Comparing the yields of organic and conventional agriculture

Verena Seufert , Navin Ramankutty & Jonathan A. Foley - Nature: International Weekly Journal of ScienceVolume 485 number 7397 pp147-272

Farm Table says:

There is much debate over the relative merits of conventional farming, which has a large environmental impact on the land it uses, and organic farming, which may require greater land use for the same yield. Central to this debate and the subject of some controversy are the relative yields of the two farming systems. Seufert present a meta-analysis of the available scientific literature on organic-to-conventional yield comparisons and conclude that organic yields are indeed lower, but that the difference varies substantially according to crop type, growing conditions, and management practices. For instance, for perennials grown on favorable soils, organic yields are just 5% lower than conventional yields, but the yield difference between the most comparable conventional and organic systems is as high as 34%. The authors conclude that the factors that limit organic yields need to be better understood to enable meaningful comparisons between the rival forms of agriculture.

Numerous reports have emphasized the need for major changes in the global food system. Agriculture must meet the twin challenge of feeding a growing population, with rising demand for meat and high-calorie diets, while simultaneously minimizing its global environmental impacts.

Organic farming:

• A system aimed at producing food with minimal harm to ecosystems, animals or humans.

• Often proposed as a solution.

• However, critics argue that it may have lower yields and would, therefore, need more land to produce the same amount of food as conventional farms, resulting in more widespread deforestation and biodiversity loss, and thus undermining the environmental benefits of organic practices.

To address the criticisms of the previous studies, several selection criteria were used:

• An analysis is was restricted 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.

• Included only studies with comparable spatial and temporal scales for both organic and conventional systems

• Included only studies reporting (or from which we could estimate) sample size and error.

Here a comprehensive meta-analysis was used to examine the relative yield performance of organic and conventional farming systems globally.

• Overall, organic yields are typically lower than conventional yields.

• Yield differences are highly contextual, depending on system and site characteristics, and range from 5% lower organic yields (rain-fed legumes and perennials on weak-acidic to weak-alkaline soils), 13% lower yields (when best organic practices are used), to 34% lower yields (when the conventional and organic systems are most comparable).

• Under certain conditions that is, with good management practices, particular crop types, and growing conditions organic systems can thus nearly match conventional yields, whereas under others it at present cannot.

To establish organic agriculture as an important tool in sustainable food production, the factors limiting organic yields need to be more fully understood, alongside assessments of the many social, environmental and economic benefits of the organic farming system.

 

 

2012 - United States - Verena Seufert , Navin Ramankutty & Jonathan A. Foley - Nature: International Weekly Journal of ScienceVolume 485 number 7397 pp147-272
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