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

Qualitative modeling is one of the methodologies employed for assessment. However, skepticism about the outcomes of such models has led to a reduction in their consideration. Consequently, this study employs the qualitative model approach of PAP/RAC to predict and determine the status of water erosion risk in the Qarnaveh watershed. This approach is juxtaposed with the RUSLE model, and influential factors are identified using Bayesian Model Averaging (BMA) to enhance evaluation, delineate vulnerable zones more effectively, and propose viable water and soil conservation strategies. Research findings revealed a 20.56 Km2 difference in predictions between the two models. Nonetheless, a meticulous spatial examination of water erosion risk prediction maps from both PAP/RAC and RUSLE models demonstrates a spatial congruence of 67.74%, predominantly within the "very high" category. Furthermore, the analysis of influential factors (slope, lithology, land use, and vegetation cover density) on the erosion risk prediction map, employing the Bayesian averaging approach, underscores slope as the most significant determinant in the developed superior patterns. In the PAP/RAC model, it exhibits adverse effects in the "very low" category but exerts positive influence in the "moderate," "high," and "very high" categories. In view of the significant influence of slope across all categories, it is therefore necessary to carefully classify and assess regional characteristics for refined predictions. Consequently, based on research findings, the PAP/RAC model emerges as the most efficacious and straightforward qualitative model for estimating water erosion risk in data-deficient watersheds, with precise consideration of its influential factors aligned with Iranian context. This methodological approach, which integrates descriptive and integrative techniques, not only facilitates precise prediction, but also facilitates the formulation of effective water and soil conservation strategies, thereby contributing to the development of a comprehensive strategy for sustainable watershed management.

Gully erosion is one of the most important and destructive forms of water erosion, and there are ambiguities regarding its initiation and development. The study aimed to identify the soil properties and other factors affecting gullies of South Nazar Abad in 2021. After the field survey, based on the Google Earth images, gullied area boundary draw, 32 gullies were selected, and their location was recorded with the GPS. A surface soil sample was taken from head cut wall of each gully and general analyses were done. The gullies watershed boundaries and morphological characteristics including area, perimeter, and slope were extracted from the DM obtained from unmanned aerial vehicle (UAV) images. The general characteristics of the soil surface in the watershed of the gullies including canopy, bare soil, and residual percent were determined by 1 m x1 m plot. The gully length, width, and depth were measured and volumes were calculated. Modeling of factors affecting gullies was done using a multivariable linear regression model (step-by-step method) in MINITAB on 70% of observations. The relationship between the volume of gullies with gullies soil properties and watershed characteristics were investigated and a suitable gully development model (soil loss) was introduced. Also, in this research, 30% of the measured samples that were not used in the model construction were used for model validation. Percentage, RMSE, CRM, NSE, CD, MAE and drel statistics were used to determine model efficiency. Principal component analysis showed that EC, Na+, Cl-, K+, Erodibility, Mg++, canopy, bare soil, and SP characteristics had noticeable effect on gullies volume. Based on the results of the research and especially based on the Nash-Shutcliffe efficiency coefficient, no reliable model has been developed. Also, the presented model is valid based on the regression at the five percent significant level and according to the validation coefficients. The model with a correlation coefficient of 0.59 and four factors K+, bulk density, crop residues, and percent bare soil could explain 35% of the changes.Strengthening and restoring crop cover in the area is recommended.

The results of the research showed that 6 factors explain 69% of the variance of sustainable agriculture indicators, and awareness of natural resources, sense of responsibility for preserving the natural resources of the village, popular organizations in preserving natural resources, the quantity and quality of drinking water with a specific value of 4.504 and the variance explanation percentage of 16.085 are the most important factors in the evaluation of sustainable agriculture. In terms of water and soil resource protection indicators, variables of job satisfaction, acceptable income status, side incomes, income class gap and replacement of other resources in case of drought have a specific value of 8.547 and its variance explanation is 28.580. The regression results show that there is a significant relationship between sustainable rural development indicators and resource protection. With a beta coefficient of 798, the economic dimension has the greatest impact. Also, the correlation level of the studied factors with resource protection was positive and high. Based on cluster analysis and independent T, most of the villages are in poor conditions.

