تنش شوری

Given that the majority of Iran's land area consists of arid and semi-arid regions, the use of plants resistant to salinity and drought stress can provide a new opportunity for harnessing the potential of the country's highly stressful climates. Therefore, this research aimed to investigate the effects of different levels of drought and salinity on the survival and morphophysiological characteristics of one-year-old Russian olive seedlings. An experimental pot study was conducted in a completely randomized block design with three replications and three observations, at three levels of drought (control 100%, 66%, and 33% field capacity) and four levels of salinity (zero as control, 4, 8, and 12 dS/m), in the greenhouse of the Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, from August to November over a period of 4 months. In this study, the content of chlorophyll and carotenoids was examined and measured. The results of this study showed that the main and interactive effects of drought and salinity stress on the measured traits were significant. The main and interactive effects of drought and salinity stress led to a decrease in chlorophyll and carotenoid content. The lowest levels of chlorophyll a (19.1 milligrams per gram leaf weight), chlorophyll b (44.0 milligrams per gram leaf weight), total chlorophyll (94.0 milligrams per gram leaf weight), and carotenoid content (39 milligrams per gram leaf weight) were observed.

Salinity stress is one of the most critical causes restricting plant growth and development in arid and semi-arid regions. It is possible to use strategies to prevent plant yield loss in these areas. One of these strategies is the use of growth stimulants. The purpose of this study was to look into the influence of humic acid and silicon consumption on bell pepper growth under different salinity levels. This experiment was carried out in the research greenhouse of the School of Agriculture, Shiraz University, in 2019. Salinity treatment as saline water had conductivities of 0, 1.7, 3.4 and 5.1 dS.m-1 and were added to the plants during the growth, while humic acid, silicon, and the simultaneous application of these two were applied to reduce the effects of salinity. Humic acid was added twice, each time 0.5 grams per kilogram of soil, and silicon was applied as a foliar spray from a source of potassium silicate with a concentration of 1%. According to the results, level 5.1 dS.m-1 of salinity decreased 63% of shoot dry weight, compared to the control. Among the stimulant growth treatments, only humic acid showed a significant effect on increased plant biomass and caused 55% increase in the dry weight of shoots and roots. Salinity significantly increased the concentration of sodium, calcium, and magnesium in the plant, resulting in 750% sodium, 176% calcium, and 101% higher magnesium for 5.1 dS.m-1 level of salinity compared to the control. The findings of the treatments revealed that each treatment generated changes in several plant features, for example, the simultaneous application of humic acid and silicon caused 76% increase in sodium concentration in the plant, and humic acid treatments caused 28% decrease in root calcium concentration. According to the results of this research, humic acid improved more than silicon treatment, and the simultaneous application of humic acid and silicon could reduce the effects of salinity.

Crop modeling is one of the widely used methods for simulating the crops yield under different farm management. However, paying attention to the sensitivity of these models to the input parameters can improve the calibration operation and reduce the simulation error. For this reason, in the current research, we analyzed the sensitivity of the AquaCrop model under planting date treatments (D1: March 5 and D2: March 15) and irrigation water salinity (S1: Karon water with an average salinity of 2 dS.m-1, S2: combination of Karon water and drains with an average salinity of 4 dS.m-1 and S3: drain with an average salinity of 6 dS.m-1) and cotton cultivars (C1: Khursheed, C2: Golestan, C3: Sajedi and C4: Khordad). For sensitivity analysis, the normalized water productivity (WP*), maximum crop transpiration coefficient (KCTrx), initial crop coefficient (CCo), crop growth coefficient (CGC), crop decline coefficient (CDC) and harvest index (HI) were used. Sensitivity analysis was done using Beven method. The results showed that the highest sensitivity was in parameters of HI (0.69) and WP* (0.6) and the lowest sensitivity was in parameters CDC (0.02) and CCo (0.3). The increase in planting date from D1 to D2 increases the sensitivity of the AquaCrop model to the HI (19%) and WP* (15%), and the increase in salinity from S1 to S3 increases the sensitivity of AquaCrop to the HI (42%) and WP* (50%). Therefore, in the farm management similar to the current research, paying attention to the two aforementioned parameters can cause the accuracy of the results in the calibration (and validation) stage.

