Physical changes in seedbed material resulting from the application of dissolved gypsum

Abstract

The effect of an initial irrigation of gypsum solution, as compared with water, on water retention and transmission in a seedbed loam and clay and the subsequent changes in porosity during drying have been studied. A marked increase in hydraulic conductivity, particularly in the clay soil, and concomitant increases in total and air-filled porosity at all matric potentials, from near saturation to oven dry, were measured. The data provide an explanation of the earlier observation that improved emergence resulting from gypsum treatment was associated with the maintenance of higher matric potentials in the surface 4 in. of soil for longer periods after irrigation.