JWSS - Journal of Water and Soil Science

Use of the curve gradient of the Soil Water Retention Curves (SWRC) in the inflection point (S Index) is one of the main indices for assessing the soil quality for management objectives in agricultural and garden lands. In this study Anneling Simulated – artificial neural network (SA-ANN) hybrid algorithm was used to identify the most effective soil features on estimation of S Index in Jiroft plain. For this purpose, 350 disturbed and undisturbed soils samples were collected from the agricultural and garden lands and then some physical and chemical soil properties including Sand, Silt, Clay percent, Electrical Conductivity at saturation, Bulk Density, total porosity, Organic Mater, and percent of equal Calcium Carbonate were measured. Moreover, the soil moisture amount was determined within the suctions of 0, 10, 30, 50, 100, 300, 500, 1000, 1500 KP using pressure plate. Then, the determinant features influencing the modeling of S Index were derived using SA-ANN hybrid algorithm. The results indicated that modeling precision increased by reducing the input variables. According to the sensitivity analysis, the Bulk Density had the highest sensitivity coefficient (sensitivity coefficient=0.5) and was identified as the determinant feature for modeling the S Index. So, since increasing the number of features does not necessarily increase the accuracy of modeling, reducing input features is due to cost reduction and time-consuming research.

Droughts are natural events and could lead to declining surface water quality of regional basin. Understanding the complex impacts of drought may help authorities to monitor changes in different regional basin and to make appropriate decision on development of a river basin management plan. In this study 20 years annual precipitation time series from 1994-2013 from 7 synoptic weather stations located in the Halil-Rood basin were analysed using both Standard Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) and then dry (-1.35 to -1.75) and wet years (1/7 to 2.45) were determined by model simulation studies. Several climate based drought indices and remotely sensed based drought indices were used for monitoring and evaluating of drought. The impact of drought on the water quality parameters in the study area was evaluated. Results showed that there was significant relationship between most of the examined water quality parameters (Ca²⁺, Mg²⁺, HCO^3-, SO4²⁺, Na⁺, total dissolved solids TDS, SAR) and drought, however there was no significant relationship between water pH and drought. The study indicated that focus on the drought indices might be helpful as a tool in improving surface water resources management under drought condition and may promote sustainable water resources utilization and management in the study area. Also, dividing the Halil-Rood basin into several homogeneous regions is recommended for future studies to prepare a better ground for studying the effect of drought on the quality of water at a regional scale.

Occurrence of local scour is one of the most significant causes of damage to the pipes. Therefore, safe and economical design of pipes in the flow path requires a good estimate. In this study, based on the important and effective parameters in the scouring phenomenon, in order to develop educational patterns according to the data obtained in the laboratory of Ahvaz Islamic Azad University, models based on artificial neural networks were created with the NeuroSolution5 software. MLP, GFF and RBF were the models used in this study; after comparing, MLP was selected as the basis for our study. Finally, the effect of each parameter on scouring was determined using the  artificial neural networks technique, based on which the  shields parameter with a very high effect (more than 95 percent) was determined as one of the most effective causes of the local scour.

Today, the rising surface temperature of the planet and its effects on the water cycle have attracted the attention of many researchers. The aim of this study was to investigate the effect of climate change on the Tajan (the upstream of Shahid Rajaei dam) catchment area. In order to study the output of CanESM2 model, the SDSM method was used to estimate the magnitude of the data. Flow discharge changes in Shahid Rajaei Dam were simulated using the weather data of Kiasar synoptic station and the temperature and precipitation changes were simulated using the climate scenarios of RCP2.6 and RCP8.5 for the 2016-2066 period. Also, the effect of different scenarios on the outflow of the Soleiman Tangeh hydrometric station was evaluated by SWAT hydrologic model. The results showed that the annual precipitation would be decreased by 58% and the air temperature would be increased by 14% under RCP2.6 scenario. Also, in the RCP8.5 scenario, precipitation would be decreased by 59.5% and the temperature would be increased by 21%. Peak discharge for RCP2.6 and RCP8.5 scenarios would be increased by 4% and 5.7%, respectively, and the average annual discharge might be decreased by 16% and 16.5% in the future period (2016-2066). Therefore, it can be planned by the investigation of conditions for cropping patterns in the downstream to consider the environmental impacts for future periods.

