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SPAIN
All of the arid regions of Spain have been moderately to severely desertified for decades, if not for centuries. Most of the damage
has been done by heavy grazing and woodcutting, but wind and water erosion on cultivated land has also been extensive.
Salinization and waterlogging of irrigated land is a major problem in parts of the Ebro River watershed in northeastern Spain.
Destruction of the native vegetation and the subsequent water erosion of thin soils on slopes has had a devastating effect on the
plant environment and on the potential productivity of the land. Mobile sand dunes are found along the Mediterranean coast.
Desertification Characteristics
During the past several centuries, heavy grazing by sheep and goats has led to the destruction of much of the herbaceous and
woody vegetation on the noncultivated land (Albareda, 1955). Water erosion has been severe on the overgrazed slopes as a
result of the loss of vegetative cover and the torrential character of the rains. Cutting of wood for fuel and construction and the
extension of dryland farming into the pasture lands has accompanied overgrazing. Plant cover has changed to a more xeric type
and surface runoff has increased.
A monoculture of grain in the cultivated regions has depleted the native fertility of the soil and has been responsible for increasing
the susceptibility of the land to wind and water erosion. Extended droughts from time to time have served to accelerate
desertification. Water erosion is severe nearly everywhere on sloping land.
Salinization and waterlogging do not affect a high percentage of the total cultivated land in Spain but important and large areas of
affected soils do occur in irrigated valleys. The major salt-affected areas in the northeast are in the Ebro River watershed in the
vicinity of Zaragosa and Herida. Seepage water from irrigation on the higher land has caused waterlogging and salinization of
lower-lying areas (Martinez, 1978). Gypsum is a common constituent of the soils.
The other major salt-affected areas are in southwest Spain near the coast. The soils are composed of fine-textured sediments
that were subjected regularly to flooding by seawater in the past. Surface and internal drainage of the irrigated land is poor and
water tables generally are close to the surface. Pumping is required to lower the water tables (Ayers et al., 1960).
Magnitude of Desertification
Approximately 50 percent of Spain is arid. In the arid regions about 70 percent is moderately desertified and 30 percent is
severely desertified .
Virtually all of the rangeland has suffered severe land degradation. Range productivity is probably stabilized at a low level now,
with little improvement anywhere. Erosion continues on the extensive dryfarm lands except in a few places where soil and water
conservation measures have been instituted. Soil fertility remains low.
Salinization and waterlogging affect about 240,000 hectares of irrigated land to various degrees (Ayers et al., 1960). Reclamation
has been undertaken in several areas. Because of the need for more agricultural production and the gradual worsening of the
salt problem, irrigation has received special attention in recent decades. Much remains to be done.
Soil and water conservation techniques for dryland farming are known but their application to the field is limited. Range
management is not a well-supported science in Spain. Considerable progress has been made in the reclamation of saline soils
and procedures for doing so are quite well-known (Martinez, 1978).
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