Yet more information on the potential for grasses in improving the global warming situation. The letter to the editor, and response to it by the authors of the paper, is of particular interest. Yet another reason to check out what the
Land Institute has been doing, for decades, on low-input high-diversity agriculture.
Carbon-Negative Biofuels from Low-Input High-Diversity Grassland Biomass - Abstract"Biofuels derived from low-input high-diversity (LIHD) mixtures of native grassland perennials can provide more usable energy, greater greenhouse gas reductions, and less agrichemical pollution per hectare than can corn grain ethanol or soybean biodiesel. High-diversity grasslands had increasingly higher bioenergy yields that were 238% greater than monoculture yields after a decade."And other news items on this report:
From Prairie Grasses to Ethanol - Almanac - Twin Cities Public Television (Realplayer required)
"U of M researchers think that the future of ethanol will be fed by mixed grasses not corn. That's the upshot of an article released in Friday's magazine 'Science.' One of the authors of this study --Jason Hill-- joins us."NPR: Making Gas from Prairie Grasses "Tilman's prairie grasses bury much of that CO2 in the soil and in their deep, permanent roots. So a good deal of the CO2 stays in the ground after the harvest.
'We have discovered a way to make biofuels that by the time the whole life cycle is done and they are combusted, there is less carbon dioxide in the atmosphere than there had been before,' Tilman says."Amber Waves of Gas?: Gasoline Alternative May Be Found in Prairie Grass - Scientific American
"Tilman says this negativity occurs because prairie grasses have complex root systems underground that typically make up two thirds of the plant total biomass, making them efficient carbon sinks: 'When they grow, they have to [absorb] a lot of carbon to keep their roots alive and to make these very extensive root systems,' Tilman speculates that these diverse systems may use more nitrate, 'the limiting nutrient' in the soil, which starves bacteria that decomposes carbon, allowing the plants to better maintain their roots. All told, the Minnesota group estimates from its own soil sampling that, per acre, these grasslands could result in the sequestration of up to 1.8 tons of carbon dioxide per year."Mixed Prairie Grasses Better Source of Biofuel Than Corn Ethanol and Soybean Biodiesel - Physorg.com
"Switchgrass, which is being developed as a perennial bioenergy crop, was one of 16 species in the study. When grown by itself in poor soil, it did not perform better than other single species and gave less than a third of the bioenergy of high-diversity plots.
'Switchgrass is very productive when it's grown like corn in fertile soil with lots of fertilizer, pesticide and energy inputs, but this approach doesn't yield as much energy gain as mixed species in poor soil nor does it have the same environmental benefits,' said paper co-author Jason Hill, also of the University of Minnesota.
To date, all biofuels, including cutting-edge nonfood energy crops such as switchgrass, elephant grass, hybrid poplar and hybrid willow, are produced as monocultures grown primarily in fertile soils."Keep on the Grass - Chemistry World
"'When prairie plants grow, about half to two-thirds of the carbon that they fix goes into the roots, which are tough, recalcitrant and resistant to digestion by bacteria or fungi,' Tilman told Chemistry World. 'It takes between one and two centuries to break down this matter and release the carbon back into the atmosphere.' According to his team’s findings, this locks up more than four tonnes of CO2 annually per hectare of land.![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
