فهرست مطالب محسن سیلسپور

This study is conducted to evaluate the concentration of nitrate and heavy metals in soil and edible organs of lettuce in Varamin plain farms for one year during 2017-2018. For this porouse, 30 lettuce fields in Varamin plain are selected and in the lettuce harvest season, soil and crop sampling are performed and the average concentrations of nitrate and heavy metals in the soil and lettuce were compared statistically with the standard limits by one paired t-test. The average concentrations of nitrate, lead and cadmium in lettuce are 2756, 1.46, and 0.11 mg / kg in fresh weight, respectively, which are 1.8, 7.3, and 1.1 times greater than the standard limit, declared by the National Standards Organization of Iran, respectively. The mean concentrations of nitrate and total concentrations of lead, cadmium, and nickel in the soil of lettuce fields are 27, 42, 0.64, and 42.5 mg /kg, respectively, while the concentrations of nitrate and lead have been 35% and 180% higher than the allowable limits, respectively. Risk assessments for heavy metals and non-cancerous diseases are performed, using formulas provided by the US Environmental Protection Agency (USEPA, 2006). In this regard, the risk index for non-cancerous diseases (HQ) is used. The risk factor for non-cancerous diseases for all contaminants is less than one, indicating that there is no risk for consumption. Accordingly, consuming 40 grams of lettuce per day does not pose a problem for an adult consumer. The bioaccumulation index for all the studied metals has been less than one. According to this study, the highest bioaccumulation factor belongs to the heavy metal cadmium, which indicates the tendency of lettuce to absorb and accumulate cadmium compared to other heavy metals. In order to reduce the concentration of nitrate and lead in the soil and prevent contamination of lettuce soils, it is recommended to avoid excessive use of fertilizers containing nitrogen and phosphorus and fertilizer application should be based on soil test. According to the results of this study, there is no serious possibility of exposure to non-cancerous diseases caused by nitrate and heavy metals from eating lettuce, but monitoring the concentration of nitrate and heavy metals in soil and lettuce at different intervals is necessary.

Spinach (Spinacea oleracea L.) is one of the most important vegetables that is rich in minerals and vitamins, and according to the nutritional value of this vegetable in the household basket. Increasing the yield per unit area with emphasis on the health of the product from the position is nececery. In this regard, combining organic fertilizers with chemical fertilizers can increase the yield of this plant. The results of many researches show that urban waste compost has the ability to be used in agricultural lands and can be an affordable organic fertilizer that can replace part of chemical fertilizers and has a special position in sustainable agriculture. Among the nutrients required by plants, nitrogen is the most limiting factor for plant growth and the key nutrient in achieving optimal performance in most crops, especially in dry areas. The most important method of providing nitrogen required in agriculture is the use of nitrogen fertilizers. Therefore, the most widely used fertilizer among chemical fertilizers is nitrogen fertilizers. Despite the role of nitrogen fertilizers as a tool to achieve the maximum production per unit area, the management of fertilizer consumption should be in a way that does not cause the accumulation of pollutants such as nitrates in the consuming organs of the products.This research was conducted with the aim of field evaluation of urban waste compost in combination with nitrogen on spinach yield and nitrate content of the product and soil.

In order to investigate the effect of different levels of urban waste compost and nitrogen in spinach cultivation, a factorial field experiment based on a randomized complete block design with 9 treatments and 3 replications under a calcareous soil in the research farm of the research and education center for agriculture and natural resources, and it was implemented in Tehran province in 2014. The waste compost factor included three levels of urban waste compost consumption (0, 10 and 20 tons per hectare) and the nitrogen factor included three levels of pure nitrogen consumption (zero, 100 and 200 kg per hectare). Each experimental plot consisted of six crop lines with a length of three meters and a distance between the rows of 60 cm. Planting operations were carried out in the second half of September with Varamin broadleaf spinach variety. Harvesting took place on November 30. The data obtained from the experiment were analyzed using F test and SAS software version 9.1. The average of the data was also performed using Duncan's multi-range test at the five percent probability level.

The results showed that the highest fresh yield of spinach was 67.3 ton.ha-1 due to the use of 10 ton.ha-1 of MSWC whit 200 kg.ha-1 nitrogen. Nitrate concentration in spinach and soil was increased by use of MSWC and nitrogen. Data showed that the highest nitrate concentration in spinach was 3200 mg.kg-1 fresh weight due to the application of 20 tons per hectare of MSWC and 200 kg.ha-1 nitrogen, which was more than the national standard of Iran. Assessing the health risk of nitrate in spinach showed that in the consumption of municipal waste compost at a rate of 10 tons per hectare with a consumption of 100 kg.ha-1 nitrogen, the nitrate content of the spinach product is 1900 mg. kg-1 fresh weight which was less than the maximum permissible standard for nitrate in national Iranian standard. The base of the results, the maximum daily intake of spinach was 137 g for the person and 47 g for the baby. Excessive amounts of these levels will endanger their health. Meanwhile, data showed that in 20 ton. ha-1 MSWC whit use of 200 kg.ha-1 nitrogen treatment, the maximum allowed consumption of spinach was only 81 grams per day for adults and 28 grams per day for a child. Therefore, to order to maintain the health of the consumer, use of 10 ton.ha-1 MSWC with 100 kg.ha-1 nitrogen is recommended.

