Soil science
S.H.R. Sadeghi; M. Kalehhouei; A. Noori; N. Naderi Marangelu; M. Havasi; A. Payfeshoordeh; M. Khairparast; S. Mostafaei Younjali; Z. Pirooznia; M. Hamzeh Bibalani
Abstract
Introduction
Soil erosion is considered as one of the critical threats to the conservation of water and soil resources. However, until now, its various components, including its spatial changes, have yet to be given due attention. In order to implement soil erosion control and conservation programs ...
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Introduction
Soil erosion is considered as one of the critical threats to the conservation of water and soil resources. However, until now, its various components, including its spatial changes, have yet to be given due attention. In order to implement soil erosion control and conservation programs in the watershed, it is essential to have basic information leading to know and accurately identify the factors affecting the degradation of soil and water resources. Meanwhile, the CORINE model has been considered as one of the practical models for estimating soil erosion and displaying the spatial distribution of soil erosion with easy and accessible inputs. The CORINE model developed based on the Universal Soil Loss Equation (USLE) was therefore employed in the present study in the GIS environment to determine the potential and actual erosion risks of the Brimvand Watershed in Kermanshah Province, Iran.
Materials and Methods
The main associated factors of soil erosion, viz. soil erodibility and erosivity, such as slope, vegetation, depth, texture, and percentage of gravel, were collected, compiled, and ultimately classified in the ArcGIS software. The Fournier index (FI) and FAO-UNEP drought index (DI) were used to prepare the input maps. The Fournier index reflects the performance of the soil erosive agent. In other words, it shows the role of rainfall on soil erosion. The FAO-UNEP drought index shows the simultaneous performance of evaporation and precipitation on soil erosion of a region. The potential soil erosion risk was obtained by combining slope, erodibility, and erosivity layers. In addition, the actual soil erosion risk map was determined by combining the vegetation map and potential soil erosion risk.
Results and Discussion
Based on the results of the vegetation distribution in the region, the use of rainfed and abandoned lands had the largest area in the watershed, with an occupation percentage of 65.48%. Furthermore, the rangeland and forest areas, with respective coverage of 29.65 and 4.87%, stood in the second and third priority from the viewpoint of the area. The region has varying slopes, but more importantly, it has a low slope. Soil texture, depth, and gravel content significantly affect the area's erosion. The soil depth in a large part of the watershed, especiallywith a slope of less than 4% is more than 65 cm where it is mainly covered by abandoned and rainfed lands. In the studied area, the depth of the soil decreases with height increase, which indicates that the high slopes of the area are dominantly outcrops. Most of the area has gravel contents between 10 and 40%. The erosion potential of the region is not that much high because of the desired features of the affecting factors. According to the potential soil erosion risk, it was determined that about 65.57, 23.62, and 10.81% of the area were classified as intermediate, low, and high erosion potential, respectively. Further, the actual soil erosion risk was categorized as low, intermediate, and high with respective areal coverage of 53.83, 15.53, and 30.64%. It is therefore implied that the amount of erosion and sediment transfer will increase if the land cover in the watershed is declined. This indicates that the erosion rate was highest in hilly areas due to lack of vegetation and soil with loamy texture. Accordingly, to curb soil erosion and prevent its associated adverse effects in the Brimvand watershed, it is strongly suggested to use lands based on their capability and potential, maintain the present cover status, and carry out management plans to restore vegetation.
Conclusion
Soil erosion remains one of the most critical challenges in watersheds, and its neglect can lead to various problems for the beneficiaries. In light of this, the present study aimed to address this issue by employing the CORINE model to assess potential and actual soil erosion in the Brimvand Watershed of Kermanshah Province, Iran. The research findings reveal the pivotal role of vegetation in mitigating soil erosion. Notably, areas with gentle slopes, which are inherently susceptible to erosion, benefit significantly from vegetation cover, leading to a noticeable reduction in erosion. However, the loss of this protective cover can trigger a rapid increase in soil erosion and subsequent loss of valuable soil resources. By shedding light on the spatial distribution of soil erosion, this study emphasizes the importance of preserving and promoting vegetation in the watershed to ensure its long-term sustainability and safeguard the well-being of those who depend on it. Therefore, land utilization should be planned based on capacity and potential of the land to curb erosion and avoid its detrimental impacts in the Brimvand Watershed. In addition, not only the current cover situation has to be maintained but also the vegetation conditions have to be improved through the implementation of managerial and reclamation plans leading to managing soil erosion.
