A study in Science (see article in Renewable Energy Access) from David Tilman, an ecologist at the University of Minnesota shows what we should have known all along: When energy crops are grown sustainably in poor soil (i.e. most of our available land) without fertiliser, a diverse mix of native prairie plants yeilds more than twice (238%) as much harvestable energy than any monoculture (including the much-hyped switchgrass) grown on the same land.
At some point, humans are going to have to realize that our production-line mentality, which seems so efficient to us, is not really the best way to do things. We like farming just one species in neat rows because it’s easier for us to comprehend. But easier to comprehend is not the same as more effective. In money management, we know that there is no one perfect security for an investor: diversification allows higher returns with lower risk. Farmers have yet to (re)learn that lesson: growing just one crop puts strains on the particular resources that crop needs most, and allows specialized pests an environment of limitless growth.
Monocultures are sub-optimal, both in your fields and your portfolio. Enron employees with their retirement fund in 100% Enron stock learned that the hard way. As we transition to a new energy economy, I hope that David Tillman, and researchers like him will help us realize that the places we grow out energy crops don’t have to be like an Enron employee’s 401(k).