STUDY OF THE EFFECT OF ZEOLITE AND AGRICULTURAL SULFUR ON THE PHOSPHORUS ADSORPTION AND RELEASE FROM ROCK PHOSPHATE IN CALCAREOUS SOIL

Abstract

Three experiments were conducted, an incubation experiment, to find out the effect of adding agricultural sulfur on the phosphorus release from rock phosphate and the amount of its adsorption on zeolite in a loamy calcareous soil taken from one of the fields affiliated with the College of Agricultural Engineering Sciences, University of Baghdad - Al-Jadriya, and zeolite was added to it at two levels (0.10) Mg.ha^-1. and agricultural sulfur at two levels (0.2) Mg.ha^-1 and rock phosphate at two levels (0.80) kg P.ha^-1 and mineral phosphorus were added in the form of Di Ammonium Phosphate (DAP) fertilizer at a level of (80) kg P.ha^-1 as a control sample with three replicates 'according to the Randomized Complete Block Design (RCBD) for an incubation period of 60 days. Furthermore, the isothermal adsorption experiment of phosphorus using the parameters of the incubation experiment at its highest levels, which were treated with different concentrations of phosphorus (100, 200, 300, 400, and 500) μg P.ml^-1, and the phosphorus release experiment for the soil on which adsorption was conducted for one level of phosphorus (500) μg.g^-1 soil, for the different treatments. The results of the incubation experiment showed a significant effect of the triple interaction between the treatments, as the highest value was (30.93) mg.kg^-1, compared to the control treatment, which amounted to (6.91) mg.kg^-1. Moreover, the adsorption experiment showed an increase in the adsorbed amount when zeolite was added to the soil, as the maximum adsorption values ​​were Xm1428.57 and 2000 μg P.g^-1 soil, and the bonding energy was 0.014 and 0.0114 μg P.ml^-1 at the soil treatment and the soil treatment with zeolite respectively. The release amount of phosphorus increased when adding agricultural sulfur and zeolite with a ratio of 10.85, 56.11 and 63.31% for soil treatment with sulfur, soil treatment with zeolite, and soil treatment with zeolite and sulfur, respectively, compared to soil treatment only.