فهرست مطالب اکبر قویدل

Heavy metal contamination in soil refers to the excessive accumulation of elements called heavy metals, which are capable of causing significant levels of biological toxicity. These metals, in concentrations higher than of tolerable threshold of plants, often cause metabolic disorders, inhibition of growth and physiological process and eventually lead to death of plants. Lead (Pb) and zinc (Zn), as the two common coexisting mineral heavy metals around the world, accumulate in the soil due to mining activity and can adversely affect the crop productivity, the agro-ecosystem components and ultimately the human and environmental health. Biochar, as a potent soil amendment agent, is often obtained by pyrolysis of agricultural organic wastes such as crop residues under low oxygen pressure condition. Trichoderma harzianum, as a plant growth promoter, has capability in stimulating plant growth under varying environmental stresses and therefore, inoculation of plant roots with this fungus could be a conceivable approach to cope with the heavy metal stress. Hairy vetch (Vicia villosa Roth) is a winter annual forage species that shows better growth performance than the other forage legumes such as alfalfa or clover under the severe environmental conditions, especially winter frost and drought.phosphorus supplementation and their interactions on the growth, physiology and P, Pb and Zn uptake by hairy vetch in heavy metal-polluted soil.

The experiment was carried out in the greenhouse of Faculty of Agriculture and Natural Resources of Mohaghegh Ardabili University as a factorial experiment based on a completely randomized design (CRD) in three replications. Heavy metal contaminated soil was collected from wheat fields around Angouran village (Angouran Rural District, Angouran District, Mahneshan County, Zanjan Province, Iran), downstream of the Zanjan's lead and zinc processing plant (Calcimin® Co.; 36°34'13.2"N 47°37'21.4"E), from a depth of about 0 to 25 cm. Two levels of biochar application (non-biochar control, 5% peanut hull-derived biochar), two levels of Trichoderma inoculation (non-inoculation control and inoculation with conidial suspension) and three levels of P supplementation (0P, non-supplementation; 11P, 11 mg P.kg-1 and 22P, 22 mg P.kg-1) were applied as the three experimental factors. The feedstock of peanut hull (PH) used in the present experiment were purchased from the local market. After thorough washing, PHs were air-dried and then well ground with a lab-scale mill and sieved using a 100 mesh sieve size. T. harzianum Rifai - T22 isolate acquired from the Laboratory of Plant Pathology, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili was revived on PDA (potato dextrose agar) medium and further incubated for at least one week at 28 °C. This experiment was conducted in an open-air vegetation yard with mean day/night temperatures of 25/17 °C, respectively. The experiment lasted for 50 days, in the period from May 16, 2020 (sowing the seeds) until July 5, 2020 (final sampling). In each plastic pot (25 cm in diameter × 20 cm in height), pre-filled with the pot mixture according to the treatments, 20 surface-sterilized hairy vetch (Vicia villosa Roth., Local landrace from Ardabil, Iran) seeds were sown and irrigated with tap water (EC = 0.21 dS m-1 and pH = 7.2) to 100% field capacity. Throughout the experiment, all the pots were re-irrigated when the soil water content dropped to 70% of the field capacity.

Application of biochar and Trichoderma fungus at not using phosphorus (P0), resulted in higher aerial biomass. Trichoderma fungus alone or with P11 level had a better result in increasing plant height. The concentration of chlorophyll a was in highest level by biochar combined Trichoderma, and P0 phosphorus applied, as well as the application of Trichoderma caused the highest concentration of chlorophyll b. The changes in relative leaf water content ranged from 85.5 to 90.5% among the treatment combinations. Phosphorus consumption at the maximum level (P22) showed the same effect in improving leaf protein compared to the P0 level. Moderate phosphorus consumption (P11) combined with biochar and Trichoderma caused the highest soluble sugar content. The highest proline content of leaves was obtained by using Trichoderma without applying biochar and phosphorus. The use of biochar alone or with Trichoderma could improve the amount of phosphorus absorption as much as the use of phosphorus fertilizer alone. Combined application of biochar and Trichoderma fungus with P11 and P22 fertilizer levels increased phosphorus absorption by 41.6% and 22.3% respectively compared to P0 level. Trichoderma fungus had no significant effect on the amount of Pb and Zn absorption in the aerial parts, but biochar significantly reduced their absorption in the aerial parts of Hairy vetch plants.

Based on the results, the application of biochar alone or in combination with Trichoderma fungus improved the vegetative traits and physiological characteristics, including increasing the concentration of photosynthetic pigments, the relative content of leaf water and soluble sugar, the content of protein and proline in the cluster flower vetch. Phosphorus absorption increased significantly when using biochar and Trichoderma. It seems that biochar helps to increase photosynthesis by creating suitable conditions in soil porosity, humidity, increasing cation exchange capacity and reducing the concentration of heavy elements, with better absorption of elements and thus improving plant growth and development. Trichoderma fungus with biological control increases the availability of elements including phosphorus by increasing the transfer of sugar and amino acids and creating induction resistance and stimulating the growth of beneficial microorganisms, and by making changes in the physiological characteristics, it increases the resistance of the plant against the stress of heavy elements.

Spinach (Spinacia Oleracea L.) belongs to Chenopodiaceae and is one of the most important leafy vegetables in the world. Spinach is a valuable human food source because its leaves are rich in minerals, vitamins, antioxidants, and phenolic compounds. Weeds are one of the significant challenges for spinach production. They can lead to a decrease in commercial biomass and spinach quality. The incidence of herbicide resistance in spinach fields has led to the use of environmentally friendly methods such as cover crops. These plants can cause physical suppression of the weeds by creating adequate biomass and developing a canopy. The aim of this study was to provide a quantitative study of the interactions of the cover crops (such as oat and daikon radish) and hand-weeding treatments on the suppression of the weeds and their effect on the vegetative growth and yield of spinach.

