The water balance of different soils on abandoned fields along a transect from the High Pyrenees to the Central Ebro Basin

Abstract

The water storage capacity of 10 typical soils on abandoned fields in five test areas along a transect from the High Pyrenees to the Central Ebro Basin is related to precipitation and potential evapotranspiration. The annual precipitation increases from 300 mm in the Central Ebro Depression to 1700 mm in the subalpine area, the potential evapotranspiration decreases from 920 mm to 650 mm. However in the High Pyrenees, months with a negative water balance are frequent. For a period of 6 years (1994-1999) the potential soil water balance was calculated on the base of physical soil properties and climatic data in daily intervals. The results show several periods with a very low content of plant available water in all test areas. They last for up to 8 months in the Central Ebro Basin and 2 weeks in the high mountain region. Beside grazing and soil erosion, the limitation of plant available water is a major reason for a slow vegetation succession on abandoned fields.