محمدرضا مصدقی

Soil and groundwater contamination by petroleum hydrocarbons might cause negative environmental impacts. It may adversely affect soil physical conditions and quality such as hydraulic properties via raising soil water repellency. Soil structure is an important physical characteristic depending on pore size distribution and continuity, and it can affect several soil physical and chemical processes. Soil structure might be affected by physical weathering processes such as wetting/drying and freezing/thawing cycles. It is possible to reproduce the natural soil structure in the laboratory by imposing wetting/drying and freezing/thawing cycles on the repacked soil samples. This would minimize the possible changes in soil structure during core sampling from the field. Few studies have been conducted about the interactive effect of oil contamination, soil texture and structure on soil water repellency and hydraulic properties. The present study aims to investigate the interaction effects of crude oil application, soil texture and weathering-induced structure on soil water repellency and hydraulic properties.

In this study, the effect of crude oil application and physical weathering on water repellency and hydraulic properties of two soils (sandy loam and clay loam) was studied in a factorial experiment of completely randomized design with three replicates. Soil samples were collected from 025 cm layer of agricultural lands in Chaharmahal-va-Bakhtiari province, central Iran (sandy loam and clay loam soils were located in 32° 43' N 51° 59' E and 32° 29' N 50° 42' E, respectively). The soil was ground and sieved through a 4-mm mesh to exclude the gravel particles and plant residues. Crude oil was solved in the n-hexane and added to soil with the concentrations of 0.5 and 1 %w/w of total petroleum hydrocarbons (TPHs). Besides, a control without crude oil addition was included in the experiment. The treated soils were then poured into stainless cylinders (height and diameter of 5 cm) and packed to natural bulk density of 1.45 and 1.43 g cm-3 for sandy loam and clay loam soils, respectively. Half of the prepared soil samples were tested immediately and named “repacked” treatment and the rest wetted and dried for five months under normal conditions in the greenhouse and was named “physical weathering” treatment. Thus, a total of 36 soil samples were prepared (2 soil types × 3 levels of water repellency × 2 weathering treatments × 3 replicates). Then, water repellency was determined by water drop pentetration time (WDPT) on the treated soil cores. Soil water characteristic curve and saturated hydraulic conductivity (Ks) were measured on the soil cores and modeled by van Genuchten equation. Soil physical quality indicators including field capacity (FC), permanent wilting point (PWP), available water colntent (AWC), macroporosity (Macro-P), mesoporosity (Meso-P), microporosity (Micro-P), and Dexter’s index for soil physical quality (SDexter) were calculated as well.

The results showed that soil hydraulic properties were significantly affected by the experimental treatments. Water retention was greater in the clay loam soil compared to the sandy loam soil. Oil contamination reduced soil water retention at all matric suctions (0 to 15000 cm) due to oil-induced water repellency and soil resistance against wetting (as observed by an increment in WDPT). The effect of oil contamination on water retention was greated in the sandy loam soil than in the clay loam soil due to lower specific surface area of coarse-textured soils. The Ks, saturated water content (s) and residual water content (r) decreased, and scaling () and shape (n) parameters increased significantly due to oil-induced water repellency. The Ks of 1% TPHs-treated samples (i.e., 5.64 cm h-1) was significantly lower than that of control (i.e., 7.98 cm h-1). The s and r significantly decreased by 1% oil contamination (i.e., 0.457 and 0.112 cm3 cm-3) compared to the control (i.e., 0.547 and 0.122 cm3 cm-3), respectively. However, the parameters  and n were significantly greater in the 1% TPHs-treated samples (i.e., 0.240 cm-1 and 1.56) compared to the control (i.e., 0.130 cm-1 and 1.36), respectively. Physical weathering significantly increased s. The The Ks and Macro-P were significantly greater in the sandy loam soil whereas the Meso-P and Micro-P were significantly greater in the clay loam soil. The FC, PWP and AWC were significantly greater in the clay loam soil than in the sandy loam soil. The FC, PWP, Meso-P and Micro-P decreased but the Macro-P and SDexter increased in the oil-contaminated soil samples. The AWC significantly decreased from 0.084 (control) to 0.049 cm3 cm-3 due to 1% oil contamination. Physical weathering intensified the oil-induced water repellency (i.e., an incement in WDPT from 23.9 in repacked soil to 30.2 s in weathered soil), and reduced water retention in the sandy loam soil more than in the clay loam soil. The Ks, Macro-P and Micro-P were significantly greater in the weathered soil samples than in the repacked ones.

As coarse-textured soils with low specific surface area are more prone to water repellency compared to fine-textured soils, they became water-repellent quicker upon physical weathering. It seems that physical weathering stimulated soil structure formation and intensified the oil-induced water repellency. The findings of this study are important for the management of oil contamination in different soil (texture and structure) conditions.

This study was conducted in the summer of 2021 to evaluate and validate the gravimetric soil water content measurements using a field oven. Ten soil types with a salinity of saturated paste (ECe) less than 4 dS m-1 and three saline soils were studied around Urmia Lake. Plots with dimensions of 1 m × 2 m were prepared for the selected soils to measure gravimetric soil water content and soil physical and chemical properties. The gravimetric water content (θm) values measured using the field oven (i.e., θmFO), were compared with those measured by a standard lab oven (i.e., θmLO). The soil water content values measured in the lab, regarded as a benchmark, were measured at 105 °C for 24 h. Temperatures of 120, 140, and 160 °C with three durations of 10, 15, and 20 min were used to dry the soil samples in the field oven. There was very good compatibility between the values of θmFO and θmLO when the soil samples were dried in the field oven for 15 or 20 min at all three temperatures. Significant linear relations were obtained between the θmFO and θmLO values as the slopes of linear relations were close to 1, the intercepts of relations were negligible and the distributions of measured data around the line 1 to 1 were unbiased. The minimal effects of soil organic matter content, clay content, salinity, and bulk density on water content measurements by the field oven indicate an important advantage of this method. These results confirm the high efficiency of the field oven for fast and reliable measurements of water content in different soils.

Due to several factors, including anthropogenic global warming, drought is increasing in many arable areas which is one of the major threats to global food security. Abiotic stresses such as water deficit severely reduce crop productivity. Using strategies subsurface irrigation with porous clay capsules and natural nanobiochar amendment could be pivotal in reducing water and nitrogen fertilizer inputs as well as the effects of abiotic stresses on plants. Biochar addition to soil may improve soil physical and chemical characteristics. Soil water retention in the root zone enhances under the same irrigation schedule following biochar application. Biochar could improve plant access to soil nutrients and pivotal in reducing fertilizer inputs to agricultural soils.

