Comparison of soil water retention at field and laboratory scales

Water content and soil water matric potential are measured in different soi l volumes and st different spatial scales in the laboratory and in the fiel d. The objective of this work was to use a large database to compare field and laboratory water retention. The database consisted of 135 datasets for soil horizons of various textures. Coarse-textured soils had the average di fference between field and laboratory water contents close to zero. On the contrary, fine-textured soils with the sand content < 50% had field water c ontents substantially smaller than the laboratory water contents in the ran ge of water contents from 0.45 to 0.60 cm(3) cm(-3) A quadratic regression explained 70% of variability in field water contents as computed from the l aboratory data. A fractal scaling of the bulk density could contribute to t he observed held-lab differences in volumetric water contents for the range of high water contents.