The results of this research showed that in the same soil conditions as the place where this research was carried out, the consumption of more than 10 tons per hectare of municipal waste compost and the consumption of more than 100 kg of pure nitrogen caused an increase in the nitrate limit in spinach and increased the risk for consumption. Therefore, it is recommended to use 10 tons per hectare of municipal waste compost and 100 kg per hectare of pure nitrogen to produce spinach while respecting the maximum allowed nitrate concentration.

In order to investigate the effects of humic acid and salicylic acid on quantitative and qualitative properties and nutrients concentrations in leaves of cotton var. Khordad, a two-year field experiment were conducted at the Tehran Agricultural  and Natural Resources Research  and education Center during 2018with randomized complete block  design as factorial with two factors as follow: soil application of humic acid at three levels (zero, seed coated and 10 L/ha as fertigation) and foliar application of salicylic acid at three levels (zero, 2 mM and 4 mM as foliar application), with a total of 9 treatments. The effect of humic acid, salicylic acid and their interaction on yield and yield components, leaf chlorophyll content, concentration of macronutrients in leaves and fiber quality were significant. The highest seed cotton yield (4409 Kg.ha-1) was obtained from the combined application of humic acid in the form of seed coated and salicylic acid in the form of foliar application at a concentration of 4mM that was 49% higher compared to the control Application of humic acid and salicylic acid improved the qualitative characteristics of the fibers, so that the maximum average fiber length of cotton fibers was 31 mm from the combined application of humic acid as seed coated and salicylic acid as foliar spraying with concentration of 4mM  was obtained, which was a 10.7% increase in length compared to the control treatment (without the use of humic acid and salicylic acid). The interaction of humic acid and salicylic acid on the mean concentration of nitrogen, phosphorus, potassium, calcium, magnesium in cotton leaves was significant. In this regard, the highest mean concentrations of nitrogen, phosphorus, potassium, calcium and magnesium of cotton leaves were 3.9, 0.43, 3.9, 1.6 and 0.99%, respectively, from the combined application of humic acid to Seed and salicylic acid were obtained by spraying at a concentration of four per thousand, which compared to the control treatment (without the use of humic acid and salicylic acid), respectively for nitrogen, phosphorus, potassium, calcium and magnesium. 44, 53, 62, 60 and 12% more. Based on the results obtained from this study, the application of humic acid in the form of seed coated and salicylic acid in the form of foliar application in saline conditions, modulates the effects of salinity stress and increases the yield of cotton and improves the quality characteristics of fibers

To evaluate the effects of different application methods of humic acid and aminochelate (Foliar application and soil application) on growth and yield of cucumber (Cucumis sativus. L), an experiment has been conducted under greenhouse conditions with factorial design based on randomized complete block with three replications during two years (2018-2019) in Tehran agricultural a natural resources research and education center. The humic acid factors are as three levels (untreated, soil application, and foliar spray) and aminochelate factor are as three levels (untreated, soil application, and foliar spraying). The effects of humic acid, the effects of aminochelate, and their intraction on yield, number of fruits per plant, fruit dry matter, and leaf chlorophyll index have been significant. The highest fruit yield, number of fruits per plant, fruit dry matter, and leaf chlorophyll index are obtained from soil application of humic acid and aminocholate, being 57.4%, 58.6%, 56.4%, and 43.8%, more than the control, respectively. Also, the effects of humic acid, the effects of amino chelate, and their intraction have been significant on concentration of macronutrients in leaf. The highest concentrations of nitrogen, phosphorus, potassium, calcium, and magnesium of the leaves are obtained from the application of humic acid and aminoclate in soil. Thus, the concentration of nitrogen, phosphorus, and potassium due to soil application of humic acid and aminolate increase by 44%, 51%, and 5%8, respectively. Based on the results, in order to achieve the maximum yield of greenhouse cucumber, the combined use of humic acid and aminocholate as soil application is recommended.

In this study, salinity tolerance of five sorghum varieties (Speedfeed, Kimia, Payam, Sepideh, and Pegah) was studied using five irrigation water salinity levels (non-saline water, 4, 8, 12 and 16 dS/m) in the greenhouse. The statistical design was a factorial randomized complete block design with 25 treatments and four replications. The studied traits included plant height, leaf area, dry weight of roots and shoots, ratio of dry weight of roots to shoots, leaf chlorophyll index, concentration of sodium, chlorine and potassium in leaves and roots. The effect of variety and the effect of salinity stress on the mean of all measured traits were significant (P <0.01). At salinities of 4, 8, 12, and 16 dS/m, shoot dry weight was lower than the control (5.72 g/plant) by16.2%, 35.1%, 55.7%, and 69.4%, weight of dried roots lost 26.6%, 53%, 72% and 82%, compared to the control (5 g/plant), and the leaf area of the plants decreased by 29.4%, 58.3%, 75.5%, and 86.3% compared to the control, respectively. There was a negative correlation between chlorine and leaf sodium concentrations with shoot dry weight. Fisher stress sensitivity coefficient was used to evaluate the salinity sensitivity of cultivars based on shoot dry weight. Based on this coefficient, Speedfeed variety had the lowest salinity sensitivity coefficient (0.73) and Pegah cultivar had the highest (1.21). Regression was determined between different salinity levels with shoot dry weight for each cultivar. Accordingly, Speedfed, Kimia, Payam, Sepideh, and Pegah cultivars suffered a 50% reduction in shoot dry weight in salinities of 13.89, 12.95, 9.73, 9.62 and 9.50 dS/m. Based on the results, Speedfeed variety had a higher salinity tolerance than other cultivars and is recommended for cultivation in saline soil and water conditions.