Greenhouse experiments were conducted in two years (2019 and 2020) on broccoli planted in sieved and non-sieved samples of a loam soil amended with natural nanobiochar (i.e., 0 and 10% by weight) under three irrigation regimes (i.e., 100, 75, and 50% of full irrigation) and two levels of nitrogen fertilizer (i.e., 225 and 300 kgha-1 N). The irrigation system was porous clay pitcher subsurface irrigation. The full irrigation (FI) treatments were watered to refill the pore space in the rooting zone to the field capacity (100% FI), while in deficit irrigation treatments plants received 75% of the full irrigation (75% FI) or 50% of the full irrigation (50% FI). Fertigation treatments included two levels of N fertigation (i.e., 225 kg N ha-1 and 300 kg N ha-1) in the seedling, vegetative growth and green head stages were applied. Physiological and morphological traits of broccoli including secondary head fresh and dry weights, secondary head density, concentration of nutrients, total chlorophyll and leaf proline were investigated.

Plants exposed to deficit irrigation and nitrogen fertigation presented a significant decrease in head fresh and dry weights, head density and also total chlorophyll, while an increase in the leaf proline content was observed. The application of NNB in soil mitigated the drought and nutritional stresses effects on the morphological traits. The results showed significant effects of the natural nanobiochar application in sieved and none-sieved soils on head fresh and dry weight, head density, total chlorophyll and leaf proline for both seasons (2019 and 2020). Natural nanobiochar addition to both sieved and non-sieved soils improved the head fresh and dry weights, head density, and total chlorophyll content. Moreover, it significantly reduced the leaf proline of broccoli plant under deficit irrigation and nitrogen fertigation. The highest values of fresh and dry weight, head density and calcium, magnesium and chlorophyll concentrations were 99.26 g, 39.79 g, 0.92 g cm-3, 5.96 mg g-1, 3.52 mg g-1 and 2.52 mg g-1 in SNAS+NR2+FI, NNAS+NR2+FI, NUS+NR2+FI, SNAS+NR2+FI, SNAS+NR2+FI and NUS+NR2+FI treatments, respectively. As well as, the lowest value of leaf proline was 0.08 µmol g-1 in NNAS+NR2+FI treatment.

Our study demonstrated some of the beneficial effects of natural nanobiochar as an organic amendment for promoting crop productivity. Hence, the integration of natural nanobiochar addition along with deficit irrigation and low N fertigation condition could be considered as a viable and optimum approach in terms of water and fertilizer saving, yield and cost. Thus, the combination of this technique and sub-surface irrigation with the porous clay pitcher system will particularly be useful in arid regions that frequently suffer with water shortages condition.

Drought is one of the most important abiotic stresses limiting the survival, growth, and production of plants in many regions of the world including Iran. Genetically, different species adopt different strategies to confront with drought. One of the mechanisms that plants have evolved to adapt to the environmental changes is stress memory. In this study, different genotypes of smooth bromegrass were evaluated to investigate the drought stress memory and drought stress tolerance based on a greenhouse pot experiment. Thirty three genotypes of smooth bromegrass were evaluated in three moisture environments: control (C), once drought-stressed (D2), and twice drought-stressed (D1D2) in a factorial arrangement according to the randomized complete blocks design with two replications. The dry matter yield decreased by 45 and 36% in the one-stress and two-stress treatments compared to the control, respectively. These results indicated the role of drought stress memory in modulating drought stress through the influence on forage dry yield and root dry weight. The root dry weight reduced in the once stress and twice stress conditions by 32 and 19%, respectively, compared to the control environment. This finding shows the significant effect of stress memory on the root growth. Based on the principal component analysis, superior genotypes were identified for future researches. Overall, the results suggested that smooth bromegrass is capable to activate some drought stress memory mechanisms related to morphological and root traits.

Smooth bromegrass is particularly adapted to areas with medium and low annual precipitations and has a high drought tolerance when compared with the other grasses. Drought is one of the most important environmental factors with adverse effects on plant growth and development and affects all morphological, physiological, biochemical and metabolic aspects of plants (Farooq et al., 2009). Therefore, it is necessary to identify drought-tolerant genotypes (Saeidnia et al., 2017b). The term stress memory was first proposed by Trewavas (2003), as the plant's ability to access past experiences to better respond to future stresses. In open-pollinated species that are difficult to develop inbred lines, such as smooth bromegrass, the main breeding method is to create synthetic varieties that are obtained through the crossing of suitable parents. Besides, half-sib matting is one of the most common methods for obtaining genetic information such as estimating the additive effects and dominance of genes (Nguyen and Sleper, 1983). Saidnia et al. (2017a) in a study on the genotypes of orchardgrass species found superior genotypes for hay production. They also examined the genetic parameters and heritability of dry matter yield and introduced the superior genotypes for the further researches. Hence, this study was designed to investigate stress memory and its effect on improving drought tolerance in a smooth bromegrass germplasm.

This research was carried out from February 2017 to June 2018 in the research greenhouse located at the Isfahan University of Technology as a pot experiment. A sandy loam soil with bulk density, field capacity, and wilting point of 1.57 g cm-3, and 12.5 and 7.4 %w/w, respectively, was used for filling the pots. The genetic materials included 33 genotypes of smooth bromegrass that were collected from different regions of the country and some foreign gene banks. The genotypes were investigated in three moisture environments including control (C), once drought-stressed (D2) and twice drought-stressed (D1D2) as a factorial experiment in the form of a randomized complete blocks design with two replications.

The analysis of variance showed that drought treatments had a significant effect on most of the traits. A significant difference was observed between the genotypes regarding the measured traits indicating high genetic diversity among the genotypes. The secondary drought stress significantly reduced most of the traits. The dry matter yield decreased by 45 and 36% in the once-stress and twice-stress treatments compared to the control, respectively. These results indicated the role of drought stress memory through the effect on dry yield of forage and root dry weight. Also, the root dry weight was reduced by 32 and 19% in the conditions of one stress and two stress compared to the control environment, respectively, which shows the significant effect of stress memory on the root system. Multivariate analysis showed that under the twice stress condition compared to the other two moisture environments, the relationships of the traits have undergone severe changes, which is a confirmation of the effect of initial stress and stress memory.

