This study was conducted to evaluate the current management of furrow and border Irrigation systems in the Dez Irrigation network. Of the eight farms studied, three grew wheat and one each grew com, sugar beets, lettuce, sesame and mung beans. The study found water application Efficiency in the five farms with furrow Irrigation systems to be 25.8% and for the three farms with border Irrigation systems to be 32.7%.The main reason for water loss was found to be runoff and deep percolation. SCS infiltration equation parameters were calculated using the obtained data. For each farm, conditions were simulated using the SCS equation. Methods for optimum Irrigation were developed based on variables such as discharge inflow, furrow/ border length and cut-off time and cut-back methods.

Using saline water for Irrigation of crops is a strategy for Irrigation water management. In this study, the cyclic application of saline and non-saline water was investigated. Field experiments were carried out during a growing season in 2012 under drip Irrigation for maize crop with nine treatments in randomized complete block design in Karaj. The treatments were based on alternative Irrigation management of saline and non-saline water on three salinity levels of 0.4, 3.5 and 5.7 dS/m and freshwater application in every one, three and five saline water application (1: 1, 3: 1 and 5: 1, respectively). The 1: 1 management was better than the other managements in terms of crop yield. The results showed that while the highest wet weight yield (56.2 t ha-1) was obtained in the F treatment (Irrigation with non-saline water constantly), but the highest Irrigation water use Efficiency based on wet weight (14.9 kg m-3) was acquired in the 3S1: 1F treatment (thrice saline water (3.5 dS m-1) andonce non-saline water, alternatively). Thus Irrigation water use Efficiency was increased in cyclic using of saline and non-saline water because of less water use in saline Irrigations, despite the relative reduction of crop yield. The results indicated that the percentage of crop yield decreased by 10.3 for every 1 dS m-1 increase in salinity level of Irrigation water in fixed management. In this study, the crop yield in alternative management was higher than mixing management.

The value of Irrigation Efficiency cannot be precisely known. Therefore, water resources planning and Irrigation network design are normally based on uncertain values of Irrigation Efficiency which ends up with disappointing results in practice. This research used "system" and "non system" approaches to analyze the data obtained from Pasha-Kola Irrigation network in Mazandaran Province in northern Iran. This network is cultivated with rice and has a shallow water table condition. Furthermore, reported data for multiple cropping projects were obtained for Dez project in the Khuzestan province and Doroodzan project in the Fars province from other investigators and used to determine the "system" Efficiency. In the "system" approach the deep percolation and surface runoff were not considered as water loss. However, these were considered as water losses in the "non system" approach. The project Efficiency for "system" and "non system" approaches considering the deep percolation as water loss were obtained as 0.87 and 0.51, respectively. However, the project Efficiency for the "non system" approach in which deep percolation was ignored was 0.85 which is similar to that obtained by the “system” approach. It may be concluded that, for Irrigation projects with single crop (rice) and shallow water table, the project Efficiency (either "system" or "non system") is generally higher than that of no shallow water multiple cropping networks. Furthermore, for rice Irrigation projects, deep percolation of water may not be considered as loss due to its potential of being reused as groundwater supply and the "system" Irrigation project Efficiency is similar to the "non system" project Efficiency. In general, it is more reliable that the "system" approach be used for evaluation of Irrigation projects. Furthermore, in a "non system" approach the deep percolation may not be considered as water loss.

This study was carried out to evaluate Hamody Irrigation network (in an area of 3079 ha) using classic and new classic Irrigation Efficiency concepts. For this purpose, firstly the main district’ s water inputs (Irrigation, rainfall and canal releases) and outputs (actual crop evapotranspiration, drainage outflow and canal seepage) were measured or estimated during the hydrological years (2006-2009). Then, the application Efficiency (classic concept) and the net and effective efficiencies (neoclassic concept) were estimated at the network level. Finally, different scenarios of water allocation were evaluated by considering new concepts of Irrigation Efficiency. The assessment scenarios include 65, 75 and 85% of water supply needs, 100% Crop Water Requirement (CWR) and a fraction of CWR without significant reduction in yield. The annual average outflows were 16% higher than the inflows, presumably due to canal seepage and lateral groundwater inflows from neighboring lands. Distribution, application and total efficiencies were estimated 68, 53 and 44%, respectively, indicating low Irrigation performance in the Irrigation network. Despite the high volume of applied Irrigation water, the actual ET was 19% less than the potential ET, indicating water-stress and crop yield reduction. The assessment of surface Irrigation systems using new classical approach showed that the net (0. 77) and effective (0. 65) efficiencies were more than the classical Efficiency (0. 53). The results of this study showed 19-47% water saving in allocation scenarios using the new concepts of Efficiency.

