فهرست مطالب fatemeh rakhsh

Heavy metals enter the environment directly and indirectly with the development of various industries of metal smelting, mining, and chemical industries. Physical and chemical methods of soil purification from heavy metals are used due to high costs and less time-consuming. Phytoremediation is a low-cost and relatively fast solution to soil pollution and increases biodiversity, reduces erosion, and increases soil fertility. In this study, the phytoremediation potential of the Camelina plant in removing heavy metals Pb and Cd from soil was investigated. The experiment was conducted in a completely randomized design with Cd (0, 3, 5, and 10 mg/kg) and Pb (0, 100, 300, and 600 mg/kg) treatments with 3 replications in the greenhouse of Razi University in Kermanshah. The results showed that with increasing the concentration of Pb and Cd, the accumulation of these elements in the roots of the Camelina plant increased significantly. Most soil biological properties at the highest concentrations of Cd and Pb were significantly reduced compared to the control. The high concentration of Pb and Cd in the roots of the plant and the low transfer factor of these elements, indicate the greater efficiency of this plant for use in plant stabilization techniques, and we cannot be used to extract heavy metals lead and cadmium from soil.

Tillage is an important component of soil management that affects crop production. In addition, tillage can contribute to agricultural sustainability and improve soil quality by altering the physical, chemical, and biological properties of the soil. One of the most useful tools for assessing soil management status in different tillage systems is soil quality assessment, and the use of quantitative indices is one of the most appropriate methods for determining and comparing soil quality. Therefore, this study was conducted to investigate the effects of different tillage systems on soil quality at two depths of 0-25 and 25-50 cm. The experiment was factorial in a randomized complete block design in the Campus Agriculture and Experimental Natural Resources. The results showed that the tillage system impacted all the studied traits with different intensities. By changing the tillage system from traditional to more conservative, the soil properties had a positive change, which resulted in improved quality. The percentage of increase and the highest variation among the biological characteristics of microbial biomass carbon was 53.49% and 42.45% respectively. Cumulative and developmental indices had the highest values in conservation, reduction, and traditional tillage systems, respectively. Overall, the cumulative quality index was more accurate in determining soil quality.

Zagros forests play an essential role in providing groundwater resources, air conditioning, soil protection and preventing erosion, and providing wildlife habitat. Today, the ecosystem of these forests has become completely fragile due to improper exploitation and destruction. This study was conducted in areas of Zagros forest in Kermanshah province that were included in the implementation of the protection plan, including Sorkhak and Tappeh Goleh in Islamabad and Qeshlaq in Ravansar. The main purpose of this study was to evaluate the implementation of the forest conservation plan on soil properties.

For this purpose, composite soil samples were collected by random-systematic method from the mentioned area and their respective control area, and their physical, chemical, and biological properties were measured. Soil characteristics in Tappeh Goleh, Sorkhak and control sites were analyzed by one-way analysis of variance and Qeshlaq soil characteristics were analyzed by T-test. The soil samples collected from the forest were air-dried in the laboratory environment and sieved (2 mm). Then their physical and chemical properties (pH, EC, bulk density, and soil organic carbon content) were measured. Soil samples were collected with sterile equipment and sieved through a 4 mm sieve. Fresh and moist soil was kept at a temperature of 4 °C for soil biological tests (basal soil respiration, metabolic quotient, and microbial biomass carbon).

The results showed that no statistically significant changes in soil EC and pH were observed in all study areas. The amount of organic carbon in Sorkhak was significantly higher. Among the measured biological properties of soil, no significant change was observed in organic carbon mineralization in all study areas. However, microbial biomass carbon and soil metabolic quotient in Sorkhak were significantly higher than those in control and Tappeh Goleh areas.