The experiment was conducted in the crop years of 2020-2021 and 2021-2022 at the Research Farm of the Faculty of Agriculture and Natural Resources of the University of Mohaghegh Ardabili with 1350 meters above sea level and geographical coordinates 38˚ 19´ East and 48˚ 20´ North with cold and semi-arid climates. The experiment was performed as a randomized complete block design with three repetitions. Experimental treatments included the first factor of oat (Avena sativa L.), daikon radish (Raphanus sativus var. Longipinnatus), their intercropping (with 50 % seed ratio), and control treatment (without cover crops). The second factor consisted of hand-weeding and non- weeding. The seed rate of oat and daikon radish was 100 and 20 kg per ha, respectively, and were planted manually at a 3×4 meter plots. In this experiment, the seeds of Spinach Viroflay were used. Seeds were sowed manually among the residues of cover crops at 1.5 cm depth. Due to the amount of precipitation in two years, irrigation was performed if needed. The inter and intra-row spacing was 20 and 10 cm. Hand-weeding was done from the planting date to the final harvest of spinach. The investigated traits included dried biomass of cover crops, the density of dominant weeds, and Simpson, Shannon-Weaner, and Margalef indices.

The biomass of cover crops was significantly affected by planting systems, seed density, and year (P ≤1 %). The results showed that the highest biomass of cover crops (538.83 gm-2) was obtained from oats. Also, the lowest biomass (325.83 g.m2) belonged to daikon radish. The dominant weeds were consisted of three species such as lamb's quarters (Chenopodium Album), italian bugloss (Anchusa Italica Retz), and common fumitory (Fumaria officinalis). The results showed that oat in two years had the lowest weed biomass (10.64 g.m2) and density of lamb's quarters, italian bugloss, and common fumitory (4.33, 5.00, and 4.25 number/m2). The maximum weed control efficiency index (57.67 %) was obtained from the oat monoculture. Also, the highest weed control efficiency index (51.47 %) was obtained from the hand-weeding. Margalef's index decreased in the first and second sampling times compared to 5.55 % and 9.85 % relative to the first year. The highest index of Shannon-Weaner's diversity belonged to control and daikon radish (0.47 and 0.47). The highest baby spinach yield and final yield in the first and second phases of sampling in two years were obtained from oats treatment (with 567.05 and 944 g.m2, respectively) and then from their intercropping (390.04 and 786.33 g.m2).

The results showed that oat and its combination with daikon radish had the highest biomass compared to daikon monoculture. The effect of oat biomass on the decrease in density and biomass of the total weeds was significant, which was due to the amount of oat seeds consumed compared to daikon radish. In addition, hand-weeding reduced the density and biomass of the weeds more than non-weeding. Hand-weeding led to the lack of opportunity for weeds' growth. As such, the improvement of the baby spinach and the final yield was due to the hand-weeding of the weeds and the presence of the cover crops biomass in the experiment. The results of are inferred that oat monoculture is suitable both in terms of reducing physical competition of horticultural plants with weeds and improving spinach yield.

This experiment was carried out in 2018 in the Lundville region of Astara for rice crop rotation, different amounts of nitrogen and potassium fertilizers, and varieties and dates of clover planting in the Gilan region. The experiment was evaluated in the form of s split-split plot with a completely randomized block design in three replications. The main factor includes nitrogen fertilizer with potassium at three levels (50, 100, and 150 kg per hectare) and the spreading of clovers in three different stages of rice growth, including after flowering, before harvest, and after harvest as split plot and secondary factors.

The results obtained from the variance analysis of the data showed that different levels of nitrogen and potassium fertilizers, distribution of clovers in different stages of rice growth, and clover cultivars on the height period, yield indices, and harvest index were significant in rice plants. Based on the results of comparing the average effects of treatments, it was observed that the highest yield of paddy per hectare was obtained under the conditions of application of 100 kg/hectare of fertilizer in the stage of spreading clovers after rice harvesting and from Iranian clover variety.

The use of nitrogen and potassium fertilizers along with crop rotation of rice and clover due to nitrogen stabilization and improvement of the soil substrate increased the height of the plant, increased the number of claws, spike length, the weight of 1000 seeds, and finally increased the yield of the rice plant.

In forest management, it is essential to maintain soil performance. Forest soils control and support many forest ecosystem services and tree growth. So, maintaining soil health is critical to sustainable forest management. Forest management practices, such as converting degraded forests into man-made forests, lead to a wide range of adverse effects on soil performance and microbial communities, including negative impacts on organic carbon, nitrogen, bacterial biomass, fungal biomass, microbial biomass carbon, and fungi-to-bacteria ratio. It is possible to achieve the appropriate method of forest management by considering the biological stability of the soil. Therefore, in this stduy, it has tried to gain a better understanding of the relationship between soil biological conditions and forest management methods and their application in sustainable forest and soil management by evaluating the effect of different forestry methods on soil biological characteristics.

To influence forest management practices on soil biological properties, three study areas with different management histories in the Asalem forest, Guilan province were selected and soil sampling using a random systematic method was collected. The selected plots included 1) control, 2) a plot with a history of project implementation in the medium term of maximum 20 years under selective management and 3) a plot with a history of long-term plan implementation, which was under the management of shelterwood method for more than 50 years. There may be effects of the implementation of past plans in the forest for many years. The number of 15 samples in each plot was collected from the nearest tree to the center of the intersection of the sides of the sampling network, from a depth of 0-30 cm, and transported to the soil laboratory at a temperature of 4°C in the winter of 2016. Sampling from all plots in the forest area was done only in the pure type of beech, so in this study, the effect of the type is constant. In this study, micro-scale habitat conditions considered to investigate microbial activities were homogeneous. In this research, three parcels with an area of ​​about 132 ha were selected. In each sample, the biological characteristics of the soil, including basic respiration, stimulated respiration, microbial carbon dioxide, and the population of microorganisms were measured, and indicators of microbial benefit and metabolic benefit were calculated. Some soil characteristics including soil organic carbon, electrical conductivity (EC) and pH were also measured. The normality of the data was checked using the Kolmogorov-Smirnov test and the homogeneity of variances was checked using the Levene's test. Due to the fact that the data had a normal distribution, one-way analysis of variance test was used for totla mean comparisons, Tukey test was used to compare the average indicators in the studied parts, and the relationship between chemical indicators the Spearman correlation test was also used for soil biology. In some cases, due to the impossibility of normalization and other assumptions, the non-parametric test has been used. Statistical analysis was done using SPSS version 22 software. Excel was used to draw graphs.