Over the past few decades, soil salinity has reduced global agricultural production by more than 50%. This problem is considered one of the main barriers to crop productivity in arid and semi-arid regions. Salinity stress affects plant growth by altering osmotic pressure and ionic toxicity, disrupting soil biodiversity. Halotolerant actinobacteria can mitigate abiotic stresses such as salinity and drought and improve soil physical, chemical, and biological properties, leading to higher agricultural crop yields. Plant growth-promoting actinobacteria also increase nutrient availability, improve plant growth, and control plant pathogens. Therefore, this research was conducted with the aim of isolating and screening halotolerant actinobacterial isolates from the rhizosphere of agricultural plants and evaluate their silicate solubilization ability and some other plant growth-promoting mechanisms. Plant growth-promoting actinobacteria were isolated and screened from the rhizosphere of agricultural crops corn, tomato, soybean, and sesame. To assess their salinity tolerance, all isolates were evaluated in culture medium with different salinity levels. Actinobacteria isolates with the ability to grow in medium containing 1M NaCl were selected and then the plant growth-promoting properties of the isolates including: the ability to produce indole compounds, solubilize inorganic phosphate, solubilize inorganic silicate, produce siderophores, ammonia, and hydrolytic enzymes including cellulase and protease were measured. A total of 67 actinobacteria isolates were isolated from the rhizosphere of corn, tomato, soybean, and sesame crops. All isolates were able to grow in a culture medium containing 0.2 M sodium chloride. In a medium with 0.5 M sodium chloride, 80% of the isolates grew. Growth was observed in 32.8% of the isolates in a medium with 1 M sodium chloride, 23.9% in a medium with 1.5 M sodium chloride, and one isolate was able to grow in a medium containing 2 M sodium chloride. All actinobacterial isolates were capable of producing indolic compounds, with isolate GP12 showing the highest production rate. Twenty isolates were able to dissolve inorganic phosphate and GP64 isolate exhibiting the highest dissolution rate with 187.8 mg L-1. Six isolates could dissolve inorganic silicate in a solid environment, and quantitative measurements indicated that isolate GP32 had the highest rate (122.79 mg L-1) of inorganic silicate dissolution. Fourteen isolates were capable of producing siderophores, with isolate GP67 achieving the highest siderophore production in quantitative measurements. Isolates GP20, GP67, GP91 had qualitatively more ammonification ability than other isolates. Regarding the production of hydrolytic enzymes, 11 isolates were able to produce cellulase enzyme, and 3 isolates had the ability to produce protease enzyme. In the current study, actinobacterial isolates demonstrated growth in high-salinity sodium chloride culture media and exhibited multiple plant growth-promoting characteristics. These isolates show promise as agents to improve plant growth and crop yield. Confirming their effectiveness and capabilities requires pot and field trials to evaluate their influence on plant development and nutrient absorption.

The effect of salinity stress on plants is very wide, and it can cause a decrease in growth, damage to the roots, decrease in yield and even death of plants by reducing the absorption of water and nutrients, reducing enzyme activity, and disrupting the physiological processes of plants such as photosynthesis and respiration (Gupta and Hong, 2014 and Awaad, 2023). Rapeseed oil, as one of the most important sources of vegetable oils in the world, is very important in various economic, agricultural, industrial, and health sectors. With the ability of growing in different climatic conditions, having low water requirement and good relative resistance to various environmental stresses, rapeseed is known as a suitable plant for crop rotation (Raboanatahiry et al., 2021). The effects of salinity on the characteristics of the rapeseed plant in the stages of germination, vegetative stages and seed ripening have been proven. Considering that different rapeseed cultivars are different from each other in terms of their susceptibility to salinity stress in different stages, a detailed assessment on the effects of salinity stress on rapeseed and the adoption of appropriate strategies to manage and reduce this stress can help in better cultivation and optimal management of rapeseed; Therefore, evaluating the response of different rapeseed cultivars to salinity stress is of particular importance in order to introduce salinity-tolerant cultivars

Experimental model In order to evaluate the response of winter rapeseed (Brassica napus L.) cultivars to different levels of salinity, an experiment was conducted in a greenhouse at the Research Greenhouse of Payame Noor University of Gandaman (Chaharmahal and Bakhtiari province). The experiment was arranged as a split-plot design within a completely randomized design with three replications. The first factor was four levels of salinity, including S0 (2), S1 (10), S2 (20), and S3 (30) (dS/m), where S0 was the Hoagland's solution as the control, and other salinity levels were the result of mixing sodium chloride (NaCl) and calcium chloride (CaCl2) at a ratio of 20 to 1 moles in the Hoagland's solution, respectively. The second factor comprised eight winter rapeseed cultivars including (Licord, Okapi, SLM 046, Modena, Opera, Symbol, Fornax and Elite). The experimental units included 40 × 40 cm pots, 35 cm in height, containing completely homogenized washed sand. Due to lack of absorption and less the plants' need for a complete nutrient solution, the pots were irrigated every other day with a solution containing half the concentration of nutrients found in the Hoagland's solution (Dehdari et al, 2005). Two weeks after establishment, the plants were thinned from 15 to 8 plants per pot to achieve the desired plant density. From the 20th day after sowing (the four-leaf stage of the plants), salinity levels were gradually applied to acclimate the plants, such that all pots, except for the control level, received incremental salinity levels of 25% of each level in four irrigation shifts, thereby applying the total salinity treatment for each level.

Collecting and preparing plant samples:

The salinity treatment continued at the specified ratios until the end of the growth stage. In this study, the traits of seed yield, dry matter traits, thousand seed weight, oil yield and oil percentage were measured. At the end of the growth stage (90 days after sowing), to measure the seed yield, dry matter traits, thousand seed weight and oil yield, six plants in each pot were randomly selected, harvested, and the above parameters were measured and calculated. Oil percentage was calculated with a Soxhlet apparatus (Joshi et al., 2008).

Statistical Analysis Statistical Analysis:

 Finally, data were analyzed using SAS software (version 9.1). Mean comparisons were conducted using Duncan's multiple range test at a 5% probability level.

