Organic farms were less polluting for a given area of land, but are often more polluting per unit of food produced that standard farming methods

“Hanna Tuomisto of the University of Oxford and colleagues, who reviewed 109 papers. Organic farms were less polluting for a given area of land, but were often more polluting per unit of food produced. They did have better soil, though, and housed more species (Journal of Environmental Management, doi.org/h8v). (From New Scientist)

Does organic farming reduce environmental impacts?  A meta-analysis of European research

Organic farming practices have been promoted as, inter alia, reducing the environmental impacts of agriculture. This meta-analysis systematically analyses published studies that compare environmental impacts of organic and conventional farming in Europe. The results show that organic farming practices generally have positive impacts on the environment per unit of area, but not necessarily per product unit.
Organic farms tend to have higher soil organic matter content and lower nutrient losses (nitrogen
leaching, nitrous oxide emissions and ammonia emissions) per unit of field area. However, ammonia emissions, nitrogen leaching and nitrous oxide emissions per product unit were higher from organic systems. Organic systems had lower energy requirements, but higher land use, eutrophication potential and acidification potential per product unit. The variation within the results across different studies was wide due to differences in the systems compared and research methods used. The only impacts that were found to differ significantly between the systems were soil organic matter content, nitrogen leaching, nitrous oxide emissions per unit of field area, energy use and land use. Most of the studies that compared biodiversity in organic and conventional farming demonstrated lower environmental impacts from organic farming. The key challenges in conventional farming are to improve soil quality (by versatile crop rotations and additions of organic material), recycle nutrients and enhance and protect biodiversity. In organic farming, the main challenges are to improve the nutrient management and increase yields. In order to reduce the environmental impacts of farming in Europe, research efforts and policies should be targeted to developing farming systems that produce high yields with low negative environmental impacts drawing on techniques from both organic and conventional systems.

H.L. Tuomisto, I.D. Hodge, P. Riordan , D.W. Macdonald Journal of Environmental Management 112 (2012) 309e320, Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Oxon OX13 5QL, UK
Department of Land Economy, University of Cambridge, Cambridge CB3 9EP, UK
Keywords:
Biodiversity Greenhouse gas emissions Nitrogen leaching Soil organic matter Life Cycle Assessment
2012 Elsevier Ltd.