In a two-year field experiment, the effects of combined application of manure and trace elements of iron, zinc and boron on the quantitative and qualitative characteristics of cantaloupe cultivar Semsouri in a calcareous soil was studied. Application of manure and trace elements increased yield, yield components and TSS (Total soluble solids). The highest cantaloupe yield(43.9 tons per hectare) and the highest average number of fruits per cantaloupe plant (4.45) were obtained from the application of 40 tons per hectare of manure and foliar application of iron, zinc and boron that increased 36 and 41% compared to the control treatment, respectively. Also, the percentage of TSS increased with the application of manure and foliar application of microelements, especially boron. The highest TSS (sugar) of cantaloupe was obtained at 9% from the application of 40 tons per hectare of manure and foliar application of iron, zinc and boron, which was 49% more than the control treatment. Data indicated that there was a significant correlation between the percentage of soluble solids in fruit and the concentration of cantaloupe leaf boron that the equation of this regression model followed the linear model.

In order to investigate effects of water salinity on germination characteristics of quinoa (Chenopodium quinoa Willd), an experiment was conducted in a factorial and randomized complete blocks design with 10 treatments and three replication, in 2020. Salinity factor was considered at five levels (zero, 5, 10, 15 and 20 dS / m) and cultivars at two levels (Titicaca and Redcardina). Effects of salinity, cultivar, and their interaction were significant on germination percentage and its rate, length of shoot, root and seedling, vigor index, stem and root tolerance index. All characteristics were significantly reduced by salinity stress, with higher reduction in Redcardina than Titicaca. Salinity stress up to 5 dS/m had no significant effect on seed germination percentage of Titicaca, while in Redcardina, difference in germination percentage between distilled water (control) and salinity of 5 dS/m was significant. The highest germination percentage (100%) was obtained in treatment without salinity for both Titicaca and Redcardina. Germination percentage at salinity levels of 5, 10, 15 and 20 dS/m in Titicaca decreased by 1.4%, 4.9%, 14.3%, and 21%, and in Redcardina, by 2.6%, 6.6%, 18.3%, and 29.7% compared to the control. Stem length of cultivars at salinity levels of 5, 10, 15 and 20 dS/m compared to the control treatment were reduced by 6.8%, 14%, 27.6%, and 39.6% for Titicaca and 7.3%, 19.9%, 43.7% and 53.8% for Redcardina, respectively. This percentage reduction for root length of Titicaca was 2.1%, 12.6%, 32.6%, and 44.2% and for Redcardina was 6.4%, 21.2%, 38.2% and 57.9%. Salinity stress of 5, 10, 15 and 20 dS/m caused the dry weight of seedlings of Titicaca to decrease by 12.7%, 27.1%, 36.8% and 46.6% and in Redcardina by 11.4%, 27.8%, 45%, and 57.1%. Based on the results, Redcardina cultivar was more sensitive to salinity stress during germination than Titicaca.

In order to investigate the effects of compost and nitrogen on quantitative and protein content of forage corn and some physical and chemical properties of soil, a factorial experiment with 9 treatments in a factorial randomized complete block design has been conducted in the farm of Tehran Agricultural and Natural Resources Research and Education Center during 2014. The treatments include three levels of residual compost (0, 10, and 20 Ton.ha-1) and three levels of nitrogen (0, 100, and 200 kg.ha-1) as urea. The effect of municipal waste and nitrogen compost on yield and yield components has been significant. The use of municipal solid waste compost has significantly increased the electrical conductivity of soil, nitrate, iron, and zinc uptake, while significantly decreasing soil reaction. Waste compost application has also improved some soil physical properties. Bulk density is significantly reduced and field capacity and soil available water are increased. Therefore, in the similar soil conditions of this ersearch, the use of 200 kg.ha-1 of pure nitrogen from the urea source with 20 Ton.ha-1 of municipal solid waste compost is recommended to achieve the maximum dry forage yield of 21.44 tons per hectare.

In a field experiment, the effects from application of nitrogen and boron on quantitative and qualitative characteristics of Varamin cotton variety have been studied at Tehran Agricultural and Natural Resources Research Center in 2016. The experiment has been carried out, using a randomized complete block design with factorial arrangement with three replications, with the main factor being nitrogen at four levels (0, 100, 200, and 300 kg ha-1) and the sub-factor, involving boron at three levels (no leaf spray, one leaf spray, and two leaf spray). The effects of nitrogen and boron and the interaction of nitrogen and boron on the quantitative traits of cotton, namely the mean number of bolls per plant, average boll weight, fiber yield, and fiber gin out, with the qualitative traits including fiber length and strength. Highest seedcotton yield (5233 kg ha-1), fiber yield (2080 kg ha-1), fiber percentage (40%), fiber length (31.3 mm), and fiber strength (29.7 g / textile) belong to 200 kg N per hectare and twice spraying of boron. There is a correlation between the qualitative properties of the fibers and nitrogen, whose regression relation follows the quadratic equation. Results show that in soils with less than 0.5 mg / kg boron and less than 0.81% organic carbon storage, nitrogen and boron application significantly increases seedcotton and fiber yield and the fiber quality is also improved. Therefore, in such soils, it is recommended to utilize 200 kg N with two times of foliar boron application from boric acid source with a concentration of five per thousand at flowering stage for two weeks thereafter.

