Iranian Journal of Soil and Water Research
Year:2019 | Volume:50 | Issue:5 |Papers Count:20

In this research, the applicability of the screen sheet, as an energy dissipater at downstream of hydraulic structures, has been studied to reduce the amount of scouring. For operation of the experiments, a rectangular flume with 0. 3m in width, 0. 45m in height and 5m in length, including a sluice gate for the flow control was used. For reducing energy of outflow from sluice gate, the screen sheets as energy dissipaters with 40% and 50% porosity were placed at distance of 1. 5m from the gate. After the screen sheet, the movable beds consist of three different grain sizes of 1. 8, 2. 6 and 5. 2 mm, with the dimensions of 1. 3m in length, 0. 3m in width and 11. 4cm in depth were used to investigate the effect of screen on maximum dimensions of the scouring hole. The results of this study showed that the thickness and porosity of the screen and its distance from the gate are effective parameters on the lenghth and depth of scouring hole. The maximum and minimum depth and length of scouring hole were occurred in the screens with 40% porosity and double 50% porosity, respectively. So that, by increasing the screen’ s porosity and thickness, the scouring whole dimension decreases. Also, by increasing the particle dimensions, the scouring hole dimension decreases.

To evaluate water, soil and plant relationships, soil water availability for plants is very important for irrigation management and scheduling. Integral energy shows the readily available water for plant in the range of soil available water. The purpose of this study was to investigate the concept of integral energy in 40 samples of paddy soils in Guilan province and to study the relationship between this index and various soil properties. The results showed that all soil samples had moderate to heavy texture. The mean Dexter S index in two soil textures including clay and clay loam was less than 0. 35 (27% of the soil samples). The mean values of integral energy in the all studied soil samples, assuming the upper limit of soil water available at saturation, field capacity (at soil suctions of 100 and 330 cm) were 226. 65, 270. 21 and 336. 91 J kg-1, respectively. The results showed that the soil texture classes with the highest value of integral energy were associated with the lowest values of S index. Moreover, the results confirm the better correlation between the calculated integral energy, assuming the upper limit at field capacity in soil suction of 330 cm, with the other soil properties. In addition, the integral energy values can be accurately estimated using soil saturation moisture and organic carbon to clay content ratio for silty clay loam (R2= 0. 70) and clay loam (R2=0. 95) textured soils, respectively.

Changing land use is one of the most important human interactions in natural ecosystems that affect ecosystem processes, especially soils. In the present study, the effects of forest (natural forest and oak plantation) and nonforest (garden, rangeland and agriculture) land sues on the variability of soil quality indices and carbon dioxide emission dynamics have been considered. In each of the proposed land uses, 16 soil samples (0-10 cm depth) were collected and transferred to the laboratory. According to the results, the highest amounts of soil organic matter were allocated to forest habitats and the highest bulk density was belonged to rangeland and agricultural areas. However, the variation of soil particle density among the various land uses was not significant, but the highest soil porosity was found under oak plantation. The natural forest has the most stable aggregates, and following deforestation and the land use change, their stability was significantly reduced. The highest amount of sand was belonged to rangelands and the highest amount of clay was allocated to natural forest, while the content of silt did not show significant differences among different land uses. The highest amount of coarse root biomass was observed in the natural forest and oak plantation, while the fine root biomass in the natural forest was the highest amount. Greater amounts of soil moisture content were found in the forest habitats (especially in winter and autumn), while the highest soil temperature was assigned to agriculture and rangeland areas (especially in summer). The emission of carbon dioxide from the soil was highest during the summer, under the oak plantation. According to the PCA output, the amount of soil organic matter, moisture content and porosity in the oak plantation have had an important role in increasing carbon dioxide emission from the soil of this type of land use compared to other sites. The results of this study confirm the protection of natural forests in order to increase the soil quality characteristics and health.