The soil organic matter plays an important role in increasing agricultural products and various nutrient cycle in the soil due to its effect on the physical, chemical and biological properties of soil. There is, however, little information regarding the effect of growth promoting bacteria on biological indices and different forms of carbon in agricultural soils of the country. Therefore, this study was aimed to investigate the effect of plant growth promoting bacteria on soil respiration, microbial quotient, organic carbon, microbial carbon biomass, permanganate oxidizable carbon, cold water extractable organic C, and hot water extractable organic C under the cultivation of wheat, Chamran cultivar. The experiment was conducted in greenhouse condition as a randomized complete design with 9 replications. Treatments consisted of bacterium inoculation (without inoculation, Enterobacter cloacae Rhizo_33, Enterobacter cloacae Rhizo_R1
and mixof both bacteria). During the experiment, some characteristics such as plant height and chlorophyll index were measured. At the end of the cultivation period, root and aerial part dry weight and grain yield were determined. Biological properties and different forms of carbon in the soil were measured after cultivation. The results indicated the applied plant growth promoting bacteria increased chlorophyll index, height, root and shoot dry weight and grain yield, as compared to the control. The minimum value of pH and the highest amount of each carbon forms were obtained by soil inoculation with different strains of bacteria, as compared to the control. The highest value of organic carbon was observed in the presence of the consortium of both bacteria with 22.7% increase, as compared to the control. The highest amount of microbial carbon biomass was, respectively, measured in the treatments containing consortium of bacteria, Enterobacter cloacae Rhizo_R1, Enterobacter cloacae Rhizo_33 with 87.67, 42 and 26.5% increment, as compared to the control. A positive and significant correlation was observed between cold and hot water extractable organic carbon, dissolved organic carbon and permanganate oxidizable carbon with soil respiration and there was a negative correlation between mentioned properties and the soil pH. The use of microbial inoculants increased the carbon content of the soil, which can play a positive role for improvement of   physical and chemical properties of the soil and plant yield.

Water scarcity is the most important factor constraining agricultural production all over the world and water shortage in agriculture must be established to use the deficit irrigation. In order to study the effects of the regulated deficit irrigation and partial root zone drying on the growth traits of Rosmarinus Officinalis L., an experiment was conducted in the center of seed and plant production of IranShahr municipality in 2017. The experiment treatments were arranged as a randomized complete block design with three replications. The irrigation regimes consisted of full irrigation, regulated deficit (RDI₇₅ and RDI₅₅) and partial root zone drying irrigation (PRD₇₅ and PRD₅₅). The results showed that deficit irrigation at 75 and 55 percent of full irrigation resulted in saving 18.6 and 34.3 percent of water consumption, respectively. Comparison of full irrigation and PRD₇₅ showed that dry weight, height of plants and number of shoots per plant were decreased by 6.7, 14.3 and 12.1 percent, respectively. However, proper development of root in PRD₇₅ increased 12.9 percent of water productivity. Therefore, by considering the problems of water scarcity, it is possible to provide PRD₇₅ as a superior treatment and a suitable strategy to cope with the water crisis in order to move towards a sustainable agricultural system.

