JWSS - Journal of Water and Soil Science

The goal of this study was to evaluate tannic acid as a coagulant in turbidity removal. Tests were designed using Taguchi method and carried out on the synthetic and natural turbid samples. In order to optimize turbidity removal by tannic acid, seven factors including pH, coagulant dosage, rapid mixing rate, slow mixing rate, slow mixing time, sedimentation time and initial turbidity were investigated. The results revealed that in optimum conditions,  tannic acid could n remove up to 71 percent of synthetic turbidity and 66 percent of natural turbidity; also, tannic acid showed more coagulation activity in the lower initial turbidities. ANOVA analysis showed that initial turbidity and slow mixing time were the most important parameters in the turbidity removal by tannic acid. In general, this study showed that tannic acid was capable of removing turbidity and could be used instead of common coagulants in the preliminary treatment.

This study covers a large agricultural and industrial area of Isfahan province, including three types of land use, i.e., agricultural, uncultivated, industrial and urban types. A total of 275 samples from surface soil (0-20 cm) were collected and water soluble fluoride concentrations of them were measured. The spatial structure of water soluble fluoride in the soils was determined by omnidirectional variogram in the GS⁺ software. The spatial distribution of water soluble fluoride in the soil was mapped by employing the point kriging method in the SURFER software. The results showed that the mean of the water soluble fluoride concentration in Isfahan soils (0.85 mg L^-1) was higher than the mean world soils (0.53 mg L^-1). The water soluble fluoride showed moderate spatial dependence, indicating that the spatial variability of water soluble fluoride was mainly controlled by intrinsic and extrinsic factors. The mean water soluble fluoride concentration was significantly higher in agricultural and urban areas, as compared with the uncultivated land. This could be due to application of phosphate fertilizer in agricultural areas and the atmospheric fallout of fluoride from the industrial sources such as steel factories. According to the generated kriging map, the higher concentration of fluoride was mainly recorded around the Zayande Rood River and in the central and western parts of the study area.

The soil quality is defined as the ability of soil to function as an essential part of the human habitat. In this study, the effects of land use change (conversion of forest lands into agricultural lands) on the soil physical quality were studied in the Gilan-e-Gharb region. For this study, soil samples were collected from surface and subsurface layers of both land uses, and the peak and shoulder slope positions, in Miandar and Vidjanan catchments. Soil physical properties such as soil texture and particle size distribution, soil hydraulic conductivity, bulk density, mean weight diameter of aggregates, water holding capacity, and the soil organic carbon content were measured. The results showed that land use change of the forest to agricultural lands resulted in a sharp decline in the soil organic matter (52%) and an increase in silt and sand percentage and soil bulk density. Also, deforestation decreased the mean weight diameter of aggregates (from 0.39 to 0.14 mm in Miandar) and clay percent.  It caused a reduction in the total porosity followed by a decrease of soil water holding capacity, and a decrease in the saturated hydraulic conductivity (from 10.34 to 1.86 cm/h), as well. In general, the results proved that the land use change from forest to agriculture severely decreased soil physical quality and its productivity.

Determination of the required water for crop and irrigation programing is of major importance in the sustainable use of water resources. The national water document is the output of the ‘net irrigation required for crops’, which is presented for the optimum allocation of water resources for the demands. The Penman-Monteith-FAO method is used in the calculation. Updating the national water document is necessary to overcome its some limitations, and to provide more adaptation to the plains conditions of the country. The objective of this study was the recognition of the existing problems of the water national document and appropriate method development for implementing in the country plains. In this regard, the required water of different crop patterns was calculated using the Penman-Monteith-FAO method in the Ghazvin plain (as a dry plain), Ghazvin province, and Fomanat plain (as a wet plain), in Fomanat province, in the period of 1976-2005. The results were compared to the water national document. It was shown that annual potential evatranspiration varied between 1330 and 1587.1 mm in the Ghazvin plain, and between 743 and 809 mm in the Fomanat plain. The calculated evapotranspiration in the present study was about 40.6% more than water national document in the Takestan station, in Ghazvin plain, as a sample station.
 

