Although yields are only part of a range of ecological, social and
economic benefits delivered by farming systems, it is widely accepted
that high yields are central to sustainable food security on a finite land
basis1,2. Numerous individual studies have compared the yields of
organic and conventional farms, but few have attempted to synthesize
this information on a global scale. A first study of this kind6 concluded
that organic agriculture matched, or even exceeded, conventional
yields, and could provide sufficient food on current agricultural land.
However, this study was contested by a number of authors; the
criticisms included their use of data from crops not truly under organic
management and inappropriate yield comparisons7,8.
We performed a comprehensive synthesis of the current scientific
literature on organic-to-conventional yield comparisons using formal
meta-analysis techniques. To address the criticisms of the previous
study6 we used several selection criteria: (1) we restricted our analysis
to studies of ‘truly’ organic systems, defined as those with certified
organic management or non-certified organic management, following
the standards of organic certification bodies (see Supplementary
Information); (2) we only included studies with comparable spatial
and temporal scales for both organic and conventional systems (see
Methods); and (3) we only included studies reporting (or from which
we could estimate) sample size and error. Conventional systems were
either high- or low-input commercial systems, or subsistence agriculture
Although yields are only part of a range of ecological, social andeconomic benefits delivered by farming systems, it is widely acceptedthat high yields are central to sustainable food security on a finite landbasis1,2. Numerous individual studies have compared the yields oforganic and conventional farms, but few have attempted to synthesizethis information on a global scale. A first study of this kind6 concludedthat organic agriculture matched, or even exceeded, conventionalyields, and could provide sufficient food on current agricultural land.However, this study was contested by a number of authors; thecriticisms included their use of data from crops not truly under organicmanagement and inappropriate yield comparisons7,8.We performed a comprehensive synthesis of the current scientificliterature on organic-to-conventional yield comparisons using formalmeta-analysis techniques. To address the criticisms of the previousstudy6 we used several selection criteria: (1) we restricted our analysisto studies of ‘truly’ organic systems, defined as those with certifiedorganic management or non-certified organic management, followingthe standards of organic certification bodies (see SupplementaryInformation); (2) we only included studies with comparable spatialand temporal scales for both organic and conventional systems (seeMethods); and (3) we only included studies reporting (or from whichwe could estimate) sample size and error. Conventional systems were
either high- or low-input commercial systems, or subsistence agriculture
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