In the present study, all the traits under investigation were affected by salinity. An increase in salinity levels across all evaluated cultivars resulted in a significant reduction in all examined traits. Based on the results, it can be inferred that the rapeseed cultivars evaluated in this study can produce an acceptable yield up to a salinity level of S1 (salinity of 10 dS/m). At this salinity level, the cultivar SLM 046, with a seed yield of 22.78 grams per pot and an oil yield of 7.97 grams per pot, was identified as the most successful cultivar. Conversely, the Okapi cultivar, with an average seed yield of 11.99 grams per pot and an oil yield of 3.71 grams per pot, was the most susceptible cultivar. Therefore, according to the findings of this study, the SLM 046 cultivar was determined to be the most tolerant to salinity at all levels tested, while the Elit cultivar was assessed as the most susceptible to salinity. Since the primary goal of producing canola oilseeds is oil production, cultivating the evaluated cultivars under salinity conditions of S3 (salinity of 30 dS/m) and higher is practically ineffective.

Exposure to environmental stressors, including salinity and drought stress, directly and indirectly causes a portion of the assimilates produced by the plant to be diverted from growth and production processes towards coping with and mitigating stress conditions (Ahmed & Umar, 2011). It has been stated that with increased salinity stress, the stressed plant experiences reduced activity and degradation of cellular biomolecules, lipid oxidation, protein structure alteration, enzyme deactivation, chlorophyll bleaching, and nucleic acid degradation, resulting in the limitation of the plant's photosynthetic system (Ahmed & Umar, 2011; Al-Sharari et al., 2023). In the present study, increasing the intensity of salinity stress from S0 (control) to S3 (30 dS/m) caused the highest percentage reduction in all evaluated traits, including seed yield and oil yield, across all tested cultivars. The results indicated that the SLM046 cultivar, with the highest harvest index (0.29) and seed yield (10.52 grams per pot) at the highest salinity level (S3), and the lowest percentage reduction in harvest index (25.64%) compared to the control, performed better in mitigating the effects of salinity stress compared to other cultivars. In salinity stress conditions, salinity-tolerant cultivars like SLM046, which can allocate remaining assimilates effectively despite limitations in phloem transport and new physiological demands due to salinity stress, are more successful. By maintaining an appropriate harvest index and directing resources towards economic yield, these cultivars produce satisfactory yields (Ahmed & Umar, 2011; Khalid et al., 2015).

This study was conducted with the aim of investigating the yield and yield components of Panicum millet plant under the conditions of combined stresses of salinity and deficit irrigation as a split plot experiment in a randomized complete block design with three replications and 48 treatments at the research farm, Faculty of Agriculture, Ilam University. Treatments included four levels of irrigation water salinity including 0.63, 3, 5 and 8 dS/m (S1, S2, S3 and S4 respectively) and four irrigation levels including 100, 80, 60 and 40 (w1, w2, w3 and w4 respectively) percentage of water requirement was done. The traits studied included leaf-to-stem weight ratio panicle length, plant height, shoot weight, thousand seed weight, seed yield and harvest index. The results showed that the applied salinity stress levels had a significant effect on harvest index traits, seed yield, thousand seed weight, shoot weight, panicle length and plant height at the 5% and there was no significant difference only on the leaf-to-stem weight ratio trait. The combined effect of salinity and deficit irrigation stress on all traits except for panicle length was significant at the 5%. Millet in the conditions of no stress (S1W1) and the highest level of stress (S4W4) applied in this study could yield 3.76 and 1.71 tons per hectare, respectively.

Plant growth promoting fungi are often useful for plants and make host plants adapt to living and non-living stressors, including salt stress, in different ways. In this regard, the identification and application of growth-promoting fungi that tolerate salt stress is one of the ways to deal with and adapt to salt stress conditions. On the other hand, different carriers have different ability to maintain the population of these fungi at the standard level and maintain their efficiency. Also, storage conditions, especially temperature, can have a great effect on their population and stability. Therefore, the present research was conducted with the aim of preparing suitable formulations of salt-tolerant fungi in order to preserve and stabilize their population in the long term. In the present study, Chaetomium globosum, Chaetomium interruptum, Clonostachys rosea, Coniothyrium sp., Epicoccum nigrum, Serendipita indica, Trichoderma asperellum, Trichoderma atroviride, Trichoderma harzianum, Trichoderma longibrachiatum and Trichoderma reesei with plant growth-promoting properties were obtained from the collection of the Department of Soil Biology and Biotechnology of the Soil and Water Research Institute in order to identify the fungal species tolerant to salinity. Their growth potential at different salinity levels including 0.045, 0.31, 0.63, 1.04, 1.36, 2.14, 3.04, 3.95 and 4.71 percent of sodium chloridewas evaluated in a completely randomized design with three replications. Also, two salt-tolerant fungal species and different carriers (pepper waste, vermiculite, stone powder, pumice, perlite, sawdust, and compost) were used to evaluate the stability of the fungal population in different formulations. The experiment was laid out in a factorial completely randomized design with three replications. The results showed that T. harzianum, T. atroviride, T. longibrachiatum, and T. reesei were less affected by the salinity of 0.045 to 4.71% sodium chloride and were able to fill the entire surface of the Petri dish (8cm) at different salinity levels. E. nigrum was also able to grow at different salinity levels, although its growth decreased with increasing salinity. T. harzianum was the only species that was able to cover the entire Petri-dish surface in seven days at the culture medium containing 2.14% sodium chloride. The formulation results showed that the carrier effect was significant in both T. harzianum and E. nigrum species. Compost, sawdust, and vermiculite were the best carriers in terms of maintaining the Trichoderma population. The best carriers in maintaining T. harzianum population after six months at cold room temperature was vermiculite (4 × 109 CFU/g), compost (3.66 × 109 CFU/g) and sawdust (3 × 109 CFU/g) and in E. nigrum species was compost (1 × 108 CFU/g) and vermiculite (8 × 107 CFU/g). In general, the results showed that T. harzianum and E. nigrum species were able to grow in culture media containing 4.71% sodium chloride and the best carriers for the formulation of these two fungi were compost and vermiculite.

