Since the 1980s many developing countries have implemented
macro-economic policy reforms to curb inflation, reduce fiscal deficits
and control foreign debt. The policy instruments used, such as exchange
rate adjustment, budget cuts, trade policy reforms, public expenditure
reviews and privatisation, have different and sometimes opposite
consequences for agricultural land use. During the same period awareness
was growing that deteriorating soil quality could become a limiting
factor to increase or even sustain agricultural production. As a result,
food availability and even accessibility for large population groups in
developing countries may be jeopardised in the near future. Recently,
quantitative models have made useful contributions to understanding the
impact of economic policy reforms on the sustainability of land use.
They provide a consistent analytical framework to deal with complex
issues such as the direct and indirect effects of economic,
agricultural, environmental and population policies, the role of market
imperfections in transmitting economic policy signals, and the
interactions between soil quality, agricultural production and household
economic decision making. Different types of models can be
distinguished: bio- economic models, focussing on the link between farm
household decisions and the agricultural resource base, household and
village models, examining the impact of the socio-economic environment
on farm household decisions, and more aggregate models, analysing
interactions between sectors and their implications for sustainable land
use.