Soil Organic Matter
Biofuels Production
Biofuels from plant material make attractive substitutes for gasoline and diesel because, in theory, they are both renewable and carbon neutral (the CO2 emitted into the atmosphere when they are used is taken back out of the atmosphere to produce more biofuel feedstock). Ethanol is a grain alcohol that can be blended with gasoline and used in motor vehicles. Many gasoline stations provide a blended fuel, which typically is 10 percent ethanol and 90 percent gasoline. Ethanol can be fermented from many sources of starch, including corn, wheat, grain sorghum, barley, and potatoes, and from sugar crops such as sugar cane and sweet sorghum.
Impacts of Harvesting Crop Residues on Soil Quality
Studies have shown harvesting of crop residues can have deleterious effects on soil quality, plant growth, and other ecosystem services. Long-term nutrient removal of crop residues following harvest impoverishes the soil, demanding their replacement using increasing quantities of mineral fertilizers. This produces an increase in production costs and greater impact on the environment. Furthermore, the reduction in the input of organic residues into the soil implies a direct reduction in carbon stocks, which negatively affects the soil biota.
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