Sustainable global food production requires tailored solutions for fertilizer use
Release Date 19 June 2009
Despite the negative environmental impacts associated with synthetic fertilizer, new research warns against a "one-size-fits-all" approach to managing global food production. In a report published in the journal Science, an international team of experts have compared three corn-growing regions of the world - western Kenya, north China and the upper Midwestern United States. While the reluctance of many policymakers to accept the economic, environmental, and social costs of subsidized fertilizer use is understandable, inadequate inputs will entrain low productivity, land degradation, and rural poverty until fertilizer for small-holder farmers is subsidised.
Synthetic fertilizers have dramatically increased food production worldwide. But the unintended costs to the environment and human health have been substantial. In intensively farmed regions, nitrogen runoff from farms has contaminated surface waters and groundwater and helped create massive "dead zones" in coastal areas. Ammonia emissions from fertilized cropland have become a major source of air pollution, while emissions of nitrous oxide form a potent greenhouse gas. These and other negative environmental impacts have led some researchers and policymakers to call for worldwide reductions in the use of synthetic fertilizers. This new research highlights the need for a more considered approach.
Most agricultural systems follow a trajectory from too little added nutrients to too much, and both extremes have substantial human and environmental costs. In some parts of the world, including much of Northern Europe and China, far too much fertilizer is used, leading to nutrient pollution and substantial damage to the environment and human health. By contrast, far too little fertilizer is used in much of Africa, particularly in sub-Saharan Africa, leading to food poverty and nutrient depletion in agricultural soils. In this case, nitrogen inputs are inadequate to maintain soil fertility and to feed people.
The authors argue that different solutions are therefore needed in different farming regions, but warn that designing sustainable solutions will require a lot more scientific data than is available at present. Professor Penny Johnes, Director of the Aquatic Environments Research Centre at the University of Reading, said "More effort is needed to develop food production systems that maintain their yields, while minimizing their environmental footprints".
She continued "The problem of mitigation of excess nitrogen loss to waters is not easily resolved. The experience of attempts to reduce nutrient losses to waters in Europe highlights the trade offs that may need to be made between food wealth and clean waters. Society may have to face some difficult decisions about modifying food production practices if real and ecologically significant reductions in nitrogen loss to waters are to be achieved".
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This research is published in "P.M. Vitousek et al. Nutrient Imbalances in Agricultural Development. Science. 19 June 2009".
The authors of the report are Peter Vitousek, Woods Institute for the Environment, Stanford University; Rosamond Naylor, Stanford University; Tim Crews, Prescott College; Mark David, University of Illinois; Laurie Drinkwater, Cornell University; Elisabeth Holland, National Center for Atmospheric Research; Penny Johnes, Aquatic Environments Research Centre, University of Reading; John Katzenberger, Aspen Global Change Institute; Luis Martinelli, University of Sao Paulo, Brazil; Pamela Matson, Stanford University; Generose Nziguheba, Columbia University; Dennis Ojima, Heinz Center for Science, Economics and the Environment; Cheryl Palm, Columbia University, Pedro Sanchez, The Earth Institute, Columbia University; G. Philip. Robertson, Michigan State University; Alan Townsend, University of Colorado-Boulder; and F.S. Zhang of the China Agriculture University.
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