Journalist Frank Drieschner from “Die Zeit” is analyzing German agriculture and the possibility of switching to full sustainable agriculture.
http://www.zeit.de/2012/13/Bio-Frage-3-Platz
His conclusion is : IT’S POSSIBLE ! BUT with less meat and less diversity for the customer (in winter)
Based on a Dutch research, standard agriculture is only 20% more productive than sustainable with a lot of environnemental destructions : overfertilization, impoverishment and erosion of grounds, reduction in the level of groundwaters, contamination by nitrates, pesticides…
Research : http://www.sciencedirect.com/science/article/pii/S0308521X1100182X