Growing concerns about water pollution and its potentially harmful effects on human being have stimulated serious efforts to develop reliable biological monitoring techniques. The bioluminescent analysis is one of the most promising approaches for the biomonitoring of the environment, due to the sensitivity of the luminescent system to even micro quantities of the pollutants. The aim of the current study was to assess the petroleum compounds toxicity using Vibrio fischeri bacterium. The growth pattern of the bacterium was determined in photobacterium broth using the optical density measurement at 600 nm, which showed the optimum growth time of 16-18 hours after inoculation. In this research, the effects of environmental parameters such as temperature, pH and various concentrations of oil on the growth and luminescence of Vibrio fischeri were examined. The results revealed that the optimum growth conditions of the bacterium after 16 hours included the temperature of 25 °C and pH 7. Besides, the growth and luminescence intensity of Vibrio fischeri were a function of total petroleum hydrocarbon concentrations in the medium, which were significantly reduced in oil concentrations by more than 4% w/v. Therefore, the Vibrio fischeri could, therefore, have the potential for monitoring of petroleum pollutants in the aqueous media.

Increase in population, agricultural development, and the reduction of surface water resources have resulted in an untapped harvest of ground water. On the other hand, the lack of attention to the balance between the exploitation and recharge of aquifers has led to a drop in water level in the aquifer. To understand the behavior of the ground water system and the status of resources and uses in the basin, as well as the situation of water exchange in these two parts, it is possible to connect reliable groundwater and surface water models The purpose of this study was to simulate Gorganroud aquifer flow by using using the groundwater model to understand the behavior of the aquifer system in different hydrological conditions and to provide a management solution to improve the  supply and demand conditions. First, the status of the aquifer under study was simulated by using the information available in the area by Modflow; then the groundwater model results were transferred to the Water Evaluation and Planning model (WEAP) by the LINK KITCHEN Software. Then different management scenarios including increased irrigation efficiency in agriculture,  the use of refinery effluents and  the reduction of river flow due to climate changes were considered as two combinations of the above scenarios to alleviate water demand under this scenario; so, projections for a period of 20 years water resources of the basin were studied. The results of modflow calibration showed that there was a good agreement between observation and simulated water table, such that the RMSE for Steady and Transient condition was 0/972 and 0/97, respectively. The results also showed that simultaneously applying multiple water management strategies seems to be better than any of its individual states, thereby reducing water withdrawal on various resources.

This study aimed to investigate the vulnerability of Sistan plain to fluctuations and Water Scarcity in Hirmand River using the vulnerability framework, by applying the resilience approach. The socioeconomic and biophysical components presented in this framework were embedded in a set of subsystems of the System Dynamics (SD) model. According to this, four levels of reference resilience were defined based on the annual flow from the Hirmand River, and the system attributes of concern were identified under the existing structure until 2050. Then, the proposed strategies to the socio-economic structure of the model were applied under two critical conditions of water scarcity and fluctuations of the river flow. The values associated to the system attributes of concern of the two mentioned conditions were compared with the reference resilience levels. The results showed the efficiency of the policy option in reducing water scarcity and the importance of the environmental impacts of the biophysical component. For example, the two modes of water scarcity and water inflow fluctuations had the revenues of 9490 and 5100 billion IRR (annual income according to the base price of 2011), but they had the same population and resident's utility, which was related to receiving 117 and 600 MCM of the environmental demand, respectively. Management, development and continuous support of the industrial sector can provide a "Success to the Successful" archetype for the socio-economic section of Sistan Plain.

The objective of this study was to investigate the impact of land use change (forest and rangelands to agriculture) on some micromorphological indices of soil quality in part of Rakat watershed, southwest of Iran. Accordingly, intact soil samples from 0-15 and 15-30 cm depths were collected from the above-mentioned land uses, and microstructure, type and abundance of voids, redoximorphic features, and humic substances were compared. The results showed that in the natural forest use, most of the voids are in the form of macropores, whereas after their conversion to agriculture, these types of voids have little development. In natural rangelands uses, voids were mainly oriented channels and of macropore type, but after switching from pasture to agriculture, they were mainly of vughy type. The results showed that natural forests (27.73%) and natural grasslands (22.28%) had more abundance of voids than forest to agriculture (19.01%) and grassland to agriculture (18.62%) land uses. In both natural forests and pasture land uses, various types of iron and manganese nodules, coatings, hypo-coatings, and quasi-coatings were significantly higher than agricultural land uses.

