Nowadays, due to limited water resources of the country and the dominance of agricultural water use, it is necessary to save water and use suitable methods in water scarcity condition and to improve soil physical properties. In recent decades, the use of pressurized irrigation systems is widespread due to high their efficiency and performance, and they have been frequently used for most trees and field crops. Wetting pattern in a trickle irrigation system is one of the most important characteristics that should be taken into consideration for designing the irrigation systems. Besides, the use of coal produced from plant biomes and agricultural wastes (i.e., biochar) as a soil amendment has been recently attracted much attentions. Biochar could improve the soil physical properties through increasing of soil porosity, aggregate stability, water holding capacity and specific surface, improved gas exchange, and reduced bulk density. The objective of this study was to investigate the effect of rice husk and its biochar application on the wetting pattern under surface trickle irrigation in two soil textures of silty clay and loam. The soil water traort and wetting pattern were also simulated by HYDRUS-2D/3D model. The rice husk and its biochar were added to the soils at the rates of 0, 1 and 2 mass percentages. Experiments for monitoring the wetting front were carried out in a physical model with length of 200, width 50 and height of 100 cm, which was filled up to a height of 50 cm by the soil. In order to investigate the effect of treatments and their levels on the wetting pattern, the experiments were carried out at a flow rate of 4 L/h with constant irrigation time and three replications. Then, the soil physical and chemical properties were measured in the treated soils. The results indicated that organic treatments increased the soil organic carbon content and water repellency, and as a consequence the soil structure and physical quality were improved. The organic carbon content and water repellency in the silty clay soil were greater than those in the loam soil. Amendment type significantly affected saturated hydraulic conductivity, organic carbon content and water repellency in both soils. The increment in amendment rate increased the organic carbon content and water repellency in both soils. The increment in amendment rate reduced saturated hydraulic conductivity in the loam soil but increased it in the silty clay soil. Organic treatments increased the soil water content in the range of field capacity to permanent wilting point; the highest increase was observed for the biochar 2% treated soil. Moreover, the addition of organic materials in the silty clay soil reduced the horizontal advance and increased the vertical advance of the wetting front. However, in the loam soil it increased the horizontal advance and decreased the vertical advance of the wetting front. Performance of HYDRUS-2D/3D model for simulating the soil water traort was evaluated based on the statistics of coefficient of determination (R2), root mean square error (RMSE) and normalized root mean square error (NRMSE). The values of R2, RMSE and NRMS in all the treatments and in both soils were above 80%, less than 5 cm and less than 20%, respectively. Overall, it can be concluded that the addition of rice husk and its biochar increased the soil water holding capacity and altered the wetting pattern in the soil. In addition, the results showed that the HYDRUS-2D/3D model has a great potential in simulation of soil wetting pattern as affected by organic material treatments. Key words Wetting pattern, Trickle irrigation, Biochar, Rice husk, Soil physical properties, Numerical simulation, HYDRUS-2D/3D.