مجله آبیاری و زهکشی ایران
سال نهم شماره 6 (بهمن و اسفند 1394)

In order to investigate effect of adding fertilizer on crop coefficient root and shoot growth of maize a factorial experiment in a completely randomized design with three texture treatment including silty clay loam, loam and sandy-loam soil and three fertility treatment was conducted at the experimental farm in Jey and Qahab district of Isfahan was conducted. Reference evapotranspiration and actual evapotranspiration of maize were measured by evaporation pan method and volumetric soil water balance method using micro lysimeters. The results of this study showed that using fertilizer caused increasing of crop coefficient of maize at all growth stages except for the initial stage of plant growth. Maximum and minimum effect of soil fertility on increasing crop coefficient of maize in the middle stage was equal to 37.8% in the loamy soil and 18.3% in the sandy loam soil with two percent fertilizer. The results also showed that the addition of fertilizer to the soil in each soil type significantly increased shoot yield (fresh and dry weight of shoot dry weight of leaf, stem and ear, plant height and the distance between nodes), but had no significant differences on corn root traits. The highest increase in fresh and dry weight of corn shoots loam soils, respectively 3.46% and 55.2% with the addition of two percent of the fertilizer into the soil, respectively.

The turbidity currents are one of agents in sedimentation of dam reservoirs which are entered in the reservoirs of dams through the increase in suspended sediments concentration in river flows. This process decreases water capacity of reservoirs and useful life of dams. Opening lower gates is a conventional method of this currents evacuation. To open the gates, having information about manner of movement and the arrival time to the dam body of these currents, plays an important role in optimal time management of the gates opening and closing. In this research, advancing the turbidity current in Sefid-Rud reservoir dam was simulated by using Mike3 Model and an unstructured mesh. The results showed that after starting the flood, the first traces of turbidity currents reached the dam through the Shah-Rud branch and determined the exact opening of the dam lower gates and was considered as the calibration model. Investigation of suspended sediments concentration profile in cross-sections showed that the maximum concentration is occurred in the depth and as moving towards the surface of water, decreases and the concentration of sediments in turbidity current entering from Gezel-Ozan and Shahroud rivers is 10.11 kg/m3 and 12.52 kg/m3, respectively and by reaching the dam is decreased to 3.93 kg/m3. The results of suspended sediments concentration profile are compared with field data in three cross-sections and the model validation was performed. High values of coefficient of determination and low values of error coefficients show the ability of model in simulation of turbidity current in Sefid-Rud reservoir dam.

Water quality is one of the most affective factors on soil infiltration. The widespread use of wastewater in recent years caused the accurate estimation of soil infiltration to be essential for achieving proper irrigation management. Therefore, Philip, Kostiakov, Kostiakov-Lewis, Green-Ampt,Horton, SCS and linear regression models for soil infiltration estimation were evaluated. Infiltration experiments were carried out in an area of 190 ha of agricultural lands under wheat cultivation, around the Zabol refinery of municipal waste water for six soil texture classes include silty clay, clay loam, sandy loam, loam, loamy sand, silty clay loam. These lands are irrigated with treated wastewater for over 10 years. The study area was divided into pixels with 150mÍ150m size. The cumulative infiltration was determined using double ring experiment. Some physicochemical soil properties were determined in soil samples taken from the center of each pixel. Despite of significant relation between soil infiltration and EC, sand, clay and silt percentage, exchangeable sodium and bulk density, transfer functions didn’t led to satisfactory results for cumulated infiltration. Kostiakov and Horton models were the best profitable models for silty clay soils. Whereas, the others were the best for cumulative infiltration estimation in silty clay loam soils. Green-Ampt and Kostiakov models were the best fitted on the observed cumulative infiltration data with root mean square, mean bias error and efficient coefficient of 0.16 and 0.15 cm, -0.03 and 0.04 cm, and 0.74 and 0.78 cm, respectively. The considerable reduction in soil infiltration due to over accumulation of salt and sodium in the surface soil layers through long term application of waste water in the study area.

