ROLE OF PHOSPHGYPSUM IN MOVEMENT AND DISTRIBUTION OF SALTS IN CALCAREOUS SOILS

Abstract

To study the effect of phosphogypsum addition in the movement and distribution of salts in the calcareous soils, a columns experiment were conducted using the plexiglass columns. Two calcareous soils were used, the first silty clay loam and the second sandy loam. phosphogypsum levels were 0, 5, 10, 15 and 20 tons ha-1 with the first of 5 cm. Distilled water Add daily to the all columns transactions with a fixed depth through Marriott Bottle Technique. The filtrates were collection daily, after stopping the addition of water, the soil was separated from the soil columns and then cut each column into four layers. Electric conductivity and dissolved ions (Na+ and Ca+2 and Mg+2) in filtrates were measured and then sodium adsorption ratio were calculated (SAR). Results showed that the addition of phosphogypsum to the sandy loam soil did not affect salt distribution at various stages of leaching. While in silty clay soil the relationship between EC and the depth of filtrates was significant decline after the first stage of leaching in the control treatment about the difference filtrates of leaching, which have been added phosphate gypsum. These results were reflected in the high values of the sodium adsorption ratio in the control treatment. Either by cutting the soil columns after the leaching process, the results indicate an increase in the values of electrical conductivity with the increase in the level of addition of phosphogypsum.