The B concentration in field-grown alfalfa was not well correlated with soluble soil B unless a stress was placed on the soil B supply. The B removed by sunflowers grown in small pots was well correlated with soluble soil B. Differences in soluble soil B due to single borate applications on 5 different soil types were apparent over a 5-yr. period. Lime applications depressed the movement of B from the surface soil. On unlimed soils, more B was retained from a summer application than from a fall application of borate fertilizer. Boron-deficiency symptoms were observed during periods of moisture stress when the subsoil soluble B level was below .05 ppm. Random samples of the apical portions of alfalfa from B-deficient plots contained less than 20 ppm. B.