The Impact of Biochar and Olive Mill Wastewater Amendments on Soil Physical and Hydrodynamic Characteristics and Soybean Productivity in the Syrian Coast

One of the most critical problems facing countries in the Mediterranean basin and posing restrictions on agricultural production is poor soil quality caused by low organic matter content (OM). Biochar, a carbon-enriched material obtained by pyrolysis of agricultural wastes proved to be efficient in soil improvement. On the other hand, olive mill wastewater (OMWW) is a byproduct of olive oil production. The combined use of these materials will reduce environmental damage paving the way to sustainable agriculture and may also offer a practical solution for enhancing soil physical properties. This research aimed to evaluate the effect of biochar and OMWW on the physical and hydrodynamic characteristics of a loam soil in the syrian coast. A field experiment was carried out using four rates of biochar (0, 1, 3, and 6 t ha-1) and three levels of OMWW (0, 50, and 100 m3 ha-1). Results showed that with increasing the levels of biochar and OMWW the soil bulk density (BD) and pores containing unavailable water <0.2 μm (PUW) decreased reachig the highest significant reduction at the biochar dose of 6 t ha-1 and OMWW level of 100 m3 ha-1 in comparison to the control. On the other hand, the combined supply of 100 m3 ha-1 OMWW and 6 t ha-1 of biochar led hydrodynamic constants (a and b) to increase indicating enhanced water absorption capacity for plants. Moreover, the soil total porosity (TP) increased significantly by (10.5%v), pores containing plant available water (0.2-10 μm) (PAW) (4.2%v) and macropores (soil air capacity) >10 μm (9.2%v) after adding 100 m3 ha-1 of OMWW and soil biochar addition at 6 t ha-1, also soybean productivity rose by (%222.187).