FAO has a paper out on organic agriculture, as part of the International Conference on Organic Agriculture and Food Security, going on in Rome as I type. Here’s a quote:
The strongest feature of organic agriculture is its reliance on fossil-fuel independent and locally-available production assets; working with natural processes increases cost-effectiveness and resilience of agro-ecosystems to climatic stress. By managing biodiversity in time (rotations) and space (mixed cropping), organic farmers use their labour and environmental services to intensify production in a sustainable way.
Those are some of the strengths, and very significant they are too. An often-quoted weakness of organic agriculture, however, is that yields are often lower than what you’d expect from “conventional” agriculture. But why? Well, according to a recent study using wheat as a model, part of the reason is that the varieties used are poorly adapted to the particular conditions of organic agriculture: “increasing yield in organic systems through breeding will require direct selection within organic systems rather than indirect selection in conventional systems… With crop cultivars bred in and adapted to the unique conditions inherent in organic systems, organic agriculture will be better able to realize its full potential as a high-yielding alternative to conventional agriculture.”