title: Measuring the environmental effects of organic farming: A meta-analysis of structural variables in empirical research.
abstract: This study examined the structural variables affecting the environmental effects of organic farming compared to those of conventional farming. A meta-analysis based on 107 studies and 360 observations published from 1977 to 2012 compared energy efficiency (EE) and greenhouse gas emissions (GHGE) for organic and conventional farming. The meta-analysis systematically analyzed the results of earlier comparative studies and used logistic regression to identify the structural variables that contributed to differences in the effects of organic and conventional farming on the environment. The statistical evidence identified characteristics that differentiated the environmental effects of organic and conventional farming, which is controversial. The results indicated that data sources, sample size and product type significantly affected EE, whereas product type, cropping pattern and measurement unit significantly affected the GHGE of organic farming compared to conventional farming. Superior effects of organic farming on the environment were more likely to appear for larger samples, primary data rather than secondary data, monocropping rather than multicropping, and crops other than fruits and vegetables. The environmental effects of organic farming were not affected by the study period, geographic location, farm size, cropping pattern, or measurement method.
authors.affiliation: ISC Agricultural Development Research Institute, 20, Beonyeong-ro 1-gil, Iksan-si, Jeollabuk-do, South Korea.
authors.forename: Ki Song
authors.initials: KS
authors.lastname: Lee
authors.affiliation: College of Agriculture and Life Sciences, Seoul National University, Gwanak-ro 599, Gwanak-gu, Seoul, South Korea. Electronic address: aggi@snu.ac.kr.
authors.forename: Young Chan
authors.initials: YC
authors.lastname: Choe
authors.affiliation: College of Agriculture and Life Sciences, Seoul National University, Gwanak-ro 599, Gwanak-gu, Seoul, South Korea.
authors.forename: Sung Hee
authors.initials: SH
authors.lastname: Park
mesh_terms: D002980:Climate; D003247:Conservation of Natural Resources; D018556:Crops, Agricultural; D036262:Empirical Research; D004777:Environment; D016015:Logistic Models; D058871:Organic Agriculture / Q000379:methods*
keywords: Conventional farming; Energy efficiency (EE); Environmental impact; Greenhouse gas emissions (GHGE); Meta-analysis; Organic farming; Structural variables