The results showed that there was no significant difference between the three components in terms of organic carbon, microbial quotient, electrical conductivity, and acidity. But baseline respiration, exhaled breath, microorganism population, metabolic rate, and carbon microbial degradation showed a significant difference in the three parts. The highest basal respiration rate (46.8 mg of carbon dioxide in one day in one gram of dry soil), substrate-induced respiration (42.77 mg of carbon-dioxide in one gram of dry soil in six hours) and microorganism population (1.09 x 108 in one gram of dry soil) and carbon microbial degradation (16.5 mg of carbon in one gram of dry soil) were obtained with a patchy management method and the lowest in the selective portion. The highest metabolic quotient (1.2 mg of oxidized carbon in basic respiration per kg of dry soil per day) in selective fraction and the lowest in solitary incremental part were calculated. The soil texture is sandy-loamy in most of the three plots and loamy-sandy in some areas. EC was in the range of 0.629-3.83 dS m-1 and soil acidity was also in the range of 5-6.5 in all three plots. There was no significant difference in soil organic carbon in three plots. Correlation analysis results of forest soil biological indicators show that soil microorganisms have a significant positive correlation at the level of 1% probability with microbial biomass. In addition to soil micro-organisms, microbial biomass carbon showed a significant positive correlation with basal respiration at the 1% probability level. Basal respiration also has a significant positive correlation at the probability level of 1% with the amount of substrate-induced respiration, soil microorganisms, and microbial biomass carbon, and besides that, the organic carbon has a significant positive correlation at the probability level of 1% with soil microorganisms, microbial biomass carbon, basal respiration, and substrate-induced respiration.

The control plot has a higher quality soil compared to the plot under shelterwood management due to the least human interference (although illegal harvests have been observed in the forest, but compared to the other two plots, human interference was minimal). According to the results, it can be acknowledged that the plot under shelterwood's management has better conditions in terms of soil biological characteristics. Knowledge of the effectiveness of the biological characteristics of the soil from the application of different methods of forest silviculture and human interventions, provides the possibility of choosing suitable methods with the habitat conditions. At the same time, it will be very beneficial to determine the intensity of breeding interventions in forest stands based on the prediction of its effects. The stability of the forest does not depend only on increasing the biological quality of the soil. Hence, it is recommended to implement silviculture operations in sheltered plots and to increase the mixture of forest stand and support species with fast decomposition of litter such as horbean in selective plots.

The most effective tool to prevent and delay resistance to herbicides, and increase weed control spectrum is herbicide tank mixtures. In order to evaluate the effects of binary mixtures of metribuzin:halosulfuron and metribuzin:flumioxazin on potato weeds, a field experiments was conducted in factorial experiments in a randomized complete block design in Ardabil in 2019 .The doses of metribuzin were 10.93, 21.87, 43.75, 87.5, 175, 350 and 700 g ai. ha-1 and halosulfuron doses were 0.78, 1.562, 3.125, 6.25, 12.5, 25 and 50 g ai. ha-1. The metribuzin:halosulfuron uses (100:0), (98:2), (93:7), (82:18) and (0:100)% mixture ratios with three replications. On the other hand, the doses of metribuzin were 10.93, 21.87, 43.75, 87.5, 175, 350 and 700 g ai. ha-1 and flumioxazin were 0.97, 1.95, 3.9, 7.81, 15.62, 31.25 and 62.5 g ai. ha-1. The metribuzin:f1umioxazin mixtures ratios were (100:0), (97:3),  (92:8), (79:21) and (0:100)% with three replications. The experiments were carried out on two-time levels: pre-emergence (7 days after planting) and post-emergence (75% potato emergence, 35 days after planting). The ED50 and ED90 values indicated (0:100)% metribuzin:halosulfuron and metribuzin:flumioxazin had the most effective treatment on total weed, convolvulus arvensis and setaria viridis biomass. Dose-effect curves demonstrated metribuzin:halosulfuron and metribuzin:flumioxazin followed an antagonistic effect based on the additive dose model (ADM) reference model.

Sunn hemp (Crotalaria juncea) is an allelopathic cover crop used for the physical control of weeds. In order to investigate the effect of Sunn hemp formulated extract with chitosan nanoparticles on the germination of some weeds, an experiment was carried out in 2021 at the Faculty of Agriculture and Natural Resources of Mohaghegh Ardabili University with three replications. The experimental treatments included weed species wild mustard (Sinapis arvensis L.) and pigweed (Amaranthus retroflexus) and extract concentration as zero (distilled water), 150 and 200 g/L. The results showed that Sunn hemp formulated extract with chitosan nanoparticles affected the germination percentage and related components in weed seeds. Also, the results indicated that with the increase in concentration (150 and 200 g/L respectively) the germination percentage of wild mustard seeds (20 and 44%, respectively) and pigweed seeds (6 and 12%, respectively) decreased compared to zero concentration. The results demonstrated that the wild mustard weed seed was more affected compared to the pigweed. Pearson's analysis showed a negative and significant effect of germination on time up to 25, 50 and 75%, mean germination time, and germination index. It also showed the positive and significant effect of germination on the coefficient of the velocity of germination, peak value, and germination value. The results emphasize the effect of Sunn hemp extract formulated with chitosan at a concentration of 200 g/L on the reduction of germination and its related components in wild mustard seeds.

