The cropping patterns used on a farm and their interaction with farm resources, other farm enterprises, and available technology which determine their cultivation.; A community of plants which is managed by a farm unit to achieve various human goals. The latter include food, fibre and other raw materials, wealth and satisfaction. Conway (1985) encompassed these multiple goals in the phrase 'increased social value'. Farmers are part of the system. They are able to set, or modify, their own goals, so two farms with identical climates and soils may be managed with different aims to achieve a different mix of outputs.