T
he aim of the present study was to evaluate the effects of sandification and composted manure on some selected chemical properties; SOM, CaCO3, EC, Soluble Calcium and pH, as well as the pore size distribution of heavy clay calcareous soil. The experiment included four levels of sand addition and three levels of compost in a split plot design with three replicates. The experiment was carried out in an agricultural bilateral cycle included wheat and maize crops cultivation as a winter and summer season, respectively. The results showed that sandification increased slightly the sand fraction and led to a little decrease in the clay one, at the end of the wheat season. This was more pronounced in the 1st soil layer than the 2nd and the 3rd subsurface layers. The residual effect of sandification (after harvesting the maize crop) and compost had no obvious effect on the soil particle size distribution. Increasing rates of sandification and compost additions led to decrease the soil content of CaCO3% with comparing initial soil, pH values and the soil salinity while the SOM% and soluble Ca ions increased. The best results were obtained under the highest rate of sandification S15 and compost addition C2. It could be concluded that the role of compost addition was effective on CaCO3 solubility and sandification had an encouraging effect as well. This relation increases the release of calcium ion (Ca+2) to soil solution, so that buffering the pH values as declined towards neutrality. The relatively high salinity of compost affected positively the calcium carbonate solubility.