Soil

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Womens farming cooperative members work to remove weeds by hand from the soil of their rice plot in Madagascar
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Contents

Issues

Soil amendments

Soil carbon sequestration

  • Soil is the second largest sink for carbon (after the oceans)
  • News:
    • A dirty way to fight climate change - 29 November 2007 by Steven I. Apfelbaum and John Kimble on Yahoo News: The authors recommend the sequestration of carbon in soils, which they describe as "one of the most overlooked yet most effective and inexpensive strategies available." They also advise that trees should not be planted where they may reduce the volume of carbon stored in the soil, such as lands that formerly were prairies or wetlands; "deep-rooted grassland or wetland plants, which sequester carbon more effectively than trees do" should be planted instead. Soil carbon can also be enhanced through "no-till" farming.
      • The authors conclude that "Scientific analyses show that recapturing atmospheric carbon into soil and plant communities is the easiest and least expensive method for mitigating climate change and that it provides many other economic, cultural, and ecological benefits. Restoring soils in currently farmed land can rein in 10 to 15 percent of the annual carbon emissions Americans create. Replanting native grasslands and restoring drained wetlands can reduce up to another 20 percent....These techniques can also produce usable bioenergy crops, food, and fiber supplies. This enables energy, food, and commodities to be produced locally, thus reducing transportation and distribution costs and their associated carbon emissions."
  • Organizations:
  • Events:
  • Resources:

Soil erosion

News:

  • For Gulf, Biofuels Are Worse Than Oil Spill , 17 June 2010 editorial by Investor's Business Daily: "Our growing addiction to alternative energy was killing aquatic life in the Gulf long before the Deepwater Horizon spill. Abandoning oil will kill more and also release more carbon dioxide into the air."
    • "Before the first gallon gushed from Deepwater Horizon, there existed an 8,500 square mile 'dead zone' below the Mississippi River Delta....Hypoxia, or oxygen depletion, caused by agricultural runoff...has been on an upward trend as acreage for corn destined to become ethanol increases."
    • "[A] 2008 study by the National Academy of Sciences (NAS) found that 'nitrogen leaching from fertilized cornfields in the Mississippi-Atchafalaya River system is a primary cause of the bottom-water hypoxia that develops on the continental shelf of the northern Gulf of Mexico each summer.'"
    • "Ethanol from corn sounds like an energy panacea, but the devil is in the details. It takes 4,000 gallons of fresh water per acre per day to replace evaporation in a cornfield. Each acre requires about 130 pounds of nitrogen and 55 pounds of phosphorous."[2]

Soil organic matter

News:

  • 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.'"
    • "The concept: When crops are planted without tilling, the soil holds more carbon, which means less goes up into the atmosphere."
    • "But scientists aren't sure no-till really sequesters carbon any better than conventional farming....Researchers have discovered that when you dig down three feet or so, plowed fields hold just as much — if not more — carbon than no-till."
    • "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)
  • Crop Residue May Be Too Valuable to Harvest for Biofuels, 15 July 2008 press release by Washington State University: "In the rush to develop renewable fuels from plants, converting crop residues into cellulosic ethanol would seem to be a slam dunk. However, that might not be such a good idea for farmers growing crops without irrigation in regions receiving less than 25 inches of precipitation annually, says Ann Kennedy, a USDA-Agricultural Research Service soil scientist".
    • "If residue were harvested, she said, soil fertility would drop and farmers would have to find other ways to increase the amount of organic matter in their soils."
    • "'We need to constantly replenish organic matter—so removing valuable residue, especially in areas with low rainfall, may not be the best practice.'"[3]

Events

Publications

  • Large-scale bioenergy from additional harvest of forest biomass is neither sustainable nor greenhouse gas neutral by Ernst-Detlef Schulze, Christian Körner, Beverly E. Law, Helmut Haber, and Sebastiaan Luyssaert, April 2012. "Owing to the peculiarities of forest net primary production humans would appropriate ca. 60% of the global increment of woody biomass if forest biomass were to produce 20% of current global primary energy supply. We argue that such an increase in biomass harvest would result in younger forests, lower biomass pools, depleted soil nutrient stocks and a loss of other ecosystem functions."
    • "The proposed strategy is likely to miss its main objective, i.e. to reduce greenhouse gas (GHG) emissions, because it would result in a reduction of biomass pools that may take decades to centuries to be paid back by fossil fuel substitution, if paid back at all.
    • "Eventually, depleted soil fertility will make the production unsustainable and require fertilization, which in turn increases GHG emissions due to N2O emissions. Hence, large-scale production of bioenergy from forest biomass is neither sustainable nor GHG neutral." [4]

Scientific papers

News

  • Fifth of Global Energy Could Come from Biomass Without Damaging Food Production, Report Suggests, 25 November 2011 by Science Direct: "A new report suggests that up to one fifth of global energy could be provided by biomass (plants) without damaging food production."
    • "The report finds that the main reason scientists disagree is that they make different assumptions about population, diet, and land use. A particularly important bone of contention is the speed with which productivity improvements in food and energy crop production can be rolled out."
    • "Technical advances could be the least contentious route to increased bio-energy production, but policy will need to encourage innovation and investment."
    • "A renewed focus on increasing food and energy crop yields could deliver a win-win opportunity as long as it is done without damaging soil fertility or depleting water resources."
    • "The report stresses the need for scientists working on food and agriculture to work more closely with bio-energy specialists to address challenges such as water availability and environmental protection."
    • "If biomass is required to play a major role in the future energy system the linkages between bio-energy and food production will become too important for either to be considered in isolation."[6]
  • Failure to act on crop shortages fuelling political instability, experts warn, 7 February 2011 by The Guardian: "World leaders are ignoring potentially disastrous shortages of key crops, and their failures are fuelling political instability in key regions, food experts have warned."
    • "Food prices have hit record levels in recent weeks, according to the United Nations, and soaring prices for staples such as grains over the past few months are thought to have been one of the factors contributing to an explosive mix of popular unrest in Egypt and Tunisia."
    • "The UN's Food and Agriculture Organisation said this week that world food prices hit a record high in January, for the seventh consecutive month. Its food price index was up 3.4% from December to the highest level since the organisation started measuring food prices in 1990."
    • "Water scarcity, combined with soil erosion, climate change, the diversion of food crops to make biofuels, and a growing population, were all putting unprecedented pressure on the world's ability to feed itself, according to [Lester] Brown" of the Earth Policy Institute.[8]
  • Analyzing long-term impacts of biofuel on the land, 3 February 2011 by ScienceBlog: "While a useful biofuel source, crop residues also play a crucial role in maintaining soil organic carbon stock."
    • "This stock of organic carbon preserves soil functions and our global environment as well ensures the sustainable long-term production of biofuel feedstock."
    • "Using a process-based carbon balance model, researchers simulated experiments lasting from 79 to 134 years to predict the potential of no tillage management to maintain soil organic carbon."
    • "'Harvesting substantial amounts of crop residue under current cropping systems without exogenous carbon (e.g., manure) addition would deplete soil organic carbon, exacerbate risks of soil erosion, increase non-point source pollution, degrade soil, reduce crop yields per unit input of fertilizer and water, and decrease agricultural sustainability,' says Hero Gollany, the author of the study."[9]
  • Is Biomass Clean or Dirty Energy? We Won't Know for 3 Years, 13 January 2011 by Solve Climate News: "The Obama administration put off for another three years a decision on whether to regulate planet-warming gases from biomass power."
    • "The delay leaves wide open a question central to the industry's future: Should turning tree parts into electricity qualify as clean renewable power in the eyes of government regulators, or should biomass emissions be regarded as a source of greenhouse gas pollution?"
    • "Biomass includes plant waste, wood chips, organic debris and whole trees, and industry representatives say burning it is "carbon neutral." They argue that new growth absorbs CO2 and cancels out emissions spewed into the atmosphere from burning the wood."
    • "Conservationists dispute that claim with a very different understanding of what constitutes the natural carbon cycle. Rotting biomass enriches soils, which capture and sequester some of the carbon of the once-living plant tissue. They argue that biomass combustion produces more CO2 than burning fossil fuels — by how much varies depending on the type of materials and how they are transported."
    • "EPA said it would bring the best science to bear on the issues over the next three years. By July 2014, it will decide how to treat biomass under its "tailoring" rule, which determines which polluters are required to account for their emissions under the Clean Air Act."[11]
