THE MOVEMENT OF SALTS, AND THE EFFECTS ON CEREAL YIELDS RESULTING FROM THE APPLICATION OF POTASSIUM REFINERY DUST TO THE SOIL SURFACE

Abstract

Potassium mine refinery dust at rates from 1.12 to 11.2 ton/ha (½ to 5 ton per, acre) was applied to a Dark Brown Chernozemic silt loam and to a Black Chernozemic loam. Under dryland farming conditions, no significant effects on yields of cereal grains have been recorded. After 5 years there is no indication that any K has moved deeper than 46 cm (18 inches). The chlorides have been removed from the surface soil and about 50% have leached to below 213 cm (7 ft). The K replaced some of the exchangeable Ca and Mg which were subsequently leached to lower depths. Much of the added K is now in the exchangeable form; some may have become fixed in the clay lattice.