In the recent decades, due to the development of the pressurized irrigation systems, the relationship between the water and energy has been extended more than ever. So, according to problems due to the water shortage, energy saving is considered as one of the most important challenges in the agriculture section. In this study, by considering the capabilities of the pumping systems, variable speed pumps have been examined in an agro-industrial region of Ashrafiyeh (Qazvin province, Iran) with an area of 85 ha. The energy consumption during the ten-year operation was analyzed in the five operation scenarios by the MATLAB/SIMULINK software. The results showed that the consumed electrical energy by using variable speed pumps was approximately decreased up to about 18 percent, as compared to the fixed speed pumps. The results of the evaluation of the consumed energy showed that the current operation circumstance increased energy losses up to about 60 percent, as compared to the other operation methods. The results also revealed that the overall energy efficiency for the current operation circumstance was 52 percent (78 percent of Nebraska Performance Criteria).

Emitter clogging for using agricultural wastewater increases the operating costs and reduces the motivation of farmers. The new method to reduce the emitters clogging is the use of a Merus ring that does not have the problems of chlorination and pickling methods, such as pollution and high cost. Due to the importance of agricultural wastewater use, this study investigated the emitters clogging and the effect of Merus ring on the emitter's efficiency in a trickle irrigation system. The treatments including irrigation water (well water and wastewater) and modified water (irrigation with Merus ring and irrigation without Merus ring), as the main factor and the emitters type treatment including Irritec (D₁), Corona (D₂), Axios (D₃), Netafim (D₄), Polirood (D₅), and Paya (D₆) as the sub treatments were performed in three replications. The results showed that the agricultural wastewater caused the emitters clogging in irrigation water and modified water treatments, but over time, the Merus ring had a positive effect on the evaluation parameters of the emitters. For agricultural wastewater, in the first and last irrigation periods, the average discharge of emitters with the Merus ring was 0.05 and 0.33 Liter per hours, respectively, more than the treatment without the Merus ring. The uniformity coefficient of emitters in the first and last irrigation periods, in well water with the Merus ring, was 0.31%and 6.67%, respectively, more than that in the well water without the Merus ring. Also, the uniformity coefficient of emitters in the first and last irrigation periods in agricultural wastewater with the Merus ring was 0.85% and 12.10%, respectively, more than that in agricultural wastewater without the Merus ring. At the end of irrigation period, the results showed that Netafim and Axios had the best and weakest efficiency, respectively. In general, the emitters used in the treatment of well water with the Merus ring had the highest discharge and the emitters used in the treatment of wastewater without the Merus ring had the lowest discharge.

In order to study the effects of different irrigation regimes and different levels of salinity on the growth parameters of Quinoa (Chenopodium quinoa Willd.), this experiment was performed in the research green house of Water Engineering Department, at f Gorgan University of Agricultural Sciences and Natural Resources, during 2016. The experimental design was a factorial with n a randomized complete design in three replications. Treatments included three irrigation levels (100, 75 and 50 percent of water requirements calculated by the evaporation pan class A) and five salinity levels (0.5, 4.3, 8, 11.8, 16 dSm^-1). The results showed that the effect of irrigation on the Leaf area index, chlorophylls and RWC (P<0.01) and Leaf length, and width (P<0.05) was significant. The effect of salinity levels on the Leaf area index, chlorophylls, Leaf length and width, RWC, Specific leaf weight (P<0.01) and Leaf petiole length (P<0.05) was significant too. The interaction between irrigation and salinity levels on chlorophylls and RWC (P<0.01) and Leaf width (P<0.05) was significant as well. According to the results, Quinoa had a good tolerance to the elevated levels of deficit irrigation. Decreasing the irrigation levels from 100 to 50 percent of pan evaporation resulted in the reduction of the Leaf area index and RWC to 24.6 and 7.3 percent, respectively. The result also showed that Quinoa had a good tolerance to the elevated levels of salinity, the mixing sea water, and tap water at rate of 30 percent, with control treatment having no significance for all of the parameters. It seems that good stand establishment in the saline soils and water conditions could be insured if proper management is applied in the farms.

