Chapter three reviews the ecological basis for primary food

production, providing a brief characterisation of the principal farming

and other primary food production systems, and outlines the significance

of four key resources that underpin agriculture in particular. Without

specifying limits or thresholds, it is clear that, through neglect or

inappropriate development, there is a danger that vital ecosystem

services could be lost unless efforts are made to restore farming methods

that provide better equilibrium with available resources. In this chapter,

we consider four major challenges that especially highlight this