  • Reality check for 'miracle' biofuel crop, 27 October 2010 by Miyuki Iiyama and James Onchieku: "It sounds too good to be true: a biofuel crop that grows on semi-arid lands and degraded soils, replaces fossil fuels in developing countries and brings huge injections of cash to poor smallholders."
    • "In an attempt to test the claims, Endelevu Energy, the World Agroforestry Centre and the Kenya Forestry Research Institute embarked on the Reality Check study supported by the German government, which we published last December."
    • "The main finding of the Reality Check is that jatropha is not economically viable when grown by smallholders in Kenya, either in a monoculture or intercrop plantation model. This is due to low yields and high production costs, and a lack of guidelines for applying agronomic and silvicultural best practices."[12]
  • 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."[13]
Sketch of an apparatus for testing biofuel potential of various agricultural wastes, created by the RPI spring 2010 biomass capstone group. Image from The New York Times blog article A New Approach to Biofuel in Africa
  • A New Approach to Biofuel in Africa, 12 July 2010 by Ron Eglash: "The biofuel concept: If you just burn plant materials, you put out a lot of bad pollutants. But if you heat the materials in a container without oxygen (“pyrolysis”), you leave most of the carbon as “biochar,” which makes an excellent soil additive (in fact Amazon Indians built up rich soils over hundreds of years using biochar). The gas that is given off by pyrolysis can be processed into clean-burning fuel."
    • "All of which sounds great, but skeptics point out that Africa is a prime target for biofuel land grabs, which destroy small farms and forest preserves. Hence the importance of using agricultural residues like corn cobs, and researching the impact."[14]
  • Big Meat: Fueling Change or Greenwashing Fuel?, 3 June 2010 by Anna Lappé in The Atlantic: "On January 13, 2009, Tyson—one of the world's largest processors of chicken, beef, and pork—and the fuel company Syntroleum broke ground in Geismar, Louisiana, on a 'renewable' diesel plant. The fuel will be produced in part with Tyson factory farm byproducts, including animal fat and poultry litter."
    • "Tyson claims these facilities produce eco-friendly, cleaner-burning fuels from scraps that would otherwise be wasted. But critics beg to differ....They charge that this fuel is renewable only in the narrowest sense, if you ignore the complete life cycle of its production. The fuels depend on energy-intensive, greenhouse-gas-emitting confined animal feeding operations (CAFOs), which require feed raised with methods that deplete topsoil and overuse synthetic fertilizer, contributing to carbon dioxide emissions."[15]
  • Land Use Offers Valuable Solutions for Protecting the Climate, 7 July 2009 by SolveClimate: "It’s well-known that the trick to reducing net carbon emissions relies on not emitting so much of the stuff and finding a way to get it back where it belongs....That’s where the land comes in. Thirty percent of greenhouse gases come from 'the land-use sector.'...So let's talk farming. Let's talk trees. And let's talk land degradation."
    • "That’s the argumentative thread running through the [Worldwatch] Institute's newest report, Mitigating Climate Change through Food and Land Use, by Sara J. Scherr and Sajal Sthapit."
    • "The first step is simply realizing the magnitude of agricultural or forestry-based contribution to emissions and, potentially, to absorption."
    • "Carbon dioxide and other greenhouse gases also seep into the atmosphere as the secondary effects of land-use changes. Exposed soil erodes more easily, and oxidizes more readily, releasing carbon dioxide into the atmosphere, while nitrogen fertilizers cause soil to emit nitrous oxide, an enormously potent greenhouse gas. The gist is that land-use change is a big problem—close to a third of the problem."[17]



Soil edit
Soil carbon (Biochar) | Terra preta

Remineralization

Agriculture edit
Issues: Ecosystem displacement | Food versus fuel debate | Intensification of agriculture | Land use change
Soil: Soil amendments (Agrichar/Biochar, Terra preta) - Soil carbon sequestration
US - Department of Agriculture | Farm Bill
Crops/Plants (Feedstocks) | Drylands | Livestock
Types of bioenergy edit

Gases: Biopropane | Biogas | Synthetic natural gas | Syngas
Liquids: Biodiesel | Biobutanol | Biogasoline | Biokerosene | Biomass-to-Liquids (BTL) | Dimethyl ether (DME)
ETBE | Ethanol | Methanol | Pure plant oil (PPO) | Pyrolysis oil | Synthetic Natural Gas
Solids: Biomass pellets | Char/Charcoal | Wood


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