Using simulation models is a key strategy in agricultural water management and an effective way to predict the impact of irrigation management and water quality on crop yield. This study aimed to evaluate the performance of the SWAP and AquaCrop models in simulating the growth and biomass production of three maize varieties under the conditions of using saline water for irrigation with a drip irrigation system at the research farm of Tehran University of Agriculture and Natural Resources Campus. In order to calibrate and validate the models, field data obtained from a factorial experiment with two factors of maize variety (SC704, 400, and 260) and irrigation water salinity (0.7, 3, and 5 dS/m) were used. In the validation stage of the AquaCrop model, the R2, RMSE, and NRMSE statistics for the canopy cover (CC) showed a high level of agreement between the measured and simulated data, with values of 0.953, 5.69, and 8% respectively. For the SWAP model, the calculated statistics for the leaf area index (LAI) were 0.477, 1.610, and 54.2%, respectively. Despite the poor performance of the SWAP model in estimating LAI, both the SWAP and AquaCrop models effectively simulated the biomass of maize cultivars under different treatments. In the calibration and validation stage, RMSE and NRMSE of both models were less than 0.5 ton/ha, with 3% (calibration) and 1 ton/ha, 7% (validation), respectively. In general, both models can be used in various studies for different maize cultivars under irrigation water and soil salinity conditions.

In the south of Iran, due to being located in the arid and semi-arid regions, the agricultural sector faces soil salinity resulting from the capillary rise of salt from the shallow saline water table to the soil surface and reducing crop yield. The objective of this research was to investigate the effect of surface drip irrigation (DI) and subsurface irrigation (SDI) methods on soil profile moisture and salinity distribution, maize (SC 703) yield, and irrigation water use efficiency in the presence of shallow saline water table (60 and 100 cm), during summer and spring seasons of 2021. A factorial experiment was conducted based on randomized complete block design with three replications in drained lysimeters filled with loamy soil (specific gravity 1.45 g cm-3) in field conditions. The results showed that the accumulation of salt above the dripper in subsurface irrigation method at both SDI100 and SDI60 treatments, was significantly more than the surface irrigation method (p<0.01). The results also revealed that summer maize yield was more than spring maize yield. Furthermore, in the summer season, irrigation in the root development zone in the SDI100 and SDI60 treatments caused an increase in the maize yield by 25 and 61%, respectively, and Water Productivity Index (WP) by 25 and 58%, respectively, in comparison to DI100 and DI60. Evaporation in SDI60 and SDI100 treatments was 26-30% and 43-51% lower than DI60 and DI100 treatments, respectively. The results of this research showed that SDI is more effective than DI in controlling soil profile salinity and plant yield.

Soil salinity, especially in arid and semi-arid regions, is one of the factors that limit the growth of plants. Excessive accumulation of sodium and chloride ions leads to reduced growth and imbalance of nutrients. The use of exogenous polyamines, including putrescine, spermidine and spermine, is considered as an effective method not only in determining their role in response to salinity, but also as a way to increase plant resistance to salinity. Camelina is an oilseed product of the Brassica family, which contains other bioactive compounds such as flavonoids and phenolic products and as a new source of essential fatty acids, especially omega-3 fatty acids. This study was conducted with the aim of evaluating the effect of different levels of sodium chloride and foliar spraying of spermine, spermidine and putrescine on seed yield and the concentration of leaf and root nutrients in Camelina plant. The experiment was carried out in March 2022 as factorial design based on a completely random design (CRD) in the form of pot culture with 12 treatments and 3 replications. The salinity stress treatment was with Urmia lake water at three levels (0, 15, 30 ds/m). Foliar treatment at 4 levels 1- Foliar spraying with spermine (2 mM), 2- Foliar spraying with spermidine (2 mM), 3- Foliar spraying with putrescine (2 mM) and control (no foliar spraying). The application time of foliar spraying was done every 3 days (totally in 6 stages) after establishing three seedlings in the pot and reaching the four-leaf stage. At the end of the Camelina plant growth season, to calculate the seed yield, the seeds in the capsules of three plants in each pot were separated and weighed. Statistical analysis of data was done using SAS software (version 9.1) and MATATC, and comparison of means was also done by Tukey's test at the five percent level. Excel program was also used to draw graphs. The results of this research showed that the salt stress was 30 and 15 ds/m compared to the treatment without salt decreased leaf potassium (52 and 17%), root potassium (44 and 37%), leaf magnesium (50 and 28%), root magnesium (56 and 24%), leaf zinc (58 and 47%), root zinc (39 and 29%), leaf iron (10 and 2%), root iron (57 and 23%) and seed yield (52 and 10%), but it increased the amount of leaf sodium (89 and 82%), root sodium (39 and 11%), leaf calcium (14 and 6%) and root calcium (76 and 28%), respectively. Also, salinity stress caused a decrease in the ratio of potassium to sodium absorption, but increased the ratio of calcium to the sum of sodium and potassium in the roots and leaves due to the increase in the amount of sodium and the decrease in potassium. At all salinity levels, foliar spraying with polyamines increased leaf and root potassium, leaf and root magnesium, leaf and root zinc, leaf and root iron, by reducing the amount of sodium in leaves and roots. Also, foliar spraying with spermine, spermidine and putrescine compared to no foliar spraying, increased the seed yield by 32, 8 and 21%, respectively. The results of this research showed that foliar spraying with spermine, spermidine and putrescine by improving the absorption of macro and micro elements in roots and leaves, increasing the ratio of potassium to sodium and the ratio of calcium to total sodium and potassium in roots and leaves could moderate the effects of salinity stress and improve the seed yield of camellia under salinity stress conditions and it prevented excessive reduction in seed yield.