Irrigation
Seyed Hamidreza Sadeghi; Mohammad Tavoosi; Somayeh Zare; Vahid Beiranvandi; Hengameh Shekohideh; Fatemeh Akbari Emamzadeh; Marjan Bahlekeh; Faezeh Khorshid Sokhangoy; Reza Chamani
Abstract
IntroductionCurrently, many disasters threaten the health of ecosystems. The pressures caused by extensive human interventions and the unprincipled exploitation of natural resources have led to the degradation of natural resources and the structure and functioning of ecosystems. Hence, evaluating the ...
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IntroductionCurrently, many disasters threaten the health of ecosystems. The pressures caused by extensive human interventions and the unprincipled exploitation of natural resources have led to the degradation of natural resources and the structure and functioning of ecosystems. Hence, evaluating the consequences of human intervention in nature and meeting the growing need of humans to receive diverse services has made it necessary to evaluate the performance of watershed ecosystems in providing different services. Healthy watersheds play an important role in providing a wide variety of ecosystem services. Therefore, watershed health monitoring and evaluation is vital for the conservation of ecosystems and achieving the optimal level of services. In such a way a suitable collaborative and executive approach is established between research and watershed management. In this connection, watershed health analysis can provide valuable help in achieving the goals of integrated management of watersheds and, of course, the balance between the needs of human societies and ecosystems. However, the assessment of the health and sustainability of the watershed affected by human activities has not been sufficiently documented yet.Materials and MethodsThe current pilot research has evaluated the health of the Shiraz Darwazeh Quran Watershed in Fars Province, Iran, and the effect of existing watershed management structures in the region on the health of the watershed with a focus on floods. For this purpose, 36 key criteria from a set of climatic, anthropogenic, and hydrologic factors were identified based on the conditions of the region and the analysis of the flood occurrence process in the watershed. The selected criteria were then categorized into the three indices of pressure (P), state (S), and response (R). After screening the selected criteria in exploring the conceptual approach of pressure, state, and response (PSR), the health status was evaluated in two cases with and without watershed management structures.Results and DiscussionThe results showed that the health condition without considering the watershed management structures was at average conditions with health index of 0.55. In addition, the results of the watershed health assessment verified the non-significant effects of stone and mortar structures on improving watershed health. So that, the health conditions was remained at average status with health index of 0.53. Therefore, it can be acknowledged that the existing watershed management structures, due to the limited both number and spatial coverage, have not been able to noticeably affect the improvement of the general conditions of the watershed, despite the effect on the factors affecting the health of the sub-watersheds where the structures have been constructed. The spatial changes of the calculated variables showed that the abandoned lands, time of concentration, area under military activities, surface of sensitive formations to erosion, high density of the drainage network, density of the roads, areas of regions with high potential in producing runoff and sediment, and size of the residential areas were the most important factors affecting the health situation of the Darwazeh Quran Watershed.ConclusionAccording to the results of the analysis of the indicators and criteria considered in evaluation of the health of the Shiraz Darwazeh Quran Watershed based on the PSR approach, it was found that the watershed had an average health status. Therefore, it can be acknowledged that the existing watershed management structures have not been able to impose a noticeable effect on the prosperity and improvement of watershed health conditions. In general, it can be said that abandoned lands, short concentration time, military activities, the presence of formations sensitive to erosion, high density of drainage network and road, and the potential of high runoff and sediment production, and the size of residential areas are among the most important factors affecting the declining the health of Darwazeh Quran Watershed. Therefore, it is necessary to pay further attention to the aforesaid factors by conducting periodical monitoring with more comprehensive data, in time and also analyzing the trend of relative changes of the indicators in order to explain the adaptive and intelligent management of the watershed. The necessary measures should also be taken into account simultaneously. Therefore, it is suggested to turn the weak points of the region into strong points by applying bioengineering measures and use the opportunities in the region such as the potential of tourism and ecological features in order to improve the health status of the watershed.
