Most arid and semi-arid soils, especially calcareous sandy soils, are widely distributed in the Middle East region; the deficiency in
their content of many nutrients particularly phosphorus and organic matter limits crops production. This study aimed to assess the
effects of adding biochar (B) with farmyard manure (FYM) and poultry manure (PM) on some soil properties, phosphorus (P)
availability, and barley growth in calcareous sandy soil. The pot experiment includes the following treatments: Control, B, B +
FYM (1:1), B + PM (1:1), B + FYM (2:1), B + PM (2:1), FYM + B (2:1), and PM + B (2:1). Biochar combined with FYM and
PM enhanced the water holding capacity (WHC) and soil organic matter (SOM) content in calcareous sandy soil. Phosphorus
availability was increased significantly by applying biochar mixed with farmyard manure and poultry manure at all treatments.
Green biomass of barley improved because of adding biochar alone, poultry manure alone, and biochar co-applied with poultry
manure at all mixing ratios. Biochar application caused significant increases in phosphorus use efficiency (PUE) by barley plants
compared to all other treatments, except for the control. We recommend adding biochar either individually or mixed with poultry
manure to improve the productivity of calcareous sandy soil.