410 Modern Agricultural Reforms
economic returns to labour or to capital, but it does not necessarily increase the
returns to land. The latter resource will become ever more important in coming
decades as the availability of arable land per capita declines.
Polyculture systems employing a combination or even a multitude of plants
commonly have higher total yields per hectare, absorbing and generally requiring
higher inputs of labour and nutrients. Where labour is relatively abundant and
land is relatively scarce, this can be an efficient and economic system of resource
use. The advantage of monocropping is that it makes mechanization, substituting
capital for labour, more effective.^9 Only where mechanical power can bring into
cultivation land that manual power cannot is greater physical production likely to
result from mechanization. This generally makes agriculture more extensive than
intensive.
Even when population is high in relation to arable area, it can be difficult to
attract or retain labour to work in farm operations. Much of the impetus for farm
mechanization has come from labour scarcities in the more economically advanced
countries. When tractors and other machines have been introduced into develop-
ing countries with the mistaken idea that this will raise production, they have done
more to displace labour than to make land more productive. Tractorization can
raise profits for those who have greater access to land and capital, but it seldom
leads to higher output per unit of land than using hand labour and animal trac-
tion, other things being equal.^10 In contrast to tractors, animals used for traction
reproduce themselves, pay returns on the farmer’s investment, and provide food,
fuel and fertilizer at the same time. Since capital is so often subsidized by govern-
ment policies, one should not consider the private profitability of using tractors
and other capital inputs as a sole or sufficient justification for their use without
analysing the full range of social costs and benefits.^11
Because polyculture is less amenable to mechanization, it requires an adequate
and reasonably skilled supply of labour. Many of the practices we discuss here are
relatively labour-demanding, using human energy and skill instead of capital and
chemicals to get more production from limited land resources. To the extent that
investments of labour are made more productive by agroecological innovations,
they can be better remunerated and lead to improvements in the agricultural sector
and the rest of the economy.
It is widely believed, with more emotion than calculation, that clean-ploughed
fields, sown uniformly in a single crop, planted neatly in rows with all extraneous
plants removed, is the best kind of agriculture. Mulch makes fields look messy, and
crop mixtures look chaotic rather than productive. But this assessment is more a
matter of aesthetics than of science. Yields, yield stability and nutritional quality
per unit of land from polyculture, although harder to measure, are usually greater
than with monoculture.^12 Furthermore, keeping soils covered protects them against
erosion.
Polycropping supported by a strategy of managing and recycling organic inputs
offers many advantages and can raise yields with equivalent inputs. When maize
and soybeans are intercropped, for example, there is about a 15 per cent gain in