Increases in organic matter will consistently result in increase of available water capacity only with coarse-textured soils. "Air capacities", "available water capacities," and "wilting points" were measured through moisture tension determinations for soils covering a wide range of texture. The structural improvement of a soil generally increases air capacity, but decreases available water capacity. Under field conditions, however, structural improvement influences soil water relationships because aggregate stabilization promotes increased infiltration of water.