Organic agriculture and the global food supply

Abstract

The principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are low yields and insufficient quantities of organically acceptable fertilizers. We evaluated the universality of both claims. For the first claim, we compared yields of organic versus conventional or low-intensive food production for a global dataset of 293 examples and estimated the average yield ratio (organic:non-organic) of different food categories for the developed and the developing world. For most food categories, the average yield ratio was slightly <1.0 for studies in the developed world and >1.0 for studies in the developing world. With the average yield ratios, we modeled the global food supply that could be grown organically on the current agricultural land base. Model estimates indicate that organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base. We also evaluated the amount of nitrogen potentially available from fixation by leguminous cover crops used as fertilizer. Data from temperate and tropical agroecosystems suggest that leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. These results indicate that organic agriculture has the potential to contribute quite substantially to the global food supply, while reducing the detrimental environmental impacts of conventional agriculture. Evaluation and review of this paper have raised important issues about crop rotations under organic versus conventional agriculture and the reliability of grey-literature sources. An ongoing dialogue on these subjects can be found in the Forum editorial of this issue.

Diversification practices reduce organic to conventional yield gap

“…[34,39]) and (ii) comparisons of yields taken from different years. Additionally, in cases where the means of organic and conventional yields were reported but the variance of those means were not (a necessary component for inclusion in meta-analysis), we obtained an estimate of the variance directly from the original authors, whenever possible.…”

A review on trade-off analysis of ecosystem services for sustainable land-use management

“…In this sense, trade-offs between agricultural production and other ecosystem services are not inevitable. Analysis on yields from agroecosystems indicated that with efforts on practice to conserve ecosystem services through measures, such as conservation tillage, crop diversification and biological control, ecosystem services trade-offs would be mitigated, with even improvements in yields (Badgley et al, 2007). These analyses suggest trade-off analysis should be incorporated into the land-use management decision making process, which can make a 'win-win' situation possible, where provisioning services are maintained and enhanced whilst other ecosystem services are supported.…”

Organic Farming for Crop Improvement and Sustainable Agriculture in the Era of Climate Change

“…Notwithstanding this potential, more research is needed on how organic farming systems perform under increased disease and pest pressures, which are important effects of climate change on agriculture (IPCC, 2007a) and on how local crop varieties adapt to climate change and variability. Organic agriculture also seems to perform better than conventional agriculture under water constraints (Hepperly et al, 2006;Badgley et al, 2007).…”