Garlic (Allium sativum L) is the second most commonly used herb of alliums after onions. This plant has significant effects on lowering blood pressure, preventing atherosclerosis, reducing blood cholesterol and triglyceride and inhibiting platelet aggregation. In recent years, the increase in the yield of this product has been of interest to manufacturers of this product with respect to the preservation of qualitative characteristics, including the maximum content of nitrate. It has been shown that the absorption of nutrients in the soil affects the yield and yield components of the plant. In this regard, the timely and adequate supply of nutrients such as sulfur and nitrogen has a special role in promoting quantitative and qualitative characteristics of garlic. In order to study the effects of nitrogen and sulfur consumption on quantitative and qualitative traits of garlic, this study was conducted with 12 treatments and three replications in the form of a split plot design in two years in Agricultural Research Center of Agricultural and Natural Resources of Tehran Province which located in Varamin in Iran. Nitrogen factor was considered at four levels (0, 100, 200 and 300 kg ha-1) and sulfur at three levels (0, 500 and 1000 kg ha-1 with inoculation of Thiobacillus). Before planting, soil samples were taken from the experimental site and physical and chemical characteristics including texture, reaction, organic carbon, lime, nitrogen, phosphorus and potassium, and iron, manganese, copper, zinc and boron were measured. Dry matter yield, number of bulbs per garlic, single plant weight, garlic weight, plant height, leaf number per plant and leaf area were recorded at the end of experiment. Garlic nitrate content and nutrient concentration in garlic leaves were also measured. Data obtained were analyzed statistically using SAS software. The effects of nitrogen and sulfur on the yield of garlic cloves, number of bulbs in cloves, cloves weights, bulbs weights, plant height, leaf area and bulb nitrate were significant as all these traits were improved. Application of 1000 kg.ha-1 of sulfur increased the garlic cloves yield by 31% compared to the control. Nitrogen consumption up to 200 kg.ha-1 increased garlic cloves yield by 58% compared to the control. The highest economic yield of garlic cloves was obtained by 1000 kg.ha-1 sulfur and 200 kg.ha-1 nitrogen, which was 104% more than control treatment. Data also showed that the effects of sulfur and nitrogen and the interaction of sulfur and nitrogen on the leaf area of the garlic plant were significant. Consumption of 1000 kg.ha-1of sulfur increased the leaf area of the garlic plant by 42% compared to the control. Nitrogen consumption up to 200 kg.ha-1 increased the leaf area of garlic plant by 39.3% compared to the control. The highest leaf area of garlic plant was obtained from 1000 kg.ha-1sulfur and 200 kg.ha-1nitrogen, which was 104% higher than control. Increase of the growth and yield of garlic was attributed to the main role of nitrogen in increasing meristematic activity, cell division, prolongation of the cell. Sulfur is one of the essential nutrients of the plant, and without sulfur, the plant does not grow and function properly. Sulfur is the fourth essential element after nitrogen, potassium and phosphorus for garlic. This element is needed in production of amine acids, such as methionine and cysteine, which are essential for the production of vitamin A, and the activation of certain enzymes. The results of studies have shown that amino acids directly or indirectly affect the physiological activity of the plant, and positively affect the growth, increase in yield and increase plant tolerance to environmental stresses. The soil reaction was affected by sulfur consumption and decreased. There was a negative correlation between soil reaction as a dependent variable (Y) and consumed sulfur as an independent variable (X), which correlated with linear relation with correlation coefficient of 0.98. Data showed that use of 1000 kg.ha-1of sulfur reduced soil reaction from 7.49 to 7.26 and increased leaf iron concentration by 88% compared to control and increased leaf zinc concentration 110% compared to control treatment. The researchers believe that sulfur oxidation and sulfuric acid production in the soil reduce soil reactions and increase the absorption capacity of phosphorus and microelements. The effect of sulfur on the concentration of leaf phosphorus was significant. The phosphorus concentration was increased significantly with sulfur application into the soil, so that 1,000 kg.ha-1 of sulfur increased the concentration of leaf phosphorus by 63% compared with the control (0.33%). Research results have shown that phosphorus absorption capacity in soil is highly dependent on soil reaction and reducing soil reaction leads to increased phosphorus absorption capacity. Researchers have reported that sulfur consumption and the production of sulfuric acid, as a result of its oxidation, reduce soil reaction and increase phosphorus availability for plants. The effect of nitrogen, sulfur and the interaction of nitrogen and sulfur on the content of garlic nitrate was significant. Garlic nitrate content decreased with application of sulfur and increased with nitrogen addition. Application of sulfur at 1000 kg.ha-1 significantly reduced garlic nitrate content by 35% compared to control. The application of 100, 200 and 300 kg.ha-1 of nitrogen increased the content of garlic nitrate 97, 210 and 308%, respectively in comparison to control. At all levels of nitrogen addition, sulfur consumption reduced the content of garlic nitrate. Garlic nitrate content decreased with application of sulfur and increased with nitrogen addition.  Sulfur application at 1000 mg.kg-1 significantly reduced garlic nitrate content by 35% compared to control (mg.kg-1). Garlic nitrate was increased by the amount of nitrogen consumed. There was a positive correlation between garlic nitrate (Y) as a dependent variable (N) and independent nitrogen (X), which correlated with linear relation with the correlation coefficient of 0.99. Researchers have argued that excessive consumption of nitrogen fertilizers is the main factor causing the accumulation of nitrate in a number of vegetables and other plants such as garlic. Based on the results of the experiment, it was concluded that nitrogen and sulfur increase the yield of garlic. Meanwhile, sulfur reduces nitrate accumulation in garlic. Sulfur consumption reduces soil pH and increases the absorption availability of micronutrients and phosphorus in the soil and causes more absorption of these elements by the plant.