Investigation of physicochemical variations of physalis crop, as a species with various medicinal and nutritional properties, was performed under combined treatments of magnetism intensity (M) in four levels of zero, 0. 2, 0. 3 and 0. 4 T and concentration of nano zinc fertilizer (N) in three levels 1, 1. 5 and 2 g/l. The results showed that the effect of combined treatments on all biochemical properties (except carotenoid factor), as well as all morphological traits (with exception of fruit diameter) was significant at 1% and 5% levels. By analyzing the phytochemical factors, chlorophyll b factor was significantly improved by 5. 3 times as compared to the control treatment, under treatments of 0. 4 Tesla and 1. 5 g/l. Also, among the morphological factors, a* factor showed the highest increment (2. 7 times as compared to the control) under 1. 5 g/l zinc fertilizer without magnetism intensity. In general, the balanced use of these treatments could be applied in economical production of this crop.

Climate warming causes prevention of the latest spring frosts and reduces the spring freeze risk during flowering. The purpose of this study was to explore the effect of climate change on the chilling requirement and the flowering date of completion of the phonological stages of different plants in Sari. A 45-year weather data (1970-1970) of Kiasar Synoptic Station were used with data access from National Centers for Environmental Prediction. The predetermined output of the large-scale climatic model (CanESM2) was used after the downscaling observation for RCP2. 6 scenarios. Using the ChillR and Climdex model, the flowering date of DOY (day of year) and the Growing Season Length (GSL) were estimated. Mann-Whitney nonparametric test and Kendall's trend were used to compare the first half of the near future (2016-2055) and the second half of the distant future (2056-2100) with the present. The results showed although the growing season length increases, but a significant difference between the air temperature in the chilling and forcing phases is caused a significant change in the appearance of phenology stages of the deciduous fruit trees in the studied area. Over the past decades (1980-2000), about two weeks was added to the length of the growing season. However, the flowering date will take place three decades earlier than the past climate. These significant changes in cultivated climate parameters lead to irreparable phonological disorders in the coming periods.

Little is known about the effects of biochar on earthworms and their interactions on soil biological properties. The purpose of this study was to investigate the effects of earthworm and cow manure biochar (compared to cow manure) on some biological properties of soil. For this purpose, the soil was treated with cow manure or its biochar in 4 levels (0, 1, 2 and 5%) in the absence and presence of earthworm and incubated for 30 and 90 days. The results showed that the number of earthworm decreased in soil treated with cow manure biochar in 30 days of incubation. After 90 days of incubation, application of 1, 2 and 5% cow manure increased the number of earthworm by 26, 91 and 104%, respectively. Application of 1% biochar resulted no significant effect on the number of earthworm, but the 2 and 5% biochar decreased the number of earthworms by 43 and 48%, respectively. The results showed that the earthworm led to considerable increase on the basal respiration, substrate induced respiration and microbial biomass carbon in soils treated with cow manure compared to cow manure biochar. Also, application of both amendment improved the soil biological properties compared to the control. On the other hand, earthworm increased and decreased the metabolic quotient in 30 and 90 days incubation, respectively. The addition of cow manure and its biochar reduced the metabolic quotient in 90 days of incubation. In addition, the soil treated with 5% cow manure and earthworm (in 90 days) had the lowest metabolic quotient. Overall, cow manure improved soil biological quality better than cow manure biochar. However, application of 1% cow manure biochar in the soil which has no negative effect on earthworm, can be also beneficial to improve soil biological quality.

Extraction of humic acid (HA) from lignite coals that are rich in humic compounds has been highlighted in recent years as a superior and prominent research issue. The conventional technique used to extract HA is based on their solubility in alkaline and acidic mediums. Most litertures have reported the extraction time and separation of HA to be 24 hours and the extraction efficiency between 10 to 80%. In this research, the intensification of HA extraction from lignite coals has been studied. For this purpose, a batch stirred tank reactor (BSTR) was first designed and then fabricated. The processing parameters such as temperature at three levels (50, 70 and 90° C), process time at three levels (1, 2 and 4 hours) and stirring speed at three levels (250, 550 and 850 rpm) were considered as independent variables and extraction yield of HA was considered as dependent variable and the performance of the constructed reactor was compared with a conventional method (Hot Plate device). The statistical results of variance analysis (ANOVA) showed a significant difference between the yield of HA extraction with the reactor and Hot Plate method. Under the same conditions of temperature, stirred speed and process time, the yield of HA extraction with the reactor was 30% higher than the Hot Plate device. The optimal conditions for extraction of HA by the reactor were obtained at temperature of 90° C, stirring speed of 850 rpm and 4 hour process time. In these conditions, 56. 8% of HA was extracted and separated from lignite coals. The qualitative results of FT-IR spectroscopy showed a predominant aromatic and rich in carboxylic, phenolic and hydroxylic functional groups with aliphatic side chains in the HA structure. The results of quantitative analysis of the CHNOS main elements and atomic ratios (C/N, O/C and H/C), confirms the quality of the used coal and also matches up the quality indices of produced HA with the IHSS standard and commercial Aldrich HA samples.