This research indicated a high genetic diversity among the smooth bromegrass genotypes in terms of stress memory responses, which can be used in the selection methods. For example, the means of dry matter yield and root dry weight decreased to a lesser extent when grown in the presence of twice drought stress, than once drought stress. This finding shows that the mechanisms of the stress memory related to morphological and root traits in this plant are activated by applying preliminary mild drought stress and help the plant to have a smaller decrease in growth. Based on the principal component analysis, superior genotypes were identified for future research. The results of this research can be used in breeding programs and future genetic research. It is also suggested that suitable genotypes be studied more in field conditions over several years.

Casing soil is an important input in the production of the button mushroom, which is usually prepared from non-renewable organic sources (e.g., peat). In order to introduce a suitable alternative to peat, and also the effect of different casing soils on quantitative and qualitative characteristics of button mushroom this study was carried out.The reaserch was conducted in a completely randomized design with 20 treatments and three replications on an industrial scale in Negin Fasl Agro-industry Company. In this respect, different alternative materials, such as mixed cow manure, spent mushroom compost (SMC), cow manure vermicompost, and SMC vermicompost in different volume ratios with peat )preaperd from north of Iran, north peat) were utilized to produce different casing soil, which used in the process of button mushroom production. Commercial and total yield traits, biological efficiency, piece weight, dry matter percentage, and mushroom earliness were determined in the applied treatments.The results showed that there was a significant difference in yield, biological efficiency, dry matter percentage, and earliness traits among the treatments. The highest total yield and biological efficiency were related to the mixture of north peat and cow manure vermicompost (50% and 50%v/v), and the mixture of north peat and SMC vermicompost (50% and 50%v/v), with 16 kg/m2 yield., In cow manure (100%), and the mixture of north peat and cow manure (25% and 75%v/v) treatments no growing mycelial occured. The lowest total yield was achieved from north peat (100%), with 9.8 kg/m2.Overall, the results showed that replacement of cow manure vermicompost, and SMC vermicompost with peat and conventional casing soil treatments could lead to save the costs, and preservation of natural resources.

Monitoring the changes in physical and hydraulic properties and stability of growth media due to root growth effects and wetting and drying cycles is important. Wetting and drying cycles can probably change physical characteristics, availability of water, air and nutrients for the plant and, as a result, might affect the growth and yield of the greenhouse plants. The growth period greatly affects the physical characteristics of the growth substrates; therefore, the watering of growth substrates should be managed according to these changes to avoid improper irrigation.

In this study, 14 growth media were prepared from individual substrates with different volumetric ratios. In order to evaluate the changes of growth media over the time (i.e., during consecutive irrigation events) in the greenhouse, 10 wetting and drying cycles were applied on the growth media in the lab. Several physical indicators including easily available water (EAW), air after irrigation (AIR), water buffering capacity (WBC) and water holding capacity (WHC) of the growth media were determined before and after the wetting and drying cycles. Besides, the subsidence, decrease of mass and decomposition of the growth media were determined over the time. Total porosity (TP), bulk density (BD), particle density (PD), pH and electrical conductivity of the mixtures were measured as well.

The pH values in the growth media varied from 5.72 to 6.94. The maximum pH value was related to sawdust- sugarcane bagasse biochar produced at 300◦C vermiculite-zeolite, and wheat straw-vermiculite substrates, and the minimum value was related to the cocopeat-perlite substrate. The values of EC in the growth media varied from 0.21 to 1.43 dS m-1. The highest and lowest EC values among the growth substrates were related to date palm bunches-vermiculite-rockwool and rockwool (0.2)-perlite substrates, respectively. The bulk density (BD) values of the growth media varied in the range of 0.163-0.401 Mg m-3. The values ​​of total porosity (TP) of the growth media varied in the range of 64.8-82.8%v/v. The highest TP was related to the cocopeat-perlite substrate. The TP values ​​of most of the substrates were greater than 70%v/v. The average values of EAW in the growth substrates ranged from 0.123 to 0.272 cm3 cm-3. The highest EAW was related to the sawdust-sawdust biochar produced at 500 ◦C vermiculite-zeolite substrate. The application of wetting and drying cycles increased EAW in most of the growth media. Therefore, it can be stated that the time had a positive effect on the EAW in most of the growth media. The average values of AIR before and after the application of wetting and drying cycles for the growth media varied in the range of 0.063-0.240 cm-3 cm3. The highest value of this indicator was observed in the sawdust-date palm bunches biochar produced at 300◦C vermiculite substrate. In all substrates (with the exception of the sawdust-sawdust biochar produced at 500◦C vermiculite-zeolite), the AIR increased after wetting and drying cycles. The range of WHC values before and after applying wetting and drying cycles was 0.453-0.699 cm3 cm-3. The highest WHC belonged to the wheat straw-vermiculite substrate. The WHC values of five growth media, including cocopeat-perlite, decreased due to the application of wetting and drying cycles, and the WHC values of nine growth media decreased. The most stable substrate after the wetting and drying cycles was rockwool-sawdust-vermiculite. The effect of time on the quantity of WBC was positive, so that with the application of wetting and drying cycles, the WBC values of most of the substrates increased. In all substrates, subsidence and dry weight reduction were observed after the wetting and drying cycles. These changes were low for the substrates with a high volumetric ratio of inorganic materials. The least change among the growth substrates in terms of decomposition (dry weight reduction) was related to the completely inorganic substrate rockwool (0.1)-perlite (%0.17). The most stable substrate in terms of subsidence after wetting and drying cycles was the rockwool-sawdust-vermiculite, which has a large volumetric ratio of individual inorganic substrates. The highest subsidence was observed in the substrates containing wheat straw (wheat straw-vermiculite and date palm bunches biochar produced at 300◦C wheat straw-vermiculite). The organic matter content in all the growth substrates decreased over time (after wetting and drying cycles). The decrease of organic matter in the substrates can be related to the decomposition of organic materials as a result of wetting and drying cycles.

The BD, TP, EAW and WHC of the majority of growth media were in the optimal ranges and for some mixtures even better than cocopeat-perlite. Wetting and drying cycles could affect the growth media through several processes such as decomposition of organic compounds, displacement and rearrangement of particles, fragmentation of particles, shrinkage, hardening and subsidence. The growth media with a high percent of organic substrates were unstable as compared with those containing a high proportion of inorganic substrates. In general, the wetting and drying cycles increased the frequency of micropores in the growth media. The wetting and drying cycles positively affected EAW, WHC, AIR and WBC of most growth media. These findings imply that wetting and drying cycles may improve the growth media according to the studied extensive variables. However, it is necessary to study the intensive variables such as hydraulic conductivity, oxygen diffusion and pore tortuosity in the growth media for better evaluation of the impact of wetting and drying cycles as well.