Soil science
S.H. Sadeghi; A. Jafarpour; M. Farajolahi; D. Khatibi Roodbarsara; M. Moradi Sefidcheghayi; M. Zabihi Silabi; M. Khosravi; E. Kolani; B. Mohammadi; M.J. Adibi; H. Azarniya
Abstract
Introduction: One of the most important causes of land degradation and reduced fertility is soil erosion, a severe threat to human welfare and food security. With the intensification of erosion and sediment transport in the watershed, water quality is reduced, and sediment production and flood risks ...
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Introduction: One of the most important causes of land degradation and reduced fertility is soil erosion, a severe threat to human welfare and food security. With the intensification of erosion and sediment transport in the watershed, water quality is reduced, and sediment production and flood risks are increased. The consequences of soil impoverishment cause irreparable damage, including the abandonment of farms, increased migration, economic, social, and political problems. In this regard, paying attention to soil and water resources conservation is one of the most necessary measures to control erosion. So that the performance of natural ecosystems increases through conserving the soil and preventing the occurrence and intensification of erosion. Therefore, it is essential to know different stages of erosion and evaluation of the factors governing it in properly managing soil and water resources in a watershed. So far, various biological methods and structures are used to control soil and runoff loss in watersheds. Since biological methods are based on ecosystems' conditions, it is essential to control soil erosion in the early stages. In recent years, extensive methods for the conservation of soil and water resources have been introduced and used in practice. Therefore, one of the most important methods of protecting soil and water resources is the use of biological methods in terms of low use of tillage operations, limited intervention, and manipulation in nature, cost-effectiveness, and also better efficiency than structural measures. However, the biological management of soil erosion has not yet been welcomed by executive experts due to the lack of a proper implementation model.Materials and Methods: The present study was conducted to investigate biological erosion management in the Gavoshan Watershed, Iran, due to distributed and manageable erosion and the available information. The Gavoshan Watershed, with an area of 7736 ha, the mean annual precipitation of 339 mm, the minimum and maximum elevations of 1635, and 2455 meters above sea level, is located in Kermanshah Province. After determining the erosion status, climatic characteristics, and plant growth conditions, the executive procedure of biological management of the region was proposed.Results and Discussion: The results showed that surface erosion is predominant in the area, and therefore the suitability of the conditions for bio-management measures was confirmed. While reporting the prevalence of sheet erosion, the results emphasized the erosion status in the low and moderate classes and the ability to perform biological approaches in the watershed based on the climatic-agricultural map. The results further showed that according to the climatic-agricultural map, the whole study watershed was divided into five categories. In this regard, the second category with an area of 3421 ha had the highest, and the fifth category with 82 ha had the lowest areas. Finally, after determining the area of different land-uses and according to the maps of soil erosion and climatic-agricultural conditions as well as ombrothermic and hetherograph diagrams, suitable rangeland species were selected and suggested for each climatic-agricultural category based on the expected characteristics of elevation, precipitation, temperature, phenology and adequate role in soil conservation. Finally, the executive plan of biological management of soil erosion in the Gavoshan Watershed was presented based on phytosociology and relevant ecological expectations. Since bio-management measures are applicable in rangelands with moderate and poor vegetation conditions, the good rangelands were not prioritized for the planning. Accordingly, moderate and weak rangelands with an area of about 4219 ha, i.e.> 54%, of the watershed were considered for biological activities. It is expected that by taking biological measures, erosion control will be done in the early stages, and by increasing the vegetation level in 54.63% of the watershed, in addition to controlling soil erosion or at least stopping it in the early stages, carbon sequestration conditions, nitrogen fixation, and increase soil fertility. The use of endemic species in this watershed would facilitate ecological balance and at the same time protect the basic resources of water, soil, and vegetation by increasing the level of ground cover.Conclusion: Biological management is a new approach in soil and water resource sustainable management that inhibits soil loss in the early stages of erosion and prevents the destruction of ecosystems. The results of the present study are anticipated to meet the expected needs in the protection of soil and water resources in similar watersheds in the west of the country. The results of the present study can be used in soil and water resources management in the western regions of the country with similar ecological conditions. Although the proposed approach can be used in most parts of the country rangelands, appropriate field studies and continuous monitoring of the proposed function will be necessary to provide comprehensive and integrated conclusions for soil and water resources management.
