Green waste biochar effects on sandy soil physicochemical properties

The organic amendment of degraded soil in South East of Tunisia was used to restore the chemical, and physical properties of soil quality investigated in this study. Biochar derived from pyrolyzed green waste at 360°C was used like organic amendment. Nines randomized plots with one square meter of the area of each plot in three replicates have been installed in the Institute of Arid Area in Mednine South East of Tunisia, with two rates of biochar 20 and 40 t/ha were investigated: 20 tons/ha (B20) (2 kg/m²) and 40 tons/ha (B40) (4 kg/m²). The results showed that biochar had a positive effect on soil's physical and chemical properties compared to non-amended soil (Untreated soil). Biochar supply at rates of 20 and 40 tons/ha, causes a decrease in electrical conductivity to achieve 2.66 mS/cm for the B40 dose after 1 year of amendment, also a decrease in the bulk density at the surface layer (0-20 cm) has been registered, the total porosity which was decreased with depth. The hydraulic conductivity is favored by the incorporation of biochar in the soil which increases the volume of voids and tends to create preferential flow paths.