The effect of organic wastes and phosphate fertilizer in the equilibrium phases thermodynamic in calcareous soils

Abstract

Abstract: A laboratory experiment was conducted to study the effect of organic waste and phosphate fertilizer on the phosphorous phases for two surface soils in the areas of ,, Kufa and Jabla, having different calcareous amounts (120 and 270) gm.kg-1 soil, respectively. Three levels of organic material, (0, 25 and 50%) were added to the soil followed by four levels of phosphorus (0, 50, 100 and 200) mg P. Kg- for incubation period of eight weeks.The results of the study revealed that Octacalcium phosphate (OCP) and Tricalcium phosphate (TCP) when the soil is treated alone,and Di-calcium phosphate (DCP), Octacalcium phosphate (OCP),and Tricalcium phosphate (TCP) are present in the event of treating the soil with 25% organic substance, while Dicalcium phosphate dehydrate (DCPD), and Di-calcium phosphate (DCP) are present in the event of treating the soil with 50% organic substance.The study also revealed the effect of high calcareous amount is clear in the precipitation of phosphorous,and effect of additional amount of phosphorous on the different phases of phosphorous is clear in the different treatments المقدمة: