جمال احمدآلی

Water is the source of life and a strategic resource for human societies. The need for this vital resource is increasing exponentially due to the increase in population and the development of industry and agriculture. People are forced to use underground water because surface water is not generally and permanently responsive to diverse needs. A decrease in their volume and many problems have been caused by the excessive use of these resources. This crisis has caused regional crises caused by the imbalance of resources and consumption, along with climate changes, has raised the issue of integrated management of water resources more than ever. Agricultural land has been developed due to the increase in population and the need for more food. Programs without principles that rely solely on the quality and quantity of underground water resources have been harmful. Groundwater aquifers are transformed into sources of the country's needs due to the heterogeneous and untimely temporal and spatial distribution of discharges and surface water flows. In recent years, with the increase in water demand and the non-supply of a significant part of it by surface water sources, the extraction - permitted and unauthorized - of underground water sources has been given much attention; so that the level of underground aquifers has decreased dramatically across the country. The purpose of the present study was to investigate the impact of the important variables of precipitation, inflation and annual population as a representative of climatic, economic and social factors on the fluctuations of the underground water level in Urmia region.

In the present study, the impact of three factors, precipitation, population and inflation, on the subsidence of the Urmia Plain aquifer has been investigated. To do this, multiple linear regressions was performed between the data of the annual loss of the groundwater level during 38 years, 1981 to 2019 with three variables of precipitation, population and inflation index of the previous year. According to the previous researches, firstly, an index of inflation has been established by comparing the average loss of the piezometric level of the underground water in
Urmia region as a dependent variable, with the three independent variables of the average rainfall of water year as the most important climatic factor, the annual population of the major centers of human concentration located in the Urmia plain of previous year, and the base coefficient of the annual monetary value of previous year compared to 1981 using a multivariable linear regression. Then, the outcome is compared to the outcomes of artificial neural networks such as four-layer perceptron, three-layer perceptron, and radial basis function. All three networks have an input layer with three neurons to receive the values of the three independent variables of precipitation, population and inflation. One or two hidden layers with a number of neurons, to perform calculations and process the relationship between independent and dependent variables; and an output layer with a neuron to provide the processing results i.e., the estimated aquifer subsidence rate. The data used in the present study were derived from the years 1981-2019. The reference of the aquifer level data is the hydrograph extracted from 67 piezometer wells in the area by the underground water unit of basic studies of the West Azerbaijan Regional Water Company. The annual rainfall data reference is of the Urmia camp evaporation station located in the company premises, which is well controlled and highly reliable as an indicator of rainfall changes in the region. Population data is sourced from the Iranian Statistics Center, while inflation data is sourced from the Central Bank of Iran.

According to the results of the reviewed models, despite the differences in the values of the numerical results, in all four models: multivariate linear regression, perceptron artificial neural networks of the four layers MLP:3-2-2-1, and the three layers MLP:3-5-1 and the radial basis function RBF: 3-5-1, it can be seen that the importance of the independent variables under study are population, inflation and annual precipitation respectively. It is obvious that a larger population needs more food, clothing, housing, etc., which, according to the concept of virtual water, ultimately leads to more use of the limited available water and soil resources. Economic activity, particularly agriculture, is increased due to the depreciation of currency and decrease in people's purchasing power, which is a result of the decrease in purchasing power and the depreciation of currency. This problem has also led to the change of land use of natural resources to agricultural lands that are either rainfed or irrigated. Explaining that rain fed lands cause more rainwater loss through capture and then evaporation and transpiration by plants planted by farmers. Irrigation of agricultural plants or gardens of irrigated lands - mainly with unauthorized water harvesting - ultimately leads to more water consumption. Additionally, humans have exploited underground water resources due to the inappropriate and untimely distribution of rainfall and surface water resources. Although by adopting new management methods, both social and economic, and improving water productivity, despite the increase in demand for water, despite our efforts to protect this vital, sensitive, and strategic resource, statistical studies, including the current results, demonstrate that we have not chosen the correct solutions. Considering some irreparable effects of the aquifer level drop, including irreversible changes in the mechanical characteristics of the soil, which lead to more vulnerability of infrastructures and facilities; the emphasis is placed on comprehensive water resource management and the concept of virtual water and its trade.