M. Hatefi; S. H. Sadeghi; R. Efanzadeh; M. Behzadfar
Abstract
Introduction: Freezing-Thawing (FT) cycle is one of the processes that affects runoff generation. It is therefore necessary to control its negative effects due to specific topographic and climatic situation of Iran. However, there is no documented research about positive effects of vegetation cover on ...
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Introduction: Freezing-Thawing (FT) cycle is one of the processes that affects runoff generation. It is therefore necessary to control its negative effects due to specific topographic and climatic situation of Iran. However, there is no documented research about positive effects of vegetation cover on controlling detrimental effects of (FT) cycle yet. The present study aimed to explain the affectability of runoff generation from vegetation cover in small experimental plots under FT cycle. Materials and Methods: In order to conduct this study, the soil was collected from Badranlou region located in 10 km west of Bojnourd in north Khorasan province. In this study, iron plots with Plexiglas walls with high ability to withstand lateral stresses and thermal insulation with dimensions of 0.5×0.5 m and a height of 0.3 m and a gradient of 20 percent in accordance with the general slope of the maternal area of the soil were used. The soil was passed from 4 mm sieve after air drying and then was placed in the prepared plots. Thirty plots were prepared for the entire selected plants species and transferred to the greenhouse and three species of A. trichophorum, M. sativa and L. prenne were planted. The species were then allowed until completing the main part of the phenological stages to maximally mimic the natural conditions governing the region. A FT cycle including three days of freezing and two consequent days of thawing and rainfall simulation with 72 mm h-1 in 30 min in three plots with vegetation cover was formulated similar to the study area situation. The entire experiments were conducted in three replicates. Similar control plots were also arranged for comparison purposes. Runoff components were measured in two minutes (three-time steps after runoff), three minutes (three second steps), five minutes until the end of the incident (three last steps) and five minutes after the end of the event. After measuring and recording the amount of runoff generation at the end of each rain event, the total amount of runoff generation in different treatments of rangeland species under FT cycle was recorded. Results and Discussion: The result showed that the treated plots of M. sativa, A. trichophorum, and L. prenne significantly (p < 0.05) reduced runoff generation by 0.97, 0.72 and 0.32 times compared with control treatments, respectively. The different effects of L. prenne and A. trichophorum species on runoff generation under the freeze-thaw cycles was confirmed. However, M. sativa did not have significant effect in reducing the amount of runoff generation compared with the control. The effect of FT cycle due to performance of ice lenses and formation of active melting layer in the soil surface was controlled owing to the presence of litter and adhesion of the surface layer of soil under treatments of M.sativa, A.trichophorum and L.Prenne. Besides, according to the measurement unlike the M. sativa, the main parts of root in two gramineae species of A. trichophorum and L. prenne were distributed superficially and caused more cohesion and improvement in soil aggregation. The runoff generation reduced in the presence of L. prenne more than the other two species. Based on the different studies, the percentage of fiber in gramineae species is more than broad-leaved species. Therefore, the presence of more fiber in A. trichophorum and L. prenne litters and subsequently their more resilience can be an effective factor in the relative reduction of runoff generation. In addition, the results of the study showed that the presence of vegetation on the soil surface increased the accumulation of fine grains on the soil surface and, if the soil remains intact, increases the stability of the soil structure. The accumulation of fine crops in the soil creates a large network of small roots in the soil and the soil particles become more adhesive. Due to the presence of the small roots in L. prenne species, there is the soil greater adhesion and further reduction of runoff in the presence of this plant. Conclusion: The results of this study verified that plant cultivation can have significant effects on reducing runoff. In this regard, Lolium prenne had maximum benefit on reduction of runoff and soil loss induced by FT cycle due to better formation of superficial root system.
