This comes on the heels of the continuing controversy over claims that organically grown food is no more nutritious than non-organic food. For example, see a Harvard article - Organic food no more nutritious than
conventionally grown food - from September 2012.
However, a March 2012 report by the Commission on Sustainable Agriculture and Climate Change ("Achieving
Food Security in the Face of Climate Change") takes a much healthier, wider perspective than just food security and yield and suggests sustainable intensification of agriculture as the most promising way forward, ie incorporating the best of organic and sustainability methods into mainstream agriculture to address both
food security and sustainable farming.
I tend to subscribe to the view that it's not just about yields. That provides too narrow a lens through which to look at the future sustainability of farming on a global scale. I saw a good article in GreenBiz in May 2012 explaining this: Organic farming debate is about more than just yields.