Water shortage is the most important factor constraining agricultural production all over the world. New irrigation strategies must be established to use the limited water resources more efficiently. This study was carried out in a completely randomized design with three replications under the greenhouse condition at Shahrekord University, Shahrekord, Iran. In this study, the physiological responses of pepper plant affected by irrigation water were investigated. Irrigation treatments included control (full irrigation level, FI) and three deficit irrigation levels, 80, 60 and 40% of the plant's water requirement called DI 80 , DI 60 , and DI 40 , respectively. A no plant cover

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Increasing water use efficiency (WUE) is a fundamental remedy for food production under conditions of water scarcity. The aim of this study was to evaluate the potential for water saving and yield improvements with use of the ET-HS model and subsurface drip irrigation. For this purpose, four irrigation treatments were installed in a silty loam soil at an experimental farm near the city of Isfahan in Iran in 2000 and 2001. The treatments included: surface drip irrigation (DI), subsurface drip irrigation at 15 cm depth (SDI 15 ), subsurface drip irrigation at 30 cm depth (SDI 30 ), and furrow irrigation (FI). These treatments were repeated for two genera of potato, Marfona and Navita (traditional genus of potato in Isfahan region), tomato and eggplant. In this research, a completely randomized block design with three replications was applied to each crop. Also, in all of these treatments, crop water requirement and irrigation schedules were determined by the ET-HS model. For this purpose, maximum and minimum temperature were measured daily and filled in the model. Based on the results, SDI 15 has the most efficient use of water in production and is substantially different from other treatments, which measured 7.84, 3.84, 13.15 and 11.64 kg m À3 in Marfona, Navita, tomato and eggplant, respectively. The results show that the maximum crop yield occurred in SDI 15 in Marfona, Navita and eggplant and in DI and SDI 15 in tomato. A part of this increase in yield in SDI 15 related to better soil moisture in the root zone, less water runoff, and less surface evaporation. Additionally, the results show considerable reduction of surface evaporation in SDI treatments. Finally, it can be concluded that subsurface drip irrigation, with drippers installed at a depth of 15 cm, and implementation of the ET-HS model for estimating irrigation scheduling, is the best irrigation method for Marfona, Navita, tomato and eggplant. Copyright aubergines, avec trois réplications en blocs totalement aléatoires pour chaque culture. En outre, pour chacun de ces traitements, les besoins en eau des plantes et la programmation de l'irrigation étaient déterminés par le modèle ET-HS. À cette fin, les températures maximales et minimales étaient mesurées quotidiennement et entrées dans le modèle. L'analyse des résultats montre que la technique SDI15 permet la meilleure utilité de l'eau et fournit des rendements significativement différents des autres techniques (respectivement 7,84, 3,84, 13,15 et 11,64 kg m À3 pour Marfona, Navita, tomate et aubergine). Les résultats montrent que le rendement maximum a été obtenu avec SDI15 pour Marfona, Navita et l'aubergine, et avec DI et SDI15 pour la tomate. Une partie de ce supplément de rendement avec SDI15 était liée à une meilleure humidité du sol dans la zone racinaire, un moindre ruissellement, et une moindre évaporation de surface. De plus, les résultats montrent une réduction considérable de l'évaporation de surface avec la technique SDI. En conclusion, l'irrigation au goutte-à-goutte souterr...

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Groundwater quantity and quality modeling is one approach for optimal use of available water resources in arid and semiarid regions. This study was conducted to simulate flow treatment and nitrate transport on Shahrekord aquifer using three-dimensional solute transport model and geographical information system. Hydraulic conductivity, specific yield and recharge values in flow simulation process and effect molecular diffusion coefficient, longitudinal dispersivity and distribution coefficient in quality model were calibrated. 120 water samples during July 2007 to June 2008 were collected monthly from 10 wells and measurements of nitrate were carried out. The results show that the developed model is successfully used to simulate flow path and nitrate transport in saturated porous media. The highest values of nitrate occur along Bahram-Abad village and the surroundings. The groundwater quality in the area represents a complex system, which is affected by different factors of pollution, such as urban wastewater and leaching of agricultural lands.