Hossein Kheirfam; Mehdi Homaee; Seyed Hamidreza Sadeghi; Behrouz Zarei Darki
Abstract
Introduction: Land degradation and soil losses are common and universal problems which is a pose threat to food security, ecosystem health and consequently sustainable development and human well-being. Meanwhile, improving the chemical and physical properties of biological soil crusts is an effective ...
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Introduction: Land degradation and soil losses are common and universal problems which is a pose threat to food security, ecosystem health and consequently sustainable development and human well-being. Meanwhile, improving the chemical and physical properties of biological soil crusts is an effective factor in soil loss controlling. Also, the chemical properties specially soil nitrogen are the important factors for soil quality determination. To this end, various strategies on techniques of amendments have been implemented to improve soil properties and quality. Although the application of most strategieshave been verified to soil quality,but their application in real conditions is restricted due to detrimental environmental effects, instability, cost and time-consuming and less accessibility. Recently, biological soil crusts enrichment based on soil microorganism inoculation and stimulation has been raised as a biological and useful strategy in soil conservation sciences. Accordingly, the present study aimed to investigate the role of individual and combined inoculation of bacteria and stimulant nutrient material into small-scale plots on soil nitrogen variation as one of the important soil chemical component.
Material and Methods: The study soil was collected from the erosion-prone and poor biological crust of a sub-watershed from Chalusrood watershed located in Mazandaran Province. The soil sampling was carried out from the upper of the soil surface using a 5cm-diameter coring polyvinyl chloride. The sampled soils were air-dried and sieved by a 2 mm-sized mesh. The Nutrient Agar and Tryptic Soy Agar general were used to bacteria isolation. The identification of isolated bacteria was carried out based on available protocols. Effective nitrogen-fixing bacteria were selected and then purified by selective Azotobacter Agar, Modified II and DSMZ1media. The purified bacteria proliferated by LB Broth medium and then inoculated into soil small sized-plots simultaneously with stimulant nutrient material throught spraying technique. The study was conducted at plot scale with 0.5×0.05×0.5 m dimensions and the plots filled by study soil based on standard protocols. The soil samples were taken at once the 7-8 days from surface of soil plots and the amounts of soil nitrogen were measured by using Kjeldahl method. As well as, experiment period was planned about 60 days. The one-way ANOVA and Tukey HSD test were subjected to statistically analyses.
Results and discussion: The results indicated that the Azotobacter sp. and Bacillussubtilis strain were selected as the most appropriate bacteria to be applied for nitrogen fixing in soil. Also, the results showed that the average total organic nitrogen in control plots ranged from 0.082 to 0.136%, which implies the soil limitation of total nitrogen. However, the measured total organic nitrogen in the bacteria, stimulant nutrient, and combined inoculation plots varied from 0.11 to 0.241%, 0.117 to 0.204%, and 0.124 to 0.374%, respectively. These results demonstrated the positive role of inoculated treatments on fixing nitrogen in the soil. Therefore, the population of Azotobacter sp., the Bacillussubtilis strain, was considerably increased after the inoculation process, and this led to converted and fixed atmospheric nitrogen (N2) into utilizable nitrogen (NH4 or NO3) in soil by using the enzyme nitrogenase as a catalyst. The statistical analyses and evaluation results were indicative of a significant (p
Davood Davoodi Moghadam; Seyed Hamidreza Sadeghi; Mahmood Azami Rad
Abstract
Introduction: It is vital to control land degradation, for conserving precious natural treasures. Quantification of runoff production and soil and nutrient loss from wild lands under different managerial systems is one of the scientific and optimal management in agriculture and natural resources, as ...
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Introduction: It is vital to control land degradation, for conserving precious natural treasures. Quantification of runoff production and soil and nutrient loss from wild lands under different managerial systems is one of the scientific and optimal management in agriculture and natural resources, as a major component of sustainable development. Many researches have been conducted to assess the effects of different land uses on soil erosion and runoff generation throughout the globe. Most of which, mainly verified the detrimental effects of human intervention on land degradation. However, limited comprehensive and comparative studies have been conducted to consider the amount of surface runoff generation, and soil and nutrient loss from watersheds with different management patterns viz. untreated and treated small watersheds.
