Water‐retention capacity in fine earth and gravel fractions of semiarid Mediterranean Montane soils

Abstract

Water retention capacity was studied in fine earth and gravel from loamy‐textured soils with medium‐low carbon content in a semiarid Mediterranean montane location. Sierra Gador, southeastern Spain. In fine earth, typical water retention curves were established at six soil water potentials (‐10, ‐33, ‐100, ‐500, ‐1000, and ‐1500 kPa), and the water retention was compared against different physical, chemical, and miner‐alogical properties. Percent total sand and organic carbon content were the variables that gave the best fit in the pedotransfer functions for the calculation of water retention at ‐33 and ‐1500 kPa. Results for water retention in gravel at ‐33 and ‐1500 kPa show that gravel can make a significant contribution to the available water in the soil. Bulk density of gravel was the property most closely related to water content at both soil water potentials, and was the variable that gave the best fit in the pedotransfer functions. Other properties that were useful with this function were citrate‐ditionite extractable Fe content, quartz, feldspathic, and phillosilicates content. In semiarid environments, the greatest differences in water retention are found between soils derived from different parent materials, regardless of their taxonomic relation.