THE EFFECT OF HUMIC ACID ADDITION MIXING WITH SALINE WATER IRRIGATION IN KINETICS OF SALTS RELEASE AND SODIUM ADSORPTION RATIO IN CALCAREOUS SOIL

Abstract

A column experiment was conducted to study the effect of added humic acid in a mixture of different salinity water in kinetics of salts release and sodium adsorption ratio in calcareous soil with a texture clay loam. The soil was taken from the surface layer (0-30 cm), dried with an antenna and passed through a 2 mm diameter sieve. It was filled with steel polyethylene columns with a diameter of 7.5 cm, height 30 cm and a density of 1.37 Mgm m-3. Place a filter under the column 5 cm high of sand and glass wool. All columns were dampened by the poetic properties to maintain homogeneity of moisture content in the entire column. The number of columns used to study the movement and distribution of salts is 4×3= 12 columns. A fixed column of water was placed above the surface of the soil column of different salinity water (0.72, 3.00, 5.00 and 7.00 dSm-1) in accordance with humic acid levels of 0.00, 0.25 and 0.50 g L-1. The washing process continued until the electrical conductivity of the added water was equal to the electrical conductivity of the running water from the columns. The electrical conductivity and sodium adsorption ratio in the candidate water was determined and the results were subjected to kinetic equations for the study of salts release over time. Results showed that the best equation for describing the relationship between the liberated salts (g l -1) and the free SAR and the time (day) is the diffusion equation and the mathematical model Ct= C0-Kt1/2 for the diffusion equation is the most appropriate in describing the relationship. It is noticed that the rate of release speed (K) increases with the increase in the level of added humic acid and any level of salt water used in the experiment and the amount of salts released and the proportion of adsorption of sodium increases over time and increase the levels of addition of the humic acid