Salinity is a serious problem and one of the main factors in reducing agricultural productivity worldwide. The use of microorganisms to improve plant growth in low quality soil is a potential solution to address this problem. The salinity resistant microbiome improves the health of the salinity affected soils, maintains ecological functions and enhances plant growth. Salt tolerant plant growth promoting rhizobacteria (ST-PGPR) are able to adjust the salinity stress adverse conditions for their symbiotic plants through several mechanisms. This study aimed to isolation, identification and investigation the characteristics of salt tolerant-plant growth promoting rhizobacteria from the rhizosphere of halophyte plants.

Salinity tolerant plant growth promoting bacteria were isolated from the rhizosphere of native halophyte plants collected from the north of Iran. Bacterial isolates were selected according to their ability to growth in 2 M sodium chloride and traits of the motility, inorganic phosphate solubilization ability in PKV-Agar medium using phosphate solubilization index calculation, and siderophore production capacity in CAS-agar medium by calculating of its production index. Then, the top 10 isolates were selected and the ability of nitrogen fixation in Burk's medium, potassium dissolution in Aleksandrov's medium by using potassium solubilization index, as well as, the production of intrinsic IAA and the tryptophan-dependent IAA were investigated. Finally, molecular identification of selected bacterial isolates was performed based on 16S rDNA gene sequencing.

Four genera of Bacillus, Klebsiella, Proteus and Halomonas were identified after 16S rDNA gene sequencing. All isolates were motile. The most of isolates belonged to the genus Bacillus. Species belonging to Klebsiella and Halomonas genera had the highest salt tolerance. Klebsiella genus showed phosphorus and potassium solubilizing ability more than other isolates. The highest amount of siderophore production was observed in the isolate belonging to Proteus genus. All isolates were able to fix nitrogen. Among the studied isolates, Bacillus isolates had the highest rate of intrinsic IAA, and the tryptophan-dependent IAA production in B. licheniformis was higher than other isolates.

Isolation of wide range of salt-tolerant bacteria with favorable characteristics from the rhizosphere of halophyte plants indicates the microbial richness potential of this area, which provides the possibility of finding useful microorganisms that promote plant growth and reduce the adverse effects of stress in plants. Keywords: Plant growth promoting bacteria, Salinity stress, Halophyte plants, Indole acetic acid

Salinity is the main problem of the fields under irrigation in many regions of the world which has been caused the farmers encountered with some questions such as determining of the optimum depth of irrigation water by using of saline water, reuse of drained water from the agricultural fields and yield reduction that resulting in reduction revenue by using of saline water. Water shortage and unsuitable quality of irrigation water are two main factors which has restricted the crop production in many regions of Iran. Among environmental stresses, salinity stress is the main factor of crop reduction. Many physiological processes of plants such as germination, seedling growth, flowering and fruit ripening are decrease by increasing in salt concentration in soil and irrigation water. Deficit irrigation and soil or irrigation water salinity decrease the matric and osmotic potential in soil water content respectively, which are resulting in reduction of water absorption by plant roots. Camelina (Camelina sativa L. Crantz) is a plant with oil seed from Brassicaceae family that interest to its planting has increased in recent years. The causes of that are high tolerance of this plant to unfavorable environmental conditions and usage possible of it for many purposes. Appropriate usage of yield- salinity- water crop production functions can be improved agricultural water consumption management in regions with scarce of water resources. Crop production functions such as linear form, Cobb-Douglas, quadratic and transcendental function models were used to simulate relative grain yield of camelina. As the area study in this research namely Kashmar plain, has been forbidden for withdraw of groundwater and many agricultural deep wells in this area have high salinity water, in order to optimum management water consumption in agriculture, determining of the best water-salinity-yield production function for crops such as oil seed plants (canola, seasame and camelina) are essential. For the first time, camelina was planted in Kashmar natural resource and agricultural research center as pilot plan in 2021. As the compounded effects of salinity and water stress on camelina grain yield has been not investigated in this area, the objective of this research was to obtain the optimum crop production function as affected by drought stress and irrigation with saline water. A greenhouse experiment was conducted as a factorial in the form of a completely randomized design with three replications. The experiment treatments were four levels of salinity including drinking water S1=0.7, S2=4, S3=8 and S4= 12 dS m-1 and three levels of irrigation water including W1 (100% provided crop water requirement), W2=0.75W1 and W3=0.5W1 applied in a loamy sand soil texture with bulk density of 1.41 gr cm-3. Linear, Cobb-Douglas, quadratic and transcendental function models were used to simulate relative grain yield of camelina. In order to determine of optimum crop water production function, statistical analysis was done on obtained data and by determining of related statistics the role of each input was characterized quantitatively. For assessing of validation, the obtained functions, the statistics including maximum error (ME), root mean square error (RMSE), determining coefficient (R2), efficiency function (EF) and coefficient of residual mass (CRM) were used. The results showed that quadratic function model was the most appropriate model for estimating of grain yield of camelina under pot planting conditions in greenhouse. Marginal product (MP) and marginal rate of technical substitution (MRTS) indices of grain yield related to quality and quantity of irrigation water showed that with increase a centimeter of irrigation water depth (hypothesized salinity is constant), camelina grain yield increased 56.8 kg ha-1. Also, MP related to irrigation water salinity indicated that with increase a unit of salinity (hypothesized irrigation water depth is constant) camelina grain yield decreased 38.7 kg ha-1. According to findings of this research it could be said that 70 mm depth of irrigation water and EC less than 4 dS m-1 is suitable for achievement to optimum grain yield of camelina under pot planting conditions in greenhouse. It is noteworthy that further consumption of water by plant (almost 300 mm) and longer of growth period duration of plant in field compared to pot planting conditions in greenhouse caused to production function coefficients recommended in this study would not be applicable in field conditions and it is necessary that supplemental studies would be conducted for determining of optimum yield- salinity- water production functions of camelina under field conditions.