In this study, volume of irrigation water, water productivity, and yield of alfalfa were measured in 300 farms in Zanjan, Fars, Chaharmahal and Bakhtiari, Hamedan, East Azerbaijan, Semnan, Khorasan-Razavi, Isfahan, West Azerbaijan, Central, Qazvin and Kerman provinces under farmers management and surface and sprinkler irrigation, various water sources, different water salinities, soil conditions, and varieties, during the growing season of 2018-2019. The results showed that the difference between average volumes of water applied by farmers, yield, and water productivity, in the studied sites were significant at 1% probability level. The average amount of applied water by farmers was 8502, 8901, 9226, 9459, 11481, 12796, 14311, 14821, 15198, 15916, 18351 and 23920 m3/ha, respectively, and the average was 13284 m3/ha. The dry yield of alfalfa varied from 2500 to 30000 kg/ha with an average of 13841 kg/ha. Irrigation water productivity varied from 0.2 to 4.5 and its average was 1.28 kg/m3. The average irrigation water plus effective rainfall productivity for alfalfa was 1.19 kg/m3. The results showed that the average applied water and alfalfa yield in surface and sprinkler irrigation methods were 15076 and 10653 m3/ha, respectively, (p<1%). These results showed that in sprinkler irrigation method, applied water was 30% less and irrigation water plus effective rainfall productivity was 41% higher. Accordingly, in order to reduce the volume of irrigation water and improve alfalfa water productivity, it is recommended to use sprinkler method in suitable climatic conditions where irrigation water is of good quality and the technical criteria of design, implementation, operation, and economic considerations are met.

A significant part of the precipitation in the upstream areas of the watersheds of West Azerbaijan province is in the form of snow, especially in the cold months of the year. Analyzing the data of these sources is very important for the optimal management of reservoir dams in the region, especially in spring, which is the season of snow melting in the respective basins. In common traditional methods for estimating water equivalent of snow storage, the height gradient relationship (linear regression relationship between water equivalent of snow and the height of snow measuring points from the surface of the oceans) is used, which sometimes due to lack of proper fit, some points are removed from the calculations. In this study, for the data of 65 snow measuring stations in snowy months of the water year 2020-2021, instead of the relation of altitude gradient, the four-variable regression of water equivalent to altitude, longitude and latitude (in the UTM coordinate system) was used. It improved the regression characteristics (an increase of more than 3 times the A.R.S., i.e. the square of the adjusted correlation coefficient, or the coefficient of determination, and a decrease of more than 10,000 times the significance level, i.e. the alpha of the correlation coefficient). Also, in order to further investigate, the simulation of relationships with artificial neural networks (selected network: three-layer perceptron with 3, 8 and 1 neurons in the input, middle and output layers) was used; So that the correlation coefficient of the estimated data with the available observations for the selected artificial neural network model was 0.97.

Saving, optimizing water consumption, and improving productivity and efficiency indicators in agricultural sector are important and necessary. Miandoab region is of particular importance as a model of reducing consumption in order to conserve real water for the restoration of Lake Urmia. This research was conducted to evaluate water consumption reduction scenarios at the farm level using AquaCrop plant model in Miandoab region. For this purpose, the information on farms related to the sustainable agriculture project of Iran's Wetlands Protection Plan in Miandoab region was used. The data from the first year (the crop year 2016-2017) and the second year (the crop year 2017-2018) were used for model calibration and validation, respectively. The evaluation of statistical indicators shows the accuracy and high ability of the model in simulating grain yield. After the calibration and validation of the model, the irrigation planning scenarios were analyzed and evaluated in the form of reducing irrigation depth by 10, 20, and 30% for the conditions of the second year. The results of field measurements in 2017-2018 showed that the average irrigation depth and the applied irrigation (Irrigation + effective precipitation) for wheat were 405.44 and 580.44 mm respectively and mean grain yield was 8340 kg/ha, then irrigation water productivity and applied irrigation productivity were 2.27 and 1.52 kg/ , respectively. Also, the results of the study of deficit irrigation scenarios showed that the S3 scenario (30% irrigation water reduction) will reduce only 10% crop yield and water productivity will increase from 1.53 to 1.72 kg/ . The values of water productivity indices were calculated using balance components and performance simulated by the model for each farm. In general, the results showed that it is possible to increase the grain yield of wheat and water productivity using AquaCrop model for proper and accurate irrigation planning and crop management improvement, in order to save and conserve water on a farm scale.