Evaluation of the ecological sustainability of different cropping systems is crucial to achieve sustainable agriculture. This evaluation is accessible via soil quality assessment. Therefore, to study the mid-term effects of different conservation tillage systems (no tillage and minimum tillage) and cover cropping on the biological indicators of soil quality, a factorial experiment in a completely randomized block design was conducted in Dastjerd region (Hamedan). Three levels of tillage (NT: no tillage, MT: minimum tillage and CT: conventional tillage) and two levels of cover cropping (C1: Lathyrus sativus and C2: no cover crop) were applied for four consecutive years. Soil sampling was performed in the fourth year of experiment in two steps (1- before cover crop plantation, and 2- after harvesting main crop) with three replications. Most indices (total organic carbon, active carbon, basal respiration, phosphatase activity) were significantly affected by cover crop, tillage systems and sampling time, as the highest values were obtained in NT-C1 in time 2 and the lowest ones in CT-C2 in time 1. For instance, after four years application of treatments, the mean active carbon content was increased from 927 mg/kg in the conventional tillage + no cover crop to 1350 mg/kg in the conservation tillage systems + cover crop. Therefore, conservation tillage practices combined with Lathyrus sativus cover crop were shown to be the most appropriate management for soil quality maintenance and improvement.

Scour around structures in the river is the most destructivr factor of these structures. Therefore, different methods have been studied to reduce it. A creation slot is one of these methods in the suitable position that can be modified to control the flow pattern scour. In this study, the effects of using two parallel chord rectangular slots  in the single spur dike  with the opening of the effective spur dike area of 10% and a ratio of a/b = 4 (a and b are the length and width of the slot) on two occasions were investigated, one near the bed (near the slot spur dike) and the other near the water surface (away from the nose of spur dike) on the pattern of erosion and sediment around the nose triangular spur dike in clear water conditions. In all experiments, flow depth and angle of the triangular spur dike installation angle were constant. The experiment was done in different hydraulic conditions (Froude number 0.287, 0.304, 0.322). Eventually the results of spur dike without slot (control experiments) were compared. The results showed the slot near the bed toward the slot near water surface and control experiments had a better performance in reducing the maximum depth of scour and deposition of sediments washed to the outer bank. The reduction of the maximum depth of scour at the slot near the bed in Froude numbers 0.287, 0.302 and 0.322, respectively, was  compared to the control experiments , which were 23%, 13% and 24%, respectively, and then compared to the slot near the water surface, which was 60%, 40% and 32% respectively.

Nowadays, water resource management has been shifted from the construction of new water supply systems to the management and the optimal utilization of the existing ones. In this study, the reservoir operating rules of Doroodzan dam reservoir, located in Fars province, were determined using different methods and the most efficient model was selected. For this purpose, a monthly nonlinear multi-objective optimization model was designed using the monthly data of a fifteen-year period (2002-2017). Objective functions were considered as minimizing water scarcity index in municipal, industrial, environmental and agricultural sectors. In order to determine the operating rule curves of reservoir, in addition to the nonlinear multi-objective optimization model, the methods of ordinary least-squares regression (OLS), fuzzy inference system and adaptive network fuzzy inference system (ANFIS) were used. Also, the reliability, resiliency, vulnerability and sustainability criteria were used to compare the different methods of reservoir performance rules. The results showed that ANFIS model had the higher sustainability criterion (0.26) due to its greater reliability (0.7) and resilience (0.42), as well as its lower vulnerability (0.13), thereby showing the best performance. Therefore, ANFIS model could be effectively used for the creation of Doroodzan reservoir operation rules.