An experiment was carried out in calcareous soil with 0.42 mg.kg-1 available boron (B) and 0.33 mg.kg-1 available zinc (Zn) in research farm of Tehran agricultural and natural resources research and education center to determine the effects of boron and zinc application on quantitative and qualitative characteristics of cotton during the two-years study with using a randomized complete block design with the factorial arrangement. Different levels of boron consumption from boric acid source (0, 5, 10 kg ha-1 application in soil and one as leaf spraying treatment) as boron factor and different levels of zinc consumption from zinc sulfate source (0, 30, 60 kg ha-1) application in soil and one as foliar application were considered as zinc factor. The main effects of boron, the main effects of zinc, and the interaction effects of boron and zinc were significant on yield, yield components, and qualitative properties of cotton fibers. The highest yield, number of bolls per plant, single boll weight, intermediate distance, and plant height and fiber length were obtained from the foliar application. To maximize the yield and improve the quality of the fibers, it is recommended to use zinc and boron foliar spray at a concentration of five per thousand twice during the growing period.

During a one-year field study, the concentrations of nitrates and heavy metals in soil and edible leafy vegetables were measured in farms in Varamin, Pakdasht, Pishva and Qarchak counties. The average concentrations of lead, cadmium and nickle in leafy vegetables were 0.2 , 0.77 and 2.1 mg/‌kg, respectively. The concentration of lead were 900% more than standard declared by the National Organization for Standardization of Iran. The average concentrations of lead, cadmium and nickel in the soil of the fields were 10.7, 1.46 and 1.18 mg/‌kg, respectively, which was less than the maximum allowed. The risk index for non-cancerous diseases was used to assess the risk of leafy vegetables consumption. The average risk index of lead, nickel and cadmium in leafy vegetables was 0.22, 0.05 and 0.03, respectively. Among leafy vegetables, the most dangerous were nitrate, lead, nickel and cadmium from lettuce, mint, parsley and lettuce. The results of the biological concentration factor calculation showed that coriander had the highest lead and nickel biological concentration factor among leafy vegetables, which indicates the tendency of this vegetable to absorb and accumulate lead and nickel compared to others. Leafy vegetables were not much different in terms of cadmium accumulation.

Among the plant nutrients required, nitrogen is the most limiting plant growth factor and the key nutrient for achieving optimum yield in most crops, especially in arid regions (Seilsespour and Momayezi, 2005). Therefore, the most widely used fertilizer among the fertilizers is nitrogen-containing fertilizers. Nitrogen is present in the structure of amino acids, nucleic acids, purine bases, alkaloids and chlorophylls. The amount of nitrogen needed by plant depends on the species of plant and soil. It is absorbed by the plant in the form of ammonium and nitrate. Plants mainly prefer nitrate ions for uptake (Dordas and Sioulas, 2008). Nitrate in the human body is converted to nitrite and, in combination with amines, is converted to nitrosamine, which is one of the main causes of cancer. In the neonatal stomach, nitrate is resuscitated to nitrite and, in the bloodstream, oxidizes hemoglobin iron and converts divalent iron to trivalent iron. Thus, hemoglobin pigments disrupt oxygen delivery to the infant's body and eventually lead to choking and death of the infant (Fewtrell, 2004). Nitrate accumulation in vegetables is often dependent on the amount and type of nutrients in the soil and is closely related to the amount and timing of fertilizer use, so that the amount of chemical fertilizer applied is one of the factors affecting it. Vegetable and vegetable products, including leafy vegetables, are of great importance in many countries because of their high nutritional value (Menard, 2008). Vegetables have been suggested by the World Health Organization to prevent no communicable diseases such as cardiovascular disease, cancer, obesity, and type 2 diabetes (FAO / WHO, 2003). However, despite the importance and nutritional value of vegetables, research has shown that about 80% of the nitrates that enter the human body are from vegetables and fruits (Kiani and Gheytasi, 2016). Due to the adverse effects of nitrate on human health, much attention has now been paid to the accumulation of this ion in vegetables and has been considered as a qualitative biological indicator in vegetables (Chen et al., 2004). Due to the lack of information on the nitrate concentration of leafy vegetables produced in the major vegetable production areas of Varamin plain, this study was conducted to determine of nitrate concentration in leafy vegetable and  evaluation of  nitrate risk assessment for vegetables consumers.
To investigate the nitrate concentration in leafy vegetables, this study was conducted in 2014 in the agricultural lands of Varamin district (Varamin, Pishva, Pakdasht), which are the hub of vegetable production in Tehran province. The leafy vegetables studied were savory, parsley, coriander, fenugreek, leek, cress, dill, mint, cabbage, celery, spinach and lettuce. Sampling was done for each crop from 30 different farms.. Di azo method (Emami, 1996) was used to determine nitrate concentration. The mean nitrate concentration in each leafy vegetable (at 30 field level) was compared with the maximum permissible nitrate level (National Standard No. 16596) by means of T-test. According to the World Health Organization (Human Health Fact Sheet, 2005) guidelines, which set the daily nitrate uptake for humans to be 3.6 mg.kg-1 body weight, the maximum daily allowable nitrate uptake through each leafy vegetable for a person with 80 kg weight was calculated.
Among the leafy vegetables, lettuce with average 3909 mg / kg fresh weight had the highest accumulation of nitrate and fenugreek with an average of 641 mg/kg fresh weight had the lowest nitrate accumulation per kg. The mean nitrate concentration of each vegetable was compared by T-test with maximum nitrate concentration for each vegetable. In all samples of lettuce, spinach and celery studied, nitrate concentration was significantly higher than the maximum, while in all fenugreek and coriander samples, nitrate concentration was significantly lower than Maximum allowed. Considering the maximum allowable daily intake of nitrate for humans (3.86 mg / kg body weight) and the average nitrate content in the studied vegetables, the maximum daily intake of each vegetable species were calculated. The results showed that daily consuming of  76 grams of  lettuce or 94 grams of spinach by a person with 80 kg weight, would maximize the amount of nitrate in the body and increase the risk to health.
The results of this study showed that some of the leafy vegetables such as lettuce and spinach contained high levels of nitrate base on the national standard of Iran. The average nitrate concentration in the leafy vegetables was 1458 mg / kg fresh weight. Maximum daily uptake of nitrate for adults is about 190 mg and more uptake, can cause harmful on the body. It is worth noting that this issue is more important for children. Therefore, it seems that the use of nitrogen fertilizers should be revised in the leafy vegetables fields. In this regard, nitrogen fertilizer application based on soil test and soil nitrate is recommended.

