جستجوی مقالات مرتبط با کلیدواژه « Soil » در نشریات گروه « کشاورزی »

Arsenic, one of the most critical environmental toxins, accumulates in plant and animal organs through root absorption in plants and subsequent ingestion by humans via the food chain or direct consumption of contaminated water. Reports have highlighted the contamination of regional drinking water sources in Bijar city, Kurdistan province, with arsenic and its adverse effects on local residents. Therefore, this research aimed to investigate the distribution of arsenic in the water and soil sources of the region and evaluate the capacity of native pasture plants to absorb and accumulate this element.

Arsenic concentrations were measured in surface and subsurface waters of a 360 km2 region using the atomic absorption-graphite furnace method. The distribution of arsenic in the contaminated area was mapped using the ArcGIS program. Three sampling areas with varying pollution intensities (A > B > C) were selected. Soil samples and aerial parts of 13 plant species were collected and analyzed for arsenic concentrations, enabling a comparison of different plant species' ability to absorb arsenic.

The intensity of arsenic contamination in surface water, soil, and plants studied in this research exceeded typical concentrations of arsenic in water, soil, and plant sources. Total arsenic concentrations in water samples ranged from 4.5 to 280 μg l-1 and correlated with electrical conductivity, total dissolved solids, and total hardness (p < 0.001). Arsenic concentration in the soil of area A (Ali-Abad village) exceeded 2059 μg g-1 of dry soil, with contamination decreasing with distance from area A. A high correlation was observed between the intensity of water and soil pollution (R2=0.84). Arsenic concentrations in the aerial parts of 13 plant species with three replications varied depending on the plant species and the intensity of soil contamination (0 to 47.8 μg g-1). The intensity of soil contamination was on average 27.66 times higher than the amount of arsenic accumulated in the plant, indicating the high resistance of native pasture plants in the region to arsenic toxicity.

Field monitoring revealed that 45% of water resources in the sampling areas exceeded the national drinking water standard for arsenic (50 μg l-1), reaching 78% according to the World Health Organization standard (10 μg l-1). Concentrations of parent materials containing arsenic compounds were higher in areas A and B than in area C, with decreasing concentrations further from area A. The sampling region significantly influenced the average arsenic concentration in water and soil samples (P < 0.05). Arsenic uptake by the plant samples exceeded typical concentrations (0.1 to 3 μg g-1), with the highest mean arsenic concentrations found in the leaves of Astragalus bisulcatus, Chenopodium album, and Mentha longifolia, accumulating more than 47.8, 35.5, and 22.5 μg g-1, respectively. The study demonstrates heavy contamination of water, soil, and plant resources in the region, with most surface water resources utilized for agricultural irrigation, animal consumption, and occasionally drinking water for village residents. The entry of arsenic into the human body, directly or through the food cycle, poses a severe health risk to the region's residents, necessitating immediate intervention measures.

Introduction and Goal:

The implementation of watershed management practices in the country and the evaluation the conducted activities and effects investigation of these projects are essential on the governing processes at watershed. However, such an important approach has to be adequately considered.

Accordingly, the present study was planned with the simulation aim of the impact of watershed management practices on hydrological parameters using the SWAT model in the Kan Watershed in Tehran Province, Iran. Therefore, the first of the initial implementation of the model was carried out, and then it was calibrated and validated. In this research, SWAT-CUP software was used to usage of various instructions and objective functions and also to test and the model calibration and validation. In order to determination and comparison of the simulation conditions with the governing conditions on watershed applied the evaluation criteria such as the coefficient of explanation and the coefficient of efficiency.

The research results showed that the model efficiency was acceptable for the hydrological simulation of the studied watershed. So, the explanation coefficient for calibration and validation was with rates of 0.69 and 0.86 respectively. Also, the Nash-Sutcliffe index for the calibration and validation obtained with rates of 0.85 and 0.93, respectively. Then, watershed management practices simulated at the level of studied watershed. The simulated results showed that the surface runoff decreased with the practices of watershed management in the form of gabion, masonry check dam, counter trench and loose- stone check dam with the values of 25, 23, 21, and 11 percent, respectively. Also, the available water was more after the practices of watershed management in the form of gabion, masonry check dam, counter trench and loose- stone check dam with rates of 19.0, 21.3, 20.5 and 10.75 percent, respectively, compared to the absence conditions of these practices at the watershed level. Also, the maximum amount of flow changes observed in the practices conditions of masonry check dams. In addition, the evapotranspiration increased with implementation of gabion. masonry check dams, counter trench and loose- stone check dams with rates of 20.19, 20.86, 19.0 and 10.87 percent, respectively.

Conclusion and Suggestions:

Based on the results of this research in the Kan watershed, the flood possibility and the flood damages can be reduced by practices of the watershed management, management and biological programs.