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.

Desertification is one of the most significant process of land degradation in all the world, especially in arid and semi-arid regions. In the United Nations Convention to Combat Desertification report (1994), Desertification is land degradation in dry-lands, resulting from various factors, including both climatic variations and human activities. This process is always associated with soil degradation, pollution and reduction of water resources, vegetation and other biological resources in natural and ecological conditions. Therefore, determining the main factors of this process can be very effective in proper land management. This research was conducted with the aim of zoning sensitivity areas to the desertification intensity based on ESAs model and providing management strategies based on scenario planning in Razavi Khorasan province.

In this research, five criteria such as climatic quality, soil, vegetation, erosion and management (human activities), and 20 indicators such as soil texture, soil depth, rock fragment, parent Material, vegetation density, fire risk, rainfall. drought, water and wind erosion, land use change, mining, livestock density in pasture, etc. were used. were used. Scoring and weighting of the indicators was done using a questionnaire and based on the expert opinions of specialists, executive managers and field experiments. The designed questionnaire included 21 questions, that classified in the form of 5 criteria of soil, climate, vegetation, erosion and management, which were distributed among the statistical population in two rounds. Management strategies and policies were also obtained in the Delphi method in the form of expert panels (brainstorming).

The results showed that the vegetation criteria with indicators such as the reduction of vegetation, the increase in the risk of fire in pastures and forests due to the continuous droughts of the past two decades and the increase in the intensity of wind and water erosion, with a value of 1.419, has had the greatest value and importance in expansion the intensity of desertification. After that, factors such as human activities (management), climate, erosion and soil respectively have had the greatest impact on the sensitivity areas to desertification in Khorasan Razavi province. In terms of the critical situation, the high percentage of the areas in the northwestern regions such as Quchan and Chenaran township due to the impacts of drought, severe changes in land use and water has become desertification. In the central, eastern and southern parts due to drought, land use changes, lack of optimal land management and wind erosion, main reason has been the expansion of desertification. Besides that, all the townships of Khorasan Razavi province have fragile conditions. This issue can be considered as an important and serious warning for the future management of Khorasan Razavi province. Therefore, in order to provide effective ways to deal with the intensity of desertification, based on the opinion of experts and specialists in the current research, by considering only the priority indicators of each of the criteria, the number of 10 cross matrix of the important indicators of each of the criteria, 20 scenarios, 6 strategies and more than 40 strategies were obtained. So that, by using the suggested strategies could be planned and managed according to regional and local conditions, to reduce the intensity of desertification.

The ESAs model uses four criteria of management, vegetation, soil quality and climate mainly to evaluate areas sensitive to desertification. So that, in this research, due to the importance of the erosion (water and wind erosion), for zoning map of sensitivity areas to desertification were used. In order to provide management plans (strategies and policy), to reduce and combat desertification in Khorasan Razavi province, management strategies such as; -sustainable management of vegetation, - water resources management and watershed management, - soil management, - livestock management and reduction of environmental hazards caused by human activities, -education, promotion and culture and sustainable management. Therefore, in this research, only the important strategies and policy that can provide a comprehensive vision of land management in Khorasan Razavi province, were suggested.

Soil conservation requires a suitable model and framework to assess soil erosion and sediment yield based on land use scenarios. Therefore, the present study was conducted with the aim of investigating the sensitivity of the G2 model to the soil erodibility factor in the Kasilian representative watershed in the period of 2001-2021. Points such as the use of global soilgrid database and comparison with soil sampling data, removal of soil erodibility in rocky areas, and removal of outlier data created by systematic error were included in the current research. The results showed that qualitatively, the rate of soil erosion estimated based on each of the mentioned points was completely in the minimum category. The initial results of the soil erosion rate obtained from the global soilgrid database and the IDW method were 4.31 and 4.33 t ha-1 y-1, respectively, which were not significantly different based on the independent t test. But the effect of other changes, including removal of soil erodibility in rocky areas and removal of outlier data on the change of soil erosion estimates using one-way ANOVA and Duncan's tests were significant (P<0.01). The estimated average rate of soil erosion in the watershed after following the mentioned points was reduced by more than 65% compared to the initial results and became closer to the data of erosion plot.

