Since 1972, the main driving force leading to pressure on land resources
has been increasing food production. In 2002, food is needed for some 2
220 million more people than in 1972 (United Nations Population Division
2001). The trend during the decade 1985-95 showed population growth racing
ahead of food production in many parts of the world, particularly Africa:
in 64 of 105 developing countries studied in this period, food production
lagged behind population growth (UNFPA 2001).
Agricultural land (defined as land under arable use plus permanent crops)
has increased steadily in developing regions but not in developed ones
(see graph). The decrease in developed regions seems to have been driven
less by availability of land resources than by economic forces, including
overproduction of major commodities and decreasing prices for farm produce.
|Area under arable and permanent crops
|Area under irrigation (million ha)
|Fertilizer consumption (kg per capita/year)
Graphs above show 30-year trends in three major
agricultural variables: agricultural area, irrigated area and per
capita fertilizer consumption. Fertilizer consumption has fallen
in Europe and North America but continues to climb - albeit slowly
Source: compiled from FAOSTAT 2001 and United
Nations Population Division 2001
Policy failure and poor agricultural practices contribute to increased
land pressure. For example, the excessive use of fertilizers and other
chemicals contributes to soil degradation and water pollution. Between
1972 and 1988, global fertilizer use grew at an annual average of 3.5
per cent or by more than 4 million tonnes a year (FAO 2001). Up to the
1980s, maintenance and improvement of fertility was thought of chiefly
in terms of addition of mineral fertilizers, and agricultural subsidies
increased the use of fertilizers further. Government policies supported
farmers by subsidizing agricultural inputs such as irrigation, fertilizer
and pesticides. A study by FAO of 38 developing countries showed that
26 of them subsidized fertilizer use (FAO/IFA 1999).
Pesticides continue to be used indiscriminately (sometimes illegally)
in places, and disposed of casually. A survey published by FAO of countries
in Africa and the Near East reported stocks of unwanted or banned pesticides
amounting to more than 16 500 tonnes at some 1 000 sites in 49 countries
Irrigation has also made, and continues to make, an important contribution
to agricultural production but the potential for future growth has changed.
The efficiency of many irrigation schemes is low and land degradation
problems are widespread. Poorly designed and implemented irrigation schemes
can cause waterlogging, salinization and alkalization of soils. Some 25-30
million ha of the world's 255 million ha of irrigated land were severely
degraded due to the accumulation of salts, according to 1995 FAO estimates.
An additional 80 million ha were reported to be affected by salinization
and waterlogging (FAO 1995b). In the 1980s it was estimated that about
10 million ha of irrigated land were being abandoned annually (WCED 1987)
although the total irrigated area has continued to rise (see graph above).