According to the rapid population growth, the challenging issue of production of economic and suitable food sources has led to greater attention to soilless culture greenhouse production systems. Components of growth media in horticulture are usually selected based on physical and chemical properties and their abilities in providing enough water and oxygen for roots. This study was conducted to investigate the feasibility of using some agricultural wastes (i.e., sawdust and wheat straw) and three rockwool types (i.e., raw, ground, ground, and sieved) as substitutes for commercial greenhouse growing media such as cocopeat and perlite. Several hydraulic, aeration, and chemical properties including easily available water (EAW), air after irrigation (AIR), water holding capacity (WHC), water buffering capacity (WBC), saturated water content (θs), bulk density (BD), total porosity (TP), water drop penetration time (WDPT), pH, and electrical conductivity (EC) were measured and scored in the growth media. Raw rockwool had larger particles compared to ground rockwool, which resulted in its faster water release. Processing of the rockwool decreased the saturated water content and saturated hydraulic conductivity due to the decrease in particle size. Four growth media were scored as very good and one was scored as good. The highest and lowest scores belonged to sawdust (34) and ground rockwool (30), respectively. The studied growth media with high TP, EAW, and WHC and low BD, EC, and WDPT can be used individually or combined with other commercial substrates for greenhouse growth media.

One of the most significant environmental crises in arid, semi-arid, sub-humid, and even humid regions is the destructive phenomenon of desertification and in the arid and semi-arid regions is wind erosion. These problems exist in large areas of Iran and it is necessary to use an environmentally friendly and economic method to solve this problem. In this study, calcium bentonite clay was used for the first time in Iran and perhaps in the worlds in the critical region of Sajzi, which covers an area of 65 hectares. Experiments were performed on the crusts after one year of mulching with bentonite clay. The results showed that wind erosion has a negative and significant correlation with the mean weight diameter and geometric weight diameter of aggregate, aggregates with diameters greater than 0.25 mm, shear strength, and penetration resistance. On the other hand, the results of the permeability test using double-ring and by three models (Kostiakov, Horton, and Philip) showed that the lowest mean square error (SSE) and the highest coefficient of determination (R2) belonged to the Kostiakov model in the mulch-applied and control samples. This result indicated the superiority of the Kostiakov model compared to Horton and Philip's models. Wind erosion intensity was also measured in situ using a portable wind tunnel at 20 points in the Sajzi region. The findings showed that mulch application has controlled more than 95% of soil erosion.

Soil water repellency reduces soil infiltrability, water availability for plants, and can increase surface runoff, soil erosion and preferential flows, and reduces environmental fertility. Land use is one of the factors affecting soil water repellency. Soil water repellency can increase runoff in areas where land use change occurs. Thus, knowledge about the soil water repellency properties is necessary for effective environmental management. Changing the soil properties upon reduction of soil wettability can affect crop growth and yield, and water use efficiency. However, relations between soil water repellency and physical and chemical properties among different land uses in the large scale have not been studied yet. Therefore, the objectives of this study were: i) to investigate the persistence and severity of soil water repellency in different land uses, and ii) to develope regression relations between the water repellency indices and soil physical and chemical properties in the central part of Mazandaran province.

In this study, the persistence and severity of soil water repellency were investigated in the paddy fields located in the plains to mountainous areas consisting of four land uses of pasture, citrus garden, paddy field, and forest located in Amol city in the central part of Mazandaran province. Ninety-two soil samples were collected to determine soil water repellency and physical and chemical properties in the dry season of the year. The persistence of soil water repellency was determined using the water droplet penetration time (WDPT) test, and water repellency index (RI) and soil-water contact angle (β) were measured using the intrinsic sorptivity test in the laboratory. Correlation between water repellency indices and soil properties was studied. Relations between the water repellency indices and soil properties were derived by multiple regression.

Soil water repellency in all the land uses was sub-critical and all of the soil-water contact angle values were less than 90°. The highest mean values of soil water repellency indices in all methods were found in the forest land use, so that Log WDPT value was significantly different from paddy field land use. Log WDPT showed positive and significant correlations (r = 0.33**) with RI, indicating that the water repellency persistence (i.e., Log WDPT) and water repellency severity (RI) are directly related in the studied soils. The correlation between soil organic matter content and calculated β in the citrus garden land use was positive and significant (r = 0.42*). There was also a positive and significant correlation between Log WDPT and soil organic matter content (r = 0.36***). Negative and significant correlations were found between calcium carbonate equivalent (CCE( and Log WDPT in the whole study area (r = -0.28**) and in the paddy field land use (r = -0.29*)

The results showed that the land use through the effect on the soil organic matter content can induce and intensify water repellency in the studied soils. Moreover, the derived regression relations indicated that soil organic matter content, total nitrogen and CCE are important properties affecting water repellency in the studied soils.

Soil salinity and sodicity is a world-wide problem of irrigated farmlands that threaten soil quality and crop productivity in arid and semi-arid regions. Soil salinity refers to the accumulation of salt in the plant root zone which reduces plant growth. The use of saline and sodic groundwater for irrigation purposes deteriorates soil quality, causing clay dispersion, and reduction in hydraulic conductivity and plant available water. It also negatively affects plant physiological parameters such as reduction of grain yield, shoot and root length, biomass, rate of photosynthesis, leaf water potential, and increases proline content. Therefore research on possible amendments for the soils in these systems is necessary. Different organic and inorganic amendments are used to address salinity problems in agricultural soils. Common organic amendments include animal manures, agricultural residues, green wastes and biochars, and the inorganic amendments include gypsum, zeolite and super absorbents. In this study, the application of biochars produced at pyrolysis temperatures of 300 and 500 °C and their feedstocks as well as a superabsorbent (SA) on the leaching of salts through the soil columns were investigated.