Allelopathy is one of the biocompatible methods to reduce the germination and establishment of weeds.In order to investigate the effect of sunn hemp extract (Crotalaria juncea) extract and oats (Avena sativa L.) on the germination of wild mustard (Sinapis arvensis), an experiment was conducted in 2022 at the Faculty of Agriculture and Natural Resources of University of Mohaghegh Ardabili University. The experiment was conducted as a factorial based on completely randomized design with three replications. The experimental treatments included the type of extract and their concentrations of zero (distilled water), 1, 5, 10, 15, and 20%. The results showed that the percentage of wild mustard seed germination and its growth components of wild mustard seeds were significantly affected by the interaction of extract type and their concentrations. The lowest percentage of germination and growth components such as plumule length, radicle length, germination speed, mean germination time, and seed germination were obtained from the concentrations of 15 and 20% of the extracts. Also, the results showed that sunn hemp extract had more inhibition on germination percentage and growth components of wild mustard seeds than oat extract. It can be concluded that with the increase in the concentration of the extracts, the inhibition of germination and the establishment power of wild mustard decreased in laboratory conditions.

With respect to the fact that the pH of the food solution has a great role in the absorption of iron element. An experiment was conducted twice plate (split plot of split plot) in the from of randomized complete block design on a strawberry plant of diamante cultivar at the researcher station of Ardebili Mohaghegh Ardabili University during the years 2015- 17. Factors included acetic acid (0, 1, 2 and %3), iron at two levels (sequestrin25gr and nano 1gr) along with two levels of agricultural soap agents (0 and % 7/5) as foliar spraying. Plant growth indices including protein, proline, resuscitation sugars, leaf starch, total phenol, leaf iron content, and yield per plant were measured. The results of analysis of variance showed that the three-way effect of treatments in all studied traits except protein and yield at the level of %1proabability on proline, resuscitation sugars, leaf starch, total phenol, leaf iron content was significant, such that the best result in the adjectives obtained from the combination of %2 steak acetic acid with iron, along with the application of %7/5 of Mooyan farming soap. and the mutual interaction of treatments at the probability level of %5 on the proten and the performance had a significant effect that which was the best results related to the combination of %2 of acetic acid with iron fertilizer without the use of Mooyan farming soap. According to the results of this study, the combination of %2 iron acetic acid composition with iron acid, along with %7/5 of the farming soap due to the reduction of leaf area tensions, improves the absorption of iron and increases the biochemical and morphological characteristics of straw berries cv.Diamant.

 Iron has a significant effect on the quantity and quality of agriculture products. Factors affecting the absorption of this element increase its efficiency. Meanwhile, the pH of the nutrient solution plays an important role in the absorption of iron. Iron is one of the essential elements for plant growth and plays an essential role in chloroplasts. Due to iron deficiency, the activity of several enzymes such as catalase, cytochrome and oxidase and ferroxin is significantly reduced. The amount of iron in the soil is high, but plants only absorb two-capacity of soluble soil, which is negligible compared to the total iron. Soil environmental conditions affect the amount of iron by the plant, so it is difficult to control the uptake of iron by the plant. It has the highest ability to absorb iron and manganese at pH less than 6. For this reason, acetic acid was used to stabilize the pH of the solution. Acetic Acid is a polar solvent and an organic compound. The use of inexpensive organic acid and citric acid in agriculture, despite its positive effects on calcareous soils and their reasonable price is still not common in Iran. Acetic acid has a carboxylic group and therefore has all the properties of an acid.

 This experiment was carried out in the form of double split-split plot in a completely randomized block design on a strawberry plant of diamant cultivar in the research station of Mohaghegh Ardabili University during the years 2015- 2017. Factors included Acetic Acid (0, 1, 2 and %3), iron in two levels (Sequestrin 25gr and Nano 1gr) along with two levels of agricultural soap agents (0 and % 7/5) as foliar spraying. Foliar application of pH nutrient solution from the three-leaf stage of plant (mid-April) to the end of May a total of five times 10 days apart in both years. Two weeks after the last foliar application (June of the second year) plant growth indices including, total chlorophyll, number of fruits per plant, fruit pH, total acidity, soluble solids, fruit volume, fruit fresh weight, fruit dry weight, and leaf iron content and fruit yield per plant was measured.

 The results of this study showed that the three-way interaction of foliar application of Acetic Acid with iron with agricultural Soap on the average concentration of leaf iron and number of fruits at the probability level was %5 and in total chlorophyll at the %1 probability level was significant, the best result in the mentioned traits was the combination of treatment of Acetic Acid %2 with Sequestrin iron with soap Moyan (%7/5). The interaction effect of Acetic Acid and iron type on traits of fruit pH, fruit volume, fruit fresh and dry weight at %5 probability level and in yield at %1 probability level were significant. Fruit volume, fruit fresh weight and fruit dry weight and yield showed the best results due to treatment combination of %2 Acetic Acid with Sequestrin iron fertilizer. But for fruit pH trait, the best results were related to the treatment of Acetic Acid %3 on the leave of Sequestrin iron. The Interaction of the iron and agricultural Soap was significant on the amount of soluble solids at %5 probability level and the total acidity strawberries fruit was significant at %1 probability level. In the case of soluble soild and Acidity, Sequestrin iron treatment and agricultural soap had the best results. According to the results of this study, the combination %2 Acetic Acid with of iron fertilizer Sequesterin in combination with agricultural soap Moyan (%7/5) due to the reduction in leaf area tensions improves the obsorption of iron and the quantitative and quality characteristics strawberries.

