Synthetic Fertilizer

Synthetic Fertilizer

Synthetic Fertilizer Degrades Soil Carbon and Nitrogen
University of Illinois scientists Richard Mulvaney, Saeed Khan, and Tim Ellsworth published studies in 2007 and 2009 with findings that synthetic fertilizer use degrades soil carbon and nitrogen.


 * "The degradation of soil C and Ν resources necessarily in­creases reliance on synthetic Ν fertilization (e.g., Singh et al., 1998), but given the value of organic matter for improving the chemical, physical, and microbial properties of soil, this strategy cannot be expected to maintain current levels of productiv­ity (Cassman et al., 2003; Tong et al., 2003). Despite ongoing genetic and cultural improvements, a 66% global decrease has occurred over the past 40 yr in the agronomic efficiency of fertilizer N (Tilman et al., 2002; Raun and Schepers, 2008). Excessive Ν fertilization no doubt contributes to the latter trend, but soil degradation is a more important concern for sustaining world food supplies (Tong et al., 2003)."

Following publication of their study, the scientists lost their grant funding from the Illinois Department of Agriculture Fertilizer Research and Education Council. ("They cut us off cold turkey," said Mulvaney. ) The studies have been the subject of controversy, but the scientists maintain the accuracy of their findings.

The degradation of soil organic matter with the application of chemical fertilizer was first recorded in the 1920s, when it was found that "Attempts to increase and maintain an abnormally high organic matter content through the excessive applications of farm manure has met with failure and resulted in excessive loss of organic carbon and nitrogen" and that "Liberal use of mineral nitrogen as measured by long-time field experiments has stimulated the decay of organic matter in excess of such action by mineral fertilizer without nitrogen."

Likewise, a 1939 paper found that:


 * "The lowest supply of organic matter after fifty years occurs in Plot No. 2 under continuous wheat given heavy additions of commercial fertilizer. This seems to suggest that the addition of the nitrogen and minerals has supplied a microbiological deficiency, and that fertilizers served thus to deplete the organic matter further here than on any other plot. With over 750 pounds of mixed fertilizers, of which no small part was mineral nitrogen, the carbon supply of the soil has been extensively burned out. That the phosphate and potassium are essential contributions toward increased microbiological activity is testified to by the higher content of organic matter in the continuous wheat plots given ammonium sulfate and sodium nitrate. These are still higher at this time in organic matter than the plot given complete fertilizer."

Related Sourcewatch

 * Nitrogen
 * Fertilizer Use in Africa
 * Second Green Revolution
 * Abuja Declaration on Fertilizer for African Green Revolution
 * Africa Fertilizer Summit June 9-13, 2006
 * Alliance for a Green Revolution in Africa
 * International Fertilizer Development Center (IFDC)
 * Illinois Department of Agriculture Fertilizer Research and Education Council

External Resources

 * Jozef Visser, Down to Earth: A Historical-Sociological Analysis of The Rise and Fall of 'Industrial' Agriculture and the Prospects for the Re-Rooting of Agriculture from the Factory to the Local Farmer and Ecology, Wageningen University, April 13, 2010.
 * Janice S. Snow, Misunderstanding Soil Ecosystems: How flawed conceptions of soil have lead to flawed U. S. land, water and climate policies, Masters Thesis, Tufts University, November 2009.
 * J. Prosser and Ken Killham. "Prokaryotes." In Soil Microbiology, Ecology, and Biochemistry, edited by Eldor A. Paul. Burlington, MA: Academic Press (Elsevier), 2007.
 * Melissa J. Brimecombe, Frans A De Leij and James M. Lynch "Effect of Roots Exudates on Rhizosphere Microbial Populations," in The Rhizosphere: Biochemistry and Organic Substances at the Soil-Plant Interface., ed. Pinton, Roberto, Zeno Varanini, and Paolo Nannipieri (New York: Marcel Dekker, Inc, 2001).
 * Franci Martin, Silvi Perotto and Paola Bonfante, "Mycorrhizal Fungi: A Fungal Community at the Interface between Soil and Roots," in The Rhizosphere: Biochemistry and Organic Substances at the Soil-Plant Interface, ed. Pinton, Roberto, Zeno Varanini, and Paolo Nannipieri (New York: 2001).
 * Lynn Margulis and Karlene V. Schwartz, Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, Third ed. (New York: W.H. Freeman and Company, 1997).
 * R. Larry Peterson, Hugues B. Massicotte and Lewis H. Melville, Mycorrhizas: Anatomy and Cell Biology (Ottawa: NRC Research Press, National Research Council of Canada, 2004).

External Articles

 * Tom Philpott, "New research: synthetic nitrogen destroys soil carbon, undermines soil health," Grist, February 24, 2010.
 * R. L. Mulvaney, S. A. Khan, and T. R. Ellsworth, "The Browning of the Green Revolution."
 * Saeed Khan, Richard Mulvaney, Tim Ellsworth, and Charlie Boast, "The Myth of Nitrogen Fertilization for Soil Carbon Sequestration," Journal of Environmental Quality, November/December 2007.
 * Wm. A. Albrecht, "Variable Levels of Biological Activity in Sanborn Field after Fifty Years of Treatment," Department of Soils, Missouri Agricultural Experiment Station, Columbia, Mo., Journal Series No. 584, 1939.
 * J.W. White, "Soil Organic Matter and Manurial Treatment," Paper read as a part of the symposiumon "Soil Organic Matter" at the meeting of the Society held in Washington D.C., November 19, I926. Contribution from the Department of Agronomy, Pennsylvania State College.