نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
سال هفدهم شماره 4 (پیاپی 66، زمستان 1392)

The estimation of crop water requirement is one the most important stages for designing different irrigation systems، programming and corrected management of water resources. Therefore، to determine the water requirement for Coriandrum sativum L. a study was conducted in College of Agriculture Research Farm at Razi University in the city of Kermanshah during two years، 2010 and 2011. For this purpose، three water balance drainable lysimeters with the diameter of 1. 20m and height of 1. 40 m were used. During the investigation، the irrigation was determined by using data logger equipment of (IDRG). The soil humidity was determined in the field capacity condition. The evapotranspiration was calculated using water balance equation. Finally، the Coriandrum sativum L. water requirement was determined to be 722. 95 and 580. 64mm for years 1388-1389 and 1389-1390، respectively. Meanwhile، the potential evapotranspiration using the Penman Monteith equation was calculated to be 643. 58 and 530. 17mm for the first and second year of investigation، respectively.

Water management in cracked paddy soils is an important issue in rice cultivation. In order to study organic matter and zeolite effect and their interaction on moisture conditions and hydraulic and physical properties of paddy soils، the organic matter (rice straw) at four levels (0، 8، 16 and 24 tons per hectare)، zeolite at four levels (0، 0. 5، 1 and 1. 5 percent)، and also moisture stages of soil at 5 levels were selected. This experiment was conducted in Rice Research Institute of Iran. Randomized Complete Block Design (RCBD) was used to study the effect of treatments on different subjects. The amount of moisture، bulk density and the distance of soil from the wall of container were measured in a 4-month period. The obtained results showed that the interaction effects of organic matter and zeolite on soil moisture content were statistically significant at one percentage level. Addition of plant residues caused an increase in soil moisture weight and reduction in bulk density compared to the control treatment. It was also found that soil moisture content and bulk density were highly correlated. Bulk density of control treatment ranged from 0. 75 to1. 7 gr/cm3، while with addition of 1. 5 % crop residue the bulk density ranged from 0. 7 to 1. 3gr/cm3. Overall results show that crop residues are effective in reduction of crack parameters of soil، but zeolite cannot be effective although it causes more maintenance of soil moisture.

This research was conducted to study the effect of natural and polyacrylamide-modified montmorillonite on the sorption of Cd from aqueous solutions. The sorption of Cd on the sorbents was studied as a function of pH (Cd concentration: 10 mg L-1) in the range of 4-8. 5، and as a function of metal concentration (Cd concentration in the range of 1-10 mgL-1) using a 24h batch equilibration. Experimental and modeling data from equilibrium investigations revealed that the Koble–Corrigan sorption model describes the interaction between Cd and the two sorbents better than the Freundlich and Langmuir models. The values of KF constant of Freundlich and KL constant of Langmuir models were higher for sorption of Cd onto the modified montmorillonite than for those of natural montmorillonite. Maximum sorption capacity calculated from the Langmuir model was 0. 6 and 0. 7 mg g-1 for natural and modified montmorillonite، respectively. These values are indications of high sorption affinity of Cd to montmorillonite in the presence of polyacrylamide. The amount of Cd sorbed by modified montmorillonite decreased by increasing solution pH while Cd sorption by natural montmorillonite increased by increasing the solution pH.

There chemical and organic matter content in garbage leachate that may affect soil physical and hydraulic properties. The main objective of this study was to evaluate the influences of the leachate of Isfahan Organic Fertilizer Factory (IOFF) on some soil physical and hydraulic properties in a soil chemically enriched by Zeolite. The treatments include two soil textures (clay loam and sandy loam) and three levels of zeolite (0، 5 and 10 percent). The treatments were applied on lysimeters scale. The results showed that irrigation with the leachate caused a reduction of infiltration and hydraulic conductivity in the clay loam soil. The hydraulic conductivities in clay loam soil without zeolite (B0) before and after irrigation with leachate were 1. 73 and 0. 36 m/day، respectively. In contrast، there were no changes in the sandy loam soil’s infiltration and hydraulic conductivity. The hydraulic conductivities in the sandy loam soil with 5 percent zeolite (A5) before and after irrigation with leachate were 3. 17 m/day. Furthermore، zeolite had a decreasing effect on those processes. The results show that irrigation with leachate caused reduction of bulk density in two types of soil and all levels of zeolite.

