Objective: Soil salinity is one of the major worldwide environmental constraints affecting agricultural production in arid and semiarid regions. Lack of proper management of water and soil resources lead to increase soil salinity and reduce soil fertility. On the other hand, it seems simple and cheap method of measuring soil salinity is necessary. The aim of this study was to determine the relationship between exchangeable SODIUM percentage (ESP) and SODIUM ADSORPTION RATIO (SAR) in some salt-affected soils of Marvdasht plain, Fars, Iran.Methods: To this purpose, fifty soil samples were randomly taken from surface (0-10 cm) and subsurface (10-20) cm from different fields of experimental site.Results: The statistical results of the study indicated that to predict soil ESP based on soil SAR the linear regression model ESP=0.941+1.119SAR with R2=0.806 can be recommended.

Introduction: Boron (B) is an essential plant micronutrient whose soil availability is influenced by many soil factors. Understanding the processes controling activity of boron (B) in the soil solution is important for soil fertility management. The reaction of ADSORPTION and desorption of boron in soil determines the amount of boron that is available to plants. ADSORPTION- desorption processes play a major role on boron equilibrium concentRATIOn and therefore on its bio-availability. Ionic strength, pH and ionic composition in exchangeable phase are among the major factors affecting B ADSORPTION reactions. Reduced ADSORPTION of boron at high pH is because of a surface potential decrease on minerals with pH-dependent charge.Ionic strength has also a considerable effect on B ADSORPTION. Several studies have been performed in the ADSORPTION of boron and the effect of factors such as ionic strength and cations has been understudied, however, the effect of SODIUM ADSORPTION RATIO and its interaction with the ionic strength on boron ADSORPTION behavior has not been reported. In this study, the ADSORPTION isotherms of boron in the soils affected by the combined effects of ionic strength and SODIUM ADSORPTION RATIO were investigated.Materials and Methods: In order to assess the effects of ionic strength (IS) and SODIUM ADSORPTION RATIO (SAR) on availability of B, the ADSORPTION of B was investigated in a calcareous soil that had low levels of electrical conductivity, SODIUM ADSORPTION RATIO and available P. For this purpose, 5 g soil was equilibrated with 20 mL of B solution (0, 2, 5, 8, 10, 15, 20 mg L-1) in 0.02, 0.06 and 0.12 M background solutions (prepared by NaC1, CaC12.2H2O, MgCl2.6H2O), at two SAR levels (20 and 100).The reaction temperature was 25°C. The suspension was centrifuged, filtered, and a sample was removed and B was determined by Azomethine-H spectrophotometric method (at a wavelength of 420 nm). B ADSORPTION in Soil was obtained by subtracting B in solution after filtRATIOn, from added boron.

Background and Objectives: In the soil science, echangble SODIUM percentage and SODIUM ADSORPTION RATIO are two different criteria to evaluate of soil alkality. For measured of ESP, it is essential to have soil Cation Exchange Capacity (CEC). But, CEC determined by using laborious method is expensive and time consuming. Developing a model that predicts ESP indirectly from a easily-measured properties to be more appropriate and economical. Researches showed a relationship between ESP and SAR. So, SAR can be allocated to predict of ESP. For this reason, many attempts have been made to predict ESP from soil. The specific goal of the research develop model to determining ESP based on SAR by OLS and BN models for Bonab soils in East Azarbaijan province, Iran. Materials and Methods: For arrived presented research, 209 soil samples were taken by grid survey (250×250) of Bonab, Iran. The site is located at mean 1300 m above mean sea level, in semiarid climate in the Northwest of Iran. Then, some soil chemical properties such as SODIUM, calcium, magnesium, SAR and ESP of the soil samples were measured using laboratory experiments. Then, two model was developed by OLS and BN. OLS estimators are linear functions of the values of the dependent variable which are linearly combined using weights that are a non-linear function of the values of the explanatory variables. So the OLS estimator is respect to how it uses the values of the dependent variable only and irrespective of how it uses the values of the explanatory. So A Bayesian network is a probabilistic graphical model that represents a set of variables and their conditional dependencies via a directed acyclic graph (DAG). Given symptoms, the network can be used to compute the probabilities of the presence of various diseases. Efficient algorithms can perform inference and learning in Bayesian networks. Generalizations of Bayesian networks that can represent and solve decision problems under uncertainty. Results: The Coefficient of Determination (R2) and Root Mean Square error (RMSE) of the soil ESP-SAR model is reported 0. 99, 0. 71 and 0. 98, 1. 63 by OLS and BN respectively. Based on the statistical result, both of soil ESP-SAR model was judged acceptable. T-test were used to compare the soil ESP values predicted using the soil ESP-SAR model with the soil ESP values measured by laboratory tests. The paired samples t-test results indicated that the difference between the soil ESP values predicted by the model and measured by laboratory tests were not statistically significant (P>0. 05). Therefore, the soil ESP-SAR model can provide an easy, economic and brief methodology to estimate soil ESP. The GMER index also indicated low estimation of two selected land evaluation method. Conclusion: The results of present study illustrated that OLS and BN models can predict ESP with acceptable limits. OLS and BN are mathematical models between input and output variables and have the ability of modeling between ESP and SAR.