Infiltration plays a pivotal role in the hydrologic cycle by effectively acting to partition water into surface and subsurface components. Direct measurement of infiltration rate is expensive and work and time consuming. Artificial Neural Networks (ANNs), Gene Expression Programing (GEP) and hybrid of ANN and Genetic Algorithm (ANN-GA) can be used for estimation of soil infiltration rate as an indirect methods. The main objective of this research was to develope an infiltration rate model in Khoda afarin region based on the collected data (88 double ring infiltration) and some soil properties. The Pierson correlation revealed among the soil properties, sand and silt contents, porosity and organic matter have the most correlation with the infiltration rate. Determination Coefficient (R2) and Normalized Root Mean Square Error (NRMSE) were calculated to be 0. 88 and 7. 9%, respectively for the ANN method and 0. 75 and 11. 3% for the GEP method. Both ANN and GEP methods perform poorly, in extrapolating the minimum and maximum amount of infiltration rate. The hybrid model of ANN-GA was the best model in terms of statistical indices including R2 (0. 93) and RMSE (6. 1%). This model comprised of 4 neurons (sand, silt, porosity percentage and OM) in input layer and 5 neurons using sigmoidal tangent functions in the hidden layer and linear activation functions in the output layer. The results indicated that the neural-genetics algorithm can be used to optimize weight parameter of artificial neural network. Overall the hybrid ANN-GA model showed better performance than the other models, so that the R2 and NRMSE for the hybrid model were 0. 93 and 6. 1% respectively. Therefore it is suggested as a powerful tool for estimating infiltration rate.

Reallocation of Water Resources in Transboundary River Basins Using the BankruptDecreasing the accessible water that is because of the natural effects such as warming the earth, population daily increase and increasing of the water requirement have caused that water allocation become one of the most important problems. This issue especially in Transboundary Rivers which pass from several countries also produces the political problems. Therefore, cross-border water resources management is imperative. One of the strategies for water resources management is optimization of resources allocation. In boundary watershed that has several beneficiaries, it is necessary to interest to the satisfaction of all the stakeholders to prevent the occurrence of conflicts between them. To achieve these goals can be use from methods of dispute resolution and optimization of water resources allocation. In this study, the Aras Border River is investigated. To solve the water problems in the basin use from subset of bankruptcy dispute resolution procedure simultaneously the particle group algorithm (PSO). The results show the superiority of Constrained Equal Loss method that results the more average of allocation for total needs. Considering that the Aras watershed is border In the process of allocation of water in the basin should be fitted to the consent of all the stakeholders to prevent of conflict between them. To solve the water issues in the basin use of the bankruptcy dispute resolution method with the optimum particle group algorithm in the allocation of resources. The results show the superiority of Constrained Equal Loss method that result more average allocation for total needs of basin. But in this way the applicant with the least need that is Turkey in this basin, be fitted in last priority. Given that this country is located in the upstream basin, apply this method in this area need to realization of alternative facilities for Turkey and satisfying the stakeholders in this country. cy Approach

Soil maps are basic in any investigation and environmental programing activities. Immense methods try to differentiate more homogenous soil units. The geopedologic soil mapping method assumes that with a categorical disintegration of geoforms, it is enabling to gain harmonized related taxonomic level. The quantitative relationship between geopedologic and taxonomic categorization is not considered in literature, though, this paper uses statistical and conditional probability methods to quantitatively analysis the conformity between the geopedologic approach and Soil Taxonomy levels. Therefore, the geoforms of study area were differentiated and 191 soil samples were excavated and genetically described. The conditional probability of each soil categorical taxa was measured in each geopedologic category. The quantitative results showed that the soils in the studied area were affected less by parent material, or the other soil forming factors had a greater effect than the role of parent materials. Also concordant with pedodiversity analysis, the observability of taxonomic categories versus geopedologic categories is properly related and in each geopedologic category the diversity of taxonomic categories from order to family level increases or homogeneity decreases. But categorical harmonization between them is not fulfilled. In this case, the geopedologic category is not able to differentiate the related taxonomic category properly. Therefore, it is proposed that the family level is differentiated in a lower geopedologic level like phase of geomorphic surfaces. In this level the characteristics like aspect, slope curvature and type of green cover can be considered.

