REHABILITATION OF SALINE SODIC SOIL BY WASHING IT WITH ENRICHED WATER OF COMBINATIONS OF PHOSPHOGYPSUM AND HUMIC ACIDS

Abstract

A field study was conducted during the spring season of 2020 on saline-sodic with clay loam texture to study 16 combinations of phosphogypsum and humic acids. The experiment was carried out by Randomized complete block design according to the order of additive treatments for factorial experiments with three replications. That is included the use of humic acids (HA1, HA2, HA3 and HA4), phosphogypsum (G1, G2, G3 and G4) and four concentrations (0.5, 1.0, 1.5, 2.0 gm l-1) for both. They were mixed in the washing water to become 16 combinations, in addition to washing with a commercial clean salt (CS) and with water of the Euphrates River only (W) to become 18 treatments. All the experimental units were washed with water enriched with phosphogypsum and humic acids combination, with a commercial clean salt and water only and water volumes were added equivalent to two times the size of the soil pores to a depth of 30 cm and then soil samples were taken from five depths within a depth of 1 m and planted with the corn crop. The results showed, in general, a decrease in the values of electrical conductivity and the sodium adsorption ratio at all the studied depths compared to what they were before washing. Washing with HA1G4 combination gave the highest significant difference in electrical conductivity, which reached 26.63 dS m-1 compared to HA4G1, CS and W washing, which were 11.42, 14.28 and 11.23, respectively. Whereas, washing with HA4G4 combination gave the highest significant decrease in sodium adsorption ratio, which was 0.83, compared to washing with CS and W, which reached 15.28 and 23.57, respectively. Combination HA4G4 gave the highest significant increase in grain yield and dry matter weight, with an increase of 67.00% and 190.62 compared to washing with water alone (W), respectively.