The properties of soils affected by salinity and processes involving degradation of soil structure have been partly recognized. However, the effects of saline and sodic condition on physical and mechanical properties of soils, have been studied to a lesser extent. In this research, the effects of electrical conductivity (EC) and SODIUM ADSORPTION RATIO (SAR) on soils possessing various amounts of organic matter were assessed under laboratory conditions. The soils were collected from the Dasht -e-Naz of sari region in the north of Iran, contained a uniform clay type, predominantly Illite. The major difference of the soils was their amount of organic matter content. The treatments consisted of solutions with given EC and SAR (two levels of ES;0.5and 4 dS/m and three levels of SAR; 0 , 5 and 15 ) with increase of SAR, the wet aggregate stability (WAS) decreased and the amount of dispersible clay (DC) increased .In similar SAR, treatments with higher EC exhibited lower DC. The order of average aggregate stability of soils were; virgin soils > soils under continuous cultivation of Festuca >soils under intensive cultivation with regular crop rotation>soils under continuous cultivation of Agropyron. The variance analysis of data showed significant differences (at 1%) between soil types, sampling depth, and SAR.

Soil salinity and alkalinity are considered as the most important problems in arid and semi arid areas. This study has been done to investigate the spatial variability of salinity and SODIUM ADSORPTION RATIO which have reciprocal effects on pistachio growth in the Kosarrize region in Rafsanjan. For this purpose a regular network of 500 meter intervals was considered and 192 soil samples were from 0-30 and collected 30-60 cm depths. Electrical conductivity of saturated soil extract (EC) and SODIUM ADSORPTION RATIO (SAR) were measured using standard methods. Statistical results showed that based on Pearson test, high positive correlation exists between EC and SAR at 99% confidence level. Therefore most of the salts must be of na type. Kriging maps illustrate that the variability of both parameters are greater in the first depth than the second one which is the result of different management strategies in the area. Also maps showed that Existences of excess salinity, SAR and also immethodical groundwater withdrawl and successive droughts in recent years have been considered as the main reasons of weak yield and even the loss of a major part of pistachio orchards in the region. The results showed that soil salinity and SODIUM in non planting areas are severe which illustrates the impact of mismanagement of the increased EC and SAR in the pistachio regions.