The results of this study showed that the forest protection plan if properly implemented in the field (Sorkhak area) will be able to revive some soil quality indicators. The provisions of forest protection management and the process of soil regeneration in these forest lands should be investigated. Among the studied indicators, soil organic carbon and microbial biomass carbon were among the indicators that responded well to the correct and complete implementation of the forest protection plan, and we have witnessed the improvement of these parameters in managed lands. This suggests that biological soil quality indicators are more sensitive to responding to land management and respond more quickly to these changes.

The maintenance of planted forests in arid and semi-arid lands is important. Soil formation in forest ecosystems is different with different tree species. Tree species have a direct and indirect effect on soil organisms. Forest ecosystems change their species composition and abundance of microorganisms, and consequently their biogeochemical cycles. The accumulation of vegetation biomass and the improvement of soil fertility can play a significant role in soil restoration.

In order to investigate the biological characteristics of the soil from 5 treatments, including agricultural (dry farming and relatively poor lands that are usually cultivated barley and wheat and have low productivity), pasture (pastures with minimal vegetation and high slopes that are affected by overgrazing have been changed to barren lands), forest with Acacia type (under and outside the crown), forest with the Cupressus arizonica type (under and outside the crown) and forest with the Pinus brutia type (under and outside the crown) randomly. Sampling was done in 3 repetitions from the 0 to 5 cm layer. The statistical sampling design of this research was completely random, in which, according to the type of afforested species, two types of coniferous forest stands (including Cupressus arizonica and Pinus brutia) and one broadleaf stand (Acacia species) were selected. Also, the area under the crown trees and outside the crown trees was also investigated. Soil samples were sampled with sterile equipment and crushed through a 4-mm sieve. Fresh and moist soil was kept at 4 °C temperature for soil biological tests. Microbial biomass carbon, soil basal respiration (197 days), substrate-induced respiration, and metabolic quotient were measured. Streptomycin sulfate was used to measure fungal respiration and cycloheximide was used to measure bacterial respiration. The activities of urease, acid, and alkaline phosphatase enzymes were determined. After measuring the biological properties of the soil, the normality of the data was checked by the Anderson–Darling test, and the homogeneity of the variance of the treatments was checked by using Levene's test. Analysis of data variance was done using One-Way ANOVA and average data comparison was done using Duncan's test at 5 and 1% probability levels (SAS 9.4 and SPSS 26).

The results of soil biological characteristics analysis showed that the highest values of soil respiration and amount of consumed organic matter, substrate-induced respiration, microbial biomass carbon, enzyme activities, and fungal respiration were measured in conifers. Although the amount of these features was also significant in broadleaf trees, they had significant differences. In this study, the high soil respiration rate in coniferous covers compared to broadleaf can be due to the high organic carbon content of the soil in this cover. According to the results of substrate-induced respiration in different coatings, likely the activity of microorganisms involved in the decomposition of organic matter in the studied habitats had a significant difference; Therefore, different coatings can affect the population of soil microorganisms as the main source of decomposition and emission of carbon dioxide by changing the quantity and quality of organic matter and other factors. Also, the highest values of metabolic quotient and bacterial respiration were observed in agricultural and pasture covers. A higher metabolic quotient in these covers indicates a decrease in the efficiency of the use of leaf litter by the soil microbial community. In general, the metabolic quotient in the bacterial community is higher than the fungal community; Therefore, it seems that the predominance of the bacterial population in agricultural and pasture cover has caused this index to increase, although plowing and cultivation, and disturbance of these covers have caused stress to this bacterial community and as a result increased the metabolic quotient deficit in these covers.

