INFLUENCE OF SIX TREE SPECIES ON WATER INFILTRATION IN SOIL

Models of water infiltration in soil that depend on a single data or measurement, such as those of Kostiakov, Philips, Horton, and Green and Ampt. do not consider the influence of surrounding trees. The hypothesis in this study was that this can influence the generic values taken in the field, and therefore, these values should be corrected. The following are factors that can have an influence: tree species, distance to trunk, tree height, and management (cultivated or not). infiltration was measured with a double-ring infiltrometer at several distances front the trunk of three species of trees cultivated under irrigation: Citrus sinensis, Citrus limon, Olea europaea, another three forest species: Eucalyptus globulus, Pinus halepensis, and Tamarix canariensis, bare ground and continuous grass (Zoysia spp) cover. After fitting the different models and using hydraulic conductivity as a parameter for this study, it was demonstrated that it is necessary to correct infiltration parameters when they are used for tree covered areas, that infiltration decreases as distance to the tree increases, and that the higher tree cover, the greater the alteration of soil hydraulic conductivity. This methodology allows determination of the optimal density for each tree species to maintain infiltration at the highest possible values.