 Based on the findings of this research, it can be concluded that Acetic acid %2, has better result on the absorption of iron fertilizer, along with agricultural soap (% 7/5) application than other treatments and qualitative traits of strawberry fruit. In treatment %2 Acetic acid most measured traits such as total chlorophyll, leaf iron, fresh weight, fruit dry weight and yield has shown a significant increase. Acetic acid by reducing the pH of the cell sauce and increasing the activity of the reductase enzyme increase the iron solubility and easily provides the iron to the plant. Due to the pH alkalinity of most soils in Iran, the use of Acetic acid in iron nutrient solution on the absorption of iron Sequestrin in combination with % 7/5 of agricultural soap due to having a hydrophilic head and a hydrophobic with %40 to %50 increase in effective of foliar fertilizers. As a result, with more absorption it can be an advanced approach to better absorption of iron by plant and increase the quantity and quality in the product.

The increasing population of the world indicates the development of urban areas, and consequently the use of appropriate methods to improve sandy soils in these areas, led engineers to think of inventing methods to improve the properties of sandy soils. One of these efficient methods to modify the behavior of unsuitable soils in geotechnical engineering is to change the properties of problematic soils, which is called improvement. In this regard, sandy soil is improved by adding materials to improve mechanical properties (compressibility, hardness, shear strength, permeability, etc.). In this study, the undeniable role of nanoparticles in the improvement of sandy soil and the effect of nanosilica along with bacteria in the biological improvement of soil samples that have not been tested, was investigated (Dejong et al., 2010). Controlling the distribution at the site of bacterial and reactant activity and the results of calcium carbonate distribution and related engineering properties below the soil surface is a major challenge for future improvements, especially if bioremediation in a surface or deep soil system (To replace the method of deep soil improvement with artificial lime). In order to commercialize the bioremediation process, further optimizations in the performance of the biological deposition process (improving the effective use of bacteria, reactants and reducing heterogeneity) should be done (Sharma et al., 2016). Therefore, the aim of this study was to investigate the compatibility of nanosilica with bacteria in order to be able to use minerals to increase the strength of biologically improved soil properties.

Frequent and widespread use of herbicides has adverse effects on nontarget species, such as earthworms. Several experiments were performed in Mohaghegh Ardabili University on 2019 to evaluate the relative toxicity of metribuzin, halosulfuron, flumioxazin individually and combination of metribuzin:halosulfuron and metribuzin:flumioxazin on Eisenia fetida. The earthworms biomass was investigated by different concentration of herbicides and sampling time (24 and 48h after treatment). LC50 values of individual herbicides demonstrated that metribuzin and halosulfuron had high effect on earthworms biomass at 24 and 48 h after treatment. Flumioxazin was less toxic than the metribuzin and halosulfuron. The results indicated that the (50:50) and (25:75)% mixture ratios of metribuzin:halosulfuron and metribuzin:flumioxain provided  higher toxicity than the other mixture ratios (100:0) and (0:100)%, respectively. Isobologram demonstrated metribuzin:halosulfuron and metribuzin:flumioxazin followed antagonistic effect meaning that the mixtures retracted the herbicides action in the earthworms relative to a Concentration Addition (CA) reference model.

Wood chip bioreactors are one of the low-cost methods to remove nitrate from effluents, including wastewater effluents. This research was conducted in Ardabil plain and in the research farm of Mohaghegh Ardabil University during the autumn of 2021. Two types bioreactors; one including wood chip and the other including a mixture of wood chip and iron chip, each with four replications  were implemented in a factorial design. Three levels of nitrate concentration (50, 150, and 300 mg.l-1) were passed through the reactors and their effluents were measured after 3, 6, 12, 24, 48, 72, and 96 hours retention time in the bioreactor. The results showed that the performance of reactors with wood chip core (54.7% removal) was better than the wood and iron chip (45.9% removal). Also, the results demonstrated that the removal percentage was in descending order at concentrations of 150, 300, and 50 mg.l-1, with the average values of 54.6, 50.3, and 45.5%, respectively. The results of variance analysis showed that the retention time have a significant effect on the amount of nitrate removal by reactors so that the minimum and the maximum removal (4.3% and 89.3%) were obtained from 3-hours and 96-houres retention time, respectively. In general, it can be concluded that under the conditions of this research, bioreactors with wood chip have acceptable performance in nitrate removal. Also, it was found for the suggested drainage coefficient in Iran (2 mm.day-1) and with a retention time of 96 hours, less than 2% of the land area is needed for bioreactor construction.

Cadmium contamination has decreased crops quality and quantity due to its uptake by plants and inhibition of its proper growth. Plants of Brassicacea family like black mustard have a high growth capacity in heavy metals polluted conditions. Some rhizobacteria can help to the movements of heavy metals in the soil. Plant growth regulators also have an important role in the induction of plant reactions to most of abiotic stresses such as heavy metals. The aim of this experiment was the evaluation of effect of growth promoting rhizobacteria, salicylic acid and brassinosteroid on reduction of cadmium stress effects in black mustard.

In order to study the effects of growth promoting rhizobacteria and plant growth regulators on physiological properties of black mustard under cadmium stress conditions, a factorial experiment was conducted based on randomized complete block design with four replications at research greenhouse of Mohaghegh Ardabili university. Experimental treatments included two cadmium levels (0 and 100 milligrams per kilograms of soil), three levels of rhizobacteria (control, Azospirillum, Pseudomonas) and three levels of growth regulators (control, Salicylic acid, Brasinosteroid). Before planting the seeds were inoculated with rhizobacteria and also growth regulators were sprayed in two stages during growth period on plants. After harvest some traits including MDA, proline, soluble sugars, photosynthetic pigments, membrane stability index and secondary metabolites were measured.

Results of means comparisons indicated that cadmium application by some effects including oxidative stress induction, increased MDA, proline, soluble sugars, phenol and flavonoid contents of leaves and decreased chlorophyll a and b, carotenoids and anthocyanin contents, membrane stability index and plant yield. Malondialdehyde and proline contents were reduced significantly by rhizobacteria inoculation and growth regulators application and phenol and flavonoid contents as well as plant yield were enhanced in both cadmium levels by rhizobacteria. Whereas growth regulators spray increased chlorophylls a and b contents, soluble sugars, membrane stability index, phenol, flavonoid, anthocyanin and plant yield and also the rhizobacteria enhanced soluble sugars, anthocyanin content and membrane stability index significantly. In addition, there was no significant difference between salicylic acid and brassinosteroid in all traits and pseudomonas inoculation compared to azospirillum indicated a significant superiority regarding some traits including membrane stability index and plant yield.

