Changing Patterns among the Kofyar of Nigeria. At the heart of most discussions of traditional farming systems is a broad theory published by Ester Boserup, a Danish agricultural economist, in a 1965 book entitled On the Conditions of Agricultural Growth . In contrast to Malthus's famous pessimistic essay, in which population growth is forever limited by agricultural productivity, Boserup sees population growth as the major cause of increasing agricultural productivity. But increases in productivity exact disproportionate increases in human labor. Boserup classifies traditional farming systems on a scale ranging from extensive to intensive.
Extensive agriculture is relatively easy.
After only a few years, the field is left to regenerate. At any given time, there will be more land in fallow than in cultivation. This can be a highly productive method of farming that requires minimal effort in field preparation and crop tending. The problem with extensive farming is that it requires an abundance of farmland, and when population density rises, agricultural techniques must change. When the acreage per person shrinks, farmers must start to cultivate plots that have been fallowed for shorter and shorter periods.