The results of this research showed that the type of planted tree species causes significant changes in the biological characteristics of the soil. The current research shows that the forest, whether coniferous or broadleaf, had the highest values of enzyme activities, basal respiration, substrate-induced respiration, microbial biomass carbon, and the lowest values of metabolic quotient compared to agricultural and pasture covers. Afforestation increases biological activity and possibly the number and diversity of microorganisms, and improves soil characteristics in the long term. In agriculture and pasture land, due to the destruction of soil and aggregates by agricultural activities such as plowing or excessive livestock grazing, the amount of organic carbon and the activity of microorganisms decreases, and with the decrease of other soil characteristics, the quality of the soil decreases over time. From this research, it can be concluded that the planting of forest species in the soils of degraded areas in the long term can increase soil organic carbon due to high-quality leaf litter, and as a result, increase permeability and soil moisture. Increasing soil organic carbon increases the activity of microorganisms, and in the long term, it will improve various soil characteristics. Planting forest plants in the natural areas of the country, which were destroyed due to the change of use to agriculture and indiscriminate cultivation and finally abandoned, can improve the characteristics of the soil and, as a result, establish the native vegetation of the region, and increase the permeability of water in the soil, the risk of soil erosion, floods, etc. reduce.

Nowadays, vast areas of forests have been changed to farmlands, and the change in land use is one of the important factors reducing soil quality. The purpose of this research is to investigate the effect of land use change from forest and pasture to agriculture on some soil characteristics in Sarab Badia area (Kermanshah province). Sampling was done in 2018 from points with the same slope in the form of a nesting site. For this purpose, four areas near each other that have the same landscape and include 3 uses of forest, pasture, and agriculture and also two depths of 0-20 and 20-40 cm were considered. Composite samples were prepared from each depth. After transferring the samples to the laboratory, the important characteristics of the soil were measured based on standard methods. The results showed that among the physical characteristics of the soil, MWD was affected more than the other physical characteristics due to the change in land use, so that by changing the land use from forest to agriculture in the subsoil layer (20-40 cm), MWD decreased by 51.04%. Among the soil chemical properties, organic carbon and total nitrogen with 52.95% decrease in top layer of the soil (0-20 cm), had the most variability due to the change of land use from forest to pasture. The metabolic coefficient was sensitive to the change in land use from forest to agriculture, as its value decreased by 92.92% in the sub layer (20-40 cm). Characteristics such as; MWD, organic carbon, total nitrogen, and metabolic coefficient are highly sensitive to changes of management conditions at the field level, so these characteristics can be used to monitor soil quality.