Saffron (Crocus sativus L.) is one of the most expensive spices in the world, and due to the high demand for it in the world markets, its cultivation is developing strongly. In addition to genetics, the region's climate and soil characteristics also affect the quantity and quality of the product. Therefore, identifying regions, whose climatic and soil conditions are close to the optimal conditions for saffron production will help us achieve the most favorable quantitative and qualitative performance.
In the present study, saffron was cultivated in six different regions of Kurdistan province (Sanandaj, Kamyaran, Ghorveh, Dehgolan, Divandarreh, and Marivan) as a randomized complete block design, and their functional and phytochemical characteristics were evaluated during three years (2020-2022). The saffron corms used in this research were prepared from Torbat-e Heydarieh city. In each region, land with an area of 25 m2 was selected. After preparation, three plots with dimensions 2x2 m with 1m distances were created. Each experimental plot consisted of 10 rows, and in each row, 20 holes were made with a depth of 15 cm and a distance of 10 cm from each other, and then one corm was planted in each hole. Irrigation was done twice a year (late September and late October). During the flowering season, saffron flowers were harvested, and their functional and phytochemical characteristics (number of flowers, dry flower yield, dry stigma yield, stigma length, crocin, and safranal content of the stigma) were measured. Total monthly precipitation and average monthly temperature for each region during the research period were obtained from nearest meteorological station. The physicochemical properties of soil samples from the studied regions were evaluated in the laboratory. Finally, the mean comparison of data (using Duncan’s multiple range test) and correlations between climate and soil data with functional and phytochemical traits (using the Pearson method) were obtained by SPSS software.
The results indicated that the maximum stigma yield in all three years belonged to saffron cultivated in Kamyaran (0.13±0.009, 1.27±0.085 and 1.54±0.052 g/m2 in 2020, 2021, and 2022, respectively). In all three years, the highest crocin content was obtained from the stigmas harvested from Divandarreh farm (53.01±15.77, 92.54±26.6 and 143.07±5.12 mg/g dry stigma in 2020, 2021 and 2022, respectively). The highest mean of safranal content in the year 2020 (4.09±0.38 mg/g dry stigma), 2021 (2.48±0.44 mg/g dry stigma), and 2022 (5.05±0.14 mg/g dry stigma), belonged to the saffron of Kamyaran (no significant difference with other regions except Marivan), Marivan (no significant difference with Dehgolan and Divandarreh) and Divandarreh (no significant difference with other regions except Kamyaran), respectively. Dry flower yield and stigma yield showed a significant negative correlation with clay (r= -0.329* and r= -0.356**, respectively), organic matter (r= -0.422** and r= -0.428**, respectively) and nitrogen (r= -0.437** and r= -0.444**, respectively), and a significant positive correlation with potassium (r= 0.544** and r= 0.561**, respectively) and phosphorus (r= 0.410** and r= 0.435**, respectively). The crocin content of stigma had a significant positive correlation with clay (r= 0.557**) and pH (r= 0.438**) and a significant negative correlation with sand (r= -0.461**). Safranal had no significant correlation with soil characteristics and altitude. Also, significant correlations were obtained between the measured traits and average monthly temperature and total monthly precipitation.
Generally, regions of Kurdistan province with less rainfall in spring, summer and early autumn; more rainfall in late autumn and during winter; higher average monthly temperature; with medium-textured soils containing more phosphorus and potassium, lower nitrogen and organic matter, and slightly alkaline pH, were identified as more suitable regions for saffron production. Based on all measured quantitative and qualitative traits, among the studied regions, Kamyaran had the most suitable conditions for saffron production.

The implementation of the forest restoration plan in the northern region of Iran has led to an increase in efforts to enhance wood production through the cultivation of poplar seedling. Particularly, poplar trees hold a significant position among wood producers due to their distinctive features. The key consideration revolves around identifying suitable and cost-effective lands for planting fast-growing species. Purpose of this study focuses on assessing the land suitability for poplar (Populus nigra L.), a prevalent forest species in the country, through a quantitative land evaluation method based on the FAO approach.
The research gathered and classified the edaphic and climatic requirements of poplar tree by utilizing various library resources, data from the soil laboratory of the Research Institute of Forests and Ranglands, and field survey (Soil Profiles). The climatic and soil characteristics were quantitatively classified into five categories: highly suitable (S1), moderately suitable (S2), low/critically suitable (S3), The Quantitative Classification of soil and climate properties was done in five classes: suitable (S1), moderate suitability (S2), low or critical suitability (S3), currently not suitable (N1) and permanent not suitable (N2). For validation, a quantitative assessment of land suitability for poplar cultivation was performed across six soil types, including Nowshahr forest brown, Nowshahr gray brown pedzolic rich in organic matter, Chamestan alluvial regosol, Chamestan Rendezina, Chalous  Pseudogley , and Karaj alluvial cambisol, using a parametric method (second root).
Results indicate that spruce thrives in wet and semi-humid regions in a dry-type manner, with ideal conditions found in areas receiving 1500-1800 mm of rainfall. In drier, semi-arid zones, irrigation is essential for meeting water requirements. Optimal growth temperatures for spruce range from 11-16 degrees Celsius in moderate climates. Poplar flourishes in soils with a light to medium texture, granular or cubic structure, good to fast drainage, and low underground water levels with adequate calcium and magnesium cations.
The study showed that the most suitable soils for poplars have a light to medium texture with a granular or crumb structure, with adequate drainage, the absence of high groundwater and the sufficient amount of calcium and magnesium cations in the soil. Soils with incomplete drainage and heavy texture do not provide suitable conditions for poplar plantations. In terms of quantitative evaluation, Mollic Udifluvents soils with medium texture had the highest score for poplar plantations.