Heavy soil erosion and sedimentation at the watershed level can trigger intense environmental consequences. This research proposes a modeling technique to estimate changes in incremental soil erosion over time and evaluate the effect of vegetation cover on soil erosion in critical areas. For this, the study employed the Water World Policy Support System (WWPSS) for simultaneous modeling of changes in vegetation cover and soil erosion. Changes in vegetation cover from 2000 to 2020 were studied by extracting data from the model databases received from MODIS VCF satellite images. The study further used maps and calculations of the run model to measure the amount of net soil erosion (erosion minus sedimentation in the same place) and subsequent change in its level under two baseline (before loss of vegetation cover) and current (post-vegetation loss) situations. It was found that the average percentage of grass-pasture cover in the studied watershed has declined from 78.36% (under the baseline situation in 2000) to about 47% (under the current situation). The average amount of net soil erosion in the two sub-watersheds of Aji Chai and Marduq Chai has increased by more than 277% and 33%, respectively, signifying them to be the most vulnerable sub-watersheds (among all the four studied sub-watersheds) to soil erosion at critical areas. Overall as expected, a 40% loss of vegetation in the studied watershed has provoked adversely hazardous consequences during the studied period while cumulatively leading to over 8 million tons of soil deterioration in 15 years. The proposed method is assumed to be advantageous by providing quantitative and rapid environmental assessments that entail precise quantification of environmental consequences like soil erosion.

Soil erosion in upstream areas has an important role in sediment entry to dams. Sediment accumulation result in decreases of dam service life, environmental problems, and acceleration of floods. In addition to climate, topography, vegetation cover and land management, soil erosion amount depends on soil characteristics and its erodibility.  In this research, soil erodibility factor and its special distribution was assessed by using of various pedotransfer functions including KUSLE, KEPIC and KDg in a part of Aliabad watershed of Roodbar, located at upstream of Sefidrood dam. The soil samples were collected from 0-10 cm depth and size distribution of soil primary particles, organic carbon content, and aggregates stability were measured. The KUSLE was calculated in two ways without codes of soil structure and permeability, and with respective codes, named as KUSLEi, and KUSLEf, respectively. The results showed that studied soils generally had coarse texture, and KUSLEi was estimated low to moderate in range of 0.11 to 0.040 ton h MJ-1 mm-1. The least soil erodibility factor belongs to KDg, which was significantly lower than the soil erodibility factors calculated by other pedotransfer functions. All of the calculated erodibility factors had significant negative correlation with mean weight diameter of aggregates which KUSLEi and KDg showed the most and least correlation with MWD, respectively. All of the erodibility factors had moderate spatial dependence, however KUSLEi showed strong spatial dependence. Therfore, it generally can be concluded that zoning map of KUSLEi  generated via kriging can be a suitable indicator of the studied soils erodibility.

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.

Today, the destruction of natural resources is one of the most important and serious challenges facing development programs. Soil erosion is among the processes that directly and indirectly threaten our country's soil and water resources. Water erosion appears on the earth in different forms, one of the advanced forms of which is the gulies. Gully erosion is one of the important processes of soil destruction, which in different climates causes significant soil losses and the production of large amounts of sediment. The purpose of the present research is to investigate the morphological characteristics of the gullies of Khuzestan province and the role of its influencing factors in the expansion of the gully areas.

 First, by collecting available data and comparing it to satellite image and other data, the province's gullies have been defined. The first field visit focused on verifying the integrity of these areas and correcting the gullies boundaries. The total area of Khuzestan province approximately is 64000 km2 in the dry desert climate, and more than 33,862 ha of it is under the influence of gully erosion. The hot semi-arid climate also covers approximately 12,1% of the province and 16,116 ha have experienced gullies erosion. After determining the area of gullies and dividing the areas above and below 500 ha, due to the difference in appearance, topography, and vegetation, 2 and 1 representative areas were selected from the hot-dry desert and hot-semi-arid climates, respectively, and 2 replicates were selected from each representative. Longitudinal and cross-sectional profiles of representative and replicated gullies were drawn and after soil sampling, all morphological features of the gullies were measured.