In this study, we used the ARIMA time series model, the fuzzy-neural inference network, multi-layer perceptron artificial neural network, and ARIMA-ANN, ARIMA-ANFIS hybrid models for the modeling and prediction of the daily electrical conductivity parameter of daily teleZang hydrometric station over the statistical period of 49 years. For this purpose, the daily data for the 1996-2004 period were used for model training and data for the 1996-2006 period were applied for testing. In order to verify the validity of the fitted ARIMA models, the residual autocorrelation and partial autocorrelation functions and Port Manteau statistics were used. PMI algorithm were   then used to model and predict electrical conductivity for selecting the effective input parameter of the neural fuzzy inference network and the artificial neural network. The daily parameters of magnesium (with two days delay) and sodium (with one day delay), heat (with one day delay), flow rate (with two months delay), and acidity (with one day delay) were obtained with the lowest values of Akaike and highest values of hempel statistics as the input of the neural fuzzy inference network and the artificial neural network for modelling daily electric conductivity predictions; then predictions were made. Also, models evaluation criteria confirmed the superiority of the ARIMA-ANFIS hybrid model with the trapezoidal membership function and with two membership numbers, as compared to other models with a coefficient of determination of 0.86 and the root mean square of 29 dS / m. Also, the Arima model had the weakest performance. So, it could be applied to modeling and forecasting the daily quality parameter of the tele Zang hydrometer station.

Class A pan evaporation method as one of the most common methods for reference evapotranspiration (ET₀) estimation has been widely used in the world due to its simplicity, relatively low cost, and ability to estimate daily ET. In this study, the performance of 8 empirical methods consisting of Allen and Pruitt (1991), Cuenca (1989), Snyder (1992), modified Snyder, Pereira, et al. (1995), Orang (1998), Raghuwanshi and Wallender (1998), and FAO/56 were analyzed to estimate class A pan coefficient and ET₀ at Fasa synoptic station located in Fars province. The calculated pan evaporation coefficients from the above equations were compared with measured pan evaporation coefficients which were obtained from the ratio of evapotranspiration calculated by the FAO-Penman-Monteith method to the rate of evaporation from the pan. The results showed that all empirical methods did not predict pan coefficient values well (R² < 0.3 and NRMSE > 0.25). The comparison results between ET₀ from empirical methods and ET₀ obtained from FAO-Penman–Monteith indicated that the FAO/56 method had the best performance (R² = 0.72 and NRMSE = 0.3). To increase the accuracy of empirical pan coefficient equations, these equations were modified with eight years (2007-2015) of meteorological data from the Fasa synoptic station and validated using two years of independent data (2015-2017). The results showed that the accuracy of all empirical models was improved and the Cuenca equation with NRMSE = 0.16 and R²= 0.63 was selected as the best equation for pan coefficient estimation and ET₀ (R² =0.85; NRMSE =0.18) in Fasa region. The sensitivity analysis revealed that the estimated pan coefficient is more sensitive to wind speed, followed by relative humidity, fetch distance, the slope of the saturation vapor pressure curve, sunshine hours, and air pressure. According to statistical results and sensitivity analysis, an equation was expanded for the Fasa region and other areas with the same climate.

In precision agriculture, a productivity rating system is a significant tool to quantitatively assess soil quality. An experiment was conducted in Bilavar, Kermanshah to evaluate the spatial variability of physical indicators of soil quality of a rapeseed (Brassica napus) field. Spatial variability analysis of soil physical properties measured on a rectangular grid (100 m×100 m) was carried out using a geostatistical analyst extension of Arc-GIS software. Five physical soil quality indicators including bulk density (BD), non-capillary porosity (NCP), field saturated hydraulic conductivity (Ks), available water retention capacity (AWC), and organic carbon (OC) were determined. The physical rating index (PRI) at each sampling point was determined by multiplying the rating values for all five parameters. Results revealed that major ranges of semivariogram for Ks and AWC varied between 137-145 m and for BD, OC, and NCP they were relatively long (161-205 m). Clay and NCP showed moderate spatial dependence (0.68 and 0.28, respectively) whereas the rest of the parameters showed weak spatial dependence. Also, the correlation between PRI and the biological yield of rapeseed was fairly good (R²=0.68). Investigation of zoning maps of soil physical properties showed an increase in BD and a decrease in AWC and NCP parameters depending on changes in soil texture and organic matter content in some parts of the field. In general, the PRI index is an important tool in the quantitative assessment of soil physical conditions, and based on it and zoning maps can improve the physical quality of soil in agricultural fields.

