ABSTRACT
Achieving sustainable agro-ecosystems is a major challenge of the current century. With increasing populations and improved living standards, the demand for food and fibre will drive the development of sustainable and more productive agro-ecosystems, particularly in less favourable regions, including drylands. This challenge will become substantially greater if the recent trend of using cereals for producing ethanol for fuel continues to expand and encourages cereal production into even less favourable regions. There is an imbalance between natural resources, population and basic human needs in many places, particularly in semi-arid regions. Agro-ecosystems in these areas can be developed and sustained, but careful management will be required and productivity will be low and highly variable even when the best technologies are used.
