SUITABILITY OF COARSE-GRADE GYPSUM FOR SODIC SOIL RECLAMATION

Costs of sodic soil reclamation can be reduced when coarse-grade gypsum is used, as the production and transport prices of this gypsum are much lower than of agricultural-grade gypsum. In a feasibility study laboratory experiments were conducted to evaluate the leaching water requirements for five gypsum grades with different particle size distributions. Results indicated that the leaching water requirements do not differ significantly for the mixtures studied, provided that the percolation rates are low. The total time of reclamation appears to increase with increasing particle size. Different methods of application of gypsum were tested. The largest efficiency was obtained when an amount equal to the gypsum requirement was partly mixed with the soil and partly applied onto the soil surface.