Iranian Journal of Irrigation and Drainage
Year:2009 | Volume:3 | Issue:2|Papers Count:16

Use of domestic wastewater and effluent from the treatment plants for irrigation purposes, despite the existence of some inorganic and organic compounds in these waters and their effects on the physical and chemical properties of soil, needs special attention. According to the experts recommend for optimal use of these types of waters, local researches are required while considering regional conditions and quality of wastewater and effluents. Therefore, in order to evaluate the soil-plant complex effects as a biological filter on wastewater pollutants and to investigate their transport below the root zone as a result of irrigation, a series of lysimeter studies were carried out in Tehran area. Drainage water samples obtained from depths of 20, 45 and 90 cm below soil surface, in the form of a two-year lysimetric research. A statistical "factorial experiments in the form of randomized complete design" (3 x 3 x 3) was used. Raw and treated domestic wastewater of Ekbatan housing complex and well water (control) was applied for irrigation of raw edible vegetables such as parsley, carrot and tomato in a clay loam soil texture. To extract the drainage water samples from different depths, a series of thin perforated drains (8 mm diameter) were installed in 20 and 45 cm from soil surface. The results showed that maximum EC in drainage water samples were observed in well water, treated and raw wastewater irrigated lysimeters respectively.Increasing the depth of sampling increased the EC quantity. The amount of EC in irrigation waters were between 0.52 to 0.88 dS/m. For drainage water samples, it changed between 1.09 to 3.21 dS/m.

Estimation of riparian forest structural attributes, such as the Leaf Area Index (LAI), is an important step in identifying the amount of water use in riparian forest areas. In this study, small-footprint lidar data were used to estimate biophysical properties of young, mature, and old cottonwood trees in the Upper San Pedro River Basin, Arizona, USA. Four metrics (tree height, height of median energy, ground return ratio, and canopy return ratio) were derived by synthetically constructing a large footprint lidar waveform from small-footprint lidar data which were compared to ground-based high-resolution Intelligent Laser Ranging and Imaging System (ILRIS) scanner images. These four metrics were incorporated into a stepwise regression procedure to predict field-derived LAI for different age classes of cottonwoods. This research applied the Penman-Monteith model to estimate transpiration of the cottonwood clusters using lidar-derived canopy metrics. These transpiration estimates compared very well to ground-based sap flux transpiration estimates indicating lidar-derived LA! can be used to improve riparian cottonwood water use estimates.

The quantity and quality of drain water should be determined to correct management on it. Therefore in this paper, the system dynamics technique was used to simulate the performance of a drainage system in unsteady state condition The system dynamics technique is one of the object oriented approach that studies and manages complex feedback systems. Its merit includes friendly and easily development and improvement of the model.It's also used as a decision tool for engineering problems.The model is capable of predicting many hydrological parameters such as water table fluctuation, drainage discharge, drain water salinity and ground water salinity. All above parameters were investigated theoretically and their trends were found to be legible. The model was validated using observed experimental field data collected from Amirkabir unit in sugarcane development plan located at khozestan, Iran. The results indicated the good agreement between the observed and simulated parameters.

Prediction and calculation of advance and recession curves in furrows require a series of accurate field measurements which is both time consuming and expensive. The basic aim of this research is application of oa flood routing method in simulation of advance rate in furrow irrigation and comparing it with results of SIRMOD models. Muskingum - Cunge model was performed with 27 series of field data and compared with SIRMOD results. Field experiments were performed in Shahid Chamran University field area, in Ahwaz, Iran.The tests were conducted in three furrows with length of 60, 80 and 90 meters, three discharges of 1, 1.25 and 1.5 liters per second and with three replications. For evaluation of the results, four indices: average prediction error of model (Er), distribution into 45o line (l), regression coefficient (R2) and average relative error of model (Ea) were used. According to the results, estimated values of advance phase in all models were more than observed values. Hydrodynamic and Zero Inertia models owned the best results with 11.19 percent average relative error. Average relative error by the Muskingum - Cunge was 13.47 percent. This object showed that the Muskingum - Cunge model is a suitable model for predicting of advance phase in furrow. Kinematic wave model gained the weakest results with 34.46 percent of average relative error. Results indicated that with a smaller furrow length and the higher inlet discharge, predictability of the Muskingum - Cunge model will be better. Finally, the results showed that the Muskingum - Cunge model is simple and found to effectively simulate the hydraulics of the advance phase of furrow irrigation.

One of the most important problems in Hydrometeorology is the estimation of reliable Probable Maximum Precipitation (PMP) for different durations that are expected to occur over a point or an area. A statistical method for estimating PMP values was developed by Hershfield based on frequency equation. Many researches had been done on frequency factor in this method but all of them lead to high estimation of PMP. In this paper the frequency factor of Hershfield method is analyzed based on local data in Ghareh Ghum watershed with 44491 Ian area. Using L-Moment method confums the homogeneity of 57 stations in investigated watershed. Based on this procedure, the frequency factor of Hershfield equation was found to be 7.63. The approximated frequency factor is in accordance with corresponding researches in Atrak watershed and Malaysia. Finally a generalized map was prepared for showing the spatial distribution of 24 h Probable maximum precipitation.