The experiment was carried out in the Irrigation Laboratory, Department of Irrigation, College of Agriculture, Isfahan University of Technology, Iran, in 2018. The experiment was conducted as a completely randomized design with three replications. A saline-sodic soil (0–30 cm layer) was sampled from the Rodasht Soil Salinity Research Center, located in the east of Isfahan, Iran. The soil was classified as Typic Haplosalids, soil texture was silt loam and comprised 610, 180 and 210 g kg-1 silt, sand and clay, respectively. Five combinations of sugarcane bagasse, rice husk, cow manure, and pine wood were considered and pyrolyzed at 300 °C and 500 °C under oxygen-limited conditions (continuous inflow of nitrogen) for 2 hours (slow pyrolysis) in a pyrolysis chamber. A control with no amendment (CT), a super absorbent (Stockosorb) (SA), feedstocks (BWM, RWM, WM, BWMR and BWR), and their biochar produced at 300 and 500 °C were considered. The five combinations were pyrolyzed at two temperatures of 300 and 500 °C to obtain the biochar samples. Then the feedstocks and their biochars, as well as the SA sample, were applied to the saline-sodic soil and incubated in sealed plastic bags at a water content of 80% of the soil plastic limit, and room temperature (25 ± 1°C) for 40 days. After the incubation, the amended soils were packed into soil columns (PVC pipes) of 15 cm diameter and 50 cm height, and leached with 4 pore volumes (PV) of irrigation water. The PV was determined using the porosity and volume of the soil column. A constant water height of 5.0 cm was held on the soil surface by a mariotte bottle. The saturated hydraulic conductivity (KS) of the soil and the leachate electrical conductivity (EC) were measured during the leaching period at every 1/3 PV leaching. After leaching, the soil samples were carefully collected from the columns. Then the soluble ion concentrations (Mg2+ and Ca2+) were determined.

At a given period, there was a lower EC of the leachate for the BWR (sugarcane bagasse, rice husk and pine wood) treatment compared to the other amendments. The KS of soil increased significantly with the application of all amendments, which could be related to the improvement of soil structure, and increased porosity and leaching of sodium. The lowest KS was observed in control, which could be related to exchangeable sodium between the solution and the soil exchange sites, and soil dispersion. The biochar treatments had less Mg2+/Ca2+ ratio than their feedstocks and subsequently, the soil aggregate stability increased in the biochar treatments. Soil quality is influenced by the physical properties of amendments that are applied to the soil. It is important to consider the pH and EC of biochar for soil amendment. The BWR combination had the lowest EC and pH compared to other combinations. Also, the BWR had the highest C/N ratio compared to other combinations, subsequently, the KS increased. Overall, this study suggested that the use of BWR300 (the biochar of BWR compound produced at pyrolysis temperature of 300 °C) and SA amendments might be suitable for the improvement of saline-sodic soils in arid and semi-arid regions. Further experiments are needed to determine the rates of amendments for different soil types and water qualities in the long–term periods and large-scale applications in saline-sodic conditions.

Sewage sludge has positive effects on chemical and physical properties of soil. Biochar production from sewage sludge, while having positive effects on the soil, can lead to its effective management, especially in relation to the environment. The objective of this study was to investigate the effect of sewage sludge and its biochar on water repellency and structural stability of two calcareous soils with clay loam and loam texture under corn cultivation. Sewage sludge was mixed with soils in the rates of 10, 20 and 40 t ha–1 (S1, S2 and S3). The equivalent application rates of biochar were 7.3, 14.5 and 29 t ha–1 (B1, B2 and B3). At the end of corn growing period, soil water repellency was measured by the intrinsic sorptivity method. Water-dispersible clay (WDC) was also measured as an indicator of soil structural instability. Results showed that the water repellency index (RI), ethanol sorptivity (SE) and soil-water contact angle (β) were significantly higher in sewage sludge and biochar treatments than those of control. However, the WDC in the sewage sludge and biochar treatments was significantly lower than the control. The values of RI and β in the clay loam soil were significantly higher than the loam soil. In both sewage sludge and biochar treatments, an increment in the application rate increased the RI. In the clay loam soil, the highest RI and SE were observed in the sewage sludge and then in the biochar treatment; while in the loam soil, the RI had the trend of biochar > sewage sludge > control. Overall, the results indicated that the use of organic treatments such as sewage sludge and its biochar would increase sub-critical soil water repellency and structural stability.

Soil salinity has a negative effect on physical, chemical and biological properties of soil. Salinity also affects the relationships between soil and plants, which in turn has a significant effect on plant growth. One of the solutions used to reduce the effects of salinity and improve the physical properties of the soil is application of organic and chemical conditioners. Organic matter as well as calcium improve the structure and physical condition of the soil. Conditioners in saline soils include soluble calcium salts such as gypsum (CaSO4.2H2O), calcium chloride (CaCl2.2H2O) and phosphogypsum (phosphorous gypsum), and acids such as sulfuric acid, sulfur, pyrite, Aluminum sulfate and sulfur lime (calcium polysulfide). Strategies aimed at evaluating and ameliorating the structural quality of soils should be developed to ensure the sustainable use of lands. The least limiting water range (LLWR) attempts to incorporate crop-limiting values of soil strength, aeration, and water supply to plant roots into one effective parameter (on the basis of soil water content). The LLWR can be a useful indicator of soil quality and soil physical constraints on crop production. Therefore, the objective of this research was to study the effects of organic and inorganic conditioners on some structural and hydraulic indices of saline sodic soils.

In this study, the effect of two types of organic and chemical conditioners and the simultaneous application of them on modifying the physical properties of 5 saline soils around the lake of Urmia were investigated. Treatments included algae, salfit and algae+salfit. The soil samples were transferred to culture boxes (40 × 40 × 40) according to the bulk density of the sampling site. The soil samples were wetted and dried several times. Conditioners treatments including application of calcium and organic compounds. After reaching the field capacity, wheat seeds were sown and irrigated with water (electrical conductivity 0.28 dS/m and pH= 7.78). It should be noted that irrigation was done at intervals of 8 days. Two months after the beginning the experiment, irrigation was stopped and soil moisture was allowed to reach a permanent wilting point. At this stage, undisturbed soil samples were prepared from the treated soil of each box and the mean weight‐diameter of dry (MWDdry) and wet (MWDwet) aggregates were measured. Then the values of least limiting water range in two suctions of 330 and 100 cm and water integral capacity of samples were measured.