The general characteristics of salt-affected soils and soil structure degradation process are partially known, but the effects of saline and sodic conditions on mechanical properties of soils are not well recognized. In this study, the effects of electrical conductivity (EC) and SODIUM ADSORPTION RATIO (SAR) on tensile strength of soils with different organic carbon contents were assessed under laboratory conditions. The soil samples were collected from Dasht-E-Naz, at Sari region in the North of Iran. The samples had the same clay mineral (Illitic) and the main difference between them was the organic carbon content, subjected to different cropping. systems. The tensile strength was determined on soil samples which had been treated by solutions having defined EC (0.5 and 4 dS/m) and SAR (0,5, 15). The tensile strength was positively related to organic carbon content, but negatively to SAR. With increasing SAR, tensile strength decreased, and at a given SAR, the treatments with higher EC showed higher tensile strength. The analysis of variance showed significant differences (at 0.01) between soil samples (four levels), soil sampling depth (two levels), EC (two levels), and SAR (three levels) for all variables under investigation. For soil factor, the order of averages were: Virgin soil> Permanent pasture (Festuca) > Intensive cropping> Permanent pasture (Agropyron).

Different types of equations have been proposed to predict the SODIUM ADSORPTION RATIO (SAR), in drainage water. These empirical equations are tested here against the data of a lysimetric study to verify their validity. To obtain the basic relationships, a set of 116 water chemical analysis throughout Iran including river water, groundwater, and drainage water was used. Also, a set of 30 drainage water analyses was used for which precise measurements of irrigation and drainage water quality and quantities were available through a lysimetric experiment. Cylindrical lysimeters with internal diameter of 40 cm and height of 180 cm were filled with a sandy loam soil and irrigated weekly with natural water. Alfalfa was grown in the columns for a period of 3 years. Simple correlations between irrigation water SAR (SARiw) and SARdw yielded very poor regression coefficient (R2= 0.108). While steady state assumption i.e. concentRATIOns being in direct proportion to 1/LF, could reasonably predict SARdw (R2=0.802), despite some variations in LF during the season. This correlation is comparable with more complex methods recently proposed.

The properties of soils affected by salinity and the processes involving degradation of soil structure are relatively well-known. However, the effects of saline and sodic conditions on the physical and mechanical properties of soils have been studied to a lesser extent. In this research, the effects of electrical conductivity (EC) and SODIUM ADSORPTION RATIO (SAR) of solutions were assessed on soils containing various amounts of organic matter under laboratory conditions. The soils used were collected from the Dasht-e-Naz of Sari region in the north of Iran and contained the same clay type, predominantly Illite. The major difference between the soils was their organic matter content. The treatments consisted of applying solutions with definite EC and SAR (two levels of EC: 0.5 and 4 dS/m and three levels of SAR: 0, 5 and 15). With an increase of SAR, the wet aggregate stability (WAS) decreased and the amount of dispersible clay (DC) increased. At a similar SAR, higher EC values were associated with lower DC. The order of average aggregate stability of soils was: virgin soils under continuous cultivation of Festuca > soils under intensive cultivation with regular crop rotation > soils under continuous cultivation of Agropyron. The analysis of variance showed significant differences (at 1%) between soil types, soil sampling depths, EC and SAR.

Water quality management in brood-stock tanks, especially in terms of water salinity and water hardness, is of great importance to the reproductive performance of the crustaceans. The SODIUM absorption RATIO (SAR) is a compound formula that has a RATIO of SODIUM ion to total calcium and magnesium ions of water. The purpose of this study was to investigate the effects of different RATIOs of SODIUM to total calcium and magnesium of (SAR) in water on reproductive indices of female freshwater prawn. For this study, 12 tanks of 80 liters were assigned to 4 treatments with 0, 5, 10 and 15 SODIUM absorption RATIOs, each with 3 replicates. After the 60-day period of experiment, different reproductive indices were measured. The results indicated that the egg clutch somatic index (ESI) and the dry weight of eggs were significantly higher in treatment of SODIUM absorption RATIO 5 than other treatments. Fertilized eggs percentage and hatched eggs percentage in control and 5 treatments were not significantly different but decreased with increasing of SODIUM absorption RATIO in 10 and 15 treatments respectively. While different levels of SODIUM absorption RATIO in water had no significant effect on total and relative fecundity parameters. Larval status index was significantly higher in treatment of SODIUM absorption RATIO 5 than other treatments. Finally, the SAR at female brood-stock tank water can be optimized to achieve the highest reproductive performance and produce the best quality larvae. Therefore, it is recommended that the authorities of the reproductive centers that do not have natural brackish-water should adjust the water absorption RATIO to 5 when making brackish-water for hatchery centers.

