One of the main objectives of promoting the development of greenhouses in Iran is increasing production productivity and water use efficiency. Accordingly, in this study the efficiency of water use in Sistan greenhouses was investigated for 2008 using Data Envelopment Analysis (DEA). In addition, determinants of water use efficiency were investigated using Tobit Regression Model (TRM). The results showed that the mean efficiencies of greenhouse units under study in the constant and variable return to scale conditions were 63 and 87 percent, respectively. Also, the mean efficiencies of irrigation water in the constant and variable return to scale conditions were 49 and 71 percent, respectively. Based on the results, in the variable return to scale condition, age, education, experience and water resource had positive and size of land had negative effect on water use efficiency. According to the findings, a suitable irrigation water price policy and extension classes seem to be effective on improvement the operation of units under study.

In this research, the effect of biochar on the efficiency of irrigation water consumption and the efficiency of nitrogen consumption at different levels of water and nitrogen fertilizer for karla plant was investigated in Zahedan. The experiment was carried out in the greenhouse conditions in a factorial manner and in the form of a completely random design with three replications (planted in February 2018 and harvested in April 2019). The treatments include three irrigation water treatments (I1) 50, (I2) 75 and 100 (I3) percent of irrigation water, four biochar treatments (zero (B1), 1.25 (B2), 2.5 (B3) and 5 (B4) weight percentage of pot soil) and three nitrogen fertilizer treatments (50 (N1), 75 (N2) and 100 (N3) percent of plant fertilizer requirement). water stress levels during the growing season were measured by weighing the pots daily. Harvesting was done once a week. A total of five harvests were done. The yield and efficiency of irrigation water consumption and the efficiency of nitrogen consumption and soil salinity were calculated at the end of the growing season in each treatment. Also, soil nitrogen and fruit sugar were measured in each harvest. The results showed that the effects of irrigation water and biochar levels on the measured parameters were significant at the probability level of one and five percent. The highest amount of yield (15.5 tons per hectare) was obtained from the treatment of 100% of the amount of irrigation water, which was not significant with the treatment of 75% of irrigation water. The use of biochar up to 2.5 percent by weight of the soil increased the yield. More use of biochar (5% by weight of soil) decreased plant yield. The highest water consumption efficiency (3.14 kg/m3) and nitrogen consumption efficiency (94.55 kg/kg) were obtained with the use of 75% nitrogen fertilizer (150 kg/ha) and 2.5% by weight of biochar. The use of the appropriate amount of biochar reduced the negative effects of moisture stress in comparison with the control. Therefore, it is recommended to use it for the plant and especially in the conditions where the plant is under drought stress or in greenhouses and storages in order to reduce the amount of water consumed and improve the performance of the plant, although it is suggested to test in The farm should also be completed.

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.

Field study of factors affecting crop water productivity is one of the most important strategies to achieve sustainable agriculture. In this study, the effect of water resources utilization methods on physical and economic indicators of water use efficiency was investigated. To achieve this goal, 30 olive groves including 16 groves under personal ownership and 14 groves under collective ownership wells were selected in Tarom located in Zanjan province. In order to calculate the water use efficiency indicators, irrigation parameters such as water consumption volume, irrigation schedule, crop yield, as well as production costs and sales revenue were determined. The average of water consumption in groves under the personal and collective ownership wells were obtained at 9800 and 12680 m3/ha, respectively. The average of CPD, BPD and NBPD indices in groves under the personal ownership wells were calculated 0.4 kg/m3, 46.9 and 24.4 thousand Rials/m3 and in groves under the collective ownership wells were 0.3 kg/m3, 36.4 and 15.2 thousand Rials/m3. The results of the independent T-test showed that there is no significant difference between the mentioned indicators in the two types of exploitation methods. Lack of control and supervision on water resources utilization, low knowledge of farmers in irrigation management and the incompatibility of water allowance with the crop water requirement, especially in groves with collective ownership wells were recognized as the most significant reasons for reducing the water use efficiency in some olive groves of study region.

In order to identify sensitivity of different potato genotypes to water stress, a research was carried out as a factorial experiment in a randomized complete block design with three replications in Karaj in 2014 and 2015. Potato genotypes at eleven levels (Agria, Caesar, Savalan, Sante, Marfona, Milva, Picasso, Hermes, Jelli, 397081-1, 397069-2) and deficit stress in two levels (stress and control) are considered. Tape irrigation was done normally and in the early stages of tuber production, watering for stress plots was disconnected and control plots were irrigated in a normal way, after reaching to ninety percent of the soil moisture deficit, irrigation was done again until the soil moisture reached field capacity and irrigation was done normally up to the end of growing season. Combined analysis of data for two years showed a reduction of biological yield, healthy tuber fresh weight, marketable healthy tuber fresh weight, LAIM, dry weight of LAIM, evapotranspiration and water usage in genotypes under the stress compared to the control. WP based on fresh weight of healty tubers and fresh weight of marketable healty tubers reduced or showed a tendency to reduction in most of genotypes under the stress. WUE based on the healty tuber yield and marketable healty tuber yield decreased under the water stress compared to the control in all genotypes except for 397069-2. The most amount of WP based on fresh weight of the marketable healty yield was observed in 397069-2, respectively (5.41) and (5) kg/m3 in two years under the stress. Based on results of this experiment, doing of additional researches in order to achieve suitable potato genotypes for planting in actual deficit water conditions of our country according to diversity of planting season, place, climate, quality of seed potato, experts and etc are recommended.

