Impacts of Biofuel Feedstock Harvesting in Tallgrass Prairies
Xue, X., Luo, Y., Zhou, X., Sherry, R. and Jia, X. 2011. Climate warming increases soil erosion, carbon and nitrogen loss with biofuel feedstock harvest in tallgrass prairie. GCB Bioenergy 3: 198-207.
The results of this eye-opening experiment revealed that the average relative depth of erosion caused by clipping was 1.65 and 0.54 mm/year, respectively, in the warmed and control plots from November 21, 1999 to April 21, 2009, that the soil erosion rate was 2148 g/m2/year in the warmed plots and 693 g/m2/year in the control plots, that soil organic carbon was lost at a rate of 69.6 g/m2/year in the warmed plots and 22.5 g/m2/year in the control plots, and that total nitrogen was lost at a rate of 4.6 g/m2/year in the warmed plots and 1.4 g/m2/year in the control plots. And Xue et al. make a point of noting, in this regard, that "the amount of carbon and nitrogen loss caused by clipping is equivalent to, or even larger than, changes caused by global change factors."
In discussing their findings, the five researchers say their results suggest that "clipping for biofuel harvest results in significant soil erosion and accompanying losses of soil carbon and nitrogen, which is aggravated by warming." And they indicate that "soil erosion is one of the most pressing global environmental challenges facing the world today, causing declining soil productivity and crop yields, which may cause difficulties in meeting the rising demand for food and energy (Brink et al., 1977; Brown, 1981, Lal, 2004; MEA, 2005)," which facts lead one to wonder if the biofuel "cure" for the global warming "disease" might not be worse than the malady itself.
Brink, R.A., Densmore, J.W. and Hill, G.A. 1977. Soil deterioration and the growing world demand for food. Science 197: 625-630.
Brown, L.R. 1981. World population growth, soil erosion, and food security. Science 214: 995-1002.
Kimball, B.A. 2005. Theory and performance of an infrared heater for ecosystem warming. Global Change Biology 11: 2041-2056.
Lal, R. 2004. Soil carbon sequestration impacts on global climate change and food security. Science 304: 1623-1627.
MEA. 2005. Millennium Ecosystem Assessment -- Ecosystems and Human Well-being: Desertification Synthesis. World Resources Institute, Washington, DC, USA.