In recent years, microbial contamination of surface and groundwater is a serious problem in some countries, leading to dangerous diseases. Soil salinity and irrigation water can affect the amount of transport or survival of bacteria in soil. In this study, the effect of different levels of salinity of irrigation water with EC: 0.5, 2.5, 6 ds/m and three manures including poultry manure, cow manure and the mixture of poultry and cow manure with 10 ton ha^-1 on the transport of Escherchia coli was investigated in disturbed soil columns with 30cm height and 10cm diameter under unsteady-state water conditions. The concentration of Escherchia coli was measured. The severity of the effluent contamination of the treated columns with water salinity was 6 ds/m, which was less than that with the salinity of 2.5 and 0.5 ds/m. This difference was significant at the 0.01 probability level. Also, the effluent contamination of poultry manure-treated columns was greater than the cow manure and the mixed manure, and the contamination of mixed manure was greater than that of cow manure. The interaction of different salinity treatments on the concentration of Escherchia coli in different fertilizer treatments was significant at the 0.01 probability level. The results showed that the concentration of the released bacteria was affected by irrigation water salinity and with increasing the salinity, the concentration of the bacteria was reduced.

One of the main sources of runoff in arid and semi-arid mountainous highlands is typically composed of before Quaternary formations. Since the structure and lithology of formations are different, varying formations can have different significance in terms of runoff and sediment. The present study aimed to investigate the sediment production potential and the runoff generation threshold on three formations (Shirkooh Granite, Shale, Sandstone and Conglomerate of Sangestan and Taft Limestone) in Shirkooh mountain slopes. The 60 mm/h rainfall intensity with the 40 minute continuity, according to region rainfall records, and the ability of the rainfall simulator were selected as the basis for the study. Field experiments were conducted in dry conditions based on one square meter plot on rocky slopes with a gradient of 20 to 22 percent and a maximum thickness of 30 cm of soil. The results showed that in 60 mm/h rainfall intensity, the minimum rainfall to produce runoff on Sangestan, Shirkooh and, Taft, was 10, 10.7 and 16.7 mm, respectively. The maximum amount of the sediment was measured on Sangestan, Taft and Shirkooh, respectively. Statistical tests related to runoff and sediment production on all three formations confirmed a significant difference at the 5 % level. In terms of the time required to start runoff, the minimum time was for Sangestan, Shirkooh and Taft, respectively. According to the results, in terms of the potential for runoff generation and sediment production, Sangestan, Shirkooh and Taft can be ranked from high to low levels.

The growth of world population and the demand for agricultural products can be regarded as one of the important issues that humanity has ever faced. There are serious concerns regarding surface and ground water pollution by nitrates because of using nitrogen fertilizers in the agriculture. Improving agricultural water management systems can reduce nitrate in drainage outflow and therefore, reduce the environmental pollution. This research was conducted to evaluate the effect of the controlled drainage and nitrogen fertilizer on nitrate leaching and environment pollution as a factorial randomized complete block design in Shiraz College of Agriculture. The treatments consisted of three fertilizer levels; 0, 200 and 300 kgN/ha, and three water table depths: free drainage, control water table at 60cm (CD60) and 90 cm (CD90) depths, respectively. According to the results, the value of drainage water and nitrate losses in the controlled drainage toward free drainage were significantly increased. The mean reduction of drainage water in CD60 and CD90, as compared to free drainage, was 59.3 and 35.7%, respectively. The decrease nitrate losses, as compared to free drainage, was 72 and 44%, respectively. The total value of nitrate leaching in 200 and 300 kgN/ha fertilizer treatments was 1.86 and 2.48 times of 0 kgN/ ha.

Understanding the distribution of different P forms in soil aggregate fractions is important in evaluating the risk of P run-off and leaching in the agricultural soils. The objective of the present research was to determine the effect of aggregate size on soil phosphorus availability and fractionation in 10 calcareous soils. Micro aggregate (< 0.25 mm), macro aggregate (> 0.25 mm) and whole soil were separated by dry sieving. Olsen P, total P, organic P, and inorganic P fractions in micro aggregate, macro aggregate, and whole soil were determined. Soil inorganic P fraction was  determined by a sequential extraction procedure including: dicalcium phosphate (Ca₂-P), octa calcium phosphate (Ca₈-P), apatite (Ca₁₀-P), P absorbed by Al oxide (Al-P), P absorbed by Fe oxide (Fe-P) and P incorporated in to Fe oxide (O-P). The results showed that the amounts of (Olsen P), (Ca2-P), (Ca8-P), (Ca10-P), (Organic P), (Al-P), (Fe-P), (O-P) and (Total P) in 70, 60, 40, 40, 60, 70, 60, 50 and 70 percent of soils, respectively, in the micro aggregates were significantly higher than those of the macro ones. Finally, by increasing the P content, particularly the smaller sized aggregates, it was likely that the eroded material would favor greater P loss.