From the economic and medicinal point of view, Aloe vera is a herbaceous and perennial plant that has attracted the attention of many farmers Iran. Climatic conditions throughout the year and the quantity and quality of irrigation water affect Aloe vera yield. For this reason, the research was conducted with the aim of investigating the effect of aforementioned factors on the Aloe vera yield and yield components. To achieve this goal, a strip-block design was carried with two factors, include: amount of irrigation water at three levels (I1: 50, I2: 75 and I3: 100% of irrigation water requirement) and irrigation water salinity at two levels (S1: 5 and S2: 10 dS.m-1) with three replications, in a research farm in Omidiye with longitude 30°37° and latitude 49°49°. The first harvest was done in the fall of 2019 and the second harvest in the spring of 2020. The results showed that in the first harvest, irrigation had a significant effects on leaf width, leaf fresh weight (P-value≤0.05), gel weight, the ratio of gel weight to leaf weight, the number of leaves and the water use efficiency (P- value≤0.01). Salinity had a significant effects on leaf thickness (P-value≤0.05), leaf width, leaf fresh weight, gel weight, the ratio of gel weight to leaf weight and water use efficiency (P-value≤ 0.01). In the second harvest, irrigation had a significant effects on the ratio of gel weight to leaf weight, number of leaves and water use efficiency and salinity had a significant effects on leaf width, leaf thickness, leaf fresh weight, gel weight , the ratio of gel weight to leaf weight and water use efficiency . In both the first and second harvests, the interaction effect of irrigation water and salinity only showed a significant effect on the water use efficiency (P-value ≤ 0.05).

In the situation where Iran is severely suffering from the lack of freshwater resources and the water resources crisis is a serious issue, paying attention to non-conventional water sources is an unavoidable necessity, in which case environmental tensions will occur. Especially salinity becomes important. To investigate the effects of salinity stress in German chamomile with the use of different culture media, factorial research was carried out in the form of a completely randomized design with three replications. In this experiment, two factors of salinity stress (Sa) (0, 50, 100, and 150 mM) and different percentages of culture medium (perlite 100%, cocopit 25%+perlite 75%, cocopit 50%+perlite 50%, cocopit 75%+perlite 25%, and cocopit 100) %) was investigated. The investigated morphological and physiological traits included fresh and dry weight of root and shoot, stem diameter, amount of chlorophyll a and b and total chlorophyll. The results showed that all investigated traits were subjected to salinity stress and showed a significantly decrease compared to the control. The culture medium containing 75% cocopeat and 25% perlite increased the fresh weight of roots by 22.11% compared to the culture medium containing 25% cocopeat and 75% perlite. Also, the control treatment had a 96.08% increase in root fresh weight compared to salt stress with a concentration of 150 mM. Regarding the amount of total chlorophyll, the results showed that Co50Pe50+Sa0, and Co75Pe25+Sa0 treatments were the most (3.93 and 4.01 mg per gram of fresh tissue, respectively) and Co0Pe100+Sa150, Co25Pe75+Sa150, Co50Pe50+Sa150 treatments. Co100Pe0+Sa150 had the lowest (respectively 2.01, 2.02, 2.06, and 2.19 mg per gram of fresh tissue). In general, it can be said that the German chamomile plant in the culture medium containing 75% cocopeat + 25% perlite can withstand severe salt stress and have acceptable growth.