Expanded abstractsIntroduction: Salinity is an important environmental stressor that affects plant growth. In saline soils, plants are subjected to some toxic ions and water shortages. Crop residues are considered major organic agricultural wastes that can be useful for the soil and the plants. Organic matter has positive effects on the soil's physical and chemical properties. Converting agricultural wastes to Biochar is an appropriate way to achieve a valuable amendment. Biochar is a carbon-rich decomposition-resistant product obtained by heating biomass in an oxygen-free chamber, being used for carbon sequestRATIOn by applying large amounts of carbon.Moreover, as a highly stable residue in the soil, it has been proven to store atmospheric carbon for hundreds to millions of years. According to different studies' findings, the application of Biochar can increase the soil's water-holding capacity, microbial activity, and nutrient availability. However, its effect on soil properties depends on its source and the extent of its application.  As the dependency of Biochar's effects on saline soils' properties in such soils has been under-researched, this study attempted to investigate the effect of palm-tree residues' Biochar on the physical and chemical properties of saline soils. Materials and Methods: the required Biochar was prepared from palm trees' residues at 500°C under limited oxygen conditions. This experiment was conducted in a completely randomized design with three replications. Biochar was mixed at 0, 0.5, 1, 1.5, and 2% rates with saline soils and incubated with humidity at field capacity for 90 days. Then, the samples were air-dried, and some physicochemical characteristics of the soil were determined. Moreover, the comparison of the means was performed using Duncan's test at a confidence level of 95%. Results: The results showed that applying the Biochar obtained from palm trees to the soil significantly increased the soil's chemical properties such as electrical conductivity (EC), organic carbon, calcium, magnesium, SODIUM, and potassium while decreased the SODIUM ADSORPTION RATIO (SAR), and the SODIUM/potassium RATIO. Moreover, while adding Biochar to the soil increased the porosity by 10% and reduced the bulk density by 4%, treatments did not significantly affect pH, available phosphorus, field capacity, and the soil's particle density. Furthermore, adding 2%, Biochar increased calcium concentRATIOn in soil by 2.08 times compared to that of the control treatment. It was also found that the changes in the soil's magnesium calcium were similar and that using more Biochar increased magnesium concentRATIOn by 2.88 times compared to what was observed in the control treatment (more than the control treatment). Therefore, the study's findings indicated that the available potassium concentRATIOn in soil increased significantly following the application of different biochar levels. It was also found that compared to the control treatment, the amount of potassium increased about 12.33 and 18.79 times, respectively, with an increase of bio-dates in 1.5 and 2% treatments. Moreover, the highest increase in SODIUM was related to applying a 2% biochar date, which was 49.35% more than that of the control treatment. Finally, using 2% biochar reduced the SODIUM ADSORPTION RATIO by 7.6%. Discussion and Conclusion: This study showed that palm trees' Biochar improved some saline soil parameters such as SAR, organic matter, and nutrients. Increased EC is due to increased SODIUM as a destructive factor and other cations such as calcium, magnesium, and potassium as helpful plant nutrients. On the other hand, the SODIUM to potassium RATIO was decreased. Moreover, it was suggested that the potassium was increased more than SODIUM, and that was why the index was improved. According to the study's findings, Biochar increased porosity due to its high specific surface area.Moreover, using 2% biochar treatment increased the saline soil's organic carbon by approximately three times. Due to the Biochar's low specific gravity, it can be expected that the soil's density is decreased by applying Biochar in soil. However, the increase in Biochar did not significantly affect the soil's particle density, which is probably due to the low weight of biochar particles versus the high weight of the soil's minerals and the amount of Biochar applied. It seems that applying Biochar as an amendment can improve the saline soil's properties and that the size of biochar particles may have different effects on changing the soil's properties, which can be investigated in future researches.