Side weir is one of the diversion structures, which widely used in irrigation and drainage networks, flood protection, urban sewage systems and water level control. The flow over the side weirs is a typical case of the spatially varied flow with decreasing flow discharge. In this study, the flow characteristics over the circularcrested trapezoidal side weir located in rectangular channels is experimentally investigated under subcritical flow conditions. In this research, the conventional weir theory with three different reference depths (y1, yavg and ycenter) for computing the weir head was used to evaluate the proposed discharge coefficient and discharge equations. Based on the experimental results, the discharge coefficient is a function of upstream Froude number, the ratio of upstream flow depth to the crest diameter, and side slope of the weir. The comparison between the experimental data and computed results indicated that the conventional weir theory with the average flow depth as the reference depth with an average error of 3. 6% is the best relationship for assessing the discharge coefficient. Thus, this method is suggested for practical purposes.

The Present study introduces the slit and solid semicircular flap plates for flow measurement in horizontal open circular canals under free flow conditions. This structure consists of a semicircular plate which is installed and hinged from its diameter along a circular canal. The deviation generated by the water flow on the plate is a function of hydraulic characteristics of flow, the geometry of the structure and flow discharge. This simple measuring structure is portable and can easily be installed in circular canals and be used with acceptable precision. In this study, based on the theoretical and experimental studies of the passing flow through the semicircular flap plate, some equations were developed for estimating the flow in circular canals via the dimensionless discharge-critical depth relation. In order to calibrate the proposed equations, the laboratory data were collected and used. In addition, to estimate the passing flow through the flap plate, an explicit relationship was developed to compute the dimensionless critical depth and discharge. The dimensionless critical depthdischarge method used in this study is able to estimate the flow discharge through the semicircular plates with an average error of 3%. Due to the low average errors of the proposed discharge equations for the semicircular flap plate (an average error of 3. 6% without considering the Reynolds number and an average error of 3% by considering the Reynolds number), this structure is suggested as a discharge measuring structure in circular open canals.

In order to investigate the effects of salicylic acid and superabsorbent polymer on yield and yield components in mung bean under different water regimes, a factorial experiment was conducted in complete randomized design with three replications in greenhouse of Razi University. Treatments included drought stress at three levels (30, 60 and 100% of FC), superabsorbent at three levels (0, 0. 3 and 0. 5% by weight) and salicylic acid at four levels (0, 250, 500 and 750 μ M). The results showed that the highest grain yield (20. 7 g per plant), biological yield (51. 4 g/plant) and number of seeds per plant (79. 1) were observed in 100% FC and application of 0. 3% superabsorbent and 750 μ M salicylic acid and the lowest values (0. 13 and 7. 5 g per plant and 16. 2 seeds per plant, respectively) were obtained in 30% FC and no superabsorbent and salicylic acid treatments. In general, the concentration of 500 μ M salicylic acid and 0. 3% by weight of superabsorbent could neutralize the effects of severe drought stress.