According to the results, most of the gullies of the province have been created in the plains with a low slope with deep soil and loamy sand texture, silt or silt loam with pasture, and sometimes agricultural land and U-shaped cross-section. Darkhazine and Sharif gullies, with 1260 and 912 cm, and Darkhazine gullies with 420 cm value have the maximum width of top, bottom and depth in the cross-section of 75%. Also, the gullies of Choghazanbil, Darkhazine and Choghazanbil with values of 30 cm have the lowest depth, top and bottom width in the cross-section area of 75%. The overall profile is scratched, and in terms of depth class, they are in the category of medium-deep gullies with a vertical top.

Intrinsic characteristics of soil, formation and geological type, climate, intensity of rainfall as natural factors, and destruction of vegetation, land use change and the lack of proper management, unprincipled road and bridge construction operations, construction and installation of oil facilities and electricity bars as human factors have played a role in the process of gully expansion. However, the diversity and change of the number and degree of influence of different factors from one point to another and the difference in their participation in the formation and expansion of the gully are based on the environmental conditions of the land. These conditions require that more research be carried out to identify as many factors as possible in the phenomenon of gully erosion and their participation in the formation and expansion of this phenomenon in different places and with different environmental conditions.

Soil erosion reduces soil fertility, weakens vegetation, deposits sediments, deforms and fills rivers due to floods, and reduces water quality. Therefore, the precision of soil erosion estimation is essential for proper watershed management. Among all-soil erosion prediction models proposed for storm-scale, one of the most widely used is the Revised Universal Soil Loss Equation (RUSLE). Due to the importance of the LS factor in small watersheds with complex topography on the final estimation of the RUSLE model, in this current research, the soil erosion results were obtained from four different LS factor methods were investigated.

Soil erosion obtained by the RUSLE model and four methods of LS factor calculation including the Moore et al. (1991), Desmet and Govers (1996), Boehner and Selige (2006), and manual method; for 38 storm events recorded during 2011 to 2019 for the Galazchai Watershed, West Azerbaijan Province, Iran.

The results showed that the mean of the topographic factor for Moore et al. (1991), Desmet and Govers (1996), Boehner and Selige (2006), and manual methods were 9.91, 5.26, 13.29, and 6.54, respectively. Comparison analysis of the methods used by the manual method showed that the ratio of the estimated mean values varied from 0.80 to 2.03. Comparing the mean of LS maps with the manual method as the basic method and calculating error estimation found that Desmet and Govers' (1996) method was more successful in the LS factor estimation, resulting in better estimation of soil erosion for the study storm events. Despite the difference in soil erosion values, almost the same spatial pattern was observed in all methods.

Analysis of the results obtained from different LS factor methods in the Galazchai Watershed verified the significant effect of the studied methods on the estimated soil erosion. Therefore, soil erosion studies need to select an appropriate method to achieve precise soil erosion to prevent errors and minimize uncertainties. Incorrect estimation of soil erosion leads to erroneous management of watersheds and loss of money and energy. The present study is new in term of comparative evaluation of one of the sensetive factors in USLE and its different versions on the estimated storm-wise soil loss at the watershed scale. It is also innovative in viewpoint of focusing on the necessity of selection of appropriate computational methods for the local managers and experts. Extensive studies are recommended to investigate other methods of calculating LS, and even other RUSLE factors at different scales are recommended for a better conclusion.

