Cultivation of calcareous soils faces many difficulties due to its properties, as it lacks organic matter, as well as low availability of nutrients, especially phosphorous. This study, using two cereal crops (wheat and barley) to study the effect of compost as a source of organic matter and nano-hydroxyapatite as a source of phosphorus onsome properties of calcareous soil and P content in plants. The main plots were compost (C) with three doses C0 (without C), C1 (12 ton/ha) and C2 (24 ton/ha), the sub plots were different sources of phosphorous [the traditional P CaH6O8P2 (S0) and nano-hydroxyapatite (nHAP) with two rates of S1 (1.5 g/L) and S2 (3 g/L)]. The nano-hydroxyapatite is characterized by X-ray powder diffraction (X-ray), scanning electron microscopy (SEM). Obtained results stated that the biological yield, grain and straw of both wheat and barley were significantly increased with treatments as compared to C0 and S0, especially with C2 and S2. In addition, there is a positive trend between treatments rate and P contentin straw and grain of both crops, the maximum increase was observed with C2 and S2.Also, the application of compost led to a change in soil chemical properties, pH wasdecreased at treatments applied and such decreases were proportional to treatments concentration increase. An opposite trend was observed with organic matter (OM) and available phosphorus. In addition, there is a positive and highly significant correlation between grain yield with P content in plants.

Many other countries have large areas of sandy soil it can be cultivated with some soil properties improvements and reduce water loss during irrigation thus, increase water use efficiency. The present study aims to evaluate the effect of adding compost (Com) 10 ton ha -1 , bentonite (Ben) 10 ton ha -1 , and a mixture of (compost 5ton ha -1 and bentonite 5 ton ha -1 (Com/Ben) on the performance of four rice varieties Giza 178, Sakha 107, Hanyou 73 and Hanyou 737 and some physical and chemical properties of a sandy loam soil under drip irrigation system. The results showed that used Com and Com/Ben resulted a significant reduction in soil pH and soil EC as well as soil contents of Na, K, and Mg, compared with control in the soil layer (0-20cm). The treatments significantly increased organic matter, water holding capacity, field capacity, wilting point, available water, and water-holding pores, while all treatments significantly decreased hydraulic conductivity and quick drainage pores in soil layer (0-20cm) compared with the control. Rice plants have been died before the flowering stage under Com and Ben soil amendments in addition to control. Grain yield, harvest index and water use efficiency have been calculated for the rice varieties under com/Ben mixture only. Rice plants under Com/Ben showed the highest root length, plant height, tillers number hill -1 and biomass yield in comparison to Com, Ben, and control. Hanyou 737 gave the highest biomass yield, grain yield, harvest index and the highest water use efficiency under Com/Ben followed by Hanyou 73.