Forest harvesting operations, especially logging, are activities that cause interference and tampering with nature. Tractor-operated systems are the most common type of small-scale equipment used in the north of Iran. Due to the direct contact of wood with the forest soil, land logging has always been associated with a wide range of destructive effects on the forest ecosystem, including changes in the soil's physicochemical properties and damage to the natural regeneration and remaining trees. After logging, deep grooves are visible in the remaining logging roads, which can cause soil erosion, landslides, and soil fall due to the high longitudinal slope of these roads. Changes in the soil's physicochemical properties are among of the most important effects caused by the exploitation and removal of wood from the forest mass. Numerous studies report the long-term recovery of the soil's physicochemical properties. A major management goal in forest exploitation is the need to minimize the effects of vehicle traffic on the forest soil because these negative effects can be significant in the long run. The soil characteristics (appearance, compactness, and texture) and chemical properties in terms of soil elements, organic matter, and pH in two control and forest exploitation areas were studied to provide solutions to reduce these effects.

The Kohmian forestry project is located in the 89th watershed of the northern forests of Iran in the area of Natural Resources of Golestan-Gorgan province. This research was conducted in Parcel 27 of the Kohmian Azadshahr Forestry Project located in Golestan, Iran. To investigate the soil's physicochemical changes due to logging with agricultural tractors, soil was sampled in two control areas and on the crossing paths by metal cylinders at three depths (0-10, 10-20, and 20-30 cm) of the soil in a completely randomized design with three replications. These samples were dried in the laboratory in an oven at 105 °C for 24 h and then weighed using a digital scale (EK4000, Japan) with an accuracy of 0.1 g. After recording the soil dry weight, the physical properties (compaction, apparent specific gravity, moisture, and texture) and chemical properties (organic matter, cation exchange capacity, nitrogen, potassium, phosphorus, calcium, magnesium, iron, zinc, manganese, copper, and acidity) were studied using standard methods.

Logging with an agricultural tractor significantly impacted both the soil's physical and chemical properties. The most notable effect was observed in the soil depths sampled from 0-10 cm and 20-30 cm. The alterations predominantly pertained to physical changes in the soil, with no significant modifications detected in the chemical properties. Notably, soil compaction in the trafficked areas at depths of 0-10, 10-20, and 20-30 cm was respectively 46.2, 3.04, and 1.73 times higher than that of the control area. Furthermore, the increase in soil specific gravity at these depths ranged from 20% to 36% compared to the control area. Chemical properties such as cation exchange capacity and the concentrations of elements (e.g., phosphorus, nitrogen, and iron) exhibited reductions of 37.62%, 63.91%, 10.2%, and 73.05%, respectively, in the top 0-10 cm depth. At a depth of 10-20 cm, only organic matter was significantly impacted by tractor traffic, with a reduction of approximately 64% compared to the control area. Chemical properties at a depth of 20-30 cm remained unaffected by tractor traffic.

The study highlights the detrimental effects of using an agricultural tractor for primary forest plot transportation. The uneven contact surface of its tires, particularly the lower contact surface in the front tire, along with the absence of a winch, leads to soil disturbance along the logging path. This disturbance includes soil compaction, increased specific gravity, and alterations in soil texture, nitrogen, phosphorus, and iron content, reduced organic matter, and decreased soil exchange capacity. To mitigate these adverse effects, it is recommended to employ specialized logging machinery, such as skidders with rakes, instead of agricultural tractors. Other measures include implementing surface protections on logging paths, restricting logging activities to periods when the forest soil is dry and less prone to damage, and proper disposal of excess logs along the logging route.

Road ecology studies are very important and valuable for monitoring the impact of forest roads on biodiversity. This study was conducted in order to investigate the effect of forest roads on the biodiversity of herbaceous species, tree regeneration and lichen in the Kalardasht forests. Sampling was done in the sample plots at distances of 0, 15, 45, 75, and 105 meters from the roadside in two controlled and harvested areas. The indices used were Margalf's species richness, Shannon-Wiener's biodiversity and Pielou's evenness index. The effects of roads on vegetation diversity in relation to soil characteristics were also investigated. The results showed that road construction in the harvested stand caused the destruction of tree regeneration, herbaceous and lichen, but the physical and chemical properties of the soil were not affected. By increasing the distance from the road, the diversity and richness of regeneration in both control and harvested areas has increased and the evenness index has decreased. On the other hand, the diversity and richness of herbaceous species has shown a significant decrease. This study reports the distance of 15 to 45 meters of the buffering effect of the roadside on the indices of biodiversity and the richness of tree regeneration, herbaceous cover and lichens. Most of the physical and chemical properties of the soil have also increased with increasing distance from the road. Also, there was a significant correlation between most of the physical and chemical properties of the soil with the regeneration of trees and herbaceous species.