Soil compaction is a major concern of farmers in Pakdasht region. Extreme soil compaction causes increase in soil penetration resistance and bulk density, also it degrades soil physica properties and reduced permeability.Moreover, water and nutrient absorption have been reduced to minimum which result to a decrease in distribution of roots, plant growth and reduction yield. The aim of this research was to study the effects of compaction in the cultivated soils at 12 farms at 10 to 35 cm of wheat cultivation; each of farms was as a treatment. The experiment has been conducted on based of randomized complete blocks design. In this research compaction is measured by digital Penetrologger in 10 different points of each farm. The results have showed that bulk density, soil penetration resistance and permeability have been changed from 1.34 to 1.79 Mg.m.-3, 0.32 to 4.54 MPa and 70 to 12 mm.h.-1 in comparison between non compacted and severely compacted soils, respectively. Extreme soil compaction causes, permeability has been reduced to 81.4%, this causes a 34% decrease in available water which subsequently resluted in 40% yield reduction. Therefore water use efficiency decreased by 39.3%. Reduction of soil compaction could lead to soil quality improvement, in increase water use efficiency, and yield.

Water is the most important agricultural constraints and its optimum use is of great importance. An experiment was performed at the Miyandoab Agricultural Research and Natural Resources Station to study water use efficiency (WUE) of furrow and micro irrigation systems (strips of drip tape irrigation) and single and two row planting systems of grain com SC 704. The experimental design was randomized complete blocks arranged in Strip Split Plots with three replications for three years (2005-2007). Irrigation treatments were placed in vertical plots and planting array of different densities were placed in horizontal plots in the form of split plots.The vertical plots comprised 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 planting array in the form of single-row and two-row planting and the (secondary) sub factor was comprised of three levels; 75, 90 and 105 thousand plants per hectare. In this research the impact of different factors on the water use efficiency, grain yield, dry biomass and 1000-kernelweight were studied. The results of the study during three successive years showed that in case of irrigation treatments the WUE in drip tape.irrigation treatments of 80 and 100% had greatest value, but in furrow irrigation treatments it had the least value.The grain yield in drip tape irrigation at 120% of water requirement had the greatest value and at 80% of water requirement it had the least value. In case of planting array, the values of WUE and grain yield in two-row planting system were greater than those in single row planting system. In case of density, WUE and grain yield of the density 90000 plants per hectare had the greatest values and those of 75000 plants per hectare had the least values. In terms of the interaction between irrigation and density, WUE had the greatest value in the treatment tape drip irrigation at 80% of water requirement and 90000 plants per hectare. In terms of the interaction between irrigation system, planting array and density, WUE in the treatment drip tape irrigation at 80% of water requirement and two-row planting system with 90000 plants per hectare had the greatest value and in the treatment furrow irrigation it had the least value.

The average of annual rainfall and evaporation in Kerman province are about 145 and 3000 mill i meters, respectively. Kerman's surface area of land cultivated with Pistachio is about 300000 ha. Due to extra extraction and continuous drought, ground water surface has been decreased, so we should try to increase water productivity. In this way this experiment was conducted to know about effect of different mulch on soil water holding capacity and prevent of evaporation from soil surface. The experiment was laid out as split plot in randomized complete block design with three replicates. Main plot was five mulch (plastic cover, gravel, straw, tillage after irrigation and control) and subplot was depth of soil moisture content with six levels (0-30, 30-60, 60-90, 90-120, 120-150 and 150-180 cm). Applied water ineach irrigation was the base on farmer allocation and measured with WSC flume. Soil moisture in different depth was measured with Trime before and after irrigation with 15 to 20 days interval. Amount of app l y water in field was earned 5000 m3 / ha-year. Results showed that effect of mulch in holding moisture in soil profile was significant (P<0.01) and depth of moisture measurement was significant (P<0.05).In comparison with other treatments, plastic cover could hold soil moisture for longtime, but gravel cover apply was simple and more practical.

