This research was conducted to evaluate the effects of biochar and barley residues on some physicochemical properties of silty loam soil and water erosion using water erosion simulator. Biochar was produced from pistachio shells under slow pyrolysis at 500°C under anaerobic condition. Biochar and barley residues were mixed to soils at three rates of 0, 0.5 and 1% (by weight), and 6.5 kg of soil was filed in trays with length, wide and height of 35 × 20 × 10 cm, respectively. The experiments were performed in 3 repetitions for 4 months as a completely randomized design. The results showed that application of 1% of biochar significantly increased P (phosphorus), K (potassium) and OC (organic carbon) of the soil in comparison with control. Also, application at both levels (0.5 and 1%) of barley residues significantly increased P, K, TN (total nitrogen), and OC. Application of biochar and barley residues significantly increased the mean weight diameter of aggregates, plant available water content, and saturated moisture content and significantly decreased water dispersible clay (p < 0.05). Consequently, the amount of water erosion decreased at the rainfall intensity of 60 mm·h-1 during 20 minutes. Generally, the effect of barley residues to improve soil properties was higher than the biochar.

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