Investigating the effect of agricultural management methods on the amount of nitrate and urea in the soil has special importance. The purpose of this study is to model and investigate the interrelation of hydraulic, reactivity, and solute absorption variables of different soil depths collected in the year of (2020-2021) from the pilot rice farm located in the Sari Agricultural Sciences and Natural Resources University, Mazandaran province, with an area of 0.6 hectares. In this study, the residual moisture of the soil (θr), nitrification rate (kn), and urea hydrolysis rate (kh) variables were modeled based on four, four, and two defined scenarios, respectively, using Wavelet-Artificial Neural Network (WANN), Wavelet- Artificial Neural-Fuzzy Inference System (WANFIS), and Wavelet-Gene Expression Programming (WGEP) models. The results showed that the performance improvement percentage of WGEP models compared to WANFIS and WANFIS model compared to WANN considering the RMSE evaluation index were obtained (16.96, 41.87), (85.72, 1.00), and (20.37, 3.27) for three variables of θr, kn, and kh, respectively. the volumetric residual moisture in the soil, and the urea hydrolysis rate variable is also highly dependent on the residual moisture in the soil. Also, the results showed that the hydraulic variables, reactivity and absorption of soil solutes can be affected by the climatic conditions of the region. Therefore, providing intelligent applicable models to estimate nitrate and urea variables in soil can help managers and farmers in proper management of water and soil resources and optimal use of nitrogen fertilizer with less time and cost.

Kelussia odoratissima Mozaff. is an endemic and endangered species of Iran. This research was conducted to investigate its distribution, geographical location, edaphic and climatic conditions, vegetation, phenology, and pests and diseases during the years 2016-2020. The results showed that K. odoratissima grows in the central Zagros Mountains at altitudes of 2000 to 3163 meters, with a cold semi-humid climate (minimum temperature of 2.6°C, maximum temperature of 17°C, and average annual precipitation of 1000 mm). The soil of the habitats was silty clay in terms of texture, rich in essential elements, and had a sufficient amount of organic matter. The release of aerial parts of K. odoratissima begins from mid-March to the beginning of April, and its vegetative growth continues until the end of June. The reproductive phase begins in the first half of July, and its flowers are formed from the middle of July until the end of July; then ripening and seed fall occur in the first half of September and the second half of September, respectively. Indiscriminate and incorrect harvesting, pests such as the seed-eating beetle (Anobiidae), a species of moth (Eupithecia sp.), and the larva of the Aethes francillana have put the plant at risk of extinction. Strengthening the role of local communities, continuous exclosure of the habitat, controlling pests and diseases, reintroduction and maintaining germplasm, and collecting populations in future programs can be very important protection strategies to prevent the extinction of this species.

Soil hydrocarbons can affect the physical, chemical and biological characteristics. Soil samples were prepared from the oil-rich area of Kermanshah province, which have been under oil pollution for a long time. 120 soil samples were collected from a depth of 0-15 cm with three pollution levels of low (L), moderate (M) and high (H) and the physicochemical characteristics were measured. Then bacteria were counted in NA and CFMM media and a positive and significant correlation was observed between bacterial population and oil concentration. The mean of oil measured by Soxhlet method was 4.03%, 9.95% and 22.50% for L, M and H levels, respectively. With the increase of oil in soil samples, ACP and ALP increased. In all samples, ACP was lower than ALP. The highest ACP and ALP were obtained 45.78 and 84.90 (gPNP.g-1.h-1µ) respectively in soil with high pollution level. Regression analysis showed that the oil percentage, sand percentage and EC with an regression coefficient of 0.71 were effective variables on the ACP, and the oil and sand percentage were also effective variables on the activity of ALP with an regression coefficient of 0.43. PCA analysis was also performed and the results showed that the first two components explained 68% of the variance between the samples. Based on the results, it was observed that natural and long-term oil pollution, with the passage of time led to the adaptation of microbial communities resistant to pollution and the number of these microorganisms and the activity of phosphatase enzyme increased.

Implementation of watershed management measures in Iran to reduce the damage caused by the misuse of natural resources has begun many years ago and is still ongoing. Evaluating the performance of previous remedial work is essential for better planning of future watershed management projects. In this regard, due to the monitoring of soil loss, runoff and sedimentation at slope and watershed scales, a suitable platform has been provided to assess the effects of watershed management measures.

The Kakhk paired watershed with an area of 217 ha is located at a distance of 300 km from Mashhad City and 35 km southwest of Gonabad City.The Kakhk paired watershed consists of two sub-watershds, the control and the treatment. A series of biological and structural watershed management measures have been implemented in the treatment sub-watershed. While the control sub-watershed is exploited according to the custom of the region. In this research, the impact of different watershed management measures on the soil loss, sediment yield and hydrology in the Kakhk paired watershed were evaluated. For this purpose, the recorded data of suspended sediment and discharge at the watershed scale, as well as the data of soil loss (by standard plots and erosion pins) and runoff (standard plots) were analyzed at the hillslope scale.

