Part 81 (2/2)

Ibid.; James Elser and Stuart White, ”Peak Phosphorus,” Foreign Policy, April 20, 2010.

364 search for new reserves is beginning again

Ibid.

365 the ”Saudi Arabia of phosphorus”

Ibid.

366 exports during the 2008 food price crisis

Elser and White, ”Peak Phosphorus.”

367 order to extend the supplies of phosphorus for fertilizers

Mara Grunbaum, ”Gee Whiz: Human Urine Is Shown to Be an Effective Agricultural Fertilizer,” Scientific American, July 23, 2010.

368 soil fertility and enhance the sequestration of soil carbon

Rifat Hayat et al., ”Soil Beneficial Bacteria and Their Role in Plant Growth Promotion: A Review,” Annals of Microbiology 60, no. 4 (December 2010): 57998; Tim J. LaSalle, Regenerative Organic Farming: A Solution to Global Warming, Rodale Inst.i.tute, July 30, 2008, pp. 23, /files/Rodale_Research_Paper_07_30_08.pdf.

369 soil and further protect against erosion

J. Paul Mueller, Denise Finney, and Paul Hepperly, ”The Field System,” in The Sciences and Art of Adaptive Management: Innovating for Sustainable Agriculture and Natural Resource Management, edited by Keith M. Moore (Ankeny, IA: Soil and Water Conservation Society, 2009).

370 fertility of the soil while diminis.h.i.+ng erosion

Huggins and Reganold, ”No-Till: The Quiet Revolution.”

371 carefully managed way can also improve yields and soil quality

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