Water resources development projects have many environmental effects, the most important of which are changing the natural regime of the river and reducing the downstream flow. The use of hydrological models allows for sustainable planning in water resources management. The Qarachai River Basin in the Salt Lake Basin has been affected by human activities in recent years. In the present study, the hydrological behavior of Qarachai catchment was modeled using 21WEAP software. The model was developed, calibrated and validated for a 25-year statistical period (1993 to 2017). To calibrate the model, the observed discharge values of Qarachai River located at Asgarabad station (catchment outlet) were calculated with computational values using Nash-Sutcliffe coefficient index. A 13-year statistical period (from 1993 to 2006) was considered for model calibration. The Nash-Sutcliffe coefficient for the calibration period was obtained 0.86. An 11-year statistical period (2006-2007) was considered for validation. The value of Nash-Sutcliffe coefficient for the validation period was obtained 0.74. These results indicate the good efficiency of the WEAP model in simulating the hydrological behavior of the Qarachai catchment. After analyzing five management scenarios, finally a combined scenario with a reliability index above 95% for each consumption sector as well as meeting the environmental needs was recognized as the top scenario. The results of the research indicate that with the implementation of this scenario, the downward trend of the aquifer compared to the current situation will be greatly adjusted and exit from the critical state will be possible by applying appropriate management measures.

Providing food security in scarcity conditions of water resources requires the optimal management of irrigation water. Estimation or determination of indices of water consumption management, such as water productivity in agricultural productions is one of the most important key in macro-planning for the supply, allocation and consumption of water in different sections such as agricultural section. Therefore, conducting a research at the national level that can lead to the real water productivity in the horticultural production in Iran, is essential and important. According to the production (3.4 million tons), a significant amount of surface and groundwater resources are consumed for apple production. This research was conducted with the aim of determining the amount of consumed water in apple orchards in selected provinces under the management of gardeners at the national level. Findings of this study could assist to the decision on management of water and agriculture.

The selected provinces were East Azarbaijan, West Azarbaijan, Ardabil, Isfahan, Tehran, Khorasan Razavi, Fars and Semnan. The water productivity in 145 sites was estimated, in addition to direct measurement of water consumption and crop yield. The factors such as irrigation systems, apple cultivars, gardeners' education, soil texture; and salinity of soil and irrigation water were also measured or recorded in apple orchards. The ANOVA was used to investigate the possible difference between the volume of consumed water, yield, and water productivity in apple production.

The results showed that the difference between the volume of water consumption, crop yield and water productivity was very significant in the orchards from provinces. The volume of consumed water and crop yield in apple orchards over the country averaged 9814 m3 ha-1 and 23.2 t ha-1, respectively. The water index was 2.73 kg m-3 in apple orchards over the country. The lowest and highest water productivity were obtained from the orchards of Fars and Semnan provinces.

Some strategies have been proposed to optimize the consumption of water resources; and to improve apple yield and water productivity in the country's level. The results of the research in apple orchards of selected provinces in Iran revealed that average of water consumption in apple orchards were 9814 m3 ha-1 with the water productivity of 2.73 kg m-3. Application of high-efficiency and well-managed irrigation systems, and other appropriate improving methods of water productivity can lead to optimal use of water resources, improve yield and enhance water productivity in production.

In this study the effects of soil moisture depletion in four different growth stages on some physiological factors such as LAI, R.Y. S.C and WSY were studied. The field experiments were carried out in in Karaj, Mashhad, Esfahan and Miandoab. Two soil moisture depletion (S.M.D) treatments (70 and 90% of available soil moisture content) were imposed at four growth stages. In addition, a control treatment was added to the factorial combination of two S.M.D. and four plant growth stage. Results showed that received water were not significant difference among the treatments. The control, 70 and 90% S.M.D received about 13067, 12607 and 12060 m3/h, respectively. Therefore, difference between treatments basically is because of the times which soil moisture were depleted and to some extend the amount of received water. 70 % S.M.D. at none of four growth stages had no effect on root yield. However, root yield significantly reduces when 90 % of soil moisture was depleted in 2nd and 3rd growth stages. Sugar content reduced when 90 % of soil moisture was depleted at the last plant growth stage. However, 70 % S.M.D. at any of four growth stages had no effect on sugar content. The justification of this kind of observation may be consumption of reserved sugar to produce new leaves. Results showed 90 %S.M.D at rapid growth stage and latest growth stage, caused impurity (especially Na) and molasses to be increased. So, in water stress condition, plant tent to accumulate Na and to some less K. 70% S.M.D. at none of four growth stages had no effect on the juice purity. Results showed that 90 % of S.M.D. at any plant growth stage (especially at 2nd and 3rd growth stages) dramatically reduced sugar yield and white sugar yield. It could be told that 100-120 days after seed planting is the most sensitive growth period (the third growth stage) of sugar beet to water stress. My recommendation is to preserve water it could be irrigation water in early growth stage.