It can be concluded that cadmium contamination via the oxidative stress induction leaded to cell membrane destruction and increasing malondialdehyde content and also it resulted decreasing chlorophyll content of plant that is associated with increasing proline synthesis under stress condition. As a result of cadmium contamination stress, the activity of carbohydrates synthesis enzymes was increased and resulted increasing soluble sugars content and consequently increasing secondary metabolites content. By the application of rhizobacteria and plant growth regulators, the effects of oxidative stress were decreased and it leaded to enhancing membrane stability and reducing malondialdehyde content. Additionally, these treatments increased chlorophyll production and decreased proline content. By increasing chlorophyll content affected by these treatments, soluble sugars production in plants was increased and it resulted increasing secondary metabolites production in plant. Considering these results, the application of growth regulators and growth promoting rhizobacteria in order to decrease cadmium stress effects on black mustard grown in contaminated soils is recommended.

Continuous use of monoculture systems and excessive tillage has degraded agricultural soils in many regions of Iran. The short-term impact of cover crops on selected soil properties was investigated in a field study in 2018. The experiment was laid out as complete randomized block with three replications. The four experimental treatments included, monoculture of oat and monoculture chickling pea, their mixture, and no cover crop as control. Highest and lowest aerial biomass were 198.1 gm-2 and 124.1 g m-2 and obtained from mixed cover crop and sole chickling pea, respectively. The higher biomass resulted in significant weed suppression, compared with control. Weed dry weight reduced by 33.04% and 41.12% in oat monoculture and mixed cover crops, respectively. The highest soil organic carbon (1.21%) and highest microbial population (6.5 × 105 per gram of soil) were obtained from mixed cover crop experimental plots. Cover crop mixture, and monoculture of oat and monoculture chickling pea reduced soil compaction by 51.5%, 50.7%, and 49.1%, respectively. However, soil bulk density, soil porosity, and rate of water infiltration were not affected by cover crop treatments. Results obtained in this study indicated that short-term changes in some soil properties are related to both, biomass and cover crop species. Overall, a mixed of cover crops was more influential on changing soil properties.

The excessive use of pesticides in recent years and their continuation in the future may have harmful effects on the microbial population of the soil, as an indicator of soil health and one of the main components of the environment. The purpose of this study was to investigate the effect of three mostly used insecticides (Diazinon, Chlorpyrifos and Imidacloprid) on ec-ophysiological and chemical indices of soil. The experiment was conducted as a factorial in a completely randomized design which included the pesticide factor at four levels (three insecticides plus control soil) and time factor at three levels (before, three months and six months after pesticide application). Concentrations of insecticides (0.1, 1 and 0.67) mg per kilogram of soil were used for imidacloprid, diazinon, and chlorpyrifos, respectively. Some biological and ec-ophysiological indices of the soil were measured at the beginning of the experiment, three and six months after the beginning of the experiment. The results showed that, the application effect of insecticides after three months affected the biological indices including dehydrogenase enzyme activity, metabolic quotient, basal respiration, substrate-induced respiration and also organic carbon decreased compared to the control -92.2%, -46.7%, -24.7%, 15.8% and -7.61%, respectively and urease enzymes activity, microbial biomass carbon, microbial biomass nitrogen, carbon to nitrogen ratio and soil microbial quotient increased compared to control 6.67%, 32.1%, 15.6%, 16.5% and 58.9. Also, the results showed that among the insecticides Chlorpyrifos and Diazinon had the highest and the least negative effect on the indices, respectively. The application of insecticides Diazinon, Chlorpyrifos and Imidacloprid at least in the short term, had a negative effect on soil ecophysiological indices and the most sensitive indices for determining the negative impact of insecticides on the soil microbial community were the dehydrogenase enzyme activity, metabolic quotient, substrate-induced respiration and basal respiration.

Bioremediation is an approach that exploits the ability of microorganisms to increase the rate and extent of degradation of pollutants and thereby removing pollutants from the environment. The moisture content and temperature are of the main environmental factors affecting growth and activity of microorganisms and accordingly affecting the efficiency of organic pollutant biodegradation.

To study the effect of these two factors a factorial experiment was carried out as completely randomized design with three replications. The factors were moisture in three levels (30%, 55% and 80% of Field Capacity), temperature in three levels (25, 30 and 35 degrees of Celsius) and inoculation with bacteria in two levels (with and without inoculation by Pseudomonas putida) which were triplicated.

The results showed that highest biodegradation rate was observed in the treatment with the moisture content of 55% F.C, temperature of 30 degrees of Celsius and inoculation with Pseudomonas putida which was 92.8% and the lowest biodegradation rate was observed in the treatment with the moisture of 30% F.C, temperature of 30 degrees of Celsius and without inoculation which was 42.3%.

These results shows that the optimization of the environmental conditions in bioremediation process may lead to 50.5% increase in the efficiency of removal.

