Erosion

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Bioenergy > Issues > Environmental issues > Climate change > Erosion

This page contains information on the causes and effects of soil erosion.

Aerial view of erosion gullies in a former tropical rainforest landscape on the island of Madagascar. This soil erosion is the result of slash and burn agriculture for rice production. Erosion can lead to desertification, also a consequence of climate change.

Soil functions as a critical carbon sink that is estimated to hold three times the carbon of all the plants on earth.[1] The carbon content of soil is diminishing annually due to anthropogenic factors including soil erosion from intensive agriculture, deforestation, and climate change-induced severe weather. The UN Population Fund's Population and Land Degradation (Annexes 1-5) report on the relationship between population expansion, land degradation and soil erosion explains that "Since the dawn of agriculture, an estimated 60 billion tons of soil carbon have risen from the soil to the atmosphere as climate-warming carbon dioxide. This amount is equivalent to a decade of global fossil fuel combustion". [2]

Adopting measures to control soil erosion is of critical importance as global demand for biofuels from feedstocks and other cultivated organic matter increases.

Issues

• Climate change
• Desertification

Organizations

• The USDA National Soil Erosion Research Lab (NSERL) is a U.S. Government national research program on soil erosion that focuses on "fundamental erosion process research, erosion control research, and...improved erosion prediction technology".

Events

News

• High Prices Sow Seeds of Erosion, 12 April 2011 by New York Times: "Long in decline, erosion is once again rearing as a threat because of an aggressive push to plant on more land, changing weather patterns and inadequate enforcement of protections, scientists and environmentalists say."
  • "Erosion can do major damage to water quality, silting streams and lakes and dumping fertilizers and pesticides into the water supply. Fertilizer runoff is responsible for a vast 'dead zone,' an oxygen-depleted region where little or no sea life can exist, in the Gulf of Mexico. And because it washes away rich topsoil, erosion can threaten crop yields. Significant gains were made in combating erosion in the 1980s and early 1990s, as the federal government began to require that farmers receiving agricultural subsidies carry out individually tailored soil conservation plans."
  • "...[G]overnment biofuels policies that have increased the demand for corn have encouraged farmers to plant more."
  • "More than anything else this year, farmers are making decisions based on how they can best take advantage of corn and soybean prices, which have soared in recent months."[3]

• Genetic map for switchgrass published, aids in study of biofuel, August 25 2010 by Andrea Johnson: "As farmers wait to produce new alternative energy crops, some USDA Agri-cultural Research Service (ARS) scientists are uncovering the secrets of switchgrass which, they say, holds so much potential as an alternative energy source."
  • "The USDA ARS Switchgrass team has found that switchgrass produces five times the cellulosic ethanol needed to cover the energy needs required to grow it and make it into fuel."
  • "It is also a perennial that reduces weed pressure and holds soils in place - preventing wind and rain erosion. It sequesters carbon long term, and it can be fed to cattle."
  • "One of the challenges with switchgrass is the need for fertilizer and water - just like corn - to produce maximum yields. Because it’s a perennial, it is challenging to get into the tall grass to apply fertilizer. The more switchgrass is harvested, the more water and fertilizer it needs to continue to thrive."
  • "Scientists hope to modify the cell wall composition of switchgrass to improve its properties for co-firing in a power plant. They also hope to use biotechnology to increase its digestibility and access to enzymes that would produce fermentable sugars for ethanol production."[4]

• Can Dirt Really Save Us From Global Warming?, 3 September 2009 by NPR: "This month the Senate is set to take up the climate and energy bill that Congress began work on last spring. One provision will likely set up a system to pay farmers for something called 'no-till farming.'"
  • "There's a possible conflict brewing here, though. Federal law and the energy bill encourage farmers to remove crop residue — the remains of the previous season's crop — to make ethanol."
  • "'That's a no-no,'" soil scientist Rattan Lal says. "'The moment you take the crop residue away the benefit of no-till farming on erosion control, water conservation and on carbon sequestration will not be realized.'"(Audio also available)

Resources/Reports

• The Bioenergy Feedstock Guiding Principles is a letter drafted by a group of NGOs that was sent to members of the United States Congress to encourage the incorporation of sustainably produced bioenergy into a comprehensive American strategy to reduce dependence on oil and address the threat of global warming. This letter warns that "if not carefully managed, increased production of biofuels has the potential to cause widespread environmental devastation....On farms and in forests across the country and abroad, imprudent biomass harvesting would cause soil erosion, water pollution, and habitat destruction, while also substantially reducing the carbon uptake of land."

• World Overview of Conservation Approaches and Technologies (WOCAT) - "WOCAT's mission is to provide tools that allow [soil and water conservation (SWC)] specialists to share their valuable knowledge in soil and water management"[5] and sustainable land management (SLM).

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