An experiment was conducted with greenhouse tomato plants to determine the effects of oxygen enrichment of the irrigation water on yield and yield components. The study was conducted based on randomized complete blocks as a split plot design with 4 replicates and 3 treatments for 2 years. It is possible to simultaneously irrigate and provide roots with sufficient oxygen via injection of ambient air by means of a venturi coupled to a subsurface drip irrigation system (SDI) called as oxygation. In this study, three levels of irrigation water aeration comprising 0 (the Control), 12 and 24 volumetric percent (i.e. air volume/water volume) was applied to tomato plants grown on a saline clay soil and saline water in a greenhouse in Esfahan Agricultural Research Centre. The type and amount of the required fertilizers were determined from the analysis of soil samples. Tomato plant growth was promoted under conditions which facilitated consistently high oxygen in the root zone. The differences between the aeration treatments and the zero aeration control were significant at the 5% level only for the fruit diameter, fruit length, the number of fruit and total fruits weight. There were no significant effects (P > 0.05) between control and aeration levels for height plant, root dry mater and plant dry mater. The results also showed that the values of yield and water productivity in the treatment of 24% oxygenation compared to the control treatment increased by 21.7% and 21.5%, respectively. Data from this study indicate that tomato production in saline soils and saline water can be improved under SDI if the subsurface drip irrigation is aerated.

Drought is the most important abiotic stress limiting the agricultural crops growth and productivity. Grapevine (Vitis vinifera. L) tolerance to drought is higher than that of most of other trees, but there are many differences between grape varieties for drought tolerance. This study was carried out as a completelty randomized design to evaluate the tolerance of some commercial grapevine cultivars imported from the other countries and several native grapes of West Azarbaijan province. One year old seedlings of studied cultivars (Rasha, Mam Braima, Yaghooti, Askari, Khalili sefid, Fakhri, Sayani, Rish baba, At ouzum, Black seedless, Superior, Flame seedless, Thompson seedless, Fiesta and Perlette were cultivated in pots and subjected to drought treatments (35, 55 and 75 %). After a drought stress for three months, the morphological traits, such as stem fresh weight, root fresh weight, stem and root dry weight, leaf area and physiological characteristics such as chlorophyll content, RWC, leaf temperature were measured. The results of this study showed that there was a significant difference between the traits of studied grape cultivars under stress conditions. Fiesta and Block Seedless were very sensitive to drought condition, while the Khalili, Rasha, and Yaghooti cultivars were able to withstand the stress conditions. Among the imported cultivars, Perlette and Flame seedlesss showed a relatively good tolerance to drought stress.

This study was carried out in 2012 to determine the total irrigation efficiency and real hydro module of Nazlouchai plain in Urmia, using water balance method. In addition to field experiments, we used data gathered from previous documents and related analytical conclusions. Field experiments conducted in 14 farmer’s fields. The result showed that water application efficiency varied from 55.4 to 78.8%. Water distribution efficiency varied from 75 to 94% and water conveyance efficiency was 66 to 92%. Total efficiency of traditional network estimated 44% and net water requirement of cropping pattern of the plain based on Penman-Monteith method calculated about 4930 m^3/ha, thus gross water requirement of cropping pattern was 11204 m^3/ha. The traditional irrigation network of Nazlouchai plain, with 29050 hectares of land, is located in the lower part of Nazlouchai basin. Annual water withdrawal from Nazlouchai river estimated about 128 Mm^3 and differential of input – output of the plain groundwater estimated about 13 Mm^3 annually. Water balance of Nazlouchai plain was negative with 29 Mm^3/year shortage. Estimation reveald that water consumption of Nazlouchai plain was 170 Mm^3 and irrigation actual hydro module of the plain 5838 m^3/yr/ha. The results showed that water efficiency of Nazlouchai plain in agricultural activities was about 85%. The results of this study showed that the actual rate of agricultural water consumption was lower than what was declared, based on national efficiency; the figures announced for water productivity in agricultural production should be reviewed too.