Drought and salinity stress are the most important limiting factors for plant growth. Selenium has been introduced as one of the useful elements against the destructive effects of stress. To the investigation of influence salinity and drought stress on water productivity and some characteristics of Mentha piperita L in the presence of selenium, an experiment on the split in time was performed in the Torbat-e Jam region, Iran in 2020, including two levels of cut (cut1 and cut2), three levels of irrigation (including full irrigation (100% of water requirement) = I1, I2=75% I1 and I3= 50% I1), three levels of Salinity (0, 50 and 100 mmol NaCl) and selenium factor in 2 levels (0 and 5 mg/l Na2SeO4). The result showed that fresh and dry weight, plant height, the number of leaves per plant, and the number of nodes decrease under salinity and drought stress. Generally fresh and dry weight, plant height, number of leaves per plant, number of nodes, Essential Oil percentage, and water productivity in the first cut was more than in the second cut. Also, foliar spraying of selenium (5 mgr/lit Na2SeO4) increased the above characteristics and also increased plant resistance against salinity and drought stress. The result showed with increasing salinity and drought stress respectively water productivity increased and decreased. the result showed that the percentage of essential oil increased by applying mild stresses in the form of deficit irrigation and then by applying intense stress, the percentage of essential oil decreased. Also result showed that the use of saline water in the conditions of drought stress caused intensification of reduction in fresh and dry weight, number of nodes and percentage of essential oil.

Considering the state of water resources in Iran, using unconventional water for irrigation is inevitable. Investigating the regional plants response to salinity is essential. an experiment was conducted on the research farm of the Agriculture Faculty, Lorestan University. Mini lysimeters (pots) with a diameter of 25 and a height of 30 cm were used. In this research, irrigation schedule was based on weighing method. The research was carried out using five quality treatments of irrigation water including S0: Water of the region (control treatment), S1: EC= 2 dS/m, S2: EC=4 dS/m, S3: EC=6 dS/m and S4: EC=8 dS/m. NaCl was used to make saline water. The growth period of Satureja hortensis was 100 days. The amount of accumulated potential and reference evapotranspiration were obtained 758.68 and 884.26 mm. The results showed that the effect of salinity stress on morphological characteristics such as plant height, stem diameter, as well as dry leaf weight and flowering branch, root and stem in Satureja hortensis was significant at the probability level of one percent. The morphological characteristics decreased as salinity stress increased. The yield of Satureja hortensis in S0, S1, S2, S3 and S4 treatments was 1732, 1598, 1412, 1328 and 1230 kg / ha, respectively. The essential oil content increased significantly as salinity stress increased. These values during different experimental treatments were obtained 1.08%, 1.2%, 1.5%, 1.58% and 1.8%, respectively.

The objective of this study was to investigate the effects of combined stresses of irrigation salinity and nitrogen fertilizer on the yield and yield components of millet plant. The field experiment was conducted as a split plot experiment in a randomized complete block design with three replications at the research farm, Faculty of Agriculture, Ilam University during growing season in 2022. Treatments included four levels of irrigation salinity including 0.63, 3, 5, and 8 dS/m (S1, S2, S3 and S4) as main plots and three nitrogen fertilizer levels including; 100, 75 and 50 % of fertilizer requirement (N1, N2 and N3) as subplots. The results showed that the effect of salinity stress was significant on leaf/stem ratio and panicle length at P<5% and for the rest of the yield components at P<1%. Also, the effect of different nitrogen treatments was significant on all components yield of millet, except leaf/stem ratio, panicle length and plant height. The interaction effect of salinity and nitrogen stress was significant on thousand seed weight, biomass weight, yield and harvest index at the at P<1% and had no significant on leaf/stem ratio, panicle length and plant height. The highest millet yield was 3.76 tons per hectare in S1N1 treatment and the lowest yield was 2.53 tons per hectare in S4N1 treatment.