The results at plot scale showed that the average annual soil loss of the two treatment and control sub-watersheds is 0.05 and 0.27 ton.ha-1.y-1, respectively. These results indicate that the soil loss in the control sub-watershed is 536% higher than the treatment sub-watershed. The amount of runoff yield in the control sub-watershed was calculated to be 138% more than the treatment sub-watershed. At watershed scale, the results showed that the total amount of suspended sediment output from the control and treatment watersheds is 379 and 85 tons, respectively, which indicates the average specific sediment of 0.4 and 0.1 ton.ha-1 in the control and treatment watersheds, respectively. The volume of runoff in the control sub-watershed is 1.3 times more than treatment sub-watershed. On the other hand, despite the difference between the treatment and control sub-watersheds in soil loss, run-off production and sediment yield, the role of maximum events in soil erosion and runoff production in both sub-watersheds is very significant. So that one to three erosive events in both studied sub-watershes are responsible for more than 80% of the soil loss in the slopes and the production of runoff and sediment yield of watersheds.

The results showed that a total of 136,000 m3 of runoff storage and 294 ton of suspended sediment control were achieved as a result of watershed operations in the treatment sub-watershed. Therefore, it can be stated that the watershed management measures carried out in the treatment sub-watershed on the one hand have reduced soil erosion and runoff production on the slopes compared to the control sub-watershed. This action has been done through increasing the vegetation, increasing the roughness of the land surface, reducing the carrying capacity of the flow and settling the materials being transported. Further, the flow from the slopes enters the waterway and is kept by watershed  management structures, and as a result, the sediment yield and volume of runoff in the treatment sub-watershed is less than the control sub-watershed.

Carbon dioxide gas, produced from fossil fuels in industrial centres and near big cities, has a significant effect on climate change and global warming. Sequestration of carbon in plants and soil of protected areas, especially national natural parks, is the simplest and most economical way to reduce atmospheric carbon dioxide. The National Bamou Park, with an area of 46,913 hectares near the industrial centres of Shiraz, Zarghan, Maroodasht and Abbarik, provided a good chance for carbon sequestration. In this research economic analysis of this park's soil carbon sequestration capability in 2022 was done.

Based on vegetation cover and geomorphological conditions, 20 and 5 locations inside and outside the park were selected for sampling. Composite soil samples were taken from the 25 profiles with a depth of 30 cm length and width of 20 cm. The Wallcly-Black method was used to determine the percentage of soil organic carbon in the laboratory. The economic evaluation of the sequestered carbon was done using the damage cost avoided method at three levels: low estimate based on the values of trade in the Prototype Carbon Fund, medium estimate based on anticipated values in the future European Union carbon trading scheme and high estimate based on the damage cost assessment made by Intergovernmental Panel on Climate Change.

Based on the results, the average measures of carbon sequestered in the soil of the lands inside and outside the park were 40.05 and 21.75 tons per hectare, respectively. Based on the t-test, the average carbon sequestered inside and outside the park significantly differs at 1%. The average economic value of avoided damage related to carbon sequestration per hectare of land inside the park at low, medium and high levels are 123.12, 410.41 and 3283.26 million rials, respectively. The corresponding amounts outside the park are 66.86, 222.88 and 1783.04 million rials. The average economic value of sequestered carbon in the soil of each hectare of land inside and outside the park, based on the t-test, has a significant difference at the level of 1%.

Conclusions and Recommendations:

The suitable conditions of vegetation and soil of Bamou National Park have caused this park to have a high economic value because of the environmental services of carbon sequestration in the soil and absorption of carbon dioxide gas. Thus, it is possible the economic value of such services is considered in financial calculations, and all or part of it is allocated for the protection and expansion of these parks. An important point about the economic value of the parks and forest ecosystems services is the possibility of buying and selling carbon sequestered or carbon dioxide gas emitted into the atmosphere. For this purpose, it is suggested to pay attention to the legal frameworks and necessary infrastructures for creating an applied market of carbon sequestration and carbon dioxide emission at the national and regional levels. In addition, concerning the natural resources of Fars province and the criteria of international climate change agreements, it is possible to use foreign capital to help create and expand national parks and forest ecosystems as greenhouse gas reservoirs. Therefore, it is suggested to use these legal agreements to attract credit from international organizations.

A review of research on soil and plant interactions in rangeland and desert ecosystems shows that the number of soil samples are not determined on a scientific basis. The present study, with the aim of using effect size and power analysis to determine the number of soil samples in three plant types of Salsola spp. was conducted in three arid and semiarid regions of Shahriar, Zirkouh and Zabol. In addition, 15, 10, and 5 soil samples were collected for each plant type, respectively. Some soil properties, including electrical conductivity, sand content, organic matter content, calcium carbonate equivalent, and saturation percentage, were determined in the laboratory. The number of samples was estimated after the initial sampling based on the calculated effect size (f) and the power of 80 % and before the sampling based on the medium effect size (f = 0.25) and the power of 60 %. The results showed that the power analysis of the three studied sites was 88, 56, and 38 %, respectively. To determine the minimum number of soil samples required to achieve a power of 80 %, at least 20 soil samples are required for Zabol and Zirkouh, and at least 12 soil samples are required for Shahriar. If there is no previous information about the soil properties, more than 50 soil samples must be collected from each plant type for a statistical comparison of three plant types with a medium effect size, a power of 80 %, and a significant level of 0.05.