Materials and Methods: The present study aimed to compare surface runoff generation,soil and nutrient loss in Kakhk treated and untreated watersheds with an area ca. 222 ha and precipitation of some 243 mm per annum. Other physical and geological characteristics of the paired watersheds were also similar to allow assessing the effects of study measures on soil, water and nutrient losses. The area under consideration has been located in Khorasan Razavi Province in northeastern Iran. The present study was performed in plots with standard size of 22.1 × 1.8 m in treating and representative areas, with three replicates and on the storm basis occurred during early 2011 and mid-2014. The treated plots were covered by biological measures viz. seeding, bunching and exclusre. The study plots have been situated on eastern,western and northern aspects with respective slope of 55, 40 and 40 %. The entire runoff from study plots were collected in a container in 0.5×1×1 m. The sediment concentration was also measured in 2-liter samples taken from the container after a complete mixing of the entire collected runoff. The sample was treated by decantation technique, oven dried and weighted by high precision scale. The transported elements, i.e. potassium, phosphorous and nitrogen were also measured in solute and particulate forms. Ultimately, the data bank was developed in Excel 2010 and got ready to be processed in SPSS 19.0 software package and statistically compared with the help of analysis of variance (ANOVA) test.
Results and Discussion: The results showed that the soil loss, nitrogen concentration, potassium concentration and sediment concentration had significant difference (p
S.H.R. Sadeghi; M.B. Raisi; Z. Hazbavi
Abstract
Introduction: The capability of a soil to resist erosion depends on soil-particle size and distribution, soil structure and structural stability, soil permeability, water content, organic matter content, and mineral and chemical constituents. Among many affecting factors on aforesaid characteristics, ...
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Introduction: The capability of a soil to resist erosion depends on soil-particle size and distribution, soil structure and structural stability, soil permeability, water content, organic matter content, and mineral and chemical constituents. Among many affecting factors on aforesaid characteristics, the freezing-thawing processes may considerably affects. Freeze–thaw fluctuation is a natural phenomenon that is frequently encountered by soils in the higher latitude and altitude regions in late autumn and early spring. Effects of freezing and freezing-thawing phenomena on soil erosion and sediment yield are important. Nevertheless, soil conservation under these phenomena by using different methods as well as soil amendments has not been yet considered. Surface application of anionic polyacrylamide (PAM) in solution has been found to be very effective in decreasing seal formation, runoff, and erosion.PAM stabilizes soil structure due to the ability of the polymer chains to adsorb onto clay particles and bridge them together forming stable domains. This adsorption can be a result of interactions between the negatively-charged functional groups of the PAM molecules and the positively-charged edges of clay minerals, orexchangeable polycations (mainly Ca2+) acting as ‘bridges’ between the negative charges of the PAM's functional groups and the negatively- charged planar surfaces of the clay. The PAM is adsorbed on the external surfaces of the aggregates and binds soil particles far apart together, thereby were shorter and evidently less effective in enhancing increasing their resistance to splash by raindrop impact and detachment by runoff. A lot of research work focused on freezing effects in soils on aggregation or increase aggregate stability and emphasis corresponding effects. But the effects of application of soil amendments on soil induced freeze and thaw cycle have not been studied yet.
Materials and Methods: The present study evaluated the performance of PAM in controlling freeze-thaw cycle effects on splash erosion from a silty loam soil. A freeze-thaw cycle was simulated in Soil Erosion and Rainfall Simulation Laboratory of TarbiatModares University. The present study was conducted under controlled laboratory conditions with a simulated rainfall. The maximum efforts were made to mimic natural conditions to get access to results with high level of fidelity. Towards this attempt, air and different soil depth temperatures were analyzed in natural condition and 10 cm soil depth was targeted for the soil laboratory experiments. The rainfall storm with 72 mm h-1 and 30 min duration was simulated and conducted for the study treatments. The soil was poured in small erosion box with 0.25 m2 surface area in three replicates. A thick filter, draining the lower 20 cm of the soil profile was generated using mineral pumices.The prepared soil sample was evenly packed into the soil plots at a bulk density of 1.3 Mg m−3 similar to that measured under natural conditions. The plots were then placed in saturated pool for 24 h and then left to be drained to achieve an average moisture content of 35% similar to that recorded for the realities in the study area. So, splash erosion rates were measured using splash cups in two control treatments without PAM subjected to freezing and freezing-thawing processes, and two other plots treated by freezing and freezing-thawing processesplus application of 20 kg ha-1 of PAM. After securing thenormality ofdata, the average net splash erosionand the average upward and downward rates of splash erosion in allexperimental treatmentswere comparedby paired sampled T-test.