Crude oil is one of the most important sources of energy and its large scale production, transmission, consumption and disposal, making it one of the most important and common types of environmental pollution in the worldwide. In order to investigate the effects of phytoremediation and bioremediation on translocation of Total Petroleum Hydrocarbons (TPHs) in crude oil contaminated soil, a factorial experiment based on completely randomized design with three replications was conducted. Three rates of crude oil contamination; 0 (C0), 2 (C1) and 4% w/w (C2) and four remediation treatments; Lolium perenne (T1), Pseudomonas putida+Phanerochaete chrysosporium (T2), Lolium perenne+Pseudomonas putida+ Phanerochaete chrysosporium (T3) and control (T0) were applied. At the end of experiment, TPHs concentrations in different depths of soil column (5, 15, 25, 35 and 45 cm depths) were measured. The results showed that the different remediation treatments decreased the TPHs concentration in the root zone and T3 treatment decreased the concentration of TPHs both in C1 and C2 contamination rates by 34 and 59%, respectively. Oil compounds were also observed in the uncontaminated sub layers which indicated oil compounds transported from upper layer to lower layers. The lowest TPHs translocation to sub layers in the soil columns observed in T3 remediation treatment and the highest amount of TPHs translocation to sub layers observed in T2 remediation treatment. Generally, remediation treatments in oil contaminated soil degrade and decrease oil compounds specially in root zone but cannot prevent oil compounds movement and translocation to sub layers. Consequently, oil compounds may enter to groundwater.

Fluorescent pseudomonads are one of the most effective microorganisms among the plant growth-promoting bacteria. They have attracted many researchers attention due to their unique properties such as motility in the rhizosphere, high growth rate, and potential for the root colonization of various plants. In most studies, rhizospheric soils were used for isolation but Pseudomonas bacteria also have been isolated from various organic fertilizers. Therefore, the present study was conducted to evaluate plant-growth promotion and biocontrol characteristics of fluorescent pseudomonads isolated from vermicompost. Then, the ability of isolates was evaluated for auxin and siderophore production, tricalcium phosphate dissolution, and secretion of growth inhibitor metabolites. Total of 43 fluorescent pseudomonads isolates were isolated and purified based on irradiation under a UV lamp and fluorescence properties. Results of the PGP characteristics revealed that all the isolates were able to produce auxin and solubilize inorganic phosphorous. The average of auxin production was 2.51 mg/l. The highest (708 mg/l) and lowest (203 mg/l) amount of soluble phosphate belonged to P15 and P43 isolates, respectively. P35 isolate showed the most efficient in terms of siderophore production in which the ratio of halo zone diameter: colony diameter was 2.04 mm (after 48 hours) and 2.12 mm (after 72 hours). The results of the hydrogen cyanide production test showed that 88.35% of isolates could secrete this metabolite. In this research, all isolates were not able to produce protease enzymes. In terms of production of this enzyme, the P17 isolate showed the highest ratio of halo zone diameter: colony diameter (2.7 mm), was the most efficient one. None of the isolates were able to produce cellulase enzymes.

The aim of this study was conducted to investigate the effect of 25 years old exclosure on the function of aerial and underground organs of Trifolium pratense since may to july of 2017. Three sites inside and three outside of the exclosure were selected in the rangelands in Shoghaldare- Namin rangelands, Ardabil. Three transects with the length of 100 meters were established in each site and from 10 plots of 1 m2 vegetation characteristics including total production, canopy percentage and forbs canopy were estimated. In order to select T. pratense stand and measure the selected parameters (to study the effect of exclosure on the function of different organs of T. pratense), in addition to previous transects, in each site was randomly established 3 transect of 50 meters. Along each transect, 10 random points and in each point the nearest plant was selected. Length of root, stem, inflorescence, plant height and basal diameter of T. pratense were recorded. Moreover, the inflorescences, stems and roots of the selected T. pratense were cut and after air-drying, they were weighed with a precision scale. Results showed that the total production in the exclosure (2413/06 kg/ha) has significant difference (p < 0/01) with the outside of exclosure (963/84 kg/ha). The production of T. pratense inside exclosure (99.83 kg/ha) has also significant difference (p < 0/01) with outside the exclosure (22.75 kg/ha). Interaction of exclosure and elevation has significant effect on canopy cover (forbs and total), number of inflorescences, basal diameter, weight of plant organs (p < 0/01) and recovery effort (p < 0/05).

This study was conducted to assess the effect of soil physical and chemical properties on diversity and structure of tree cover in oak forests with an area of 275 hectares in Qamyshlh city of Marivan Kordestan, Iran. For this purpose, a total of 90 samples, each 10 yards, randomly laid out on a regular gird network were selected and in the center of each plot, soil samples were taken at the depth of 0 - 30 cm. Results revealed that the average diameter of trees had a significant positive correlation with phosphorus, potassium, organic matter and carbon to nitrogen ratio in the soil. The results also showed that there is no significant relationship between the most measured soil characteristics and richness, evenness and diversity indicators. However, soil pH with Pirlo and Simpson indexes and phosphorus with Margalef index had a significant negative relationship. Correlation between the percentage of tree species and soil characteristics showed that among the studied species, Q. branti were more sensitive to changes in soil properties compared with other species. However, the analyses of ordination methods showed that there is no direct relationship between species distribution and soil properties. In addition to the soil effects, due to the proximity of the forest land to rural residential areas, it can be said that the most influential factor in shaping the composition, diversity, and structure of Qamyshlh tree species are human factors.

This study aimed to investigate the effect of five herbicides (Tribenuron-methyl, Metribuzin, Trifluoralin, Haloxyfop-methyl, and 2, 4-D (on the soil dehydrogenase and urease activities.

The experiment was conducted as a completely randomized design with five herbicides and a control with three replicates for six months and the enzyme activities were measured at beginning of the experiment, and after three and six months. The concentration of herbicides was 0.27, 0.67, 0.67, 0.67, and 0.1 mg/kg soil for Haloxyfop-methyl, Metribuzin, Trifluoralin, 2, 4-D, and Tribenuron-methyl, respectively.

The results showed that the effect of herbicides on the enzyme activities was significantly different (p0.01). After 3 months, the herbicides decreased the urease activity in comparison to the control (34.9 µgN.g-1). The most reduction was related to Trifluoralin (24.8 µgN.g-1) which was 28.9% lower than the control. Urease activity increased after six months compared to three months, and this increase was 41.5% for Trifluoralin herbicides (35.1 µgN.g-1). Urease activity in control treatment in six months was not significant compared to the three months. All of the herbicides significantly reduced the dehydrogenase activity after three months compared to the control (0.6 µgTPF.g-1), so that the dehydrogenase activity was observed in Haloxyfop treatment with 0.01 µgTPF.g-1, which was 98% lower than the control. In all treatments, dehydrogenase activity after six months was significantly higher than that in the three months, so that the highest dehydrogenase activity was observed in 2,4-D treatment (1.44 µgTPF.g-1), which was significantly higher than the control.