 In the field of vegetation studies, there are statistical and graphical methods to estimate the number of plots needed for sampling, and their application has been approved in numerous research studies. In a review of research on soil and plant interactions in rangeland and desert ecosystems, it seems that the number of soil samples are not determined based on a scientific basis. Either by autecology or synecology, soil samples were taken from different depths at the first and end points of each transect according to the soil depth by using the random-systematic method (i.e., a total of 6–8 soil samples). The sampling scheme captures all the decisions and information, such as the purpose of the sampling, financial constraints, sampling method, sample size, method(s) of statistical analysis, and accuracy of results (Arzani and Abedi, 2015). One of the most frequent problems in statistical analysis is determining the appropriate sample size (Rostampour and Eftekhari, 2023). The present study has the aim of using effect size and power analysis to determine the number of soil samples in three plant types in the halophyte-psammophyte ecosystem of the arid and semi-arid regions.

The present study was conducted on three plant types of Salsola spp. in three arid and desert areas of Shahriar, Zirkouh, and Zabol. At Shahriar, Zirkouh and Zabol sites, 15, 10, and 5 soil samples were collected for each plant type, respectively. Then, the soil samples were passed through a 2-mm sieve and some soil properties, including electrical conductivity, organic matter content, sand content, calcium carbonate equivalent and saturation percentage were measured in the laboratory. In general, for estimating the number of samples based on power analysis, there is a need for three factors: effect size, power, and significant levels. In the present study, two methods were used to determine the number of soil samples: 1) the estimation of the optimal sample number after the initial sampling based on the calculated effect size (f) and the power of 80 %, and 2) the minimum number of samples before sampling based on the medium effect size (f = 0.25) and power of 60 %.

The results showed that with an increase in the number of soil samples, the power analysis of the three studied sites was 38, 56, and 88 %, respectively. To determine the minimum number of soil samples required to achieve a power of 80 %, at least 20 soil samples are required for the Zabol and Zirkouh sites, and at least 12 soil samples are required for the Shahriar site. If the effect size is unknown due to the absence of data variance, the numbers of samples required for the sample sizes of small, medium, and large, and to reach a power of 60 % at the level of 0.05, are about 209, 35, and 14 samples, respectively. If there is no previous information about the soil properties, for a statistical comparison of three plant types with a medium effect size, a power of 80 %, and a significant level of 0.05, more than 50 soil samples must be collected from each plant type.

As per guideline, a power of 80 % is often considered an acceptable threshold, and studies with a power of less than 50 % should not be usually conducted. Accordingly, only the Shahriar site has a power above 60 %. Therefore, sampling from the Zirkouh and Zabol sites was not adequate for the statistical analysis. If there is no previous information about the soil properties, at least 50 soil samples should be collected from each plant type to compare the statistical significance of the three plant types with a medium effect size (F = 0.25) and a significant level of 0.05.

This study was carried out with the aim of investigating and knowing the chemical and physical characteristics of Astragalus parrowianus Fischer and the relationship of these characteristics with soil and topographical characteristics in Jalamabadan rangeland of Joveyn city. At first, the studied area was divided into four places where A. parrowianus was present for sampling. In July and August of 2019, the study area was visited to take samples of tragacanth and then by using of scientific resources and the guidance of local operators, 4 different sites with the presence of A. parrowianus were identified. Then, in each of the places, the tragacanth was extracted from the plant bases and A profile was dug at a depth of 0-60 cm in order to prepare a soil sample. Quantitative characteristics of tragacanth, including production, ash, viscosity, and qualitative characteristics of Tragacanth, including potassium, calcium, phosphorus, and sodium elements, arabinose, galactose, fructose, glucose, sucrose sugars, and proline, serine, and valine amino acids were measured. In the collected soil samples, the factors of electrical conductivity, percentage of sand, silt, clay, pH, soil water saturation percentage, potassium and organic matter were determined in the laboratory using standard methods. Also slope, aspect and elevation maps were prepared in order to determine the topographic characteristics. Then, using one-way analysis of variance, the difference between the sites was investigated in terms of quantitative and qualitative characteristics of tragacanth and soil characteristics. Finally, using the Redundancy Analysis (RDA), the relationship between the environmental characteristics and the characteristics of tragacanth was investigated. Among the soil characteristics, the amount of organic matter, the percentage of clay, sand, the amount of gravel and electrical conductivity have significant differences in the studied sites. While potassium, pH and percentage of silt have no significant difference among the studied sites. Except for valine, magnesium, sucrose and galactose, the physical and chemical characteristics of tragacanth have significant differences among the investigated sites. Site 1 has the lowest amount of viscosity, calcium, sodium, fructose, proline and the highest amount of product and ash. Site two has the highest amount of potassium, phosphorus, arabinose, glucose, and proline. The third site has the highest viscosity, calcium and serine and the lowest sucrose and galactose. Site four has the lowest amount of ketira, potassium, phosphorus, arabinose, glucose, ash, serine and the highest amount of sodium and fructose. Also, about 90% of the changes are justified by the first axis of the RDA diagram and the variables of height above sea level (72%), soil alkalinity (42%), slope direction (36%), electrical conductivity (34%) and slope percentage (33%) were the most important effective factors in differentiating the different growth locations of A. parrowianus in Jalmabadan region. According to the results, the characteristics of tragacanth gum are influenced by environmental factors, and each of the characteristics of tragacanth gum are affected by certain environmental characteristics. From this, for various industrial purposes that certain characteristic of Katira gum is important, it is necessary that the effected environment in which the species grows or its gum is harvested should be in optimal conditions.

