Gully erosion in Andalucia, Spain
Source: J M Moreira
In Spain, it has been estimated (ICONA, 1991) that about 44 per cent of the territory is affected by some kind of erosion and 18 per cent (about 9 million hectares) is losing more than 50 tonnes of soil per hectare per year (t/ha/year), a level considered as the critical load for erosion. More than 90 per cent of the eroded land is located in the Mediterranean zone of Spain, where fires aggravate the situation. The major landuses concerned are essentially degraded woodlands (which lose about 95 t/ha/year of soil), non-irrigated grassland (which lose about 36 t/ha/year), sclerophyllous vegetation or the so-called maquis or garrigue (which lose about 21 t/ha/year), and to a lesser extent cultures of vine, almond or olive trees. According to ICONA, the average soil loss in Spain is about 27 t/ha/year.Considering that soil formation in this area is about 2 to 12 t/ha/year, the desertification rate through soil degradation is alarming. The cost of the direct impact of erosion on the environment (considering the reduced lifetime of reservoirs, the loss of agricultural production and the damage due to flooding) is estimated at 280 million ECU per year. The cost of rehabilitation to restore plant cover, improve water retention and protect soil is estimated at about 3 000 million ECU over a period of 15 to 20 years.
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