||Classical political economists, and Malthus and Ricardo in particular, developed in the early stages of the demographic transition in Europe a macroeconomic theory of the relations between population growth and agriculture. Ricardo (1817) distinguished between intensive and extensive agricultural expansion: extensive expansion presumed the extension of cultivation into new lands which were marginal and therefore subject to diminishing returns to labour and capital whereas intensive expansion enhanced the output of existing lands through the application of better weeding, fertilizer, drainage and so on, which was also subject to diminishing returns to labour and capital. Ricardo, like Malthus (1803), assumed that population increase would be arrested by a decline in real wages, by increases in rents and by per capita food decline.
There is a third form of intensification which rests upon the deployment of the increasing labour force to crop farmland more frequently (i.e. to increase the cropping intensity or to reduce the fallow). The reduction of the period of fallow (the period of non-cultivation or recovery in which land is allowed to regenerate its fertility and soil capacities) was a major way in which European agriculture increased its output during periods of population growth, as observed at the time when Ricardo and Malthus were writing. Fallowing does not imply poorer or more distant land but as the fallow length is reduced greater capital and labour inputs are required to prevent the gradual decline in crop yields and the loss of fodder for animals. Esther Boserup (1965, 1981) made the fallow reduction a central plank of her important work on agrarian intensification. While fallow reduction is also likely to yield diminishing returns, these are more than compensated for by the additions to total output conferred by increased cropping frequency.
In the eighth century the two-field system predominated in western Europe but by the twelfth and thirteenth centuries the three-field system had come to displace its two-field counterpart in high density regions. By the eighteenth and nineteenth centuries the fallow had begun to disappear entirely. Boserup (1965) saw this fallowing reduction as the central theme in agrarian history and the centrepiece around which the Malthusian debates over overpopulation and famine ultimately turned (cf. Malthusian model). In her view, output per man hour is highest in the long fallow systems â€” for example the shifting or swiddening systems of the humid tropical forest zone in which diverse polycropping of plots for one or two seasons is then followed by a fallow of 15-25 years (depending on local ecological circumstances: cf. shifting cultivation) â€” and population growth is the stimulus both for reduction in fallow and the innovations associated with intensified land use.
Boserup envisages a progressive series of fallow reductions driven by the pressure of population (and the threat of exceeding carrying capacity). Long fallow systems which are technologically simple (associated only with the digging stick and the axe) are displaced by bush fallow (6-10 year fallow) and short fallowing (2-3 year fallow) in which the plough is a prerequisite. Annual and finally multiple cropping appear as responses to continued population pressure. Across this progression of intensification is a reduction in output per man hour but a vast increase in total output. The shift to annual and multiple cropping also requires substantially new forms of skill and investment, however, which typically demands state organized forms of investment and surplus mobilization. Boserup saw much of Africa and Latin America as occupying an early position in the linear model of intensification in which output could be expanded by fallow reduction. The â€œBoserup thesisâ€ refers to the relationship between population growth and agrarian intensification measured through fallow reduction and a decreasing output per man hour.
Implicit in the Boserup thesis, though she did not develop these implications, is the changing role of land tenure, the increasing capitalization of the land, and more complex forms of state-society interaction. Indeed, Boserup\'s work has been taken up by a number of archaeologists and anthropologists who have charted patterns of state formation and social development in terms of agrarian intensification.
Boserup\'s anti-Malthusian theory lays itself open to all manner of charges, including a unilinear form of techno-demographic determinism and a general lack of attention to the ecological limits of forms of intensification (Grigg, 1980: cf. teleology). It is not at all clear how or whether Boserup\'s thesis can be applied to market economies. Indeed, her thesis does not seem to be much help for example in the English case: in its essentials the agricultural technology of the eighteenth century (the Norfolk four-course rotation) had been available since the Middle Ages, and although the eighteenth century was a period of population growth, the previous period of sustained demographic growth from the mid sixteenth century had witnessed no intensification as such (Overton, 1996). Processes of intensification are naturally on the historical record and the reduction of fallowing in the Third World â€” whether driven by demographic growth or not â€” has been and continues to be documented (see Guyer, 1997). But intensification is a socially, culturally and politically complex process. To the extent that fallow reduction involves someone working harder and differently, the question of who works, when and for what return (a question played out in terms of age, gender and class in the peasant household) is not posed by Boserup. Here the newer work on household dynamics has more to offer (Carney and Watts, 1990).Â (MW)
References Boserup, E. 1965: The conditions of agricultural growth. London: Allen and Unwin.Â Boserup, E. 1981: Population and technological change. Chicago: University of Chicago Press.Â Carney, J. and Watts, M. 1990: Disciplining women? Signs 16 (4): 654-81.Â Grigg, D.B. 1980: Population and agrarian change. Cambridge: Cambridge University Press.Â Guyer, J. 1997: An African niche economy. Edinburgh: Edinburgh University Press.Â Malthus, T.R. 1803: An essay on population. New York: Dutton.Â Overton, M. 1996: Agricultural revolution in England. Cambridge: Cambridge University Press.Â Ricardo, D. 1817: The principles of political economy and taxation. Cambridge: Cambridge University Press.