In order to determine the critical nitrogen concentration of canola leaf and studying the correlation of yield and yield components of this plant with leaf nitrogen concentration, 35 farms were managed in the same way of Varamin plain and in the dominant soil serie (Varamin), were selected during 2016. Leaf samples were pick up from these farms at flowering stage and were prepared for analysis. In harvest season, all 35 fields were harvested and the mean grain yield was determined. The critical nitrogen concentration in dry leaves was determined at 3% by using Kate and Nelson's graphical method, for 90% relative yield. There was a significant correlation between the content of canola leaf nitrogen as independent variable (X) with other traits, including grain yield and yield components as dependent variables (Y) at the 35 studied farms. The results of the studies showed that canola seed yield was affected by leaf nitrogen content. The content of nitrogen in canola leaves was significantly correlated with grain yield. This correlation was followed by a quadratic function with a coefficient of explanation of 0.97. Relative yield of canola seed increased only to 4.36% nitrogen concentration of leaves, and since then, the increase in leaf nitrogen did not affect grain yield.

In order to evaluate the effects of municipal waste and nitrogen fertilizer application on spinach yield and heavy metal concentration in soil and spinach, a field experiment with 9 treatments was conducted in a factorial design. The effect of municipal waste compost, nitrogen and their interaction on yield was statistically significant. The highest yield of spinach at 68600 kg ha-1 was obtained from 20 ton / ha compost with 200 kg ha-1 nitrogen. The increase in the concentration of cadmium, nickel and chromium was higher than the maximum concentration of heavy metals in the spinach shoot, respectively, by 700, 279, 471 and 272%, respectively. On the other hand, application of 10 ton / ha of municipal solid waste compost along with 200 kg / ha nitrogen produced 67300 kg / ha with heavy metals within the product range. The use of municipal waste compost significantly increased the total concentrations of soil lead, nickel, cadmium and chromium, but this increase was not beyond the permissible range. However, limited use of municipal waste compost at 10 ton / ha with 200 kg / ha nitrogen, together with monitoring of soil and plant concentrations of these metals can increase yield of spinach, without heavy metal concentration. Exceeds the standard range in crop and soil.

Considering the development of industry and technology, the accumulation of environmental contaminants, especially heavy metals (HMs) in the soil lead to increasing concern about the food security. The purpose of this study was to assess the environmental risk of heavy metals using soil pollution indices. For this purpose, thirty five soil samples were taken from agricultural area in seven sites. The total and available concentration of metals extracted by Aqua Regia and DTPA were determined by an atomic absorbtion spectrometer. Geoaccumulation index (Igeo), enrichment factor (EF), pollution index (PI), contamination factor (CF), potential ecological risk (RI), and availability ratio (AR) were calculated. Mean total concentration of Cd, Pb, Zn, Ni, Co, Cu and Cr were 0.09, 52.3, 146, 25.0, 4.90, 42.1 and 73.1 mg/kg, and their available values were 0.035, 5.07, 7.10, 0.047, 0.041, 3.01 and 0.030 mg/kg of soils, respectively. The highest values of Igeo, EF, PI, RI and AR indicators were found in Cu (1.69), Cr (8.70 ), cu (5.21), Cr (43.52), and lead (10.87), respectively. Integrated pollution index (IPI) calculated using the average of total CF was 4.08 indicating the higher contamination class in the area whereas IR value was in acceptable ecological range (IR= 109). Analysis of Igeo and IR data showed that Pb, Zn and Cu vary by anthropogenic activities in the area while Cd and Co values are solely affected by lithgenic factor. Agricultural inputs and urban wastewaters can be the major factor increasing of pollutants in the agricultural soils in the area. Monitoring the pollutants concentration in the agricultural soils as well as in agricultural products is essential to conserve natural resources and obtain food security.

