Tentative assessment of soil survey approaches to the characterization and interpretation of air-water properties of soils

Procedures used by soil survey organizations in characterizing and interpreting the air—water regimes of soils in France, Germany, The Netherlands, England and Wales, the United States and Canada are summarized and compared. The strengths and weaknesses of the systems are discussed, and research is suggested to resolve problems and to improve the basis of interpretations. The importance of sound field estimates supported regularly by reliable measurements is emphasized. Field estimates are essential in view of the dynamic nature and the spatial variability of some soil physical properties related to the air—water regimes. Research needs include continued development of improved methods of measuring air—water properties of soils, development of improved guidelines for estimating these properties from soil morphology, and identification of the relevant soil properties that can be estimated reliably. Interdisciplinary research is required to integrate expertise in hydrology, soil physics, agronomy and pedology with a view to improving the characterization and interpretation of air—water properties of soils.