The effects of weathering and erosion on Quaternary rocks and deposits depend on several factors, some of which are related to the nature of the rock and other factors are related to the external environment. Investigating all of the erosive factors is difficult and complex, therefore, the effective factors should be prioritized and taken into account in order to be able to determine a statistical relationship between the erosive factors and sediment statistics. Investigating the weathering and erodability of rock units is very important because of scientific and experimental knowledge of the rock's erodability in the region and as a result, their ranking and also their resistance to erosive factors can be a great help in evaluating the erodibility of rocks and for decision-making about the erosion control project in the region. For this reason, this study was conducted with the aim of investigating the weathering and rating of the rock mass resistance of geological formations to erosion in the West Islamabad region.

In this research, the role of weathering was investigated with the Lewis Peltier method using isotemperature and isohyetal maps that were produced in the ArcGIS environment using climatic data. Various parameters can be effective in weathering processes, the most important of which are average temperature and annual precipitation, and Peltier models are also created based on these two parameters. For analyzing the resistance of stone units, the inherent characteristics of the parent materials which include mineralogical composition and texture were used. The types of stones and formations in the region were identified using geological maps and Google Earth. In the last stage, the analysis and interpretation of the results and finally the classification of rocks and formations in the study area were done using a qualitative method.

According to the Peltier diagram and the precipitation and temperature of the study area, the results showed that the prevailing regime in the area is moderate chemical weathering. Also, out of the nine morphogenetic states in the Peltier model, two semi-arid and savanna states occur in the climatic conditions of the region. The study area is diverse in terms of rainfall due to its topography condition. The highest rainfall and the lowest temperature belong to the northern part of the region, and the highest annual rainfall is about 700 mm, which is considered one of the Savan regions in terms of morphogenetic regions. The dominant feature of the Savan region can be called the activity of runoff and the moderate influence of the prevailing winds in the region. Other parts of the study area are considered as part of the semi-arid region due to rainfall and average temperature. The most important geomorphodynamic features of these areas are the influence of wind and moderate to intense running water activity. Water erosion occurs due to heavy rainfall in an area. So, if the amount of runoff is high, water and river processes can be intensive, but this situation in the diagram may be somewhat misleading because in areas with high rainfall and high temperature, this type of erosion is weak. Pelletier probably drew this diagram based on the vegetation, precipitation, and temperature condition, because in areas with high temperature and high precipitation, rich vegetation is formed, which prevents soil erosion due to the presence of foliage and an extensive root system. The erodibility of rock and sedimentary units has been divided into six classes considering lithological factors. Each of the sedimentary units that have the highest level of sensitivity and erodibility is classified in the sixth class, that is, very weak, and according to the degree of sensitivity of the units located in the next classes, it decreases with the decrease of the class number, so that the facies located in the first class has the lowest sensitivity. According to the evaluation carried out in the study area, the least erosivity is related to limestone outcrops. Dolomite sensitivity changes from one to four in different areas, and the most sensitivity is related to discontinuous debris deposits, including The types of alluvial sediments of river beds and floodplains, the alluvium and alluvial cones are related to Qt2 and have a level of sensitivity of 6. The comparison of the results of the classification method presented in this research with the amount of observed sediment yield indicated that considering other effective parameters on erosion, it can be trusted with a high and acceptable level of confidence and it can be used to rate the stone units and formations susceptibility to erosion.

As a result of weathering processes, the connected rocks will change to large and small separated materials. These materials rarely remain fixed on the slopes and they move on the slopes due to the gravity and the weight of the mass of materials or under the influence of the transport processes and are transferred to the foot of the mountain in different forms. In the West Islamabad region, due to the heavy rainfalls, mostly moderate chemical weathering occurs. Chemical weathering includes a set of chemical processes and interactions as a result of which substances in the atmosphere such as water, carbon dioxide, and oxygen show a chemical reaction against the minerals in nature, and as a result, new materials and minerals with different characteristics from the primary minerals will be created. Based on field observations and studies, dissolution is one of the most important chemical reactions common in the region. Considering that the dominant regime in the study area is chemical weathering and more than 90% of the area is in the semi-arid area, which is affected by the moderate to the severe activity of running water, as well as the inherent sensitivity of the rocks in the area to erosion, various types of erosion can be seen in the area, which makes it necessary to have suitable soil conservation programs in the region.