The objective of this study was to compare water and nitrate losses and water use efficiency in two alternate furrow irrigation regimes (fixed and variable) with conventional every-furrow irrigation under fertigation. Field experiments were carried out at the Experimental Station of the College of Agriculture and Natural Resources, University of Tehran, Karaj, in 2010. Three fertigations were applied for maize during the growing season. The results indicated that water losses in runoff were smaller in the alternate furrows method compared to the conventional every-furrow irrigation. Nitrate losses in runoff for the first, the second, and third fertigations were, respectively, 32.4%, 44.3%, and 80.3% in the conventional furrow irrigation, 31.2%, 35.1% and 40.2% in the fixed alternate furrow irrigation, and 25.7%, 32.7% and 36.9% in the variable alternate furrow irrigation, respectively. There was no significant difference between the conventional and the variable alternate furrow irrigation in terms of biomass and dry matter yields. water use efficiency for the conventional, fixed alternate and variable alternate furrow irrigations were 1.61, 1.31 and 2.82 kg/m3, respectively. Variable alternate furrow irrigation not only decreased water and nitrate losses in fertigation but also significantly increased water use efficiency.

2Deficit irrigation is one of the irrigation management methods that is used to increase water use efficiency. Considering the internal plant adaptability characteristic to water shortage, Partial Root Drying method has been introduced in recent years. In this field research improvement of water use efficiency for Soybean was determined. This experiment which was conducted at four furrow irrigation treatments at the Research Field of Tehran University in Karaj in 2008, consists of full irrigation (100% soil moisture deficit compensation), conventional deficit irrigation at 50 and 75 percent soil moisture deficit compensation and Partial Root Drying at 50 percent soil moisture deficit compensation with three replications. The amounts of irrigation used were exactly compensation level (negligible loss). Results indicated that water use efficiency according to Duncan's Multiple Range Test at the five percent level of probability there was a significant difference between partial root drying treatment (PRD50%) and conventional deficit irrigation treatment at fifty percent soil moisture deficit compensation (DI50%),. water use efficiency in PRD50% compared with DI50%, DI75% and full irrigation increased by 48.3%, 61.9% and 70.1% respectively.

Deficit irrigation is one of the irrigation management methods that is used to increase water use efficiency. Considering the internal plant adaptability characteristic to water shortage, Partial Root Drying method has been introduced in recent years. In this field research improvement of water use efficiency for Soybean was determined. This experiment which was conducted at four furrow irrigation treatments at the Research Field of Tehran University in Karaj in 2008, consists of full irrigation (100% soil moisture deficit compensation), conventional deficit irrigation at 50 and 75 percent soil moisture deficit compensation and Partial Root Drying at 50 percent soil moisture deficit compensation with three replications. The amounts of irrigation used were exactly compensation level (negligible loss). Results indicated that water use efficiency according to Duncan's Multiple Range Test at the five percent level of probability there was a significant difference between partial root drying treatment (PRD50%) and conventional deficit irrigation treatment at fifty percent soil moisture deficit compensation (DI50%). water use efficiency in PRD50% compared with DI50%, DI75% and full irrigation increased by 48.3%, 61.9% and 70.1% respectively.

The effects of grafting two greenhouse tomato cultivars (Durinta and Valouro F1) onto three tomato rootstocks (Beaufort, Maxifort, and Spirit) under different irrigation regimes [(50%, 75%, and 100% crop EvapoTranspiration (ETc)] were studied by evaluating the vegetative growth, proline, chlorophyll, and mineral content of the leaves as well as fruit yield and Total Yield water use efficiency (TYWUE). Plant height, stem diameter, leaf area, and total yield decreased, whereas proline and TYWUE increased, with increasing water stress. Between the two tested cultivars, Durinta showed more vigorous growth than Valouro. Plant growth, proline, Ca+2 and K+ concentrations, fruit yield, and TYWUE were higher in grafted plants than in non-grafted plants. Adverse effect of high water stress (50% ETc) was evident in the non-grafted plants, particularly in Valouro. A positive effect of grafting was observed when Beaufort was used as the rootstock. Durinta grafted onto Beaufort (DB) under moderate irrigation regime (75% ETc) exhibited water savings (25%) and higher yield (21. 6– 30. 8%) and TYWUE (55. 1– 55. 5%) than fully irrigated (100% ETc) control (non-grafted Durinta). The results indicated that grafting onto appropriate rootstock could alleviate some of the negative effects of water limitation on greenhouse tomato plants.