In arid and semi-arid ecosystems, woody and perennial plants are considered as a key factor in wind speed reduction and windblown sands sedimentation. The present study aims to evaluate the effect of different levels of soil additives on morphological characteristics of Calligonum bungei Boiss. A greenhouse experiment was conducted in factorial plan in a randomized complete block design RCBD. In design of experiments, applied treatments were natural and municipal waste compost biochars as soil additives, each in four levels of 0, 1, 3 and 5%, mycorrhiza present or absent, and plant type. Results showed that treatment NO. 7 cause increased 34.62% in plant height, 42.38% in collar diameter, 554.02% canopy cover volume, 124.04% root length, 30.92% fresh weight of shoot, 36.23% fresh weight of root in mycorrhizal plants and treatment NO. 23 cause increased 39.24% in plant height, 35.98% collar diameter, 152.1% canopy cover volume, 17.74% root length, 68.53% fresh weight of shoot, and 20.75% fresh weight of root in non-mycorrhizal plant accordance with control treatment. Among the used treatment, those in the absence of mycorrhiza due to poor-quality of mycorrhiza and lack of interconnection between plant and mycorrhizal fungal networks had better growth than those of non-mycorrhizal plants. According to the results, treatment No. 7 due to low cost, greater accessibility, improve of soil fertility, and plant establishment were recommended in desert regions.

Urmia Lake, as a hyper saline and very shallow lake, located in the northwest of Iran, has had reduced water level of about 40 centimeters each year over the past two decades and is drying, which this problem has led to social and environmental consequences. In this research, the indexes of environmental and agricultural sustainability were evaluated using performance criteria influenced by climate change and water management strategies for the Zerrinehrud and Siminehrud river basins as the largest sub-basin of Urmia Lake Basin. Modeling of hydrologic behavior of these basins was performed by WEAP21 model. The LARS-WG downscaling model was used to simulate climate change.Then the model was analyzed for three future emission scenarios (A2, A1B and B1), for the period 2015-2040, and five water management scenarios: (1) keeping the existing situation (S0), (2) crop pattern change (S1), (3) improving the conveyance and distribution efficiency (S2), (4) combining the improvement of conveyance and distribution efficiency with improving the application efficiency using modern technology (S3), and (5) the combination of crop pattern change with the improvement of total irrigation efficiency (S4). The results showed that the highest values of indices ​​of environmental sustainability and agricultural sustainability were related to the scenario of combining the crop pattern change with improving the total irrigation efficiency under the B1 emission scenario (B1S4). In this scenario, the average annual flow of water entering the Urmia Lake from Zarrinehrud and Siminehrud river basins will be equal to 1292 and 351 MCM per year, and as a result, the environmental flow requirements of the lake will be supplied from these basins.

In the arid and semi-arid regions, agriculture has led to decline in water levels in major lakes such as the Aral Sea, Urmia, Hamoun and Bakhtegan lakes. The major objective of the present study was to evaluate the environmental and agricultural sustainability of Zarrinehrud and Siminehrud river basins as the largest sub-basin of Urmia Lake basin. The sustainability index was calculated using reliability, resilience, and vulnerability performance criteria. In this study, the irrigation water deficit (IWD) index was calculated for the irrigation districts. Irrigation demand and irrigation water deficit indices were calculated using WEAP21 model. Results showed that the environmental sustainability of Zarrinehrud and Siminehrud river basins to supply the environmental flow requirements of the Urmia Lake during the studied period was 0.39 and 0.41 respectively. Nevertheless, the agricultural sustainability index of Zarrinehrud and Siminehrud river basins was 0.64 and 0.74 respectively. Moreover, the amount of IWD index showed that water demand for all irrigation districts has not been fully met. The above results indicated that the Zarrinehrud and Siminehrud river basins were unstable both in terms of the environment and agriculture. Whereas during the study, the changes in land under cultivation in most irrigation districts had an increasing trend, ttherefore, it can be concluded that agricultural development and the addition of water harvests for agricultural use have been the main cause of environmental and agricultural instability.