Water scarcity particularly in arid and semi-arid areas has been threatening food security for millions of people. Considering that Iran is located in an arid and semi-arid zone and crop production is not possible without irrigation management. In areas where crops are irrigated management and proper planning are necessary for optimal use of water. Due to the quantitative and qualitative decline of groundwater resources, it is essential to optimize water use in agriculture. One of the methods to optimize water use in agriculture, especially in arid regions, is to use yield-water-salinity functions. Also, Selenium has been introduced as one of the useful elements against the destructive effects of salinity and water stresses. Peppermint with the scientific name Mentha piperita L is one of the medicinal and aromatic plants whose essential oil has many medicinal, food, cosmetic and health uses. Given that salinity stress and drought stresses are serious issues and problems in arid regions, in such conditions, it is very important to predict crop performance under drought and salinity conditions.Therefore, this study was performed for the prediction of Mentha piperita L yield and the determination of optimal production function under salinity and water stress conditions in a research greenhouse in the Torbat-e Jam region.One of the other innovations of this research is the investigation of the effect of selenium on these production functions and also on water productivity, with the assumption of increasing plant tolerance against salinity and drought stress.An experiment of the split in time was performed in a completely randomized block design with three replications including two levels of cut (cut1 and cut2), Salinity factor in 3 levels (0, 50, and 100 mmol NaCl, three levels of irrigation (including full irrigation (100% of water requirement) = I1, I2=75% I1 and I3= 50% I1), and selenium factor in 2 levels (0 and 5 mg/lit Na2SeO4).To properly establish the plants, the plants were irrigated every other day for two weeks after the transfer of the rhizomes, then as soon as the emergence of new leaves, the pots were treated with sodium selenate (Na2SeO4) in the form of foliar spraying with concentrations of 0 and 5 mg/l, foliar spraying was done three times every other day, and 24 hours after the last foliar spraying, plants under other treatments (salinity and drought stress) were placed. Salinity treatments were added to the pots from the lowest amount and higher concentrations were added gradually over several days. To determine water requirement was used Class A evaporation pan and water treatments were applied based on it. To calculate the water requirement, plant coefficients of peppermint were determined for the initial, development, and middle growth stages, respectively, 0.69, 1.03, and 1.27. 30 days after the application of salinity stress and drought stress, the first cut was done, for a more detailed investigation, the second cut was done 45 days after the first cut.Yield data of Mentha piperita L (yield of two cuts gathered for better estimation together), once in the presence of selenium and once in the absence of selenium were fitted to different production functions including simple linear, Cobb-Douglas, quadratic, and transient models and the optimum one was determined after sensitivity analysis. The results showed that the coefficient of determination (R2) for estimation of the yield in the presence of selenium by quadratic, transcendental, simple linear, and Cobb-Douglas functions were 0.986, 0.981, 0.946, and 0.897, respectively. In the absence of selenium these coefficient were 0.998, 0.995, 0,959 and 0/871, respectively. According to the results of this research, the quadratic production function is recommended as the optimal production function for the yield of Mentha piperita L in the presence and absence of selenium in the Torbat-e Jam region. Therefore, to optimize the agricultural water consumption for the peppermint plant, it is suggested to use the quadratic production function in this region. Also, the results of the statistical parameters show a higher accuracy of the fitted function in the absence of selenium than in the presence of selenium.Also, the results showed water productivity in the presence of selenium was 17.81% higher than its value in the absence of selenium. It can be concluded that Selenium increases water productivity.

Biochar as an efficient strategy for the improvement of soil properties and organic waste management may reduce the potential effects of abiotic stresses and increase soil fertility. However, the effects of this organic amendment on soil microbial indicators under combined salinity and pollution have not been studied yet. Therefore, the objective of this study was to evaluate the influence of sugarcane bagasse biochar on some soil bioindicators in a Cd-polluted soil under saline and non-saline conditions. A factorial experiment was carried out with two factors, including NaCl salinity (control, 20 and 40 mM NaCl) and sugarcane bagasse biochar (soils unamended with biochar, amended with uncharred bagasse, 400 oC biochar, and 600 oC) at 1% (w/w) using a completely randomized design. Results showed that salinity increased the mobility of Cd (12-17%), and subsequently augmented its toxicity to soil microorganisms as indicated by significant decreases in the <a href="javascript:void(0)">abundance and activities of the soil microbial community. Conversely, sugarcane bagasse biochar application reduced the concentration of soil available Cd (14-18%), increased the contents of soil organic carbon (89-127%), and dissolved organic carbon (4-70%), and consequently alleviated the effect of both abiotic stresses on soil microbial community and enzyme activity. In conclusion, this experiment demonstrated that the application of sugarcane bagasse biochar could reduce the salinity-induced increases in available Cd and mitigate the interaction between salinity and Cd pollution on the measured soil bioindicators.

Salinity is one of the most important abiotic stresses that has many negative effects on plant growth. To investigate the effect of salinity water irrigation stress on morphological and physiological characteristics of sorghum, an experiment was conducted in a randomized complete block design with 3 replications in soil columns located in the Agricultural and Natural Resources Research Center of Mazandaran Province. The number of experimental columns was 15 and the duration of the experiment was 56 days. Salinity treatments included well water (control) (S1=0.995 dSm-1), Mix seawater and well water in proportions 1/4 (S2=4.680 dSm-1), 2/4 (S3=8.130 dSm-1), 3/4 (S4=13.710 dSm-1) and seawater (S5=15.910 dSm-1). In this study, dry and wet weight of shoots, seeds and roots, diameter and height of main stem, leaf area index, leaf area, harvest index, biological yield and resistance indices of sorghum were measured. The results of analysis of variance showed that the effect of salinity on all measured traits was significant. Increasing the salinity level of irrigation water from control (S1) to treatment (S5) caused a significant decrease at the rate of 1 to 70% in all measured traits except harvest index and root to stem ratio. Also the results of this study showed that the best salinity level to achieve maximum yield in sorghum (Equivalent to 13/218 g) is salinity level (S1). Regarding resistance indices, S1 treatment had higher k/Na and Ca/Na ratios than other treatments, which were 6.67 and 1.4, respectively. Also, the results of comparing the mean of traits between different treatments showed that there were no significant differences between S3 and S4 treatments in traits such as grain yield, straw yield, plant height, leaf area, harvest index, dry weight of root and resistance indices that Up to 3: 1 ratio, seawater to well water can be used to grow sorghum. Also, the relative yield of sorghum to salinity did not decrease by about 3.65 dS /m, which was considered as the tolerance threshold of this plant. But after increasing the salinity of soil saturated extract, plant yield decreased and at salinity of about 15 dS /m was halved. The slope of the sorghum yield reduction line at this stage was calculated to be 3% dS / m.