In the twentieth century, soil quality and health declining has become a major challenge due to application of poor and polluted water sources. Accordingly, the effect of different concentrations of cobalt chloride and cadmium chloride in irrigation water (0 (control), 100, 200 and 400 mM) on some soil microbial indices during vegetative growth of the medicinal Savory plant (Satureja hortensis L. ), in two separate experiments was carried out in a completely randomized design with three replications in the research greenhouse of Agricultural Faculty in Ilam. The experiments were done in 5 kg-pots with 26 cm in height and 30 cm in diameter and longed for two months in 2014. The results showed the highest values of basal respiration rate and substrate induced respiration in the control and the lowest values of these two indices in 400 mM concentrations of cadmium chloride and cobalt chloride. In terms of soil microbial biomass carbon, the highest value (308 mg. kg-1 soil) and the lowest value (190 mg. kg-1 soil) were found in the control and 400 mM concentration of cadmium chloride salt solution, respectively. The highest (27 mg. kg-1 soil) and the lowest (14 mg. kg-1 soil) values of soil microbial biomass nitrogen were found in control and 400 mM concentration of cadmium chloride, respectively. As well as, the lowest (19 mg. kg-1 soil) amount of soil microbial biomass nitrogen was obtained in 400 mM concentration of cobalt chloride salt solution. The highest amount of microbial quotient, metabolic coefficient and microbial biomass were observed in the control treatment. The microbial biomass carbon and microbial biomass nitrogen ratio increased by irrigation water with different concentrations of cobalt chloride. Increasing the concentrations of cadmium chloride and cobalt chloride showed a negative effect on the microbial quality of the soil, which will pay more attention to the quality of irrigation water for health and quality of the soil microbial community, and hence the quality and overall health of the plant, and ultimately represent health and food safety.

One of the improvement approaches for irrigation efficiency in arid and semi-arid regions is to use soil amendments. The purpose of this study was to investigate the effects of different levels (0, 0. 5, 1, 1. 5 and 2 g/kg of soil) of superabsorbent polymers A, perlite and zeolite on the physical properties of sandy loam soil in factorial randomized complete block design with four replications. Soil moistures were determined at seven suction points from 10 to 1500 kPa. The results of this study showed that the 2g super adsorbent polymer per kg of soil increased soil porosity, mean weight diameter of aggregates and available water for plant up to 2. 6, 2. 71 and 1. 40 times, and reduced the bulk density of the soil up to 0. 82 times, as compared to the control. Also, the results showed that in all suction points, the soil moisture content increased significantly as compared to the control.

The deficiency of macro-nutrients such as phosphorus and potassium is very important due to vital roles of these elements. Although the total amount of phosphorus and potassium in the soil is high, the formation of insoluble forms of phosphorus, as well as the stabilization of potassium in silicates, has led to the shortage of these essential elements. The use of microorganisms, having the ability to dissolve insoluble phosphate forms and potassium fixed in silicates, can be effective in reducing the deficiency of these elements for the plant. In this research, 7 species of Trichoderma fungis were selected and their effects on the release of phosphorus and potassium were evaluated in Pikovskaya’ s, Alexandrov’ s and modified Pikovskaya’ s media. The results showed that in Pikovskaya’ s broth medium, phosphorus release rate by different species of fungi was consistent with decreasing pH. Trichoderma koningii, T. harzianum, T. citrinoviride and T. viridescens had the most phosphate solubilizing ability and increased soluble phosphorus by 244, 205, 191 and 190%, respectively. In both Aleksandrov’ s and modified pikovskaya’ s media, which contain both insoluble inorganic phosphate and potassium as biotite, it was observed that the dissolution rate of tri-calcium phosphate was lower than that of pikovskaya’ s medium which has available potassium. T. koningii in Aleksandrov’ s medium and T. harzianum in modified Pikovskaya’ s medium had the highest ability to release potassium from biotite. These species increased potassium in solution by 123 and 20% compared to control, respectively. In general, the results showed that Trichoderma fungi has the ability to solubilize phosphate from tri-calcium phosphate and release potassium from biotite under in-vitro conditions.

High temperature and evaporation and low quality irrigation water are the most limiting factors for irrigation of sugarcane in Khuzestan. Subsurface drip irrigation can be successful with proper management. Therefore, this study was conducted to examine the effect of subsurface drip irrigation on Water Productivity and sugarcane yield. Two factors consist of installation depth (15, 20, 30 cm) and emitters spaces (50, 60, 75 cm) were applied in a factorial experiment with randomized complete block design. The results of variance analysis of quantity characteristic indicated that there were significant differences between treatments in terms of installation depths, emitter space and their interactions at 1% probability level. Also the results of quality characteristics showed a significant differences among the emitter's spaces at 1% probability level. Investigation of water productivity index showed that there were significant differences among the emitters space for sugarcane and sugar production at 1% probability level. But there was no significant differences among emitter depths and depth-space interactions. The maximum quantity yield occurred in drip laterals with 50 cm emitter space and 20 cm installation depth. The highest quality yield was seen in laterals with 50 and 60 cm emitter spaces and 15 and 20 cm installation depths. The highest water productivity for sugarcane and sugar production was obtained 7. 18 and 0. 87 kg /m3 in laterals with emitter space of 60 cm and installation depth of 20 cm. Also the least water productivity for sugarcane and sugar production was 5. 17 and 0. 61 kg/m3 in laterals with emitter space of 75 cm and installation depth of 20 cm. Finally, according to the obtained results and considering other conditions, laterals with 50 cm emitter space and 20 cm installation depth are suggested for irrigation of sugarcane fields.

