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1 April 2010 Response from Simpson
Tom Simpson
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I appreciate Werner Flueck's comments and generally agree with the opening concern and ending statement, but have a different perspective on much of what lies between the two. “Peak phosphorus” (P) is real and should be a general concern, not just with biofuels. However, many of the biomass uses I discussed, such as gasification or pyrolysis, concentrate the P in char or ash, thus facilitating recycling. Further, many soils in the United States and elsewhere have excessive P levels from long-term manure application. Biomass production may allow “mining” and recycling of excess P without affecting crop yields while improving water quality.

Flueck refers to high pesticide use and declining yields in a “few years” with switchgrass, which is counter to my knowledge. Pesticide use is primarily at establishment, and even then, may not be what is needed annually to grow corn. Most research I have seen indicates about a 20-year productive life span for a switchgrass stand. Improved seeds and seeding methods are reducing time of establishment to one year. I agree with his conclusion that biofuels, of all kinds, should be an interim solution to liquid energy security, so critical, productive land resources can be returned to food production.

Tom Simpson "Response from Simpson," BioScience 60(4), 257, (1 April 2010).
Published: 1 April 2010

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