A meta-analysis of the differences in environmental impacts between organic and conventional farming

摘要

Purpose - This paper aims to perform a meta-analysis of the literature comparing the environmentalrnimpacts of organic and conventional farming and linking these to differences in managementrnpractises. The studied environmental impacts are related to land use efficiency, organic matter contentrnin the soil, nitrate and phosphate leaching to the water system, greenhouse gas emissions andrnbiodiversity.rnDesign/methodology/approach - The theoretic framework uses the driver-state-responsernframework and literature data were analysed using meta-analysis methodology. Meta-analysis isrnthe statistical analysis of multiple study results. Data were obtained by screening peer reviewedrnliterature.rnFindings - From the paper's meta-analysis it can conclude that soils in organic farming systemsrnhave on average a higher content of organic matter. It can also conclude that organic farmingrncontributes positively to agro-biodiversity (breeds used by the farmers) and natural biodiversity (wildrnlife). Concerning the impact of the organic farming system on nitrate and phosphorous leaching andrngreenhouse gas emissions the result of the analysis is not that straightforward. When expressed perrnproduction area organic farming scores better than conventional farming for these items. However,rngiven the lower land use efficiency of organic farming in developed countries, this positive effectrnexpressed per unit product is less pronounced or not present at all.rnOriginal value - Given the recent growth of organic fanning and the general perception that organicrnfarming is more environment friendly than its conventional counterpart, it is interesting to explorernwhether it meets the alleged benefits. By combining several studies in one analysis, the technique ofrnmeta-analysis is powerful and may allow the generation of more nuanced findings and therngeneralisation of those findings.