Effect of air-drying on the water retention curves of disturbed samples of three soils od Costa Rica derived from volcanic ash

Abstract

Logarithmic regression curves of soil moisture retention were determined and found to be of the best fit to data from air-dried, field-moistened samples of Hydric Dysthandepts. When air-dried samples were previously field-moistened, the curves demonstrate in a statistically significant manner, a greater loss of moisture retention for Hydric Dysthandept that do not experience a dry season and have allophane as the predominant clay mineral than for those that do experience a dry season and have metabaloisite as the predominant clay mineral. The loss of water retention is greater at low suctions than at high suctions. The importance of determining vegetation curves for samples of Hydric Dystrandepts stored at field moisture is raised.