Sandstone Soils of the Cedar Forests of the Aures (Algeria): Characteristics, Water Reserve, and Incidence on the Hydric Balance Assessment

In the Aures cedar forest, the surface strongly declined. This decrease would be probably greater due to the droughts that occurred at the end of the last century. In forest soil, the water availability is the best mean to improve the forests’ resilience to drought and to the new climatic conditions. Using the hydric balance, it is possible to estimate periodically the hydric deficit and the available hydric reserve in the soil. The aim of this work is to analyze the role of soil characteristics on the useful soil water reserve and its influence on the water balance. The results show that water retention at the wilting point is very well correlated with soil CEC. The high potential of water retention correlated well with the bulk density. However, useful reserve (UR) depends on the nature of the soil constituents but also their organization. Thus, the water content is positively correlated with the water potential, clay content and organic matter content, and bulk density. Referring to the water balance obtained with potential evapotranspiration, the results indicate that the soil is dry between April–May–June–July and October–November between 4 and 7 months according to the relevant useful reserve of soil, altitude, and weather conditions. The water supply is involved in all quantification of water deficit indicators (earliness, duration, and intensity). The advantage of considering the useful water reserve (UR) in the water balance is to approach the real conditions of the water supply of forest stands.