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EROSION
Ryan Flynn
APES
1/13/17
Soil Erosion: Degradation and
Conservation
■ The ideal soil for agriculture is a loamy mixture with a pH close to neutral that is also
workable and capable of holding nutrients.
■ Soil is naturally far from this ideal, especially with increased soil degradation due to
human impact.
■ Common problems are:
– Desertification
– Salinization
– Waterlogging
– Pollution
– Nutrient Depletion
– Structural Break Down
Soil Eroding Mechanisms
■ Removing plant cover
– The roots keep the soil compacted
■ Wind erosion
■ Water Erosion
– Rill Erosion
– Splash Erosion
– Sheet Erosion
– Gully Erosion
Global Problem
■ Humans are the primary cause of erosion.
– Human activities move over 10x more soil than all other natural processes
combined.
■ 47 Billion acres of the worlds croplands suffer from erosion or other forms of soil
degradation.
■ Erosion happens all over the world
Dust Bowl
■ In the early 1930s, a drought exacerbated the ongoing human impacts of soil
erosion and degradation.
– The leading cause of this was farmers removing native grasses
■ Strong winds eroded millions of tons of top soil, causing for a blackening rain, snow
and dust.
■ Nearly 10 cm of topsoil was lost in some areas.
Soil Conservation Service
■ As a result of the Dust Bowl, the U.S. Government increased research of soil
conservation.
■ Assess the lands resources, problems, and opportunities for conservation.
■ Draw of science to prepare an integrated plan for each property.
■ Work closely with land users to ensure that conservation plans to harmonize with
the users’ objectives.
■ Implement conservation measures on individual properties to contribute to the
overall quality of life in the watershed region.
Irrigation
■ Irrigation - The artificial provision of water to support the agriculture.
■ This is very helpful when trying to yield the largest amounts of crops possible.
■ Waterlogging – This occurs when over irrigation happens and more water is given to
a crop land than it can hold.
■ Salinization – This occurs when there is a buildup of salts in the surface soil layers.
Soil Conservation Solutions
■ Crop Rotation – Rotating crops that grow in a given area from year t year can help
replenish nutrients in the soil.
■ Contour Farming – Plowing perpendicular to the slope of the hillside to prevent rills and
gullies.
■ Terracing – Transforms slopes into a series of steps like a staircase. This helps plant on a
hillside without loosing larges amounts of soil from water erosion.
■ Intercropping – Spatially mixed arrangements of crops.
■ Shelterbelts – Taller plants such as trees planted around the cropland to shield from
wind.
■ Reduced Tillage – When the crop land is not tilled which leaves remains of plants from
prior years present while planting new crops.
Works Cited
Brennan, Scott R., and Jay Withgott. Environment: The Science behind the Stories. San
Francisco: Pearson/Benjamin Cummings, 2005. Print.