This paper investigates the performance of LQR centralized automatic control systems, using water level difference error strategy in main irrigation canal suffering from water scarcity. The purpose is to evaluate the equitable water distribution in main irrigation canal in conditions that the amount of water inflow into the canal is less than total water demands. Therefore three operational scenarios of normal conditions; sudden changes in water off-taking from the main canal; and deficit in supplied water are selected. A centralized LQR automatic control system is designed and tested under the mentioned operational scenarios. Performance assessment indices were also calculated during the simulation and reported in the results. The results show the reasonable performance of the designed controller in the first two operational test scenarios. Also in third one, the controller shows acceptable distribution of water level error so that equitable index varies in a limited ranged from 0.15 to 0.18. The results indicate acceptable performance of LQR controller using water level difference error operational strategy and consequently providing an equitable distribution of water along the main canal

Development of an empirical equation to estimate accurately potential evapotranspiration (ETo) is essential for programming of crops water requirements in natural ecosystems and agriculture sectors. Therefore, the aim of this research is to select the appropriate empirical equation to calculate potential evaporation for arid and semi-arid climates of Fars province. For this purpose the FAO-Penman-Montieth standard equation was employed to evaluate the efficiency and potential of empirical equations (Hargreaves-Samani, Jensen-Haise, Makkink, Turc, Thornthwaite and Blaney–Criddle) to estimate potential evapotranspiration of Shiraz and Lar stations, as reference stations for arid and semi-arid climates, respectively, in Fars province. After selecting the appropriate equation, the monthly potential evapotranspiration was calculated for all stations. Finally, the province spatial ETo distribution was determined. The results of this research showed that among the selected empirical equations the Hargreaves-Samani had the highest correlations (r ≥ 0.96) with FAO-Penman-Montieth calculated data for both arid and semi-arid climates, therefore, selected as the appropriate equation for the province. The spatial ET distribution map showed that the air potential evaporative is reducing northwards.

To identify the dynamism of any system, it is required that its nonlinear behavior is identified on the basis of some specific algorithms, such as chaos theory study. Recognition of behavior of one parameter such as temperature, which is a key component of any climate theoretical model, is critically important. In this research, the behavior of a 25-year time series of daily maximum temperature in Kerman station as one of climate parameters using dynamically nonlinear were analyzed. Accordingly, the parameters required for the reconstruction of phase space, time delay and embedding dimension were calculated as 82 days and 7, respectively. The results showed that there was chaos in the time series. So, correlation dimension and maximum Lyapunov exponent were obtained to be 2.78 and 0.0149, respectively.

In order to optimal operation of water resources and citrus production sustainability in the north of Iran, it is essential to consider economical aspects in deficit irrigation. The objective of this study was to determine irrigation water threshold depths which provide maximum profit under limited land or water resource availability. .For this purpose, a field experiment carried out with Thomson navel orange on flying dragon rootstock, irrigated by drip irrigation, in Ramsar (north of Iran). The treatments, arranged in randomized complete block design, were five different water levels,including 40, 60, 80,100 and 120 percent of irrigation requirement (IR). Optimal depths of irrigation water were determined with mathematical method suggested by English. The statistical compare of means showed that yeild differnces at water levels of 80, 100 and 120 percen of IR were not significant. Also, this differences between 60 and 80 percent were not significant. The relations between yeild and costs with used water were obtained quadratic polynomial and linear functions, respectively. Irrigation water depth at maximum yeild (Wm = 199.8 mm) was a little (%1) much than water depth under water - limiting condition (Wl) and therefore maximum net income per unit of land, earned at the depths, had a small difference. By applying water depth under water- limiting condition (Ww = 127.1mm), water use decreased by 36 percent. In that case, irrigation water productivity (19.2 kg/m3) and net income per unit of water increased by 41.8 and 23 percent, respectively. Moreover, citrus cultivated area can be increased by 57% with Ww. In conclusion, for condition in which land is the most important limiting factor of citrus production and there is no quantity and quality limitation of water, economically optimum depth of irrigation water is 198mm. The optimum depth in water scarsity condition is 127mm

One of the principles of water efficient use in agriculture is to increase the water use efficiency through appropriate planting methods and resistant varieties to deficit irrigation. This study was carried out to evaluate the effects of water consumption and planting methods on yield and water use efficiency of the potato in Kaboutarabad Agricultural Research Station (Isfahan Region). For this purpose, using a split- split plot design based on Randomized complete block with three replications, the effects of planting methods (single-rows and double-rows planting) as main plot, water consumption (60, 80, 100 and 120 percent of the net water requirement) as sub plot and potato varieties (Sante, Marfuna and Rynda) as sub-sub plot were investigated. The results showed that in both years, the yield of potato was higher in the irrigation with 100 and 120 percent of net water requirement. In addition, double-rows planting had higher yield compared to single row planting while the yield was not affected by the potato varieties. In the first year, the lowest and highest water use efficiency were observed in 60 percent of net water requirement with single-row planting and 80 percent of net water requirement with double-rows planting treatments, respectively. In second year, lowest water use efficiency was observed in 60 and 100 percent of net water requirement treatment while highest water use efficiency was occurred in 120 percent of net water requirement treatment. According to this research, in the areas with the same conditions, potato irrigation with 100 percent of net water requirement leads to the highest yield and water use efficiency. In case of water source shortage, the highest water use efficiency is occurred with 60 percent of net water requirement. In both cases, double-rows planting method is preferred to single row planting.