Sesame (Sesamum indicum L.) is one of the most important oilseed crops in the world. Drought stress is one of the environmental factors limiting sesame production. The effects of water deficiency can be reduced by inoculation of plant roots with mycorrhiza fungi. In this experiment، the objective was to determine the effects of different levels of water application (60، 80 and 100% of soil moisture depletion) using surface drip irrigation method and inoculation of plants with mycorrhiza on WUEag of sesame. The experiment was arranged using a factorial design based on randomized complete block design with three replications. The field experiment was conducted at the Agricultural Research Farm of Isfahan University of Technology in 2011. Results showed that the effect of irrigation regime on WUEag of seed yield was not significant. However، the effect of mycorrhiza on WUEag of seed yield was significant. The highest WUEag (0. 74 kg/m3) was related to irrigation regime of 80% and mycorrhiza. The effect of irrigation regime and mycorrhiza on WUEag of oil yield were significant. The highest WUEag (0. 43 kg/m3) was related to irrigation regime of 100% and mycorrhiza inoculation.

As pressurized irrigation is not possible for all circumstances، the use of modern techniques in surface irrigation is essential. In this paper، BISEDOM، a new mathematical model for evaluation، design and optimization of border irrigation is introduced. The effects of weighting coefficients of indicators are investigated based on the potential to improve and the most appropriate weighting scheme in optimization process is presented. In this model، volume balance equations for hydrodynamic simulation and SA method for optimization steps are used. Due to the nature of the SA، its parameters are determined by the method of sensitivity analysis. In this model، evaluation of different combinations of decision variables (inlet flow، length، width and slope of the strip) and consequently the performance of irrigation efficiencies reagent strip in an objective function is possible. Finally، the results indicate that the proposed method for weighted indicators has significant effects on improving performance of border irrigation. Model validation results in three parts of design، evaluation and optimization in comparison with SIRMOD and asymptote method showed that the results are very close to each other. The results also indicate that the proposed model has a good efficiency in comparison with other existing models especially for optimization purposes.

Landslide as a global disaster causes great human and financial damages. Identification of landslide causes and zonation assist in instability control and construction projects siting. This study aimed to identify landslide causes and instability zonation in Ardal county، Chaharmahal va Bakhtiari province، Iran، using Analytical Hierarchy Process (AHP). Current landslides were delineated through field survey and interpretation of Earth Google images and geologic maps. By using Digital Elevation Model (DEM)، slope، aspect، geologic، soil، distance to faults، distance to roads، distance to rivers and landuse/landcover maps and expert knowledge، the pairwise comparison matrix was designed. The weights for all the involved thematic maps were calculated and susceptible zones were mapped. The hazard map indicated more than 77% of current landslides are located in the severe and very severe hazard classes. Comparing landslide hazard map and trigger maps revealed the most influential factors in landslides are distance to roads and slope maps while distance to faults and aspect show the lowest impacts on landslides.

It is necessary that ETr (Alfalfa-reference evapotranspiration) values be converted to ETo (Grass-reference evapotranspiration) or vice versa. The main objective of this study was to develop ETr to ETo ratios (Kr values) for a growing season in Shahrekord plain، Shahrekord، Iran. Mean monthly and total (growing season) values of Kr were calculated based on 185 daily ET data set in Chaharthakhteh Agricultural Resaerch Station of Shahrekord. The ETr and ETo values were calculated using six models for developing Kr values. The models included the Standardized American Society of civil Engineers Penman-Monteith (ASCE-stPM)، American Society of Civil Engineers Penman-Monteith (ASCE-PM)، 1982 Kimberly-Penman (KP)، and modified Jensen-Haise (JH). Kr values as a function of some of the climatic variables in FAO56 Irrigation and Drainage Paper were compared with lysimeter ETr values. For the growing season، Kr values based on lysimeter study was 1. 12، which was comparable to 1. 12، and 1. 16 for ASCE-PM، and JH، respectively، but was far from 1. 27 for 1982 KP models. ETr values in each method compared to ASCE-stPM-ETo were not comparable to 1. 40 derived from Kr value based on FAO56 method.