The objective of this study is to evaluate Avan modern Irrigation network with an area of 10985 ha. The main district’s water inputs (Irrigation, precipitation and canal releases) and outputs (actual evapotranspiration of crops, outflow surface drainage and canal seepage) were measured or estimated during the hydrological years of 2006 to 2009. The district-level Irrigation performance was poor (mean value of seasonal Irrigation consumptive use coefficient-ICUC in the studied years were equal 37%), due to the low distribution (66%) and on-farm (53%) efficiencies for the 1385-88 Irrigation seasons. Thus, despite the high volume of applied Irrigation water, the actual district ET was 19% lower than the maximum achievable ET, indicating that the water-stressed crops yielded below their maximums. By using neoclassical approach, it was shown that the values of net (0.83) and effective efficiencies (0.68) were more than classical Efficiency (0.53) in surface Irrigation systems. The results obtained in this study showed that effective Efficiency has suitable expression about Irrigation management and method at farm scale, whereas net Efficiency only considers the concept of reuse of beneficial losses on spatial scale larger than the field. Potential reductions in water allocation were analyzed for three ICUC values (65, 75, and 85%) and two scenarios of modernization (I and II). In scenario I, where the aim was to achieve maximum ET and crop yields, water allocation could be reduced from 34.8 to 50.2% of the current allocation. In scenario II, where the aim was to achieve the maximum conservation of water under the actual ET and crop yields, reductions in water allocation would be much higher than current allocation (47.4 - 59.8%). Thus, significant volumes of water could be conserved in the rehabilitation of this district by increasing the distribution Efficiency and, in particular, the on-farm Irrigation Efficiency.

The objective of this study is to evaluate Avan modern Irrigation network with an area of 10985 ha. The main district’s water inputs (Irrigation, precipitation and canal releases) and outputs (actual evapotranspiration of crops, outflow surface drainage and canal seepage) were measured or estimated during the hydrological years of 2006 to 2009. The district-level Irrigation performance was poor (mean value of seasonal Irrigation consumptive use coefficient-ICUC in the studied years were equal 37%), due to the low distribution (66%) and on-farm (53%) efficiencies for the 1385-88 Irrigation seasons. Thus, despite the high volume of applied Irrigation water, the actual district ET was 19% lower than the maximum achievable ET, indicating that the water-stressed crops yielded below their maximums. By using neoclassical approach, it was shown that the values of net (0.83) and effective efficiencies (0.68) were more than classical Efficiency (0.53) in surface Irrigation systems. The results obtained in this study showed that effective Efficiency has suitable expression about Irrigation management and method at farm scale, whereas net Efficiency only considers the concept of reuse of beneficial losses on spatial scale larger than the field. Potential reductions in water allocation were analyzed for three ICUC values (65, 75, and 85%) and two scenarios of modernization (I and II). In scenario I, where the aim was to achieve maximum ET and crop yields, water allocation could be reduced from 34.8 to 50.2% of the current allocation. In scenario II, where the aim was to achieve the maximum conservation of water under the actual ET and crop yields, reductions in water allocation would be much higher than current allocation (47.4 - 59.8%). Thus, significant volumes of water could be conserved in the rehabilitation of this district by increasing the distribution Efficiency and, in particular, the on-farm Irrigation Efficiency.