According to the initial analysis, all soils used were saline and the amount of calcium carbonate was high in two soils (number 3 and 5). Soil organic carbon content was also low. The results of salfit analysis also showed that the dissolved calcium and sulfur content were 8 and 3.9%, respectively. The results showed that soil 1 had the highest amount of MWDwet and soil 5 had the lowest amount of MWDwet. The highest and lowest aggregate stability values were obtained in soils 3 and 5, respectively, where soil 5 was very saline soil. The studied soils differed in terms of soil water relations. The highest amount of LLWR330 was found in soil 5, while the lowest amount of LLWR100 and IWC parameters was also obtained in same soil. The results of this study showed that salfit treatment caused the highest increase in aggregate stability (74.9%) LLWR330 (14.5%) and integral water capacity (26.2%) compared to the control and the highest mean weight‐diameter of aggregates in both wet and dry conditions was obtained in salfit-algae treatment (52.4% and 40.4% increase, respectively). The results of correlation analysis among the measured parameters showed that the highest correlation was found between aggregate stability and MWDwet. Among the measured parameters, aggregate stability had the highest correlation with other parameters and the correlation of this parameter with LLWR330, LLWR100, IWC and MWDwet were 0.36, 55, 75 and 88 %, respectively. Soil water integral capacity also had a significant correlation (p < 0.01) with LLWR330 (0.84) and MWDwet (0.7).

The effect of initial soil properties on studied parameters was significant and the use of conditioners improved studied parameters, and use of conditioners increased indices structural and hydraulic of saline soils. In general, the results of this study showed the positive effect of conditioners on physical properties of the studied soils, in which salfit and salfit-algae have a better effect on studied parameter, and they could be useful to improve soil physical condition. It seems that the application of different rates of conditioners as well as their interaction with each other should be considered according to the basic properties of the soil.

This research was performed to determine the effect of inoculation of two species of arbuscular mycorrhizal fungi (AMF) on soil available water (SAW) and glomalin concentration under drought and salinity stresses according to a factorial based on completely randomized design with three replications. Treatments included two plant species Atriplex canescens and Haloxylon ammodendron with inoculation of two fungal species Glomus geosporum and Glomus mosseae plus two levels of salinity stress at 7 and 14 dS m-1, and two levels of drought stress including maximum allowable depletion (MAD) of 50 and 80%. After one year of treatments, plant available water (PAW), least limiting water range (LLWR), integral water capacity (IWC), total and easily extractable glomalin concentration and soil organic carbon (SOC) content were measured. Results indicated a significant increase in SOC, glomalin concentration, PAW, LLWR, and IWC by increasing the salinity level in treatments inoculated with G. mosseae and G. geosporum. The highest percentages of increase in PAW (147%), LLWR (140%) and IWC (85%) as compared with control were observed under combined salinity and low drought treatment (14 dS cm-1 + MAD of 50%) in A. canescens inoculated by G. geosporum. The highest concentrations of total glomalin and easily extractable glomalin were observed in both plant species under salinity of 14 dS m-1 and severe drought treatment (MAD of 80%) with the inoculation by G. geosporum and G. mosseae. Overall the results of this research indicated a reduction in negative consequences of drought and salinity stresses in the soil under cultivation of A. canescens and H. ammodendron, with application of mycorrhizal fungi.

Subsurface leaky irrigation systems are one of the novel irrigation systems developed in recent years. In this system, the pipes are located below the soil surface and water is distributed in root zone with a very low pressure of less than one meter water column. This system can be widely used in small gardens with quantitative and qualitative water restrictions. Optimal design of these systems depends on the effect of different parameters on water infiltraion and wetting pattern. For this reason, the volume of water infiltration is investigated at different Subsurface leaky irrigation strategies. The inlet discharge and volume of applied water at each strategy differs from 0.1, 0.2 and 0.35 liters per second and 30, 60 and 90 liters, respectively. The humidity of the soil is also measured in wetting area at the end of each experiment. The results show that inlet discharge in feeding stage has dramatic effect on water infiltration, while the volume of applied water has more effects in discharg stage. Measurements of wetting pattern at the end of experiments also showed that water infiltration increased by 17% with increasing the inlet discharge into the system. The developed models in feeding phase and discharge and feeding phase in non-free surface flow had correlation coefficients of 0.69, 0.77 and 0.66, respectively, which show their higher accuracy in comparison with other phases.

Double Ring (DR) and Time of Ponding (TP) methods are two field methods for determining infiltration rate in the sprinkler irrigation system. However, the boundary conditions and the nature of the flow on the soil surface in the sprinkler irrigation system are different from the DR method. The aim of this study was to investigate the relationship between the measured infiltration intensity values with the double ring and ponding time methods in different soil textures. The first factor consisted of two methods and the second factor consisted of five soil textures in Isfahan province and the experiments were performed in three replications in the form of a factorial statistical design. The results showed that the infiltration intensity values obtained from the DR method were on average 2.7 times higher than the values determined in the TP method and the final infiltration values of the DR method were 5 times higher than those of the TP method. The difference of infiltration values was higher in the fields with coarser texture (sandy clay loam) and less in the field with clay loam texture. The maximum final infiltration rate was observed in the field with loamy sand soil texture and the minimum final infiltration rate was observed in the field with clay loam soil texture. The results indicate the need to adjust and correct the final infiltration of DR method in the design of sprinkler irrigation systems. It is suggested to use TP method to determine the infiltration velocity values for designing sprinkler irrigation systems. If DR method is used, it is recommended that the infiltration values be modified with the given development equations before application.

Drought is the most important known abiotic stress which strongly affects the growth and yeild of different crops worldwide. Among all the mineral nutrients, potassium (K) plays a particularly critical role in plant growth and metabolism, and also contributes to the survival of plants and adequate biomass production under various biotic and abiotic stresses, especially under drought stress. Under drought stress conditions, K regulates the stomatal opening and helps plants adapt to water deficits. In this study, the effect of phlogopite, as a potassium-rich source and a soil chemical conditioner, to help moderate the adverse effects of drought stress on barley growth and yield under greenhouse conditions was evaluated.

This study was conducted as a completely randomized design with factorial arrangement and 3 replications in the hydroponic greenhouse of the Isfahan University of Technology. The growth medium was a mixture of quartz sand and phlogopite and different levels of drought stress were applied. Plants were supplied with either a complete or a potassium-free nutrient solution during the five-month growth period. At the end of the experiment, shoots and roots were harvested separately and their dry weight recorded. The amount of potassium in the extract prepared by the dry ash method was determined by a flame photometer. The percentage of potassium release from phlogopite in potassium-free nutrient solution was calculated and elemental analysis (XRF) was performed on several selected samples.

