The volume of water held by a unit thickness of a soil horixon at field capacity can be estimated by multiplying the bulk density by the moisture weight percentage after desorption at 1/3-bar tension. Serious errors may result, especially in fine-textured soils, if the 1/3-bar moisture percentage value is obtained by the use of crushed, sieved samples. More reliable estimates can be made if both the moisture weight percentage and the bulk density values are obtained by the use of undisturbed samples.