Due to the climatic conditions of Iran, increasing water scarcity, and the effect of drought stress on the efficiency of irrigation water consumption and chemical fertilizers application, an experiment was conducted to investigate the effect of irrigation intervals (6, 9, and 12-day intervals), different levels of nitrogen fertilizer (200, 300, and 400 kg urea per hectare) and cultivation methods (on-ridge or heeling up and in-furrow) on yield and productivity of sugarcane as a factorial design based on randomized complete block design in 3 replications at Hakim Farabi Agro-Industry Company in Khuzestan province. The results showed that the maximum (106.73 tons/ha) and minimum (59.10 tons/ha) sugarcane yields were observed in 9-day and 12-day irrigation intervals, respectively. Also, the highest sugarcane yield (99.89 tons per hectare) was obtained in the treatment of 400 kg urea per hectare and the in-furrow planting method resulted in a higher yield compared to the on-ridge planting method. The highest water productivity in sugarcane stem yield and sugar production with 3.55 and 0.34 kg per cubic meter of applied water, respectively, was obtained in a 9-day irrigation interval. A significant increase in water use efficiency in sugarcane stem yield was observed in 400 kg urea/ha compared to the other two fertilizer levels. However, there was no significant difference in water productivity of sugar yield between different fertilizer treatments. The results showed that 6 and 9-day irrigation intervals in most of the studied traits were not significantly different. Therefore, using a 9-day irrigation interval is suggested in the studied area when the sugarcane cultivation area is high and the amount of available water is limited. In-furrow planting method can also be effective in reducing water consumption. Therefore, deficit irrigation and proper nitrogen fertilizer consumption can be very effective in sugarcane cultivation.

In addition to the distribution of elements in the soil solid phase, element species in the solution are also very important due to their importance of providing elements for root uptake. For a deeper study of the chemical cycle of elements in saline soils treated with biochar, the study of speciation is very useful and provides a method to reduce or transform the toxicity caused by toxic elements in saline soils. Therefore, to investigate the effect of biochar on Cd speciation in two saline calcareous soils, 15 mg kg^-1 Cd as cadmium chloride was added to the soil sample (200 g), and the soils were incubated for three weeks at 25±2 °C at 80% field capacity. After the incubation period, salinity levels of 20 and 40 mmol kg^-1 as sodium chloride (equal to 3.65 and 7.30 dS m^-1) were added to the soils. Then, the 1% (w/w) of the sugarcane bagasse and biochars produced at 400 and 600 °C were added to the soils, and then incubated for three months at 25±2 °C at 80% field capacity. At the end of the incubation period, for the speciation of Cd in the soil solution (in a 1 to 2 ratio), the concentration of dissolved cations and anions in the soil samples was measured. The results showed that the interaction between salinity, biochar, and soil on Cd²⁺, CdCl⁺, CdCl₂⁰, and Cd(SO₄)₂^2- was significant. The application of biochar in sandy soil reduced (p <0.05) the concentration of CdCl⁺, CdCl₂⁰, CdSO₄⁰, and CdOH⁺ species compared to the control soil, while it did not affect clay soil. Also, salinity caused by sodium chloride in sandy soil increased the concentration of CdCl⁺ and CdCl₂⁰ species and decreased CdSO₄⁰ and CdOH⁺ species compared to the control soil (p <0.05). The results showed that biochar in saline sandy soil was more effective than clay soil in reducing Cd toxicity.