Balancing the Use of Crop Residues for Biofuels with Impacts on Soil and Greenhouse Gases

by Jessica Bass

The use of crop residues as a second-generation source of biofuels may hold potential to help the United States fulfill its 2022 goal production quota outlined in the 2007 Energy Independence and Security Act. Yet, this annual accumulation plays an important role toward maintaining soil organic carbon (SOC) stocks and reducing soil erosion, protecting field health to sustain year-after-year of yields. Adler et al. (2015) use the DayCent biogeochemical model to analyze the costs and benefits of crop residue removal and use based upon its impact on crop yield, SOC content, and N2O emissions, over the course of twenty years. They examined these relationships with respect to a variety of anticipated treatment options, including: a baseline condition with no residue removal, a sample of 50% residue removal without any replacements, 50% residue removal with a nitrogen replacement equivalent to the amount removed, and a 50% residue removal and equivalent application of a high-lignin fermentation byproduct (HLFB). Continue reading

Biotic Impacts of Fracking

by Emil Morhardt

How does shale-bed energy development, including hydraulic fracturing, affect ecology? There have been a number of studies looking into this, and a new review paper by Sara Souther at the University of Wisconsin and seven colleagues at a diverse array of other institutions summarizes the current knowledge and where the gaps are in it. Their legitimate fear is that much damage will be done before much is known about the issues, and there is plenty of experience with other rapid industrial development to warrant concern. As an example, consider the damming of nearly all the rivers on both the east and west coasts of the US with little attention paid to the consequences for salmon.

The big issues they identify are subsurface and surface water contamination by fracking Continue reading