The reclamation of salt-affected soils which occur on 831×106 ha can be effective in increasing agricultural production. Cultivation of plant species which are resistant to salinity can improve the soil by increasing the solubility of calcite and releasing the calcium in soil solution. This study was conducted as a column experiment with a saline-sodic soil (SAR = 23. 8، EC= 12. 88 dS m-1، pH= 7. 7، CaCO3= 15. 15 %). Three plant treatments including Sesbania acuelata، Cyanodon dactylon and Rubia tinctorum، and three chemical treatments including gypsum in two levels (50% and 100% gypsum requirement) and sulfuric acid with a control were arranged. All treatments were replicated 3 times. The soil columns were similarly leached by 41 liters of tap water during 30 days in 8 stages. After leaching، SAR and EC in soil، the amounts of sodium in leachate and total amount of sodium in plants shoot were determined. Results showed that the SAR was decreased compared to control by the plant treatments and the chemical amendments by about 59% and 65%، respectively. Moreover، two plants of Cyanodon dactylon and Rubia tinctorum had maximum amount of leachate sodium، which shows an impressive role of these plants in dissolution and leaching of exchangeable or sediment sodium in comparison with the other treatments. According to salient performance of phytoremediation in improvement of physicochemical properties of soil compared to chemical amendments، phytoremediation can be recommended as a profitable low-cost and effective method for remediation of saline-sodic soils.

To study the effects of irrigation durations and land slopes on wetting pattern dimensions، some experiments were performed using an emitter with constant discharge of 4 liters per hour by 2، 4، and 6 hours irrigation durations. Experiments were conducted on lands with the slopes of 0، 5، 15 an 25 percent، with silty loam soil texture in 3 replications in Fathali region، Mogan plain، Iran. Results showed that increasing the land slope caused an increment in wetting pattern dimensions and bulk، in constant irrigation durations. When slope increased، the depth of infiltrated water along the emitter had a little decrease which wasn’t significant. The upstream and downstream components of wetting pattern were symmetrical on 0 percent slope but not on steep lands. So، optimizing the water use، which is saved in the soil، depends on the land slope and the crop should be planted 10 to 25 centimeters away from the dripper. The investigation of soil moisture distribution on wetting pattern in slope lands showed that contrary to the flat lands the main part of the moisture is accumulated in lower part of the emitter، and wetting pattern in these sloping lands was larger than in flat lands.

In order to assess hydraulics of LNAPLs in soil، the soil retention curves of petroleum and water were both determined through hanging column method. And، the hydraulic conductivity of petroleum and water were determined by steady head method. The water and petroleum hydraulic conductivities were 7. 27 and 57. 84 cm. day-1، respectively. The soil retention parameters were obtained based on van Genuchten، Brooks-Corey and Campbell models. In addition، the soil hydraulic conductivity for both fluids was predicted based on Mualem- Brooks-Corey، Burdine- Brooks-Corey، Mualem-van Genuchten and Campbell models. The accuracy assessment of models was performed by ME، RMSE، CD، EF and CRM. The results indicated that the magnitudes of the pore-size distribution parameters and the bubbling pressure parameters were reduced in NAPL-air system compared to water-air system. Due to unusual hydraulic behavior of petroleum and soil-petroleum interactions leading to remaining substantial petroleum content in porous media، more matric potential is needed to drain out petroleum from soils compared to water. Thus، soil provides more retention for petroleum at a given quantity of fluid. Owing to high amount of petroleum kinematic viscosity، the saturated soil hydraulic conductivity of petroleum was lower than that of water. However، soil hydraulic conductivity for petroleum was larger than water at more than 100 cm matric head.

