ABSTRACT
Agriculture occupies 35 percent of the world’s land surface and is the single largest consumer of freshwater resources, using a global average of 70 percent of surface water supplies. Agriculture and forestry are inextricably linked, not least because agricultural expansion is one of the driving forces behind deforestation and forest land degradation. Traditional farming and silvicultural activities may cause land degradation when a population is forced to farm on marginal lands through economic incentives or displacement. There is a long history of environmental problems caused by transformation of forested and grassland areas to cultivated and grazed land, and of exploitation of forest resources for timber, fuel-wood and food. The effect of rising nitrate concentrations in surface waters on aquatic ecosystems is better established. Eutrophication of lakes, reservoirs and coastal zones arising from the enrichment of surface waters by nutrients has become widespread.