Fingerprint method determines the contribution of sediment in the land units. In this method, a suitable composite (set) of diagnostic properties and a multivariate mixing model are employed to estimate the relative contribution of sediment sources to sediments transported to watershed outlet. The purpose of this study was to determine the contribution of different sediment sources in the Beheshtabad watershed with 308 km2 area. For this purpose, 36 soil samples were taken from sedimentary sources (0-5 cm depth) and 10 sediment samples from watershed outlet. In each of the sources, initial traces were evaluated by Kruskal-Wallis test. In the second stage, an optimal combination of tracers for each source was obtained using diagnostic analysis functions, and finally, in the next step, the contribution of each user in sediment production for each sampling method was determined using Collins et al. model. The contribution of agricultural, rangeland, rainfed and residential land use was equal to 67.88, 7.63, 19.40, and 5.10 %, respectively. Results showed agricultural has maximum share in sediment with 67.88percent. Due to the fact that the contribution of sediment in agricultural lands in the study area is high, special attention should be paid to the way of agricultural operations.

It is the main objective of the present study to identify the factors affecting farmers’ unwillingness to convert their sloping agricultural lands into orchards. The study is a descriptive and survey one using a statistical population of 250 farmers in Galikesh County, Golestan Province, who rejected the idea of changing their sloping crop lands to orchards. For this purpose, 150 farmers were selected using the multi-stage random sampling method and the Krejcie and Morgan Table and a questionnaire was used to collect data in 2021. The content and face validities of the questionnaire were confirmed using the opinions of extension, soil protection, and horticulture experts at Golestan Agricultural Jihad Organization. The validity of the questionnaire was determined using Cronbach's alpha method to obtain a coefficient of 0.85 and data analysis was performed using SPSS19. Based on the results obtained, the following 12 factors affected farmer unwillingness listed in a descending order of significance: non-availability of production tools, farmers’ subculture, complex cultivation operations, lack of government support, investment cost, lack of confidence in experts, lack of knowledge, non-compliance behavior, non-observable operation results, sparsely distributed agricultural lands, uneconomical results, and lack of confidence in responsible government agencies. These parameters explained about 75.189% of the total variance among the factors involved. Also, the results indicated that extending low-interest loans, high-quality and high-yield seedlings, water availability, and tools and implements to farmers as well as communication with influential local leaders and trustees to solicit their opinions during the various stages of protection operations may be suggested as helpful in convincing farmers to accept the conversion.

Soil erosion followed by sediment production is the most important phenomenon that causes soil and environment degradation in many areas and is increasing. Sediment fingerprinting is a method to identify sediment sources and determine the contribution of each source to sediment production. The present research was carried out to evaluate the relative erosion sensitivity of lithological units and to determine the contribution of each unit in bed sediment production using geochemical properties in the Vaz River located in Mazandaran province. The 33 soil samples were taken from the whole watershed and one sediment sample at the outlet of the watershed. Then, five tracers of B, Al, Sc, Mo, and Sn were selected as the optimal combination using three statistical tests range tests, Kruskal-Wallis, and discriminant function analysis. Finally, using optimal tracers and a combined multivariate model, the contribution of lithological units with very high (A), high (B), medium to high (C), and medium (D) sensitivity in bed sediment production were obtained using FingerPro statistical package and R software. The results showed that the contribution of lithological units with very high (A), high (B), medium to high (C), and medium (D) sensitivity in bed sediment production were 24.23, 50.77, 15.62, and 9.36%, respectively. Then, the specific contribution of each sensitivity class was also calculated to remove the effect of area on the results. The Qal lithological unit including the Quaternary sediments in the river bed and banks with very high sensitivity to erosion (A) and a specific contribution of 0.0807 % per hectare had the maximum contribution in bed sediment production in Vaz River.