In order to assess water supply and demand, water allocation and crop water productivity, Abshar Right Irrigation Network in Zayandehrud basin, Esfahan province, was divided into eighteen units. The criteria for this division were soil salinity, type of water resources (ground or surface water), and ground water (wells) salinity.The criteria were divided in the GIS environment based on their informational layers. Based on long time lysimeter data of reference crop in Kaboutar Abad Research Station, FAO Penman-Monteith method was calibrated and then was used to estimate crop water use for the existing cropping pattern. Irrigation water supply and demand for each irrigation unit during different months of the year was determined through effective rainfall, crop water use, the amount of water delivered to the each irrigation unit, the rate of ground water withdrawal, cropping pattern and intensity. Crop water productivity was calculated for 1385-86 and 1386-87 periods. In this study, average crop water productivity was detennined to be 1.29 and 1.07 kg m-3, respectively, for 1385-86 and 1386-87 periods. Average crop water productivity based on wheat for the above mentioned periods was determined to be 0.55 and 0.77 kg m-3, respectively. Based on water and agricultural products costs and price of crop selling, average crop benefit and net benefit water productivity for 1385-86 period was determined to be 1060.8 and419.6 Rials m-3, and for 1386-87period, was 2392.9 and 666.7 Rials m-3, respectively. Further analysis of these indexes indicated that water supply and demand in different months of the year and spatial distribution of supply to irrigation units was not appropriate.

The use of new technologies for enhancing water and nutrient use efficiency will become more important over time, especially in arid regions with limiting water availability. Application of superabsorbent polymers is a proper method to enhance water and nutrient use efficiencies, Superabsorbent hydrogels absorb and store water hundreds times of their weight and improve some soil physical properties. In this research, the effect of " superabsorbent polymer on the yield performance, growth indices (length of shoot), water use efficiency and N, K, Fe and Zn uptake of a nursery plant (Cucumis sativus var. Gavrish), was evaluated. The greenhouse trial was conducted using factorial experiment with a completely randomized.design layout in which the treatments were two soil textures (sandy and clay loam), three irrigation regimes consisting 50%, 75% and 100% ETc and the hydrogel treatments were soil containing 0, 4, 6 and 8 g/kg hydrogel. The results show that use of 4 g/kg superabsorbent polymer Superab A200 in a light texture soil and without stress or 25% deficit irrigation is recommended to achieve the best marketable yield and desired water use efficiency.

Optimal irrigation scheduling requires to crop-water production function. Crop-water production function describes relationship between crop yield and applied water. A field study was conducted to compare various genotypes of wheat to water using line source sprinkler irrigation. The effect of variable water supply on yield, analysis of water production function with the seasonal rainfall, comparison of deficit and full irrigation strategies and crop coefficient (Kc) during the growth stage of six wheat genotypes were considered. Four locations where they were provided by the decline in irrigation with distance from the line source, during the growing season to meet 100 % (W1), 76 % (W2), 52 % (W3) and 39 % (W4) crop water requirement. The experiment used a strip plot design to examine the effect of the fixed irrigation rates on six cultivars treatments (CI=TAJAN, C2=N-80-6, C3=N-80-7, C4=N-80-19, C5=N-81-18, C6= Desconcido) with four replications.Within each irrigation treatment of each strip were divided into six cultivars treatments, along the length of the laterals. Result indicated that the grain yield was affected by irrigation treatment and cultivars. The maximum.grain yield was obtained in W1Cztreatment (4742 Kg/ha) and the minimum grain yield was obtained in W4C1 treatment (3546 Kg/ha).Investigation of water production functions have shown that under deficit irrigation, for 250 mm of seasonal rainfall with the same its distribution, there is no need to irrigation all of the cultivars.Contrary, in the full irrigation strategy, with 250 mm of seasonal rainfall, the cultivars of C1to C6need to 115, 122, 87, 94, 92 and 97 mm additional water as supplementary irrigation to maximize production, respectively.The quantitative comparison of deficit and full irrigation strategies were showed that deficit irrigation was more useful strategy for obtaining more production as compared to full irrigation.

Water and energy resources are too limited relative to the highly increasing demand of them. These limitations will be even increased considering the growth of world population. Therefore, more water and energy consumption will be used for higher amount of agricultural productions. Moreover, regarding to the virtual water trade as an approach to compensate water shortage problem, crop production with high amount of water and energy requirements in arid regions may not a rational strategy. Sugar beet, a highly water consumer crop, is one of the most important agricultural crop in Khorasan Razavi province of Iran. According to our estimation in this paper, average consumption of water, fuel, and electrical energy for production of one kilogram of sugar by the surface irrigation method is 5.0 m3, 2.3 lit, and 4.8 KW-hr and in under pressure method is 45m3, 2.6 lit, 5.5 KW-hr, respectively. In this paper, it has been also proved that considering the amount of water consumption for producing of one kilogram of sugar, importing sugar from other exporting countries of sugar in the world, will be more efficient than producing sugar in Iran and it will lead us to save more resources both in Iran (665-750 millions m3) and over the world (372 - 456 millions m3).In addition, it has been shown that if we compare the net cost of required water and energy for producing sugar in Iran with world market prices of sugar, importing sugar will be more economically beneficial. The results shows that considering virtual water concept in national management strategy could end up with a stable development and promising future and also could provide solutions for water shortage in our country in which food, water and energy will be most challenging future problems. It should be considered that, in this paper, only water and energy have been considered and other aspects like job opportunities, industrial problems and other social aspects have not been considered.Therefore, considering virtual water trade with comprehensive researches may playa key role in sustainable developing.