Fred Kirschenmann is a deep thinker when it comes to making agriculture sustainable. He's had an organic farm since the 1960s and been involved with green issues in theory and practice for five decades. We ask him the tough questions on how to make agriculture sustainable. Fred argues that large-scale farming that relies on very few crops with little genetic diversity and large scale industrial economics is no longer viable. There are challenges coming - a less stable climate - the increasing cost of fuel - the shortage of fertilizer and the ageing of the current generation of farmers. We need a greater diversity of crops and to inspire a new generation of farmers who want to grow food for their local communities. Greater diversity of crops is better for the soil and more robust in a less stable climate. Fred's greatest hopes lie in changing from annual crops to perennial ones. It is quite amazing how much this will benefit the soil, water retention and the fundamental economics. Fred explains to us some of the more recent research that is helping to create perennial food crops that will greatly assist in this transformation to a more sustainable model.