Changing land use may have a major influence on physical, chemical, and biological soil properties with a consequence for soil functioning and productivity. Abandonment of agricultural lands is actually a kind of restoration of these lands to their original natural conditions, which is often done through human intervention. Soil restoration after land abandonment is a complex phenomenon. The pastures of our country are typically cultivated in rainfed methods, and the use of agricultural inputs such as animal manure, poisons, and chemical fertilizers is not very common. Therefore the continuous cultivation of a product and the lack of use of agricultural inputs causes a gradual decrease in fertility and increase erosion. Hence, after years of cultivation, the production potential decreases, and the land is abandoned.
This study was conducted to determine the effects of land abandonment on some physical, chemical, and biological soil properties in the 0-20 and 20-40 cm depth at three different sites including Lal Abad, Qaleh Kohneh and Chalab-e Pain, using 2×2 factorial layout arranged in a completely randomized design (CRD) with three replications. The physical, chemical, and biological characteristics of the soil were measured by conventional laboratory methods. Electrical conductivity of saturated paste extract (ECe) with electrical conductivity meter device in saturated paste extract, pH of saturated paste with pH meter device, and bulk density by cylinder method were determined in the samples. The amount of dispersible clay (DC) was determined by the method of Gee and Bauder and the Mean Weight Diameter (MWD) was determined by the method of the wet sieve. The amount of absorbable phosphorus by extraction method and total soil nitrogen by Keldahl method were measured in the samples. The amount of soil organic carbon (OC) in the samples was determined by the method of Walkley and Black. Mineralization of organic carbon (soil respiration) (Cmin) and metabolic quotient (qCO2) were obtained by validated and conventional methods.
 The results showed that the abandonment of agricultural lands significantly increased the MWD and reduced the amount of dispersible clay. Bulk density also decreased due to the abandonment of agricultural land in all areas except the Qaleh Kohneh area. The results of the analysis of the chemical characteristics of the soil indicated a decrease in soil pH in all areas and depths, except in the Qaleh Kohneh area. The biological results also showed that the abandonment of agricultural lands caused the change in biological characteristics. Abandonment of agricultural lands in all three regions led to an increase in microbial biomass carbon and soil microbial respiration. High microbial respiration in abandoned lands is probably related to more organic carbon in these soils. Loss of soil organic matter due to cultivation and improper soil management is often the main reason for reducing soil respiration in agricultural lands compared to abandoned lands.
Changing land use from agriculture to abandonment improved the physical, chemical, and biological indicators of soil quality, especially the surface layer of the soil, which ultimately led to the improvement of soil quality in all the studied areas. It can be concluded that the release of agricultural lands has increased soil health by increasing the carbon input into the soil, improving the soil aggregates, and improving the microbial activity of the soil.

Sustainability in agriculture at regional scale is about balancing food security with maintaining environmental health. Therefore, agricultural operations are sustainable when they maintain the health of the environment, the interaction between plant and animal production, social acceptance and economic benefits (Kumaraswamy, 2012). Excessive use of environmental resources and excessive consumption of chemicals in agriculture have caused environmental problems and reduced sustainability (Quintero-Angel & Gonzales-Acevedo, 2018). Therefore, it is necessary to study the patterns of energy consumption and efficient use of energy in agriculture, which is one of the basic principles in sustainable agriculture. Emergy analysis, as suitable tool for this purpose, is used in the various ecosystems (Odum, 2000; Brown & Ulgiati, 2004). Emergy analysis is able to determine the degree of sustainability of connected ecological and economic systems. Emergy indices are effective tools for integrating ecological-economic systems and make it possible to measure and compare all aspects of these ecosystems (Patterson et al., 2017). The purpose of this study was to evaluate sustainability indices for rapeseed (Brassica napus L.) production systems using emergy indices and provide suggestions for sustainable product of the crop in Kalaleh county. 

In this study, production systems of rapeseed were evaluated using emergy sustainability indices in Kalaleh County (Golestan province), during the period of 2018-2019. For this purpose, 50 rapeseed fields were selected as Cochran equation. First, the spatial and temporal boundaries of the system were defined (Odum, 1996; Odum, 2000) and resources were divided into four categories: renewable environmental resources, nonrenewable environmental resources, purchased renewable resources and purchased nonrenewable resources (Amiri et al., 2019). Emergy flow for each input was multiplied by their transformities in joules and grammes (Odum, 2000). Finally, emergy indices such as renewability, emergy yield ratio, emergy self-support ratio, environmental loading ratio and emergy sustainability index were calculated and evaluated in rapeseed production systems. 