Reducing water consumption in greenhouses is one of the main concerns for growers. This study was conducted in order to compare actual grass reference evapotranspiration that measured with a micro-lysimeter with estimated values of the calculation methods. The site of the study is a greenhouse that located in five kilometers from city of Mahan (south of Kerman province) with altitude 1880 meters above sea level. Meteorological data have been measured in the greenhouse environment from 13 November 2011 to 22 March 2012. The reference evapotranspiration was measured by two micro-lysimeters. In this study, 12 Computational models have been considered. In order to use these methods, meteorological data, including wet and dry temperatures, mean daily temperature, relative humidity, solar radiation and sunshine duration were measured in the greenhouse. In addition, the amount of pan evaporation was measured by a reduced pan. The results showed that FAO-24 Radiation method having the best overall performance (r=0.65, RMSE=0.81, d=0.8, MAE=0.65) and Mc-Claude method did show significant differences under all conditions evaluated (r=0.11, RMSE=3.32, d=0.32, MAE=3.16) in this climate under greenhouse condition.

Study of seepage in irrigation canals has been widely considered by researchers due to the importance of water losses, degradation of the land and environmental problems. Canal lining cracks is one of the main reasons of the water losses and reduction of water delivery efficiency. In this study, seepage rate in three concrete lined canals of Marvdasht Plain (Fars Province), were evaluated using SEEP/W, MSEEP and empirical models, and compared with ponding method results. Results of SEEP/W and MSEEP models showed no significant difference to the results obtained from ponding method. Results of SEEP/W model showed 11.3 percent of error comparing with ponding method in the first canal. For the second and the third canals this error was about 16.8 and 12.6 percent for MSEEP model, respectively. Using ponding method, the final seepage rates were about 402.8, 434.9, 218.8 mm per day in the three canals, respectively. The final seepage rate obtained by SEEP/W model was 448.3, 513.7, and 269.0 mm per day in three canals, respectively. The final seepage rate estimated by MSEEP model was 530.4, 508.2, and 246.3 mm per day in the three studied canals. The empirical seepage models were calibrated using the data obtained from ponding method in the studied region. The differences between results of un-calibrated Misra model and ponding method were not significant for the first and the third studied canal. The errors of seepage estimation for these canals were 9 and 37.1 percent, respectively. The difference between ponding method and other empirical models were significant. Among the modified empirical models, the results of Davis and Wilson, and Ingham models were closer to ponding method. The coefficient of determination and estimation error of Davis and Wilson model was 0.8486 and 2.23 percent error, while for Ingham model these values were 0.8430 and 2.27 percent, respectively.

This research was conducted on completely randomized block design in a split plot experiment during 3 years in Hamedan consisting of three levels of irrigation (75%, 100%, 125% water requirement) as main plot and cut off dates of irrigation as sub plot, (current date, a week before and a week after the current date of irrigation in the region) at three replications. Garlic bulbs were harvested 20 days after cut off irrigation and the effect of cut off dates and different levels of irrigation on some qualitative factors during 6 months of storage were measured. The relationship between color, weight loss and sprouting with water - use efficiency were determined at the end of storage duration. Results showed that during storage, pyruvate content, color changes, weight loss and sprouting increased and moisture content of cloves decreased significantly. Pyruvate content, weight loss and spoilage increased and color changes decreased due to the delay of cut off irrigation. The amount of water irrigation showed no significant effect on measured factors. With increasing water - use efficiency, weight loss, spoilage and color changes decreased. Consequently, 75% water requirement with the highest water - use efficiency and cut off date a week earlier than the current date was appropriate for this region.

