ED-STEEP: Education Solutions to Environmental
andSoil
Economic
Problems
ED-STEEP
Invertebrates
Fact Sheet
Soil Erosion Research Highlights











Erosion directly decreases productivity by reducing soil depth and removing topsoil which
contain much of the soil’s organic matter.
The loss of soil organic matter (the reservoir for plant nutrients) and topsoil (contains 80% of
soil’s native fertility) lowers water holding capacity, reduces infiltration, adversely affects
soil tilth, and decreases soil fertility.
Erosion makes soil more susceptible to further erosion.
Erosion carries soil to streams, lakes, and other bodies of water, contributing to siltation and
sedimentation problems. Eroded soils also contains attached nutrients and possibly
pesticides, diminishing water quality and posing a risk to aquatic plants, fish, and other
aquatic life.
Erosion by wind decreases air quality and can be a health risk.
Average annual soil erosion from an 88-acre section of a watershed landscape (77% of area)
which had sustained erosion from 1963 to 1988 was estimated at 7.8 tons/acre/year. Total
erosion during this period was estimated at 907 tons/acre. This is equivalent to roughly 6
inches of soil depth on each of the 88 acres of the watershed which sustained erosion
(Busacca and Cook).
Researchers concluded that relative changes in aggregate stability can be predicted from
changes in organic carbon and clay contents on the field landscape.
Specific soil properties were often associated with slope position. Organic carbon and water
contents were generally lowest on summit and shoulder positions, which were the more
eroded areas, and highest on the footslope and toeslope positions, which had deeper soil of
the Palouse series. Aggregate stability was lowest on upper slope positions and highest on
lower positions. As organic carbon content increased, aggregate stability also increased.
Crop yields have increased on a field average basis, but the increase has come more from the
areas with deeper topsoils than areas with shallow topsoil or exposed subsoils.
Technological advances in farming in the Palouse Region, and perhaps nationally, has largely
intensified the problem of erosion, rather than reduce it (Walker and Young)
No-till and other conservation tillage systems can have a yield advantage over conventional
tillage systems on eroded and sloping landscape positions because of increased soil water
storage and reduced evaporation (Pan and Hopkins). Deficiencies in available soil
phosphorus in the subsoils of eroded ridgetops and sideslopes contribute to reduced yield on
those landscape positions.
Dryland crop production is highly dependent on plant-available soil water throughout the
growing season. One factor which impacts soil water storage and yield potential has been the
loss of topsoil through water and tillage erosion. Soil erosion almost always reduces soil
water storage potential and subsequent yields. Two different impacts are involved. One of the
most frequent is a reduced rate of water infiltration into the soil. This increases the potential




for water loss through surface runoff and evaporation. A second impact of erosion is the
reduced water storage capacity as topsoil depth declines.
Erosion reduces aggregate stability by decreasing the presence of large macropores in the
soil. This reduces the rate of water infiltration. The organic matter-rich surface soil is the
first to erode. As erosion continues, aggregate strength and the rate of water infiltration into
the soil declines. Through erosion and intensive tillage, soil organic matter content has
typically declined 50 percent or more on most Northwest cropland over the past century of
cultivation.
The increasing exposure of subsoil layers (which usually has higher clay contents) by erosion
has seriously reduced water storage potential. As soil clay content increases, pore size
decreases and soil particles disperse more readily, sealing surface pores. Subsoil layers also
have a lower organic matter content than the topsoil, and consequently have lower soil
aggregate stability,
The eroded "clay-knobs" of the Palouse region of eastern Washington and northern Idaho are
prime examples of lost productivity due, in part, to reduced soil water storage from lowered
infiltration rates and increased runoff and evaporation. For comparison, the water infiltration
rate into uneroded Palouse area soils is commonly about 0.6 to 2 inches per hour compared to
0.06 to 0.6 inches per hour where clayey subsoil layers are exposed on hills and ridges.
The loss of soil in small runoff-erosion channels, called rill erosion, is a common type of
over-winter soil erosion in the Northwest. Rill erosion can have a significant detrimental
effect on grain yield in the growing crop. Yield losses up to 46 percent were recorded in
rilled areas compared to nonrilled areas. Even shallow rills appeared to cause a yield loss,
apparently because of decreased plant vigor and survival over the winter. Researchers
estimated a 7 bushel per acre winter wheat yield loss where a rill occurred every 10 feet
across the slope.
Reports
PNW Conservation Tillage Handbook, Soil Erosion Impacts on Productivity - Chapter 1
 Conservation farming and sustainability, D. Wysocki. 1990.
 Radioactive fallout provides estimator for soil erosion, R. Veseth.1990.