In order to investigate the effect of different levels of municipal waste compost and nitrogen on the yield of tomatoes and the concentration of heavy metals in fruit and soil, a field experiment was conducted with 9 treatments and three replications in the form of split plot design in Agricultural Research and Education Center of Tehran Province for one year. The main plot consisted of three levels of compost consumption (0, 10 and 20 t ha-1 with a moisture content of 22% by weight). Subplots consisted of three levels of nitrogen application (0, 100 and 200 kg ha-1). The effect of urban waste compost, the effect of nitrogen and their interaction on yield of tomatoes were statistically significant at the level of one percent. The highest yield of fruit 68785 kg ha-1 was obtained from 20 ton.ha-1 compost with 100 kg ha-1 nitrogen. Consumption of 20 tons per hectare of urban waste compost significantly increased the concentration of lead, cadmium and nickel in tomato fruit at 2804, 2400 and 3022 percent, respectively, compared to control. However, the concentration of any of the above elements in fruit was not more than the maximum allowed national standard of the country. Also, municipal waste compost increased the concentration of total lead, nickel and cadmium in soil, which was allowed in this concentration increase. Also, there was a significant correlation between the concentration of lead, cadmium and nickel of tomatoes with total concentration of these elements in the soil.

In a field study, the effects of different amounts of municipal solid waste compost and nitrogen on cotton characteristics and chemical properties of soil were studied. The statistical design was split plot. Different levels of municipal solid waste compost (0, 20 and 40 t ha-1) were considered as the main factor and different levels of nitrogen (0, 100 and 200 kg ha-1) were considered as sub plots. The results of the experiment showed that the effects of municipal solid waste compost, the effect of nitrogen and their interaction on cotton yield and qualitative properties of the fibers are significant. Municipal solid waste compost and nitrogen, each alone, increased yield, but the highest yield was 4787 kg ha-1 from municipal solid waste compost consumption of 40 tons per hectare with 100 kg / ha nitrogen per hectare. Consumption of more nitrogen at this level of compost did not have a significant effect on yield. Consumption of municipal solid waste compost had a significant effect on the chemical properties of soil, so that, with the use of municipal solid waste compost waste compost, soil reaction (pH) decreased significantly and the values of electrical conductivity, organic carbon, nitrate, available iron and zinc showed a significant increase.

Salinity is one of the most important limiting factors for crops, because of most agronomic and horticultural crops are sensitive to salinity. On the other hands, considerable lands of the world were affected by salinity and they are increasing day by day. An experiment was conducted with five levels of irrigation water salinity in soilless culture and greenhouse condition to evaluate the effects of salinity on growth parameters of two olive rootstocks.Data showed that salinity decreases significantly some growth parameters such as shoot dry weight, root dry weight, shoot dry weight to root dry weight, and shoot elongation and decreasing amounts of all growth parameters by salinity in Zard rootstock were more than that of Mission. Shoot dry weight, leaf dry weight and root dry weight at 16 dS.m-1 salinity treatments were decreased 80, 80 and 69 percent respectively compared to control. Data also demonstrated that among different growth parameters, leaf aria had the most sensitivity to salinity and leaf relative water content(LRWC) had the lowest sensitivity to salinity. Base on the results, relative leaf aria was decreased 25 percent at 2.3 and 5.0 dS.m-1 salinity in Zard and Mission rootstock, respectively. Salinity status for 25 percent decrease of relative dry weight of these parameters were 2.8, 2.9 and 4.4 dS.m-1 in Zard rootstock and 5.3, 6.1 and 6.9 dS.m-1 in Mission rootstock respectively.Data analysis showed that there were a regression equation among salinity and some growth parameters such as relative leaf aria, leaf number, leaf water content and leaf chlorophyll. Data showed that the slope of regression fit line in Zard rootstock was more negative than Mission rootstock. These results confirmed that some variables such as relative leaf aria, leaf number, leaf water content and leaf chlorophyll content were more sensitive to salinity in Zard rootstock in compare to Mission rootstock.Data also showed that salinity status to for 25 percent decrees of relative leaf aria, leaf number, leaf water content and leaf chlorophyll content in Mission rootstock were 5.06, 5.51, 20.39 and 11.5 and for Zard rootstock were 2.33, 2.81, 15 and 8.61 dS.m-1 respectively. Data also indicated that 25 percent decrease in total relative dry matter were in 7.0 and 3.6 dS.m-1 salinity in Zard and Mission rootstooks, respectively. On the whole, evaluation of plant growth parameters and their sensitivity to salinity indicated that Mission rootstock had more tolerance to salinity and was recommendable to cultivation in salt affected soils.

A greenhouse experiment was carried out to evaluate the effects of salinity stress on growth and macroelements contents of two olive varieties in soilless culture medium. In the research, one-year old saplings of two olive varieties, ‘Zard’ and ‘Mission’, were subjected to different salinity levels induced by NaCl including 0, 4, 8, 12 and 16 dS/m-1 for 5 months. Based on the results, total dry weights of the varieties were decreased at 16 dSm-1­­ compared to control up to 63 and 85% at ‘Mission’ and ‘Zard’, respectively. Also, a 25% reduction in total dry weight was observed under salinities of 7 and 3.6 dSm-1 for ‘Mission’ and ‘Zard’, respectively. Salinity was decreased the concentrations of macronutrients and increased the concentrations of Na and Cl in roots and leveas of the both varieties. Compared to control, Na and Cl concentrations in leaves and roots was increased under salinity of 16 dS/m-1­­ ­at 1660 and 679% for Na and 1069 and 506% for Cl. In all salinity levels, Na and Cl concentrations in the leaves and roots of 'Zard' variety were more than that of 'Mission'. Thesa data demonstrated that ‘Mission’ has a more salinity tolerance than ‘Zard’, and could be used as a salt-tolerant variety for cultivation under salinity conditions. The defence mechanisms of ‘Mission’ are restricting in absorbtion and translocation of Na to aerial parts and accumulate a proper concentration of K in Leaves.