Spur dikes are one of the many kinds of hydraulic structures, and they are employed in stabilizing rivers’ outer walls and redirecting the flow. Considering the importance of understanding flow pattern around the spur dikes, the present work firstly simulated the flow pattern around a T-shaped spur dike located in a 90 degree bend channel. The rigid-bed channel’s curvature radius and radius to width ratio were respectively 2.4 and 4. FLOW-3D was used in order to simulate the flow pattern, and the effect of section constriction on the flow pattern was studied afterwards. VOF was used for distinguishing the water surface profile from the open surface model, and RNG k-ɛturbulence model was employed to model the turbulent flow around the spur dike. The piece of research indicated an acceptable correspondence between numerical and experimental results. The results obtained through various simulations per 10, 20 and 25% constrictions of the section indicated that increase in section constriction would increase the water surface fluctuations, and the maximum height upstream and the minimum height downstream were observed in the case of the large spur dike. In addition, the vortices appear over a longer area of the bend, downstream the spur dike.

Regional development planning requires knowing of climate parameters and adaptation to climate change in future. This is especially more important for Mazandaran province which economy is mainly dependent on agricultural production. In this study, changes in minimum temperature, maximum temperature, precipitation, solar radiation and the number of hot and freezing days of Ghaemshahr city (Mazandaran province) were predicted by the year 2100 and possible effects of these changes on the agriculture of the region was discussed. The climatic variables were predicted by HADCM3 general circulation model under A1B, A2 and B1 scenarios using LARS-WG downscaling model. Evaluation of the model using statistics including model efficiency, coefficient of determination, root mean square error and mean absolute error indicated acceptable performance of the model to simulate future climate conditions in the region. Increases in monthly average of minimum and maximum temperatures in the warmer months will be more than those in the cold months. Increase in the minimum temperature was generally higher than that of the maximum temperature. The average of minimum temperature increase for all scenarios in future periods was 1.65 ° C, while it was 1.13 ° C for maximum temperature. In January, February, March, April, October and November, rainfall generally will increase compared to the base period and in the other months, it will decrease. Also, the amount of solar radiation will decline in all scenarios. On average, potential evapotranspiration will increase by 8.24, 10.47 and 12.68 % during 2011- 2100 compared with the base period under B1, A1B and A2 scenarios, respectively. Based on the results, modification in cropping calendar and pattern and improvement of irrigation and drainage practices are necessary to provide sustainable agriculture in the region under climate change.

Long engineering background of water structures in Iran can also increase the potential and the quantity of their relevant researches, but they have always been facing with lack or not having useful and useable resources for conservation, rehabilitation and fortification of historical and contemporary water structures and always this question “How Can We Conserve and Rehabilitate a Historical Water Structure?” lairs on our consideration in case of coming in contact with, which shows well enough the necessary deliberation from different points of view such as : architecture, rehabilitation, structure, hydraulics, archaeology, geology, hydrology, meteorology, eco-tourism, cultural, social and … about these kind of remains. This research has been done on 170 structures including bridges, weirs, water delivery canals in Iran. The measures of appraisals for decision making on necessary time and cost, social, cultural, cultural heritage, environmental, discussions, existing native technology for construction, rehabilitation and materials, geology, technical and structural discussions have been done during different expert sessions with the authorities and then the importance coefficient of each measure has been calculated by using Double Matrix Method. The weight of each measure has been taken from the expert inquiries. Finally the score of each option from the total points find by multiplying the weight of measure by the importance coefficient. The result of investigations show from the total of 45 investigated structures there are 9 cases where the new structural establishments have higher score where the rehabilitation of historical structures take priority in the other cases. It is necessary to mention, there are several reasons for less score for repairing of those 9 structures. First of all, maybe the changes in climate and decrease of rainfall cause the existence of a structure becomes pale in a certain place, so either to establish a new structure or repairing one shouldn’t be wise. This problem comes back to the wrong site selection of those 45 structures during early studying phases, which have been done by different experts with different viewpoints. The second reason, the lack of economical justification for rehabilitation of those historical structures with extreme destruction which made practically impossible to discuss about renovation and rehabilitation. The point should pay more attention in the following table No.7 is the higher score of rehabilitation of historical structures than establishing new ones. According to the analytical hierarchy process it has been cleared the rehabilitation of Korit & Torogh Dams are in priority from the technical, structural, cultural heritage, social, economical and … points of view. But unfortunately, according to the wrong decision which made in passed a new dam has been constructed near Historical Korit Dam with very high cost and longer time, but the results show the establishment of this new structure has been a great mistake. But the rehabilitation and renovation of Golestan Mashad & Abassabad Behshahr which have been made according to a proper and suitable decision based on a line of complete studies which have been approved. The results show the parameters such as native materials and technics for construction and cultural heritage have least effect on decision making for establishing a new structure.