In a rangeland ecosystem, it is important to pay attention to environmental factors and their effect on the distribution and establishment of plants in order to plan exploitation. The purpose of this research is to investigate the relationship between the cover of some species and environmental factors in the north of West Azerbaijan province. For this purpose, in the period from mid-May to the end of June 2021, sampling of vegetation in eight rangelands sites with different vegetation combinations in Chaipareh and Khoy Counties in a systematic-random method with the establishment of transects and plots one square meter was done. In each of the rangeland sites, the percentage of rangeland species coverage was recorded. Topographical factors including elevation above sea level, slope percentage and geographical aspect of the range were recorded for each site. Soil samples were taken from each of the sites at five points from 0 to 20 cm depth and taken to the laboratory to measure soil parameters. The results of the use of detrended correspondence analysis (DCA) showed that the importance of the axes based on the specific value decreases from the first axis to the second and third axis, and as a result, the major contribution of changes in the distribution of plant species is related to the first and second axis. The results of DCA showed that the specific value of the first axis is (0.36) and the second axis is (0.23). Changes in species distribution due to soil and topography factors were investigated using the linear redundancy Detrended Analysis (RDA) method. The results of the redundancy analysis showed that the four axes explain a total of 83% of the variance of species composition changes by environmental factors, and therefore this indicates that the investigated parameters have a direct effect on the distribution of species, but because the first axis, it has the highest value (0.295) and is related to different soil parameters, and this indicates that the contribution of soil on the distribution of species in the study sites is more than the topographical parameters. The general results of this study showed that the distribution of rangeland species in the study sites is influenced by soil and topographical factors. It seems that the higher the altitude, organic carbon, saturated moisture, percentage of sand, silt and clay, the slope and direction of the range and calcium in the rangeland site, the more frequent the presence of some species such as Artemisia fragrans Willd, Antemis koteschyana Boiss, L., Cynodon dactylon and Ceratocephalus falcatus L. increases and as the amount of soil cations, electrical conductivity, lime percentage and soil acidity decrease, the abundance of some other species such as Phlomis olivieri Benth, Teucrium polium L., Alyssum minutum Schltdl. and Tanacetum polycephalum Sch.Bip is more common in study sites. Using the results of this research, the growth conditions of the existing species have been determined to some extent, and considering that some species have economic and medicinal value, if the user's goal is to use the species for planting of medicinal plants, it is recommended to pay attention to the soil and topography of the region if they are economic under the conditions of hand planting in similar areas.

The purpose of the present study was to investigate the phytoremediation of soils contaminated with heavy metals by microorganisms.

This study was conducted with a review-descriptive method on the studies conducted on herbal treatment.

The results of this study showed that many techniques have been developed to clean soils contaminated with heavy metals. Among these techniques, plant extraction (plant treatment) has been presented as an effective and cheap cleaning method, in which the absorption and collection of pollutants in plant tissues is considered. In this method, by harvesting plants from the soil, the pollutants are removed from the soil. In agricultural lands contaminated with heavy metals, the selection of metal-tolerant crops to remove pollutants from the soil can be a new strategy for land management. A number of cadmium accumulating species that have been reported based on the results of hydroponic and pot tests are species with high biomass, including corn, sunflower and Indian mustard for refining areas contaminated with heavy metals.

Various physical, chemical and biological methods have been suggested for the treatment of areas contaminated with heavy metals and other pollutants, which are mostly costly and uneconomical.

In previous sediment fingerprinting studies, optimization of tracer signatures are not considered. Therefore, with different composite fingerprints, the amount of contribution from different sediment sources can be different from each other. Accordingly, the optimal composite fingerprint was determined using an approach of multi-stage refinement of tracers and reduction of uncertainties in the Idelo watershed in Zanjan province. In this approach, the ability and conservative behavior of tracers to separate sources are evaluated using variability ratios, conservatism test, range test, and finally, the conservative composite fingerprint as optimal composite fingerprint was determined. The detected composite fingerprint based on the introduced approach was different from a composite fingerprint obtained from conventional methods. Also, based on the aforesaid approach the related contribution of the geologic units in sediment yield were estimated 49, 32 and 19 percent for young alluvial deposits, red gypsiferous marl and old alluvial clastic, respectively. These results were different from those obtained using conventional and old fingerprinting methods with 11, 85 and 4 percent contribution in sediment yield for the aforementioned geologic units respectively. Generally, these results highlight the importance of applying the approach of multi-stage refinement of tracers and uncertainty reduction in determining the optimal composite fingerprinting of sediment.