Planning, designing and managing water resources systems today unavoidably include impact prediction. Impact prediction includes modelling. In the present study the hydrological model WEAP21 was calibrated and validated on the Zarrineh Rud and Simineh Rud Basins. Zarrineh Rud and Simineh Rud rivers with a discharge potential of 3 billion m3 per year have a 50% portion in Urmia Lake Basin. In the present study the soil moisture method was used for the hydrological simulation of model WEAP21. An 11-year statistical period (from 1994-95 to 2004-05) was planned for calibrating the model. The analysis of results of model simulation using the statistical indices showed that coefficient of determination, Nash-Sutcliffe coefficient and index of agreement for different stations were as follows, respectively: Inflow to Boukan dam hydrometry station: 0.9, 0.83, and 0.95; Nezam Abad hydrometry station: 0.75, 0.74, and 0.92; Dashband hydrometry station: 0.82, 0.81, and 0.95 and Miyandoab bridge hydrometry station: 0.75, 0.75, and 0.92. A nine-year period (from 2005-06 to 2013-14) was planned for validating the model. The analysis of results showed that coefficient of determination, Nash-Sutcliffe coefficient and index of agreement for different stations were as follows, respectively: Inflow to Boukan dam hydrometry station: 0.88, 0.85, and 0.96; Nezam Abad hydrometry station: 0.72, 0.7, and 0.91; Dashband hydrometry station: 0.86, 0.85, and 0.96; Miyandoab Bridge hydrometry station: 0.8, 0.78, and 0.93. Generally speaking, the results of simulation showed that the model had a good performance.

An experiment was performed at the Miyandoab Agricultural Research Station to study yield and water use efficiency of furrow and tape irrigation systems in one-row and two-row planting patterns, and to investigate density of grain corn SC704. The experimental design was a completely randomized block arranged in Strip Split Plots with three replications in 2010. Irrigation treatments were applied in vertical plots, and planting arrays of different densities were applied in horizontal plots in the form of split plots. The vertical plots were comprised of four irrigation treatments, including three levels (80%, 100% and 120%) of water requirement by use of drip tape irrigation and 100% of water requirement in furrow irrigation, and the horizontal factor was a planting array in the form of single-row and two-row planting patterns and the sub factor was comprised of three levels: 75, 90 and 105 thousand plants per hectare. The results showed that furrow irrigation had the highest rate of grain yield, about 18.6 ton per hectare, and the treatments of tape irrigation of 120%, 100% and 80% had 18.4, 18.2 and 14.9 tons per hectare, respectively. Although the furrow irrigation treatment had higher yield than the rest, there was no significant difference between treatments except for the 80% of tape irrigation. Thus, by utilizing tape irrigation without a great decrease in the yield, water use efficiency improved. The comparison between treatments of tape irrigation of 80%, 100%, 120% and furrow irrigation led to grain yields of 2.3, 2.2, 1.9 and 1.4 kg/m3, respectively. Also, the highest water use efficiency and maximum yield were obtained from 90000 plants per hectare.

In this research the performance of Aquacrop model was calibrated and validated to predict crop yield and water use efficiency of Maize in Miandoab region. The field experiment was conducted on strip split plot based on completely randomized design for SC704 variety of maize under three irrigation treatments¡ with three repetitions include: 80¡ 100 and 120% crop water requirement and three planting densities (75000¡ 90000 and 105000 bushes in hectare) and planting in one and two rows under drip irrigation system during 2005 and 2006. The model was calibrated by first year’s (2005) data¡ and validated by second year’s (2006) data. Results show that the Aquacrop Model has a high accuracy in forecasting of yield and water use efficiency with perfect and precise calibration. Normalized Root Mean Square Error (NRMSE) of yield and water use efficiency prediction was obtained for validation about 1.92 and 1.82%. The Nash-Sutcliffe efficiency (EF) of yield and water use efficiency prediction were calculated for model validation about 82.5 and 97.7%¡ respectively that indicated modeling with high accuracy. Therefore¡ based on calibrated crop coefficient in this study¡ the Aquacrop model was suggested for applying of different irrigation level and crop density and implants type (one or two row) managements in this region.