The shoot and root dry weight and potassium uptake of plants grown in the phlogopite containing media were higher than those in the control media. These two parameters were also higher in plants received complete nutrient solution as compared to those supplied with the K- free nutrient solution. Drought stress reduced yield and potassium uptake. The highest levels of loss of dry weight and potassium uptake were observed in plants supplied with the K-free nutrient solution under severe drought stress. There was a significant positive correlation between the shoot dry weight and K uptake and also between the root dry weight and K uptake. The results of the elemental analysis of phlogopite particles before and after application in the growth medium were consistent with the amount of potassium uptake by the plant. The highest percentage of potassium removal was observed under no drought stress conditions. In general, it looks like that the application of phlogopite alleviates the negative effects of drought stress by releasing its interlayer potassium, due to the important role of potassium in regulating stomatal opening and closing, increase photosynthesis rate and water retention in plant tissues.

The results of this study showed that the application of phlogopite was useful as a natural and low-cost source to supply K requirement in plant growth medium to reduce the effects of the drought stress, especially in the greenhouse.

Shortage of water resources and deterioration of water quality have urged the need to develop new technologies for the removal of contaminants from water. Heavy metals produced by municipal and industrial activities are among the most toxic contaminants present in the natural and waste waters. Different methods have been developed for the elimination of heavy metals from water resources and industrial waste waters. Adsorption is an effective and economic method for the water purification purposes. Nowadays, clays and natural polymers have been widely used as the adsorbents for heavy metals, due to their eco-friendly nature, natural abundance, low cost and high specific surface area. If these adsorbents are used as a hybrid material, some of their physical and chemical restrictions would be alleviated. In this study, polyacrylic acid–bentonite hybrids and natural bentonite were compared in terms of Pb adsorption in the batch and fixed-bed column systems. Besides, the effect of pH on Pb retention was investigated in both systems. The results of the batch studies showed that Langmuir and Freundlich isotherm models were appropriate in ing quilibrium Pb sorption data. Pb sorption by the sorbents was increased with the rise in solution of pH from 4 to 6, showing the greatest Pb sorption capacity at pH values of 4 (83.29 mg g-1) and 6 (103.3 mg g-1). Different indices of filtration and adsorption, including average relative effluent concentration, relative adsorption index, relative transmitted index, and filtration coefficient, were calculated from the break-through curves, indicating that the polyacrylic acid-bentonite nanocomposite was superior in the Pb sorbtion, as compared to bentonite. Also, a higher pH value resulted in the greater Pb removal from the solutions.

An investigation was carried out for the journals in 13 branches of Agricultural Sciences and Natural Resources at the Department of Agricultural Sciences, IR Academy of Sciences. A total of 200 Iranian scientific journals were qualitatively evaluated. As part of that project, the results of 10 journals in the fields of soil science published in 2014 are reported. Ten indices for evaluating the format of the journals and five indices for the quality of the articles published in the journals were designed and used. The data were statistically analyzed to rank the journals. Results showed that none of the journals received the highest ranking (very good). Twenty percent were good, fifty percent were medium, twenty percent were weak and ten percent were placed in the very weak category. The journals were also compared by the following criteria in relation to published articles: innovativeness, applicability and up-to-datedness of articles and practical usefulness and necessity of publication of the journal. In this regard, Biology Journal scored highest. Journals of Soil and Water Conservation Researches, and Soil Management and Sustainable Production scored highest for the necessity of publication. None of the assessed journals showed any preference in view of practical usefulness.

A challenge of sustainable development is related to agriculture, food security, and conservation of water and soil resource, under the current crop production paradigm. Increasing crop yields often have negative environmental impacts. Soil salinization and sodication are major environmental hazards that limit agricultural potential and are closely related to agricultural unsuitable management and water resources overexploitation, especially in arid climates. In this study, we investigated the negative impacts of saline and sodic irrigation water on soil properties that it is necessary to study the factors affecting the degradation of soil structure to implement proper land management and we intended to help the farm producer or landowner to understand the fundamental differences between these two problems. Samples of clay loam and sandy loam soils were treated in 5 wetting and drying periods with different types of water quality (which combinate different levels of EC and SAR). Soil water content of samples was achieved at soil matric suctions of 0, 10, 20, 40, 60, 100, 300, 1000, 2000, 4000 and 15000 cm. Also, dispersible clay and saturated hydraulic conductivity were determined. Results showed that increasing of SAR caused dispersion of clay and saturated hydraulic conductivity was decreased with increasing of dispersed clay. Increasing SAR caused some macropores and mesopores changed to micropores and as result enhanced water retention especially at high matric suctions. Water retention capacity was enhanced by increasing in water EC as that flocculated soil particles and created new soil pores.

Soil organic carbon (SOC), as a great constitute of soil organic matter (SOM), has an important role in chemical, physical and biological processes of soil. SOM or SOC is a key parameter of soil quality and a soil fertility indicator. SOM has an essential role in formation of soil aggregate and its stability, water and nutrients adsorption, water holding capacity, infiltration of air and water, hydraulic conductivity, soil water repellency and carbon sequestration. Various studies have shown that the quantity and quality of SOM can be affected by anthropogenic activities such as farming practices and other economic development activities. It has also been reported a high rate of SOM loss on eroded lands. Hence, monitoring temporal and spatial variation of SOM is essential for evaluating long-term soil productivity management. However, conventional soil sampling and chemical measurement of SOC, especially in large geographic scale, is tedious, time consuming and expensive. Therefore, rapid and precise assessment of SOC content can be useful in long-term management of soil. The objective of this study was to investigate the ability of soil visible-near infrared (Vis-NIR) spectroscopy for estimating SOC in Zrebar lake watershed of Marivan, Kurdistan province, Iran.

A total of 100 soil samples were collected from the studied region, with an area about 10718 hectares. The spectral reflectance and physicochemical properties of all soil samples were measured under laboratory controlled conditions. After recording of the spectra, different pre-processing methods were applied and compared. Then, pedo-transfer functions (PTFs) and specto-transfer functions (STFs) were developed to estimate SOC content using stepwise multiple linear regression (SMLR). The accuracy and reliability of the derived PTFs and STFs were evaluated using coefficient of determination (R2), normalized root mean square error (NRMSE), mean error (ME), index of agreement (d), and ratio of performance to deviation (RPD) statistics.

Based on the results, soil organic carbon showed high and significant (significance level of 1%) correlations with spectral reflectance values at wavelengths 858 and 1916 nm. The results indicated that the derived PTFs had the higher accuracy (R2avg=0.83, NRMSEavg = 24.55%) to estimate SOC in comparison with the STFs (R2avg=0.44, NRMSEavg= 44.31%). However, SOC could be also fairly estimated by the derived specto-transfer functions (Ravg2=0.52, RPDavg= 1.44).The results also revealed that the Savitzki–Golay smoothing filter with 1st order derivative was the best spectral pre-processing method to reduce the effect of random noise and improve the calibration models.

