عنوان مقاله [English]
The latest recommendations of the International Commission on Irrigation and Drainage from the 8th Micro-irrigation Congress held in 2011 in Iran was to develop a global orientation for subsurface micro-irrigation methods. The congress focused attention on the international dimensions of water scarcity, especially in arid and semi-arid regions of the world. Aridity and the cumulative effect of successive droughts in Iran have made the clay subsurface irrigation system of concern to farmers, experts, and researchers. Although this irrigation method is traditional and has both advantages and disadvantages over other subsurface micro-irrigation methods, with modification to its mechanism, it can be a suitable application for Iran. The hydraulic properties of porous clay capsules have a major effect on the performance of clay subsurface irrigation systems. The present study determined the relationship between seepage rate-time and seepage rate-hydrostatic pressure of porous clay capsules used in clay subsurface irrigation systems. The experiments examined three soil textures (sandy loam, silty clay loam, silty clay) under actual field conditions on the large scale. They were conducted as a randomized complete block design with a split plot layout and three replications. The results obtained over three months of operation at 2, 3 and 4 m of hydrostatic pressure show that the daily seepage rate of porous clay capsules were significantly affected by soil texture. In addition, the effect of operating pressure on the seepage rate of porous clay capsules in the three soils was significant. Also, the results of testing of seepage rate-hydrostatic pressure over a two-week period for the three soil types showed a nonlinear relationship (power) between the two irrigation system design factors. The best hydrostatic pressure for porous clay capsules in the three soil textures was 3.5-4 m.
Abu-Zreig, M., Khdair, A. and Alazba, A. 2009. Factors affecting water seepage rate of clay pitchers in arid lands. University Sharjah. J. Pur. Appl. Sci. 6(1): 59-80.