Total emergy input for the rapeseed production was estimated as 1.64E+16 sej ha-1 year-1. In rapeseed production, dependence on environmental and nonrenewable inputs was higher than purchased and renewable inputs. Soil erosion emergy was the largest emergy inputs of the total in rapeseed production system with share of 47.31%. Also, fossil fuel emergy was the largest emergy inputs of the purchased with share of 38.41%. In this research, we calculated the transformity equal to 2.59E+05 sej j-1, specific emergy equal to 7.33E+09 sej g-1, emergy renewability equal to 8.16%, emergy yield ratio equal to 2.17 and emergy investment ratio equal to 0.85. Also, emergy self-support ratio, standard environmental loading ratio, modified environmental loading ratio, standard emergy sustainability index, and modified emergy sustainability index were estimated 0.54, 13.81, 11.27, 0.16 and 0.19, respectively. Despite the higher contribution of environmental resources in the rapeseed production system, the high share of soil erosion as a non-renewable input along with the unreasonable consumption of some nonrenewable purchased inputs, such as fossil fuels, led to a decrease in renewability and an increase in environmental load. Based on evaluation of emergy indices, rapeseed ecosystem had the high production efficiency and resource consumption efficiency and it had the great potential to increase economic productivity. However, rapeseed production in Kalaleh county had low environmental and economic sustainability. The implementation of conservation tillage methods and the modernization of machinery can contribute to a reduction in the consumption of nonrenewable and economic inputs in rapeseed production ecosystems. This reduction in input consumption not only alleviates environmental pressure but also enhances sustainability. By prioritizing the use of renewable environmental inputs and minimizing the utilization of nonrenewable and economic inputs, the emergy sustainability index can be improved.

The rapeseed ecosystems exhibited high production efficiency and resource consumption efficiency, along with significant potential for increasing economic productivity. However, despite the substantial contribution of environmental resources in these systems, the prevalence of soil erosion as a significant portion of the total emergy input resulted in a decline in renewability, an escalation in environmental burden, and ultimately a decrease in sustainability. It appears that enhancing management methods to minimize the consumption of nonrenewable and economic resources would be effective in bolstering the environmental and economic sustainability of rapeseed farming ecosystems in Kalaleh county.

One of the functions of rangeland ecosystems is to prevent soil erosion and increase nutrient retention capacity. The present study was conducted to highlight the effect of Rangelands degradation on the preservation of Mg, Ca, N, P, and K elements in the soil and emphasize the role of rangeland plants in preventing the wastage of these elements in the rangelands of the Salman watershed in Qom. For this purpose, a sample was taken from the soil of the habitat in each work unit, in the classes of poor and good rangeland conditions, representing degraded and non-degraded rangeland, respectively. Then, the amount of eroded soil was determined from each unit using the modified PSIAC (MPSIAC) model. In the following, the amount of loss of nutrients using the results of soil analysis and related relationships, was calculated and based on the replacement cost method; by estimating the alternative fertilizer, the monetary value of maintaining nutrients by the ecosystem was calculated. The results showed that the destruction of the rangeland ecosystems of the region causes erosion equivalent to 35.68 tons per hectare per year, which damages the functional services of the ecosystem at an annual cost of 11.6 billion rials (11606427781 rials) by reducing the nutrients of the soil. Also, each hectare of good rangelands in the region can prevent the loss of nutrients with an approximate value of 335.6 thousand rials. The results indicate the effective role of the rangeland ecosystem in controlling erosion and preventing the loss of soil nutrients. What is certain to emphasize more the role of rangeland ecosystems in soil erosion control; it is recommended that are also estimated the amount of soil erosion by other common methods, such as the global model of soil erosion (USLE), EPM, etc., and the results are compared with each other in future research.