The accumulation of heavy metals in water, sediments, and soils has led to serious environmental problems. In recent years, several processes have been developed with the aim of reducing or recovering heavy metals from contaminated environments. Physical and chemical approaches are capable of removing a broad spectrum of contaminants, but the main disadvantages of these methods lie in the increased energy consumption and the need for additional chemicals. In recent years, the processes such as bioleaching, biosorption, bioremediation, phytoremediation, and bio precipitation are all based on the use of microorganisms that have the ability to solubilize, adsorb, or precipitate heavy metals. Therefore, it is necessary to find some solutions to reduce the negative effects of heavy metals in soil. A factorial experiment was conducted in the greenhouse of the Faculty of Agriculture, the University of Zanjan, using a completely randomized design with three replications. In this experiment, the effects of different levels of soil cadmium (0, 5, 10, 25, and 50 mg/Kg) and soil inoculation (without inoculation and inoculation with Glomus mosseae, Glomus intraradices, Glomus mosseae + Rhizobium trifolii, Glomus intraradices + Rhizobium trifolii bacterium, Rhizobium trifolii, Glomus mosseae + Glomus intraradices and Glomus mosseae + Glomus intraradices + Rhizobium trifolii) on growth of berseem clover were assessed. The results of this study showed that the soil cadmium levels has a significant effect (p < 0.05 and p < 0.01) on fresh weights of aerial parts and roots, height, number of the plant in the pot, Fe, Zn and Cd concentrations in aerial parts and roots of berseem clover. The fresh weights of aerial parts and roots, height, number of the plant in the pot, Fe and Zn concentrations in aerial parts and roots of berseem clover decreased as the levels of soil cadmium increased. The lowest concentrations of iron and zinc were measured in treatment with 100 mg Cd/Kg. Also, Cd concentration in aerial parts and roots increased as the level of soil cadmium increased. The results of this experiment showed that soil inoculation with mycorrhizal fungi and Rihzobium trifolii had a significant effect (p < 0.05 and p < 0.01) on fresh weights of aerial parts and roots, height, number of plant per pot, Fe, Zn and Cd concentrations in aerial parts and roots of berseem clover. The inoculation of soil with mycorrhizal fungi and Rhizobium trifolii increased the fresh weights of aerial parts and roots, height and No. of plant per pot. The highest fresh weights of aerial parts and roots of berseem clover, height, and number of plant per pot were obtained in treatments co-inoculated with Glomus mosseae and Rhizobium trifolii. The highest and lowest concentrations of iron and zinc in aerial parts and roots of berseem clover were measured, respectively, for the treatment co-inoculated by Glomus mosseae and Rhizobium trifolii and control treatment (without inoculation). However, the opposite trends were found in Cd concentrations in the plant. The highest and lowest Cd concentrations in aerial parts and roots were measured in control treatment (without inoculation) and treatment co-inoculated by Glomus mosseae and Rhizobium trifolii (MT), respectively. Bioremediation and phytoremediation are considered as two very safe and necessary technologies which naturally occur in the soil by microbes and plants and pose no hazard to the environment and the people life. The procedure of bioremediation and phytoremediation can be simply carried out on site without initiating a major disruption of normal actions and threating the human life and the environment during transportation. Bioremediation and phytoremediation are used less than other technologies for cleaning-up the wastes and contaminated soils. Microorganisms and plants possess inherent biological mechanisms that enable them to survive under heavy metal stress and remove the metals from the environment. These microbes use various processes such as precipitation, biosorption, enzymatic transformation of metals, complexation and phytoremediation techniques of which phytoextraction and phytostabilization have been very effective. However, environmental conditions need to be adequate for effective bioremediation. The use of hyperaccumulator plants to remediate contaminated sites depends on the quantity of metal at that site and the type of soil. The results of this experiment showed that the Rhizobium trifolii and Glomus mosseae could be used to reduce the soil cadmium contamination. Also, the berseem clover is a hyperaccumulator plant for phytoremediation of cadmium in soils. According to the results of this study, co-inoculation of mycorrhizal fungus Glomus mosseae and Rhizobium trifolii can be recommended to improve the yield and uptake of micronutrients such as iron and zinc in cadmium contaminated soils.

Cadmium is a very mobile element in soil that is absorbed by plant roots and translocation of cadmium from root to shoot deteriorates crop quality. It enters the food chains of humans and animals easily and is a potential threat to human health. The increase of contaminated areas in the country and the existence of farms under cultivation of various forages and the use of these forage products in the animal feed led to this study was carried out with the aim of investigating the effects of arbuscular mycorrhizal fungi and Rhizobium leguminosarum bv. trifolii on the yield of berseem clover (Trifolium alexandrium) under cadmium stress.

A factorial experiment was conducted in the greenhouse of Faculty of Agriculture, University of Zanjan, using a completely randomized design with three replications. In this experiment, the effects of different levels of soil cadmium (0, 5, 10, 25 and 50 mg/kg) and soil inoculation (without inoculation and inoculation with Funneliformis mosseae, Rhizophagus irregularis, Funneliformis mosseae + Rhizobium leguminosarum bv. trifolii, Rhizophagus irregularis + Rhizobium leguminosarum bv. trifolii, Rhizobium leguminosarum bv. trifolii, Funneliformis mosseae + Rhizophagus irregularis and Funneliformis mosseae + Rhizophagus irregularis + Rhizobium leguminosarum bv. trifolii) on growth of berseem clover (Trifolium alexandrium) were assessed.

