Modern agriculture is based on three simple priniples:  specialization, simplification and concentration.  In this system it is assumed that cheap energy, adequate water supplies and other natural resources will always be available and that we will be able to sufficiently maintain the ecological health of the ecosystem despite ecological degredation inherent in the system.  All of these assumptions must now be challenged.  Given the depletion of soil, water and energy resources a new system of agriculture based on biological diversity and biological synergy, rooted in principles of ecology and evolutionary biology must now be developed.  Such systems will have to be adapted to local ecosystem ecologies.  Farmers throughout the world are already developing such systems, and they may serve as models of agriculutre for the future