Breakdown of established agricultural systems
Decline of traditional land use practices
Traditional systems of agriculture, forestry and pastoral land use, which have been in place for centuries, are being broken down by a variety of factors, including: low population density due to rural depopulation, the "green revolution" and inappropriate changes in agriculture, change in long-standing land practices and habits forced upon small peasant and tribal communities by environmental stress of many forms, and political discouragement of traditional styles of extensive land use, such as ranching.
The Earth could, in theory, support far more than its present population but the distribution of good soils and favourable growing conditions does not match that of the population. Although land degradation is occurring all over the world, the problem is particularly serious where local food production cannot provide an adequate diet or even enough for bare survival. Their low agricultural yields and the pressures of high population growth have forced millions of small farmers to clear forests and cultivate fragile marginal lands, causing soil erosion and deepening rural poverty.