The results of this study showed a significant effect (1% and 5% probability level) due to soil cadmium levels on dry weights and N, P, K and Cd concentrations of aerial parts and roots of berseem clover. The dry weights and N, P and K concentrations of aerial parts and roots of berseem clover decreased as the levels of soil Cd increased. The highest dry weights of aerial parts and roots, N, P and K concentrations were measured in treatment co-inoculated with Funneliformis mosseae and Rhizobium leguminosarum bv. Trifolii and without Cadmium. Also, the lowest dry weights of aerial parts and roots and macronutrient concentrations were observed in treatment 100 mg Cd/kg and without inoculation with microorganism. Soil contamination with Cd decreased the dry weight of aerial parts and roots by 66.49 and 71.11%, respectively. the highest Cd concentrations in aerial parts and roots were measured 11.25 and 17.80 mg/kg in treatment 100 mg Cd/kg and without inoculation with microorganism and the lowest Cd concentrations in aerial parts and roots were 0.0012 and 0.0046 mg/kg in treatment co-inoculated with Funneliformis mosseae and Rhizobium leguminosarum bv. Trifolii and without Cadmium. The results of the mean comparison of data showed that the Cd concentration in the roots was higher than the aerial parts, and in treatment 100 mg Cd/kg without inoculation with microorganism, Cd concentration of roots was 36.8% higher than the Cd concentration in aerial parts.

Based on the results obtained from this study with the increase in Cd levels of soil, the dry weights and N, P and K concentrations of aerial parts and roots of berseem clover decreased. Soil inoculation with mixture of fungi and bacteria reduced the effect of Cd stress on the growth of clover. Also, the separate inoculation with arbuscular mycorrhizal fungi also reduced the concentration of Cd in the aerial parts and roots. According to the results of this study, in contaminated soils can be used co-inoculated with Funneliformis mosseae and Rhizobium leguminosarum bv. Trifolii to reduce the Cd concentration and increase the yield of plants.

Mobilization and stabilization of organic matter in soils represent a set of complex processes involving the processing and decomposition of organic matter by diverse communities of soil fauna and microorganisms, as well as chemical-physical interactions with mineral particles of soil. Clay minerals have high effects on the soil organic matter dynamics. Clay minerals with the physical protection of organic matter play an important role in reducing the rate of decomposition of organic matter. The effects of soil texture on the soil organic matter dynamics have been investigated in many studies, but the effects of exchangeable cations and clay types on mineralization of organic nitrogen and microbial biomass nitrogen have not been given much attention. For this reason, the aim of this study was to evaluate the effects of types and clay contents and exchangeable cations on the mineralization of organic nitrogen and microbial biomass nitrogen.
Material and Appropriate amounts of homoionic Na-, Ca- and Al- clays from Georgia kaolinite, Illinois illite and Wyoming montmorillonite were mixed with pure sand to prepare artificial soils with different clay contents, exchangeable cations, and clay types. The artificial soils have zero, 5 and 10% clay from Georgia kaolinite, Illinois illite and Wyoming montmorillonite that their clay minerals saturated with Ca, Na and Al. Alfalfa plant residues were incorporated into the artificial soils and the soils were inoculated with microbes from a natural soil and incubated for 60 days and concentration of NH4-N and NO3-N were measured every 15 days. In the artificial soil samples, microbial biomass nitrogen was measured by the fumigation-extraction method in the end time of incubation period.
The results of this study showed that the percentage of mineralized nitrogen in the two-month incubation period, was higher in the pure sand than in soils containing 5% and 10% clay, indicating that clay contents influence the capacity of soils to protect and store organic nitrogen. Microbial biomass nitrogen increased as the amount of clay in the soil increased. The highest and lowest amounts of microbial biomass nitrogen measured in soils with 10% clay (9.26 mg per 50 g dry soil) and pure sand (4.31 mg per 50 g dry soil), respectively. There was a significant influence of exchangeable cations on the percentage of mineralized nitrogen and microbial biomass nitrogen. The microbial biomass nitrogen and the percentage of mineralized nitrogen were highest in Ca-soils and lowest in Al-soils. The percentage of mineralized organic nitrogen in two months of incubation period was highest in soils with Georgia kaolinite clay and lowest in soil with Wyoming montmorillonite clay. The amounts of microbial biomass nitrogen in soils with Wyoming montmorillonite clay were lower than soils with Georgia kaolinite and Illinois illite clays. The percentage of mineralized organic nitrogen increased as the incubation period increased. The results of this study indicated that organic nitrogen mineralization rates and microbial biomass nitrogen were affected by types and clay contents and exchangeable cations and interaction of organic matter with clays and is an important process as it slows soil organic matter decomposition.
Mixing the alfalfa residues with artificial soils and incubation samples allowed to study the effects of types and clay contents and exchangeable cations on the percentage of NH4+N, NO3--N, mineralized nitrogen, and microbial biomass nitrogen. Soils with different clay contents have different surface areas and cation exchange capacities; therefore, it is concluded that organic nitrogen storage of soils is, partly, controlled by the surface areas, cation exchange capacity and physical protection provided by the soils. Nitrogen mineralization and the amounts of microbial biomass nitrogen were different in soils with different exchangeable cations. It is concluded that exchangeable cations exert their influence on microbial biomass and hence nitrogen dynamics by controlling the size and activity of the microbial population through modifying the physicochemical characteristics of microbial habitats. Since various clay minerals have different specific surface areas and cation exchange capacity and the physicochemical changes induced in the soil environment as a result of variations of exchangeable cations is much greater in soils with higher cation exchange capacity and specific surface area. It seems the effects of clay mineralogy on the dynamics of organic materials and microbial biomass, in part, arise from the type of exchangeable cations present on the exchange sites of the clay minerals.