In order to study the effect of Irrigation in different times on yield and Irrigation water use Efficiency in grape orchards, an experiment was conducted with randomized complete blocks design with 4 treatments and 4 replicates in Takestan Grape Research Station of Ghazvin, Iran in 2004-2005. Treatments included: (A) Control (furrow Irrigation based on conventional Irrigation in Takestan vineyards), (B) Furrow Irrigation (on the base of phenological stages: inflorescence forming date, berry set, berry growth and verasion), (C) Furrow Irrigation (20 days once after berry set) and (D) Furrow Irrigation (30 days once after berry set) until grape ripening at Takestan region. The amount of water required in each Irrigation on all treatments was based on water requirement of vineyards and the distance between two Irrigation intervals as. The area of experimental plot was 120 m2. The results showed that B treatment increased yield and Irrigation water use Efficiency as compared to other treatments. In this treatment, the average yield was 16.05 ton/ha and Irrigation water use Efficiency was 3.3 kg/m3. Irrigation water use in B treatment compared with control treatment was reduced by 27.8%. The amount of water used in this treatment was less than other treatments. Therefore, timely Irrigation and based on phenological stages in grape vineyards not only increased yield and Irrigation water use Efficiency but also decreased Irrigation water consumption.

Considering the importance of water consumption management in the agricultural sector, in this research, the application water Efficiency and the water consumption volume in wheat fields of Semnan province were investigated. The volume of inflow, outflow, soil moisture before and after Irrigation and the depth of root were measured and based on them, the values of application water Efficiency was determined. The results showed that there is the most water losses in the first Irrigation and the application water Efficiency varies according to several factors such as farm management, depth, length and slope of furrows, physical properties of the soil. The average values of application water Efficiency in the surface Irrigation method were estimated at 30.6%. Inattention to the characteristics of the soil, the slope of the land, the depth and length of the furrows, the lack of proper leveling and inappropriate timing of Irrigation with the plant's water requirements, and the low flow rate entering the furrows have caused an increase in water losses in the fields. The average volume of water consumption in Shahrood, Semnan, Damghan and Garmsar was 7700.7, 6628.3, 5875.4 and 7890.8 m3/ha, respectively. Comparing the calculated water requirement with the volume of Irrigation water showed the application of deficit Irrigation in the wheat fields of Semnan and Damghan. Also, the results showed that the calculated water requirement was higher than the values in the national water document. According to the area under wheat cultivation in the province, for every one percent increase in application Irrigation Efficiency, about 793,000 m3/ha of water will be saved.

Optimum use of renewable water resources is one of the economical goals of the governments. Sustainable development was considered as an active design process by the farmer that should focus on creating and maintaining adaptive capacities in order to tune the farm system to an everchanging environment. Because sustainability involves social, ecological and economic aspects, the farmer must be enabled to integrate soft and hard parameters in decision-making. The objective of the research described in this paper was to develop a model that helps decision makers to design a sustainable agricultural system. Mathematical programming (MP) has been a widely used tool for studying and analyzing agricultural systems. As a result of this study of water sustainable agriculture, we present lessons for future project development and policy formulation and reform. The results indicate that, with improving of Irrigation Efficiency, groundwater resources level will be increased.

Increasing Irrigation Efficiency and reducing water losses in gardens is necessary due to the severe shortage of water resources in the country. In order to increase the Irrigation systems Efficiency it is necessary to evaluate them. For this purpose, 6 gardens with basin Irrigation system were selected. The amount of Irrigation water volume, depth of root development, yield, application Efficiency (early, mid and late of the growing season) and water productivity were determined. Also, the water requirement was calculated by the Penman Monteith method using meteorological data (recent ten years) and compared with the values provided in the National Water Document. In apricot orchards, the average application Efficiency varied from 43.3 to 58.4 percent (average of 49.7 percent) and in vineyards from 41.7 to 61.9 percent (51.4 percent on average). Deep percolation was the major portion of Irrigation water losses in apricot and grape gardens by 49.7 and 51.4%, respectively. The average water productivity of these products was 0.78 and 5.2 kg.m3 respectively. The results showed that in gardens where land leveling and water supply of the trees were well done, Irrigation Efficiency and water productivity were significantly increased. Comparing the computational water requirement with the volume of Irrigation water shows the imposition of deficit Irrigation in these gardens. The results also showed that the computational water requirement was much higher than the values mentioned in the National Water Document, which highlights the need to update the National Water Document.