Impact of Biochar and Compost on Hydro-physical Properties and Yield Grown on Sandy Soil

A laboratory soil column experiments were conducted to investigate the effects of biochar, compost and the mixture of both on hydro-physical properties of a sandy soil. In this research, leaves of the date palm was used as the source material for biochar production. The leaves were collected from different locations, exposed to direct sunlight to dry out, and then cut down to small pieces (7-10 cm). The pieces were packed tightly in a container to minimize the air volume and to provide nearly oxygen-free conditions. The container was tightly covered and subject to outdoor pyrolysis at a temperature of 400-450°C ± 10°C.  For intermittent evaporation, water retained and wetting front,  an Acrylic columns (5 cm internal diameter and 40 cm in length) were filled manually with air dried soil to 30 cm depth at the same bulk density of the field soil (1400-1500 kg m-3). Compost and/or biochar were mixed with the air dried soil for making the layer of mixture at rates of 1, 2 and 4% by weight. The thickness of layer was 10 and 20 cm from the surface of soil column. The columns were subject to five wetting/drying cycles (each cycle is one week long) by the application of 25 cm3 week-1 of tap water (EC ≅ 0.4 dS.m-1).  Both infiltration and saturated hydraulic conductivity were measured in separate soil columns packed with the soil and soil-biochar mixture. Minidisk infiltrometer was used for measuring the infiltration rate. The results indicated that applying biochar restricted the movement of water penetrability as a result of decreasing the water front and saturated hydraulic conductivity. The mixture of both biochar and compost at 4% gave the best results. Our results clearly demonstrated that applying biochar to sandy soil has significant impacts on improvement of sandy soils physical properties. Therefore, applying biochar under arid conditions could be a promising amendment for increasing soil productivity.