The aim of applying water stresses are two fold: a) to enhance Water Use Efficiency (WUE) and, b) to reach optimum-agronomic objectives (including, enhancing certain qualitative parameters of the crop, preventing excessive growth of aerial shoots of crops like sugar beet, etc.). This study was performed to evaluate the effect of irrigation interrupting time and its influence on the quality and quantity of sugar beet. The experimental design used Completely Randomized Blocks (CRB) methodology with 5 treatments; one to five weeks irrigation interruption before harvesting. Each treatment was planted on 5 lines with a 7 m length. The row spacing was 60 cm and the plants were 20 cm apart. The results of simple and combined analysis of variance in twoyears for different traits (root yield, impure sugar yield and white sugar yield, sugar content) showed that there is no significant impact by varying the parameters within the 5% statistical variance. Also, results of mean comparison for white sugar yield in the combined analysis proved that the greatest yield belonged to the 4th and 5th treatments with 9.11 and 9.12 ton/ha, respectively. Therefore, there is no significant difference regarding characteristics studied in statistical group, though even in some cases water stress can improve quality and increase sugar content percentage. So, irrigation interruption 4-5 weeks before harvesting in October can be suggested.

Water is one of the most important restrictive factors in crop production. Therefore, optimum use of water resources in line with sustainable agriculture is mandatory. In this research the effects of different amounts of allowed soil water depletion at various growth stages of root sugar beet and its effect on qualitative and quantitative characters of the crop were studied. The experimental design was randomized complete blocks in a factorial arrangement with 2 factors and 4 replications. The trial was conducted at Miyandoab Agricultural and Natural Resources Research Station, West Azarbaijan for 2 years (2004-2005). Growth stages of sugar beet (factor A) at four levels included the first (S1), second (S2), third (S3) and fourth (S4) growth stages. Allowed soil water depletion (factor B) at 3 levels 65-70% (I1), 85-90% water depletion (I2) and 45-50% of water depletion (Control, I3) were applied at all growth stages. Different quantitative and qualitative traits of sugar beet and the amount of the water used for each treatment were measured and recorded. The results showed that generally the different growth stages influenced qualitative characteristics of root with less effect on root yield, while water stress (different levels of water depletion) influenced qualitative both and quantitative characteristics of root. Although, water depletion caused low root yield but in some cases due to improvement of qualitative root characteristics and sugar extract, it recompensated for root yield reduction. The greatest WUE, based on root yield, and the lowest WUE belonged to S3I1 (5.42 kgm-3) and S1I2(3.88 kgm-3) treatments, respectively. The greatest WUE, based on white sugare content, and the lowest WUE belonged to S2I3(0.64 kg/m3) and S4I2(0.33 kgm-3), respectively.

Deficit irrigation is one of the major methods for water use optimization in irrigatinglands. The main aim of this research is two fold: to evaluate the impact of deficitirrigation, first on the yield its components by measuring the increase the yield and thedecrease in the amount of water usage per hectare, and secondly on the different growth stages of the seed corn. RCBD was used as the experimental design and repeated four times. The plots of irrigation intervals were at three levels: 100 mm, 130 mm and 160 mm of cumulative evaporation from class A pan. The sub plots were different amounts of water requirements: 50%, 75% and 100% of total required water. Statistical calculations including simple analysis of variance, complex analysis and mean comparisons were performed for the traits: seed yield, ASI, corncob length, plant height, number of seeds in row, 1000 kernel weight and the percentage of green coverage. The results of the complex analysis showed that the effects of irrigation intervals (the main factor) and water requirement (the sub factor) had a significant difference regarding seed yield, ASI, corncob length, plant height, number of seeds per row and 1000 kernel weight. The interaction impact between irrigation intervals in water requirement became significant only for ASI at statistical 5% level. It is recommended in the region where the trial was conducted the irrigation intervals to be 15 days. With regard to the low decrease in yield and other yield-dependent traits in 75% water requirement relative to 100% water requirement, it is recommended to use 75% water requirement for irrigation of corn in the region in order to save water and cultivate more lands with the saved water.