In this study، the influence of spatial heterogeneity of rainfall on flood hydrograph prediction in three mountainous catchments in south west of Iran was studied. Two interpolation techniques including Thiessen polygons method and Inverse Distance Weighting method were applied to compare the rainfall patterns of surrounding rain-gages in hydrograph simulation with rainfall patterns of nearest rain-gage from the catchment outlet. It was found that the best simulated hydrograph is obtained from rainfall pattern of the nearest rain gage. Moreover، the results did not show any relationship between spatial variation of rainfall and outlet hydrograph. Formation of different local rainfall patterns due to non-stationary rainfall field provoked by irregular topography and their effect on interpolation procedure caused important biases in interpolated rainfall hyetographs obtained by Thiessen and IDW methods. It seems that the observed biases in the response of the catchments are the result of inaccurate representation of spatially averaged rainfall rather than its spatial variability. Hence، in mountainous catchments with irregular topography، the lack of sufficient records caused by poor rain gage arrangement can be highlighted as the dominant source of uncertainty in modeling the spatial variations of rainfall.

One of the most important issues in trickle irrigation design is investigating the emitter''s characteristics، the effect of factors on flow rate، and finally appropriate emitter selection. Therefore، in this study nine types of pressure compensating emitters with codes of A، B، C، D، E، F، G، M and N، made based on trickle irrigation physical model were tested and the effects of four different water temperatures (13، 23، 33 and 43°C) with different pressure ranges (between zero and 1. 2 times more than the maximum pressure) on the emitters were evaluated. All experiments were carried out based on ISO 9261 standard and IRISI 6775 standard of the Institute of Standards & Industrial Research of Iran. The obtained results at all the tested temperatures، no emitter has x more than 0. 2 and all emitters were pressure compensating types. The effect of temperature on the flow rates of models F، M and N was significant at 95% confidence level. Increase in temperature showed an increase in the flow rates of the above mentioned models.

Check dams are considered as main measures for flood and sediment control in watersheds، and their uses have been rapidly increased from 1990 onward in Iran. This research is done in Darjazin watershed in north of semnan city. The check dams have been constructed from 15 years ago in two sub basins of the watershed for flood control in Mahdishar. More than 650 check dams were evaluated for effects on flood. The collected data in the field was fed to ArcGIS software. The effects of these structures on flood reduction were evaluated by HEC-GeoHMS extension and HEC-HMS model. Because of homogeneity of watershed management projects in the basin due to building more check-dams in different watercourses، any flood discharge is related to check dams. Evaluating the effects of check dams on flood by t-test showed significant differences between flood discharge before and after construction of check dams at 5 percent level. So، check dams have been able to reduce flood discharge by 16. 7 percent on average.

Four partial root zone drying (FULL، 1PRD50، 2PRD50، 3PRD50) treatments were investigated on tomato characteristics and water use efficiency using completely randomized design with five replications. In the control treatment (Full irrigation)، all water requirement of plant was met in the root area equally during the growing season. Roots in 1PRD50، 2PRD50 and 3PRD50 treatments were divided into two equal parts and each side of root was irrigated one، two and three times، respectively. Results showed that the highest (44. 43 g) and lowest (24. 57g) tomato mean weights were obtained at full irrigation and 3PRD50، respectively. Maximum of diameter (43. 1 ml) and fruit number (46 No) was observed in the control and minimum of these traits (15. 6 ml and 20 No، respectively) was observed in 3PRD50 treatment. There was a highly significant difference between fruit number in all treatments. Highest yield and marketable yield was obtained in the control and 1PRD50 treatment، respectively. The highest irrigation water use efficiency was obtained in 1PRD50 (48 percent more than the control) and the lowest value was in 3PRD50 (27 percent lower than the control). Based on results of this study، partial intermittent irrigation (1PRD50) is recommendable for tomato production.

