Mounds associated with shrubs in aridic soils of northeastern Patagonia: Characteristics and probable genesis

Abstract

Studies of mounds associated with shrub clumps in northeastern Patagonia indicate that these forms have an average major diameter of 355 cm and an average height of 41 cm. Mound cover and density are 40% and 450 mounds/ha respectively. Mound and intermound soils present a similar textural composition as well as a similar coarse fragment content (10–20%). Root and organic matter contents are significantly higher whereas calcium carbonate is significantly lower in the mound than in the intermound soils. Mounds may represent a relict land surface level, lowered in the intermound area mainly by wash erosion. Mound development is related to discrete shrub clumps that shelter the underlying soil. Once established, the shrub clump and the underlying mound remain as a stable and self maintained system.