College of agriculture / University of Baghdad


A lab experiment has been carried out using a low content of lime soil treated with saline solutions of chlorides of calcium, magnesium, and sodium, and different rates 100/0, 50/50, and 0/100 of calcium, magnesium, and sodium applied on one concentration of 50 meq.l-1. Phosphorus is added in five concentrations (0, 25, 50, 75, and 100) ppm. Treatments were lab incubated for 90 days, then desorption isotherms of phosphorus are studied through Langmuir equation applications. Released phosphorus is studied. Results show an increase in the average of bonding energy in the treatment of single cat ion where it is (1, 0.68, 0.75) ml.µgP-1 of Ca, Mg, and Na treatments respectively. Also, bonding energy average of mixed cat ions (0.34, 0.20, 0.55) ml.µgP-1 of Ca/Mg, Mg/Na, and Ca/Na treatments of 50/50 rate where the maximum adsorption average are (Xm) at (4000., 188.4, 3030 .) µ Soil-1 of single cat ions of calcium, magnesium, and sodium. While when there is a pair of cat ions, they are (322, 526, 1000) µgP.gSoil-1 of Ca/Mg, Mg/Na, and Ca/Na of 50/50 rates, where the average released phosphorus of Ca, Mg, and Na are (29.1, 54.7, and 51.8)µ Soil-1 respectively, while released phosphorus of pair cat ions are (62.90, 73.90, 57.03) µ Soil-1 of Ca/Mg, Mg/Na, and Ca/Na respectively.