The results show that the herbicides significantly decreased the activity of the enzymes compared to the control during the three months. After six months the enzyme activities recovered to the level before herbicides application. Probably this was due to a short lifetime of herbicide in the soil which was less than six months.

In order to study the effect of pesticides on soil biological quality, three herbicides and insecticides with the highest consumption rates, on soil eco-physiological and chemical indices were investigated.

The experiment was carried out as factorial in a completely randomized design with seven treatments of which were triplicated. The pesticides were applied as constructed by the manufacturer and then the pots maintained in a greenhouse condition for two months. Then, some of the soil eco-physiological and chemical indices were measured after one month and also after two months.

The results showed that in comparison with the application of the pesticides caused a significant decrease in soil bacterial and fungal population, basal respiration, substrate-induced respiration, microbial biomass carbon, microbial biomass nitrogen, and microbial quotient and a significant increase in soil metabolic quotient. The results also showed that the application of the pesticides has no significant effect on soil organic carbon. The results showed that, although soil eco-physiological indices decreased after one month, the indices increased after two months reaching the level that was before application of the pesticides. The results also showed that 2, 4-D had the highest and Chloropyrifos had the lowest adverse effects on the indices.

It could be concluded that application of the pesticides which are used in this work decreased soil biological quality short terms.

Success of the phytoremediation technique depends not only on plant species, but also largely on the interactions of plant roots with the rhizosphere microorganisms. These microorganisms, especially bacteria with plant growth promoting traits, can improve efficiency of phytoremediation by helping to proper plant establishment, increasing root system growth and, consequently, increasing plant growth and enhancing heavy metal uptake. Considering the important role of soil microbial community in increasing the remediation of polluted soil with plants, this research was conducted with the aim of isolating, screening, investigating the traits of cadmium and lead-resistant bacteria and introducing superior isolates. Soil samples were taken from Cd and Pb contaminated soils of the Shahid Tondguyan oil refinery and after measuring some physical and chemical properties, heavy metals resistant microorganisms were isolated from them. Resistance to cadmium and lead was determined in the isolates, and then the ability of the superior isolates to produce phytohormones of auxin, secretion of growth inhibitor metabolites and solubilization of insoluble inorganic phosphate were evaluated. In this study, thirty microorganisms were isolated from contaminated soils. After examining the appearance of the colony, its color and margin, as well as the growth rate, at the end, 20 different isolates were selected. 70% of the studied isolates showed a very good growth in culture medium up to a concentration of 8 mM l-1 of lead and cadmium. The results of evaluation of plant growth promoting traits in the top 10 isolates in terms of resistance to heavy metals of lead and cadmium showed that all of these isolates had the ability to produce auxins and dissolve insoluble inorganic phosphates. The highest (10.20 mg l-1) and the lowest (0.64 mg l-1) auxin production were observed for C4 and C2 isolates, respectively. The average solubility of tricalcium phosphate by isolates was 106.91 mg l-1. 80% of isolates had the same ability to produce siderophore. The highest rate of production of this metabolite was observed in the isolate C1 with a halo to colony ratio of 23.3. Among 10 studied isolates, three isolates, K2, K5 and C8, were able to produce hydrogen cyanide, protease and cellulase enzymes.

Cover crops are a strategy for enhancing the soil health and quality in agricultural systems. The relationship between cover crops and soil biological activity is an important component of soil health. Cover crops affect many of the physical, chemical and biological properties of the soil through soil organic carbon. Additionally, they prevent the loss of soil nutrients by quickly growth and creating a suitable plant canopy on the soil surface. The aim of this study was comparing the effect of mono and mixed cropping of cover crops on soil physical and biological properties improvement on short term condition.

In order to investigate the effect of cover crops on some physical and biological properties of the soil an experiment was conducted based on randomized complete block design with three replications at research farm of the University of Mohaghegh Ardabili in 2017. Experimental treatments were monoculture of rye (Secale cereal), chickling pea (Lathyrus sativus L.) and hairy vetch (Vicia villosa) (100%) and their dual and triple intercropping with 50% and 33.3% seed proportions, respectively. The base of seed rate on rye, chickling pea and hairy vetch monoculture were 100, 25 and 25 Kgha-1 respectively.

The results showed that the highest biomass of cover crops (530 gm-2) obtained from rye monoculture and the lowest biomass from hairy vetch monoculture and hairy vetch+ chickling pea (85.5 and 91.6 gm-2 respectively) intercropping at the terminating time of the cover crops. Also, the comparison of the means showed that the highest organic matter (0.53%) and soil microbial population (2600000 number per gram) were obtained from rye + chickling pea +hairy vetch intercropping. The soil organic matter (SOM) increased 11.3% by rye + chickling pea +hairy vetch intercropping relative to control (no cover crop). The highest number of earth worms belonged to rye monoculture treatments. On average, earthworms in all of cover crops treatments increased by 80.5% relative to control. Also, the intercropping of rye +hairy vetch caused the lowest bulk density (1.01 gcm-3). The soil bulk density reduced 6.17% by rye + chickling pea relative to control. Cover crops decreased the time of water infiltration in the soil. The minimum time required for water infiltration on growing (8.39 Sec.) and terminating time of cover crops (4.99 Sec.) obtained by hairy vetch monoculture and rye + chickling pea intercropping.

Cover crops either monoculture or intercropping even in one plant growth season improved soil physical and biological properties. Rye and hairy vetch had the highest effect on dual and triple intercropping system. Key words: Cover crops biomass, Earthworms count, Soil microbial population, Organic matter, Soil health.