Agassi, M., Soil Erosion Research Station, Emeq Hefer, Israel
Shainberg, I., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Morin, J., Soil Erosion Research Station, Emeq Hefer, Israel

Loess and grumusol soils with sodicity levels of 2.5, 6.5 and 17-21 percent were spread over with 3, 5 and 10 t/ha of powdered phosphogypsum (PG) and were rained with distilled water (DW). Phosphogypsum at the rate of 5 t/ha increased the final infiltration rate (FIR) of the loess with ESP of 2.5, 6.5 and 21.0, from 3.0, 1.1 and 0.9 mm/h, respectively in the control to 13.4, 8.5 and 8.3 mm/h, respectively. The final infiltration rate of the same soils with the same ESP levels, rained on with saturated gypsum solutions was lower than that obtained by the PG powder treatment. It was suggested that, besides their effect on the electrolyte concentration of the percolating water, PG particles on the soil surface interfere with the continuity of the crust and may act also as a mulch, and thus increase the IR of the soil. © 1986 Springer-Verlag.