The rate of metal transfer from the solid phase to solution is an important factor governing their concentration in the soil solution and its availability. In this research, the release rate of Zn in contaminated soils from Isfahan was studied using solutions citric acid, oxalic acid and malic acid 0/01 M during the period of 2 - 504 hours and its relationship with soil characteristics was investigated. The results showed that low molecular weight organic acids could release Zn in the contaminated soils. The Zn released by acids was in the order citric acid> oxalic acid> malic acid. Variation range of Zn released a solution of citric acid, oxalic acid and malic acid, which was 38/9 -21173, 25/2 - 26761 and 25/5 – 20650
mg/kg of soil. Zn released in citric acid solution was higher than that of the two acids. Based on the determination coefficient and standard error estimates done by the kinetic equations, the release of Zn of the contaminated soils and three acid solution was described by the first order equation, elovich, parabolic diffusion and power function, with a high coefficient of determination and a low standard error. Correlation results showed that for the Zn release with the index of Zn usability, there was a significant correlation at 5% level. Showed Multivariate regression model showed that Calcium carbonate, pH and EC affected characteristics of Zn desorption.

Nitrification is one of the most active biological processes in the soils receiving ammonium nitrogen. The rate of this process is under the influence of several factors and their interactions. In this study, the effects of ammonium concentration and moisture content on the extent of nitrification in two soil samples named A (Loam) and B (Clay loam), which had been taken, respectively, from Marand and Ahar areas, were investigated. A two-week factorial incubation experiment (25±0.5°C) was conducted in a completely randomized design with three replications. Factors were urea nitrogen at five levels (0, 50, 100, 200 and 400 mg N kg^-1), moisture content at three levels (0.55FC-0.60FC, 0.75FC-0.80FC and 0.95FC-FC) and two soil types (A and B). At the end of the experiment, concentrations of ammonium and nitrate as well as the values of pH and EC were determined. Based on the results, average nitrification at 0.55FC-0.60FC was 22 percent lower than that at 0.95FC-FC and no significant difference was observed between 0.75FC-0.80FC and 0.95FC-FC. Nitrification at the treatment of 400 mg N kg^-1and 0.55FC-0.60FC was decreased considerably and 25 percent of the added ammonium was accumulated. The average ammonium concentrations did not significantly vary among the levels of 50, 100 and 200 mg N kg^-1, but these concentrations were significantly lower than those of 400 mg N kg^-1. Moreover, EC and pH values of the soils were significantly increased and decreased in response to the nitrification (0.54 dS m^-1 and 0.59 at the application level of 200 mg N kg^-1, respectively). On average, the results showed higher nitrification (40.3 mg N kg^-1) in the soil A (Loam texture) than the soil B (Clay loam).

The persistent scattering interferometry (PSI) technique is a valuable tool in displacements' monitoring of earth's surface. The persistent scattering interferometry (PSI) based on persistent scatterrer (PSInSAR) is one of the techniques used to reduce constraints (temporal and spatial incoherency). It is based on persistent scatterer and monitor displacement of only the pixels with timely-constant properties of scatterer. In order to detect and monitor landslides,  two time series SAR data sets including PALSAR ascending images from 2007 to 2010 and ASAR images from 2003 to 2010 with C-band and L-band wavelength were applied, respectively. Also, the PSI technique was implemented in a landslide near Noghol village, Padena, Semirom of Isfahan province. The results revealed  that both PALSAR and ASAR data set were efficient in identifying Noghol landslide. The results obtained  from ASAR and PALSAR images processing (with the values of 1253 mm and 1578 mm in two stages of time 4 and 7 years, respctively) were compared. The obtained vertical displacement's rate of the landslide by using ASAR data was more suitable because of its descending orbit. However, PALSAR images that indetified  more persistent scatterrer points were better in the  detection of the  landslide area. The results of GPS and PSInSAR techniques revealed that landslide displacement values and aspect were the same, confirming 135 centimeters of displacement to the  west aspect. Finally, a combination of radar data in two different passes provided the possibility of monitoring the mechanism of landslide and its movement direction.