According to the studies, environmental factors can affect the secondary metabolites in plants, including the essential oil and its chemical composition. therefore, it is essential to understand the effect of these factors and which of the environmental factors have a more effective role on the quantity and quality of secondary compounds extracted from plants. the purpose of this study is to investigate and compare the effect of physical and chemical properties of soil and climate factors including temperature and rainfall on the chemical composition of the essential oil of the medicinal species of Stachys lavandulifolia in the northern and southern aspects of Bagh tilak rangeland of Sari.

The present research was conducted in Baghtilak rangeland, which is one of the summer pastures of Mazandaran province. in order to take samples, plant samples were taken according to the patchy distribution of the plant in the region, the aerial branches of the plant were randomly collected in three selected spots with three repetitions from the northern and southern aspects in late June.then the soil samples were also collected at the base of the plant from a depth of 0-30 cm. after the samples were transferred to the laboratory, the essential oils of the plants were extracted by clevenger and their composition was determined by GC and GC/MS.  Soil samples were also measured and evaluated based on existing guidelines. also, the required meteorological information was obtained from the Kiyasar meteorological station. in order to analyze the quantitative and qualitative data of soil and essential oil, the normality of the data was first checked using the Kolmograph-Smirnov test. after confirming the normality of the data, using the independent T-student test, the comparison of plant chemical compositions and soil quality indicators in the two northern and southern spects was performed by SPSS version 22 software, and the relationship between the plant chemical composition data was analyzed. It was done with soil quality indicators and climatic data by PCA principal component analysis method in PC ord5 space.

The results showed that the yield of essential oil in the southern aspect is significantly higher (P≤0.05) than the northern aspect. Also, among the compounds obtained from the essential oil, the compounds α-Pinene, α-Fenchene, p-cymene, Sabinene, Thymol, α-Thujene, Limonene, GermacreneD, bicyclogermacrene, cis-sabinene hydrate with the highest amount have a significant difference from they showed themselves in two aspects. the data obtained from principal component analysis into main components in relation to soil and climatic factors with essential oil compounds indicate that soil chemical factors including EC, OM, Mg, MWD, bulk density, sand and silt have a stronger relationship compared to other factors. also, in this analysis, soil factors such as apparent specific gravity, pH, Ca, sand, and the climatic factor of temperature have a positive and direct relationship with Sabinene, β-Pinene, Myrcene, α-phellandrene, p-cymene, Limonene, cis-sabinene hydrate compounds, thymol, Germacrene D, bicyclogermacrene and Phytol. also, soil factors such as EC, OM, bulk density, silt, Cao, P, Na, SAR and precipitation climatic factor have a negative and inverse relationship with Cyclofenchene, 1-8-Cineole, cis-ocimene, α- Terpineol, Terpinene-4-acetate, Bicyclo, Caryophyllene and Hexadecanoic acid were established.

Conclusion :

The result of this research shows that the quantitative and qualitative performance of medicinal plants is affected by factors such as the type of species, climatic characteristics, soil characteristics and topographical conditions, and the effect of environmental factors on the components of secondary metabolites can be due to the different effects of these factors on The biosynthetic pathways of these compounds in the plant. also, the present study showed that the yield of essential oil obtained from the Stachys lavandulifolia plant in the southern aspect of Baghtilak rangeland is significantly higher than the northern aspect, so it is recommended to consider more for the exploitation of this aspect.

In this study, the effect of the effluent from rainbow trout ponds was investigated on the yield, concentration and uptake of nitrogen, phosphorus and micronutrients on the silage corn in the Golpayegan research station for Husbandry and Agriculture in Isfahan. 45000 fish with an average weight of 10 ± 2 g were uniformly divided in 9 ponds (20 × 2.2 × 1.3 m) for six months. The research was conducted in a complete randomized block design with five treatments in triplicate. The treatments were included 1) irrigation with well water without any fertilizer as the control, 2) irrigation with well water and use of urea, triple superphosphate and potassium sulfate as the fertilizers, 3) irrigation with fish ponds effluents without any fertilizer, 4) irrigation with fish ponds effluents and use of the fertilizer, and 5) irrigation with fish ponds effluents with 50 percent of the fertilizer. Results showed that the use of fish ponds effluents significantly caused increasing in corn yield and concentration of zinc, cupper, nitrogen, phosphorus, manganese and iron (p<0.05). In addition, using fish ponds effluents with the 50% of chemical fertilizer led to increase corn yield by 44 percent compared to the control group (p<0.05). Moreover, the uptake of iron, zinc, copper and manganese by corn were increased significantly compared to the control group through use of fish ponds effluents water with fertilizer (p<0.05). The highest and lowest yield of corn was obtained in the irrigation with the effluent of fish ponds effluents coupled with chemical fertilizers and the control group, equal to 73.7 and 44.4 tons per hectare, respectively, which had significant difference with each other (p<0.05). Therefore, the use of fish farm effluents for production of corn not only increased the yield but also dramatically enhanced fertilizer utilization.