A position paper of the
American Society of Agricultural Engineers
Our soil resource is vital to the survival of the human race.
Not only does it provide the literal foundation of our existence,
it is the source of most of the agricultural products that sustain
us and our way of life-food, fiber, timber, and energy. Because
damages to soil quality are nearly always permanent, preservation
of this resource is critically important to maintaining
agricultural productivity and environmental quality.
One of the most widespread threats to soil quality is wind and
water erosion, an ever-occurring process that impacts our lives in
numerous ways, the direst of which is lost food production. It is
estimated that soil erosion is damaging the productivity of 29%
(112 million acres) of U.S. cropland and is adversely affecting the
ecological health of 39% (145 million acres) of rangeland.
In addition to on-site soil loss, erosion results in off-site
sediment movement that can cause problems downstream. Sediment can
deposit and clog drainage ways, increase potential for flooding,
decrease reservoir capacity, and carry nutrients and pesticides
that degrade water quality. Current assessments by the U.S.
Environmental Protection Agency of impaired water bodies indicate
that 40% of the stream miles and 45% of the lake and reservoir
areas are impaired because of sediment. Therefore, minimizing
erosion is not only important for saving the soil, it is essential
for preserving potable water resources and improving water and air
Engineers and others have made progress over past decades to
understand and control erosion. However, the pressures of increased
population on land use and agricultural production continually
create new and additional soil erosion problems. Funding of
innovative research to identify and develop new or improved
practices/systems for successfully combating soil erosion is of
paramount importance for obtaining a significant reduction in the
rate of erosion in the future.
- Federal and state governments, and their agencies, need to
increase their support for soil erosion research. Research support
has been dwindling at a time when new erosion and related problems
need to be addressed to maintain an affordable, abundant, safe, and
secure food supply.
- Increased educational efforts and financial incentives are
needed to implement both currently acceptable and newly generated
technologies to reduce soil erosion and sediment transport. Given
the current agricultural economy, it is unreasonable to expect
producers alone to bear the risk and financial burdens of
implementing new and sometimes costly practices.
- New programs are needed to reward good stewards of the land who
are already using soil conservation practices, in order that those
practices are maintained. Rather than only addressing new problems
and problem areas, special efforts are needed to maintain the
progress already made toward a sustainable agricultural
Soil erosion is a complex process encompassing detachment,
transport, and deposition, and is caused by wind, water, and
physical disturbance. Soil erosion reduces land productivity,
challenges agricultural sustainability, and degrades soil, air, and
water quality. Indirectly, soil erosion also degrades environmental
quality through contam-inants attached to the sediment. Soil
erosion interacts bly with the global carbon cycle and climate
change processes. In some conditions, these impacts are so severe
that they reduce quality of life and economic well being, and, in
poorer nations, they can even threaten survival.
Substantial progress has been made over the past 50 years in
understanding erosion and sediment transport and their impact on
the environment. This understanding has led to the development and
adoption of a wide variety of erosion control practices. But
problems caused by erosion and sediment continue and much remains
to be accomplished. The increased awareness of erosion impacts on
air and water quality and on global climate change raise new
challenges for erosion researchers in three key areas: Wind
erosion, Water erosion, and Quantification of erosion.
Research into the detachment, transport, and deposition of soil
must be a high priority in order to better define these processes
and their potential consequences. With this information, better
control methods can be developed and implemented.
Soil erosion research must rapidly evolve and improved
strategies must be developed to respond to the new and increasing
demands of erosion assessment and resource conservation.
High-priority examples include strategies for monitoring erosion as
it varies in time and space, along with assessment of off-site
There must also be an effort to increase the awareness of
policymakers and the general public of the impact of erosion and
sediment transport on food production and overall environmental
quality and the need for continued support of efforts to assess
these impacts in order to maintain a secure food supply and protect
Erosion researchers and field practitioners have identified the
following as the most critical challenges that must be addressed
over the next 5 to 20 years.
- Long-term and large-scale coordinated monitoring and broad data
collection efforts. This allows researchers to better ascertain the
impacts of land man-agement policies and practices on erosion,
sediment delivery, and the resulting degradation of soil, air, and
water resources. These efforts must more fully re-flect the spatial
and temporal scale of erosion and its impacts, and the topographic
complexity of the processes.
- Greater interdisciplinary efforts in developing erosion
prediction and control technology, and for ensuring better adoption
of those technologies at the local level. Land managers and end
users must be more involved in the entire process in order to
increase the rate of adoption.
- More effective, better-organized and useful methods of
collection of erosion data and the development of tools to enable
more productive data sharing.
- Continued work on understanding the fundamental processes
involved in both erosion and sediment transport by water, wind, and
physical disturbance, and in how best to model those phenomena.
Although our understanding has in-creased greatly over the past
decades, there are still some substantial gaps, including such
processes as stream bank and gully erosion, transport and
deposition processes, effects of sediment on biotic integrity, the
role of dust in climate change, etc.
- Efforts to significantly increase our understanding of the
transport of sediment by wind or water, and the off-site impacts of
this sediment on air and water quality.
Successfully addressing these issues will result in a greater
understanding of erosion and sediment transport processes, leading
to improved erosion control practices and better tools for land-use
planners. This will ultimately result in more effective and
efficient protection of the soil, air, and water resources.
This consensus document was developed by the American Society of
Agricultural Engineers, with input from participants of the
symposium "Soil Erosion Research for the 21st Century," sponsored
by ASABE and thirteen other professional societies and agencies.
ASABE, the Society for engineering in agricultural, food, and
biological systems, has 9000 members worldwide and a long history
of leadership in solving problems related to erosion control and
soil and water quality. ASABE members are uniquely qualified to
generate new technical information on soil erosion, translate that
information into more effective practices, and ensure that those
who produce the world's agricultural goods are educated
Adopted as an ASABE position paper December 2002.