Soil quality is the permanent soil ability to function as a live system within ecosystem under different land uses. Investigating the impact of land use type on soil quality indicators could help to distinguish sustainable managements and therefore, to inhibit soil degradation. In order to evaluate the effect of different land uses on soil quality indicators, a research based on a randomized complete design in Rabor region, Kerman Province, Iran, was conducted. A total of 104 samples were taken from the soil surface (0-15 cm) of four land uses including: pasture (28 samples), forest (25 samples), agronomy (27 samples) and garden land use (24 samples). Soil quality indicators were measured as: soil organic matter, particulate organic matter, and bulk density, plant available water capacity, S index, cation exchange capacity (CEC), electrical conductivity (EC), soil pH, and phosphatase enzyme. According to the results, land use types had a significant effect on all indicators except S index at 1% probability level. The maximum amount of soil pH, bulk density and phosphatase enzyme was obtained from forest land use. On the other hand, the maximum amount of the other indicators was attained from the garden land use. Totally, garden land use, due to having high organic matter, could improve the soil quality. However, the pasture land use had the worst soil quality due to the weak cover and the low organic matter.

Yield is a function of root distribution and activity. In flood conditions, root growth and efficiency are essential for crop productivity. The goal of this study was to investigate the effect of different irrigation regimes on the root development, yield and yield components of green pepper (green Hashemi cultivars). This study, which was based on a completely randomized design with three replications under greenhouse conditions, was done at Gorgan University of Agricultural Sciences and Natural Resources in 2016. Different irrigation regimes consisted of 3 levels (100, 125 and 150 percent of water requirement). The results showed that the effect of different irrigation regimes on root volume, root length, root area and number of fruit was significant at 1 percent level (P<0.01), but water use efficiency, and fresh and dry weight of fruit were significant at 5 percent level (P<0.05). The results also revealed that green pepper plants were sensitive to over irrigation. Increasing irrigation levels from 100 to 125 percent of pan evaporation resulted in the reduction of root volume, root length, water use efficiency, number of fruits, and pepper fresh weight to 20, 13.8, 26, 29and 6.4 percent, respectively. As the conclusion, with the increase in water irrigation level, the fresh weight of the fruit was significantly decreased.

The concern about the war and the threat of terrorism and weapons application and prohibited weapons is growing; on the other hand, the contamination of soil, plant and disease outbreaks in the community is increasing. The main problem with crops, especially wheat in the contaminated soils of war zones, are associated with the high concentrations of heavy metals and toxic things, especially arsenic. Zeolite is one of the solutions to the problem of contaminated soils in war affected areas. The aim of this study was to determine the effect of the ionic strength of zeolite on the adsorption of arsenic and nutritional properties of wheat in contaminated soils including weapons. The experiment was carried out in a  factorial arrangement involving  a randomized complete design with three replications. Treatments included four levels of zeolite 2.5 (a₄), 1.5 (a₃), 0.5 (a₂), 0 (a₁) percent of the weight of the soil and two soil recourses, one obtained from out of the war zone (without contamination) (b₁) and other one was from the contaminated soil to weapons (b₂). The results showed that soils contaminated by weapons increased the concentrations of arsenic in wheat. Also, with the application of Zeolite in the contaminated soil treatments, there was a significant reduction at 1% level and a remarkable increase in nitrogen, phosphorus, potassium and calcium in the wheat grain in both soils.