Modernization of irrigation canals as an operation improvement tool is essential to promote the performance of canal networks and indeed requires control systems. Proportional integral derivative (PID) algorithms have more applications than the other controllers in different places of the world، but tuning these controllers for different hydraulic conditions of canals is considered as a major problem for designing control algorithms. Since the bottom slope is one of the effective factors in the water flow dynamic behavior، in this research، the distant downstream Proportional Integral Derivative feedback control with decouplers was designed with a change in longitudinal slope in a reference canal and its performance was investigated. The canal characteristics were used to tune this controller and the system identification as a new method was applied for determining canal characteristics. SOBEK hydrodynamic model modulated with MATLAB software was used to design and run the control algorithms، and slope influence on water flow behavior، tuning controller، and coefficients of controller were investigated with different values of slope. Then، controller performance for hypothetical period of operation in various scenarios was evaluated with computation performance indices. The results showed less resonance behavior of water flow and less potential of controller in steep slope

In this study، a completely randomized experiment was designed with five irrigation treatments and three replicates. The irrigation programs were raw wastewater (T1)، treated wastewater (T2)، a combination of 50% raw wastewater and 50% fresh water (T3)، a combination of 50% treated wastewater and 50% fresh water (T4)، and fresh water (T5). The experiments were run within a greenhouse. The lysimeters were built up in September 2009 and they were filled with a two layer soil. The upper (30 cm) and lower (40 cm) layers were sandy loam and sandy clay loam، respectively. The results showed that the effects of watering treatments on transfer coefficients of heavy metals from soil to shoots (except Cd) and tubers of potato (except Zn and Cu) were significant (p <0. 01). Maximum and minimum transfer coefficients of heavy metals were observed in the (T1) and (T5) treatments، respectively. Also، the transfer coefficients of Cd from soil to shoots were lower than tubers. In the case of Zn، Cu and Pb، transfer coefficients from soil to tubers were lower than shoots. In this study، the maximum transfer coefficients to shoots were Cd (0. 331-0. 463)، Zn (0. 383-0. 230)، Cu (0. 173-0. 386) and Pb (0. 003-0. 057)، respectively. Maximum transfer coefficients toward tubers (except T5) were Cd (0. 439-0. 572)، Cu (0. 081-0. 138)، Zn (0. 170-0. 217) and Pb (0-0. 017)، respectively. The combination of wastewater and fresh water use in short-term irrigation might be feasible، but a heavy metal monitoring program is necessary.

Copper is considered as one of the most important nutrient elements for plants. If its contents are concentrated higher than the standard value it can be considered as a pollutant element. The content of absorbable copper in the area around Sarcheshmeh copper mine can be significantly high. In this study، samples of soil were collected in summer through a particular sampling method with chimneys of Sarcheshmeh plant as the center of sampling area within a radius of 6km، in three different directions (Rafsanjan، Sarcheshmeh City and Sarcheshmeh mine) and. The total concentration of absorbable copper and some chemical properties of soil (i. e. pH and EC) were measured for 122 surface samples (depth of 0 to 35 cm). There was a significant negative regression between pH and total absorbable copper content، and a significant negative regression was observed between EC and total absorbable copper content. The best fitted model was spherical model، and Ordinary Kriging was applied to map the absorbable copper content. Results showed that most concentration of copper occurred in the Rafsanjan direction. Also، regarding wind orientation which blows towards Rafsanjan، the chimneys probably have a significant effect on increasing copper content in Rafsanjan; moreover، the copper content is substantially higher around chimneys than other areas. Also، transition of copper elements from chimneys by wind can be significant up to 4 km from Sarcheshmeh plant.

Drip irrigation is a new method of irrigation that is rapidly growing in different countries. The emitters are the most important parts of a drip irrigation system. Many factors such as physical، chemical and biological clogging، pressure، water temperature affect the emitter´s uniformity of water emission. In this study، to investigate pressure effect on the hydraulic performance of emitters، 7 kinds of compensating emitters in the market were selected and studied in laboratory conditions. For this purpose، a drip irrigation system was designed in irrigation laboratory in faculty of water sciences engineering، Shahid Charm University، Ahwaz. Average flow of emitters، Manufacturer´s coefficient of variation of emitter (CV)، emission uniformity (EU)، Christiansen coefficient of uniformity (CU) and Flow Variations for all types of emitters at pressures of 5، 10، 15 and 20 meters were calculated and compared. Also، in order to compare the pressure compensating capacity، for every emitter the equation of Flow- pressure was extracted. Results showed that the D-type emitter has the best hydraulic performance from among the emitters tested. Therefore، to achieve higher efficiency and also to use it on slopes and uneven lands this emitter is recommended as the best. However، performances of other emitters are also acceptable.