The surface elevation of a shrinking soil provided good estimates of the change in profile water content under alfalfa. Surface shrinkage was found to change linearly with water content as measured by neutron and gamma attenuation devices. Extracted soil cores were tested in the laboratory to obtain the linear shrinkage ratio, b. In the field, shrinkage was calculated as the average elevation change of small ceramic plates. Compaction of the soil by harvesting machinery had no adverse effect on the linearity of the shrinkage/water loss relationship, but lack of compaction resulted in nonlinear shrinkage as the soil was unconsolidated and may have exhibited sub-surface horizontal cracking. These cracks were attributed to roots which anchored the soil during shrinkage. In a second study, local values of swelling (b′) from initial measurements before and after irrigation were superior estimators of measured water loss compared to a single universal b value from independent tests.