Rice plants need about 9000-21000 m 3 /ha water (depending on the climate). In Iran , due to climatic conditions, rice is irrigated. But in the case of water shortage, farmers don’t irrigate the land by continuous flooding method and use periodical irrigation. Periodical irrigation can save water. But, in the middle of irrigation events, the soil cracks and these cracks create difficulties for future irrigations. Frequency, size and development of the cracks affect water and solute traort, plant development, and the potential for groundwater pollution. Therefore, water management is an important problem in rice cultivation. The present research was performed to study the changes in physical properties related to cracking and moisture conditions of three paddy soils treated with zeolite. The experimental design was split factorial with three replications. Three soil textures (clay, silty clay loam, and sandy clay loam), two sizes of zeolite (0.4-1.0 mm, and 0.4 mm) each in three levels (2.5, 5, and 7.5 g/kg soil), four irrigations, and two sampling times were investigated. To compare soils with/without plants, rice was cultivated for the three soil textures and two zeolite sizes at 5 g/kg treatment. Control treatment had no zeolite. Soils in each treatment were poured in plastic pans of 54 cm diameter and 17 cm height. Soil moisture content, bulk density, width and depth of cracks, distance from the rims, and soil subsidence were measured in each irrigation event. The results showed that addition of zeolite didn’t cause significant difference in crack width, distance from the pan rims, and soil subsidence between control and zeolite-added treatments. Coarse zeolite at 7.5 g/kg soil caused significant reduction of crack depth. Reduction of crack depth at 2.5 and 5 g/kg level coarse zeolite and three levels of fine zeolite were not significant as compared to control. The results showed that addition of coarse zeolite could be effective in reduction of crack depth. Addition of both sizes of zeolite stored more soil moisture. Three levels of zeolite increased soil moisture, but zeolite size was not effective in this respect. Therefore it is concluded that having more specific area is not the only important factor in increasing soil moisture, and the effect of zeolite on soil structure should be considered. On the other hand, using coarse zeolite could save the expenses, because no grinding is needed. Rice plants saved more soil moisture and reduced crack depth and width. Plant roots played an important role in soil consistency. Generally, the results showed that zeolite is not able to reduce crack parameter as the crop residues or Key Words : zeolite, crack, paddy soil, rice irrigation.