Irrigation management is one of the important factors influencing the development and distribution of plant roots, which is considered by many researchers. The purpose of this study was to study the growth and distribution of corn root in various irrigation management systems. This research was carried out as a split plot in a randomized complete block design at Kabootarabad Research Station in Isfahan. The main factor was consisted of three levels of irrigation regime I1 (100%), I2 (80%), I3 (60%) and the sub-factor was included three irrigation methods, conventional, alternative and fixed furrow irrigation. The measured parameters of root were length, surface, volume, fresh and dry weight, which were carried out in 5 stages of plant growth including 9-leaf, 14-leaf, inflorescence emergence, milking and physiological examination. The results showed that the effect of irrigation regimes and the type of irrigation method on root traits was statistically significant at 5% level. The highest amount of root traits was corresponded to I1 regime and conventional furrow irrigation, and the lowest one was corresponded to I3 regime and fixed furrow irrigation. The highest amount of root traits was obtained in the soil layer of 0-20 cm for all regimes and irrigation methods. From the 9-leaf to the milky stage, the root traits had a bullish trend, then after constant and at the end of growing season declined. Generally, a suitable root system for absorption of water and nutrients required by the plant can be achieved by application of a deficit irrigation rate up to 20% in conventional furrow irrigation or alternative furrow irrigation, which leads to save water consumption.

In the context of integrated water resources management, assessment of water allocation scenarios is very important and complex. There are different and sometimes conflicting indicators in water resources management that have different values in different areas. Regarding this, evaluation of allocation scenarios involves performing the spatial multi-criteria analysis. The aim of this study was to evaluate water resources allocation scenarios using a spatial decision support system. Therefore, the compromise programming method with the economic, social and environmental indicators has been implemented in the Aras basin. In the first step, the indicators were considered as lumped and distributed form with equal weight. In the second step, the sensitivity of the compromise programming method was analyzed changing one of the indicators weight, while maintaining the other indicators constant. In step three, group and fuzzy decision making approach was used to determine the weight of the indicators. Then, scenarios 1 to 5 ranked fifth, third, second, first and fourth respectively. The results of this study showed implementing spatial distribution of indicators influence both scores and rankings of the water resources allocation scenarios. So that the Spearman correlation coefficient of the rankings, caused by application of lumped and distributed indicators, was calculated to be 0. 6. Also, application of the compromise programming method, group-fuzzy weight and distributed indicators leads to a change in ranking and reduce correlation coefficient up to 0. 2. Regarding the effect of two parameters, including the type of indicators and the group-fuzzy weight of indicators, on the scenarios ranking results, a significant uncertainty in the process of assessing scenarios could be occurred if the proposed parameters would not be considered. Therefore, it is essential to consider the spatial distribution of the values and the group-fuzzy decision-making should be used to determine the weight of evaluation indices.

As agriculture consumes the most parts of water resources, management and control in this sector plays a significant role in water resources management. In this study, simulation-optimization approach was applied using soil and water assessment tool (SWAT) in combination with non-dominated sorting differential evolution (NSDE) algorithm to find the best operation curve for wheat irrigation in Mahabad basin. The wheat production in 2011 to 2013 was considered for SWAT calibration and validation. According to the hedging rule, a twoobjective function was used to increase the crop yield and reduce the irrigation volume. The optimum results showed by reducing the annual irrigation rate from 200 mm to about 100 mm, the wheat production will be 2. 114 ton/ha which is equal to the current irrigation pattern yield. This approach could maximize the economic cost by introducing the best irrigation pattern and consequently reduce the groundwater recharge and surface run-off 34% and 13%, respectively.