Sustainable Agriculture and Food: Four volume set (Earthscan Reference Collections)

Past Successes 291

tional practices, with fewer or no outside inputs, yield gains are modest, of the
order of 1 per cent or less per annum. Production grows, barely perceptibly and
largely as a result of increases in cropped area, until a critical threshold is reached
when a transition to a new basis for production occurs. Much-improved varieties
appear, farmers turn to inorganic fertilizers and synthetic pesticides, invest in irri-
gation and drainage and adopt a range of other new technologies, including the
purchase of agricultural machinery.

Figure 13.1 Cereal production, cereal yields and calorie supply in the developing

countries, 1961–1986