Vinasse is a byproduct of the sugar industry. Sugarcane or Sugarbeet is processed to produce crystallinesugar, pulp and molasses. The latter isfurther processed by fermentation to ethanol, ascorbicacid or other products. After the removal of the desired product (alcohol, ascorbicacid, etc.) the remaining material is called vinasse. Vinasse is sold after a partial dehydration and usually has a viscositycomparable to molasses. Commercially offered vinasse comes either from sugarcaneand is called cane-vinasse or from sugarbeet and is called beet-vinasse. On average, for each liter of vinasse, 12 liters alcohol produced. Vinasse is a material with dark brown color and the smell of burned sugar, which is rich in potassium, calcium, magnesium, phosphorus and nitrogen.
To determine the effect of vinasse and additive nitrogen and phosphorus on growth and yield of tomato, a factorial pot experiment was conducted at ZanjanUniversity in 2008. Two different plant nutrient including N and P and their combination (N) were added to vinasse with three different concentrations to form experimental treatments. In addition to these treatments, three control treatments with vinasse of different concentrations, but with no additive were also included in the experiment. Each treatment used with two different application methods (soil application and soil foliar application).The experiment had 24 treatments, a complete randomized design and three replications. The vinasse used in this experiment was diluted with water 10, 20 and 40 times to make a nutrient solution of three different concentrations of tomato plant. The amounts of nitrogen and phosphorus that were added to vinasse were 224 and 62 mg/l, respectively. Phosphorus and nitrogen were applied to as super-phosphate triple and calcium nitrate and ammonium nitrate respectively. After being deployed to ensure complete installation of tomatoes in pots containing perlite (about 2 weeks after the transfer of seedlings tothe pots) treatments wereapplied to the pots. It should be noted that initially, three tomato seedlingswere planted in each pot at later stage after the plants were thinned to one plant per pot.Five months later after planting seedlings, fruits were picked and measured separately. At the end of the growth period, fruit yield, leaf and some quality characteristicsof fruit were measured.
Results The results showed that the effects of vinasse concentrations on fruit yield, dry matter content of fruit, dry weight of root and plant height were significant at p