed.
Says Renard, "For the last 4 years, ARS scientists, in cooperation with
the Soil and Water Conservation Society, have helped train employees of the
NRCS and the U.S. Department of the Interior's Bureau of Land Management so
they could put RUSLE to practical use helping farmers, ranchers, and
RUSLE is already in use by NRCS and other agencies as a tool to identify
sites with excessive soil erosion caused by rainfall and surface water runoff,
according to Foster. It can help farmers tailor conservation systems to
One important use of the new program will be to develop conservation
compliance plans to reduce soil erosion on over 36 million acres that farmers
will return to cultivation when their Conservation Reserve Program contracts
RUSLE can also be used to plan rangeland resource conservation, as well as
for resource inventory work.
"The original program was a powerful tool used by soil conservationists
for over three decades," says Foster. "It's helped farmers keep
valuable topsoil on their farms.
"Managers have used it to determine regional and national costs
associated with erosion. It has also helped them to develop and implement
public policy aimed at protecting the environment. And," he adds,
"the new version will do even more."
The RUSLE program, user's guide, and documentation are available for $295
from the Soil and Water Conservation Society [7515 Northeast Ankeny Rd.,
Ankeny, IA 50021- 9764] as part of an ARS Cooperative Research and Development
Agreement with the society. By Dennis Senft and Hank
Sedimentation Laboratory, P. O. Box 1157, Mc Elroy Drive, Oxford, MS 38655;
phone (662) 232-2940.
"Newest Soil Erosion Formula "Goes
Commercial"" was published in the
September 1995 issue
of Agricultural Research magazine.