Overall, the results indicated that although the performance of STFs was not superior to the corresponding PTFs for estimating SOC, but this approach can be used as a reasonable indirect method in case of unavailability of PTFs.

Wetting pattern in a trickle irrigation system is one of the most important characteristics that should be taken into consideration for designing the irrigation systems. Improving the dimensions of the wetting pattern will increase the water use efficiency and irrigation systems. The objective of this study was to investigate the effect of rice husk and its biochar application on the wetting pattern in a silty clay soil under surface trickle irrigation. A box with the length of 200, the width of 50 and the height of 100 cm was used. To easily fill and empty the model, it was filled up to a height of 50 cm. The rice husk and its biochar were added to the soil at the rates of 0, 1 and 2 mass percentages based on a factorial arrangement of the treatments in a completely randomized design with three replications. Biochar was prepared in a special furnace at 500°C without oxygen. The experiments were done with a flow rate of 4 liters per hour with the irrigation time of 3 hours. The results of the analysis of variance showed that the organic treatments increased the soil water content in the range of field capacity to a permanent wilting point; the highest increase was observed for the biochar 2% treated soil. Also, the addition of rice husk and biochar in the silty clay soil reduced the horizontal advance and increased the vertical advance wetting pattern.

Soil quality is affected by the type of land use and management. Evaluation of soil quality indices is a suitable guide for adopting sustainable management practices and preventing soil degradation. The goals of this research were to explain soil variations and to determine the most important soil quality assessment indices. Therefore, totally 50 soil samples were collected from four land uses including forest, pasture, rain fed and irrigated farmlands in Lordegan watershed. Then soil characteristics consisted of soil bulk density, soil texture components, calcium carbonate equivalent, cation exchange capacity, pH, electrical conductivity, organic carbon, total nitrogen, carbon to nitrogen ratio, microbial basal respiration and mean weight diameter of aggregates were measured. Also, average monthly temperature, annual precipitation, elevation and slope of sampling points were determined. The results of principal component analysis illustrated that organic carbon, sand content, annual precipitation and elevation were the most important factors causing soil variations in the area. This method could explain 81% of soil variations in the region by creating 5 principal components. Furthermore, various kind of land uses were distinguished successfully according to a set of selected soil attributes using Discriminant Analysis. The percentage of correct classification in this analysis was 94%. The results of this study emphasize on the applicability of multivariate statistical methods in the assessment of soil quality. The individual examination for each of selected indices indicated the high quality of forest soils compared to the other land uses. However, rain fed farmlands had a poor quality situation. Therefore, achieving sustainable management in the area requires the prevention of land use change and the restoration of degraded lands for improving soil quality.

Location of soil moisture sampling in irrigation management is of special importance due to the spatial variability of soil hydraulic characteristics and the development of root system. The objective of this study was determination of the suitable location for soil moisture sampling in drip-tape irrigation management, which is representative of the average moisture in the soil profile (θavg) as well. For this purpose, soil moisture distribution (θij) at the tassel stage of maize and one irrigation interval (68-73 day after plant) were measured at the end of season. The results showed more than 70% length of the root of plant was located in 30 cm of the soil depth. By accepting ±10% error in relation to the averaged soil moisture, some region of soil profile was determined which was in the acceptable error range and also near the averaged soil moisture (0.9θavg<θRec<1.1θavg). By overlapping θRec in one irrigation interval, the appropriate location for soil moisture sampling was the horizontal distance from drip-tape line to 20 cm and the depth of 10-20 cm from the soil surface. To determine the appropriate place for soil moisture sampling, the development of root system and the maximum concentrated root length density in the soil profile extracting the maximal soil moisture should be taken in to account, parallel with the averaged soil moisture.

Long-term use of treated wastewaters for irrigation adds compounds and/or ions to soils which might alter the soil physical, hydraulic and mechanical properties. Soil mechanical properties are closely linked with the plant growth. This study was conducted to investigate the effect of short-, mid- and long-term applications of the treated wastewater of Mobarake Steel Company in Isfahan on the soil penetration resistance and shear strength in the company green space. Soil penetration resistance and shear strength were measured using a pocket penetrometer and in situ shear box, respectively. The results showed that soil penetration resistance (i.e. soil hardness) at both dry and wet conditions significantly was increased upon short-, mid- and long-term applications of wastewater; 19 years of the application of wastewater resulted in the highest soil penetration resistance at wet condition, but the well water did not significantly affect it. Surface crust in the non-irrigated locations increased the soil penetration resistance, but the irrigated sealed soils were not significantly different from the virgin soil in terms of dry and wet penetration resistances. For the soil shear strength parameters, wastewater, well water and surface crust did not significantly affect soil cohesion (c), they but significantly affected the angle of internal friction (φ). Overall, soil shear strength parameters were not greatly affected by the irrigation water treatments because of the dominant effect of the soil fractions (texture and gravel content) and the microstructure.

The effect of water quality on soil water retention, structure, and hydraulic conductivity in two soil textures was studied. Undisturbed soil samples were treated in 5 wetting and drying periods with 6 different types of water quality consisting of 2 levels of EC (0.2 and 10 dS m-1) and three levels of SAR (1, 5 and 12). Undisturbed soil samples were equilibrated on sand box apparatus to soil matric suctions of 0, 10, 20, 40 and 60 cm and on pressure plate apparatus to soil matric suctions of 100, 300, 1000, 2000, 4000 and 15000 cm. The van Genuchten-Mualem model was fitted to simulate the measured soil water characteristic curve. Soil physical quality index (S) and the inflection point of water retention curve (θINFL) were evaluated using fitted parameters. Also, the macro-porosity, meso-porosity, micro-porosity, available water content (AWC100 and AWC300), and saturated hydraulic conductivity were measured. The study was conducted in a completely randomized design with three replications. Results showed that increasing EC caused soil particles flocculation, by developing some new pores and, consequently, increasing water retention capacity. Although increase in SAR dispersed soil particles, alteration of some macro-pores and meso-pores to micro-pores enhanced water retention, especially at high matric suctions. But, the available water content did not change significantly. Also, increase in water EC enhanced water retention at all matric suctions and the highest moisture content at inflection point was seen at EC of 10 dSm-1. The increase in SAR and decrease in EC were directly related to decrease in saturated hydraulic conductivity. Soil physical quality index (S) decreased by sodium increment, which indicated the reduced soil physical quality.