 Erosion makes soils more erodible, R. Veseth. 1989.
 Native range and cultivated soils compared, R. Veseth. 1988.
 Technology no substitute for conservation, R. Veseth. 1987.
 Management considerations for eroded cropland, R. Veseth. 1987.
 Erosion-productivity relationships, R. Veseth. 1987.
 Erosion reduces water storage and yield potential, R. Veseth. 1986.
 Tillage erosion – changing landscapes and productivity, R. Veseth. 1986.
 Rill erosion reduces current crop yields, R. Veseth. 1986.
 Crop yields decline with topsoil loss, R. Veseth. 1985.
 Erosion impacts on the Palouse misunderstood, R. Veseth. 1985.
Soil Loss Prediction Under Different Tillage Systems, Based on the Estimation of Rill Density,
Flow Velocity Distributions and Transport Capacity. 2002. Mancilla, G.A., S. Chen and D.K.
McCool. Proceedings, Research & Extension Regional Water Quality Conference 2002.
Vancouver, Washington.
Predicting Erosion and Sediment Yield Using Geographic Information Systems (GIS):
Application to the Lawyers Creek Watershed. 2002. Fernandez, C., C.O. Stockle, J.Q. Wu and
D.K. McCool. Proceedings, Research & Extension Regional Water Quality Conference 2002.
Vancouver, Washington.
Assessing adoption of best management practices for reducing wind erosion on the Columbia
Plateau. 2002. Wandschneider, P.R. Northwest Columbia Plateau Wind Erosion/Air Quality
Project 2002 Annual Report.
Cover crop management and assessment strategies in irrigated systems in the Columbia Plateau.
2002. Pan, W., B. Frazier, B. Stevens, and M. Stannard. Northwest Columbia Plateau Wind
Erosion/Air Quality Project 2002 Annual Report.
Economics of wind erosion control. 2002. Young, D. Northwest Columbia Plateau Wind
Erosion/Air Quality Project 2002 Annual Report.
Examining the entrainment process for loess soils on the Columbia Plateau through intensive
field measurements: new tools for measuring and modeling wind erosion and dust emissions.
2002. Kjelgaard, J. and K. Saxton. Northwest Columbia Plateau Wind Erosion/Air Quality
Project 2002 Annual Report.
Flex-cropping and chemical fallow potentials for dryland farming. 2002. Stockle, C., J. Wu and
M. Flury. Northwest Columbia Plateau Wind Erosion/Air Quality Project 2002 Annual Report.
Grower technology access and adaptation for profitable farming systems that control wind
erosion. 2002. Veseth, R. Northwest Columbia Plateau Wind Erosion/Air Quality Project 2002
Annual Report.
Integrated crop production of spring wheat in semiarid regions. 2002. Young, F. and W. Pan.
Northwest Columbia Plateau Wind Erosion/Air Quality Project 2002 Annual Report.
Measuring and modeling of PM10 from windblown dust. 2002. Claiborn, C. and B. Lamb.
Northwest Columbia Plateau Wind Erosion/Air Quality Project 2002 Annual Report.
On-farm testing of cropping systems technology to improve profitability and erosion control in
low and intermediate rainfall areas of eastern Washington. 2002. Esser, A. and R. Veseth.
Northwest Columbia Plateau Wind Erosion/Air Quality Project 2002 Annual Report.
Rotary subsoiling to reduce erosion and improve infiltration in newly-planted winter wheat after
summer fallow. 2004. Williams, J.D., S.B. Wuest, W.F. Schillinger and H.T. Gollany.
Washington State University, Department of Crop & Soil Sciences, 2004 Field Day Abstracts:
Highlights of Research Progress, J. Burns (ed.), Technical Report 04-2. 2004.
Soil quality changes in no-till management adoption for wind erosion control. 2002. Kennedy,
A.C. and W.F. Schillinger. Northwest Columbia Plateau Wind Erosion/Air Quality Project 2002
Annual Report.
Understanding the geologic inputs of dust into the atmosphere of the Columbia Basin. 2002.
Busacca, A., D. Gaylord and M. Sweeney. Northwest Columbia Plateau Wind Erosion/Air
Quality Project 2002 Annual Report.
Wind erosion control research for dry cropland. 2002. Schillinger, W., H. Schafer, B. Sauer, R.
Jirava, R.J. Cook, D. Young, A. Kennedy, D. Rowell, D. Wellsandt, D. Wellsandt, T. Paulitz, F.
Young, R. Veseth, G. Giri, S. Schofstoll and C. Warriner. Northwest Columbia Plateau Wind
Erosion/Air Quality Project 2002 Annual Report.