A greengouse experiment was conducted to evaluation of salinity stress on growth parameters of two olive cultivars during 2013-2014 at Agricultural and Natural Resources Research Center of Tehran. In the experiment, effects of five levels of irrigation water salinity including 0, 4, 8, 12 and 16 dS.m-1 were evaluated on ʻZardʼ and ʻMissionʼ olive cultivars under soilless culture. Data showed that salinity had significant effects on all growth parameters in both olive cultivars. Leaf dry weight, shoot and root dry weight, leaf chlorophyll index, shoot and root tolerance index, shoot and internodes length, leaf area, leaf number and leaf relative water content were affected by salinity and significantly decreased. These reductions were more in ʻZardʼ comparing to ʻMissionʼ. Shoot dry weight, leaf dry weight and root dry weight were decreased 80, 80 and 69 percent, respectively at 16 dS.m-1 salinity treatments with compare to control. Leaf sodium (Na) concentration and rate of sodium to potassium (K) in leaf were increased and leaf potassium concentration was decreased by salinity. Increase of Na and decrease of K were more in ʻZardʼ comparing to ʻMissionʼ. Also, leaf and shoot dry weight were affected by concentration of Na, K and Na: K in leaf and there were a significant correlation among these parameters with leaf and shoot dry weight. Results indicated that ʻMissionʼ variety were more salt tolerance than ʻZardʼ.

Super absorbent polymers because of Water absorption and hold water can increase the water-holding capacity of the soil and decreases tension caused by dehydration effect. This study evaluated the effects of different levels of superabsorbent polymer and water stress on yield components in maize In Agriculture Research Center of Varamin city in July 2012 Was carried out as a pot factorial complete block randomized design with 3 iteration. Treatments consisted of four levels of water stress، w1، w2، w3 and w4 (50، 75، 100 and 125% of crop water requirement) and 4 superabsorbent Hybrozom s1، s2، s3 and s4 (control، 3، 5، 7 grams per kilogram potting soil). Traits Review was Included: Length of Bush، Fresh weight of leaves and Dry weight of leaves. The Results indicated that، with increase rate of superabsorbent polymer was increased leaf dry weight، total dry weight and plant height so that this parameters in the treatment s4 (7 grams per kilogram of soil) than controls، respectively 63. 72، 90. 14، 36. 42 percent has increased.

There are a lot of evidence on the effects of potassium and Zinc to increase wheat yield and improving seed quality and reducing of cadmium uptake by plant. An investigation carried out to study the effects of these two elements in the process of Cd uptake by wheat and effects of these elements in other growth parameters. The statistical design was split plot with three main factors (without potassium، potassium consumption based on soil test potassium and potassium consumption tow time more than soil test potassium) and four sub plots (control Zn، soil Zn consumption، foliar Zn application and، Zn in Soil and consumption combined with foliar application). The experiment was done in a wheat field in southern of Tehran، which many years were irrigated with wastewater. The results of experiment showed that the main effects (potassium effects) on grain yield، straw yield، spike length، number of grains per panicle and grain weight is significant. The above characteristics increased by use of potassium based on soil test recommendation significantly and extra use of potassium did not any effects on these parameters. Secondary effects (Zn) on the above traits were significant. Grain yield، straw yield and grain weight were not affected by different methods of Zn application، but combined use of Zn as soil application and foliar، produced the greatest amount of panicle length and number of seeds per ear. The main effects of zinc and potassium was significant on the concentration of mean grain cadmium. Consumption of these elements significantly reduced grain cadmium concentration. Use of potassium tow time more than soil test recommendation was the highest decrease in cadmium concentration by 34 percent. Use of Zn in soil combined with foliar application was the highest effects on seed cadmium decrease by 17. 8 percent in compare to other method. The concentration of cadmium in seed was affected by Potassium and Zinc interaction and decrease significantly. Use of potassium tow time more than soil test recommendation and Use of Zn in soil combined with foliar application decreased seed cadmium concentration by 48. 6 percent significantly. Data also showed that there were a significant correlations between seed potassium and seed zinc concentration and the amount of seed grain cadmium with the quadratic equation، so with increasing concentrations of potassium or zinc، cadmium concentrations of grain declined. On the whole، to reach maximum yield with minimum grain cadmium concentration، Use of potassium tow time more than soil test recommendation and use of Zn in soil combined with foliar application، eventually in lands the same place of research experiment، was recommended.

This experiment was carried out to investigate the effects of municipal solid waste compost (MSWC) and chemical fertilizers on yield and quality of wheat and P and OM in the soil at Varamin Agriculture Research Center. The experimental design was randomized complete block with 6 treatments and 4 replications. Treatments were included: T0= control، T1= N، P and K chemical fertilizers based on soil test، T2، T3، T4= orderly of 10، 20، and 30 ton ha-1 MSWC، and T5= combination of T1 / 2 + T3. Grain yield، straw yield، grain protein percentage، iron (Fe) and zinc (Zn) content of grain، and P and OM in the soil increased with increasing MSWC rate. The greatest grain yield، straw yield، and P accumulation in the soil occurred when both chemical fertilizers and MSWC were present (T5). No significant differences were observed among treatments for Fe and Zn content of grain. Soil OM was significantly higher in the MSWC treatments than the control or T1. The grain protein percentage increased in T1 and T5 by use of N fertilizer.