Results and Discussion: According to the results of statistical analyses, the PAM application had a significant effect (p
Seyed Hamidreza Sadeghi
Abstract
Awareness of the variety, quality and quantity of sediment transport rates in different time scales, is inevitable for monitoring the hydraulic behavior of channel and flow affected by the mining activities and proper management of sand removal. However, less comprehensive studies have been conducted ...
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Awareness of the variety, quality and quantity of sediment transport rates in different time scales, is inevitable for monitoring the hydraulic behavior of channel and flow affected by the mining activities and proper management of sand removal. However, less comprehensive studies have been conducted on fluvial behavior and characteristics of the bed load under different conditions. The present study therefore aimed to investigate the effect of sand mining with different harvesting and hydrological conditions on particle size distribution and morphometric characteristics of bed sediments for three sand and gravel mines viz. Vaze-e-Olia, Vaze-e-Sofla and Alesh-Roud in Mazandaran Province, Iran. In order to achieve the study purposes, different bed sediments characteristics were computed by GRADISTAT and GIAS softwares after extracting bed sediments morphometric specifications with the help of Gravelometer and Paint software for sampling sites located in the upstream and the downstream of the study mines. The samplings were taken place on monthly basis during a year from February 2012 to January 2013. The results of the study showed that the different natural and sand and gravel mining conditions and other anthropogenic activities affected the particle size distribution and morphometric characteristics of riverbed sediments. According to the statistical analyses, most of the variables were non-significantly (P>0.07) differed in the upstream and the downstream sites in the study mines.
S.H.R. Sadeghi; M.S. Zarif Moazam; Kh. Mirnia
Abstract
Abstract
The proper management of a watershed depends on recognition of effective elements and investigation of their behavior in different conditions. Till date, many researches have studied the role of topographical general characteristics on hydrologic behaviors. Whereas, the changeability of hydrologic ...
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Abstract
The proper management of a watershed depends on recognition of effective elements and investigation of their behavior in different conditions. Till date, many researches have studied the role of topographical general characteristics on hydrologic behaviors. Whereas, the changeability of hydrologic properties under different conditions, especially in Iranian watershed has been rarely taken into account. This research aimed to assess the role of slope steepness and aspect on runoff and sediment characteristics in Educational and Research Watershed of Tarbiat Modares University (Kojour) watershed located in southeastern of Nowshahr Township, Iran. Experiments were conducted by using a pressure rain simulator with an intensity of 1.6 mm min-1 and a plot in dimension of 30×30 cm in two slope ranges i.e. ≤ 25 and > 25% and eastern and western aspects. These experiments were done in three replications and in particular places on monthly basis from October 2008 to June 2009. The study was formulated in factorial and Latin square designs and the associated results were then analyzed with the help of SPSS 17 software package. Results showed that the affect of slope on runoff volume was significant (p
S.H.R. Sadeghi; H. Asadi
Abstract
چکیده
آب نمود واحد یکی از مهم ترین و رایج ترین روش های پیش بینی دبی سیل از داده های مشاهده ای است. در حوزه های آبخیز فاقد داده های بارش و روان آب، امکان تهیه آب نمود واحد ...
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چکیده
آب نمود واحد یکی از مهم ترین و رایج ترین روش های پیش بینی دبی سیل از داده های مشاهده ای است. در حوزه های آبخیز فاقد داده های بارش و روان آب، امکان تهیه آب نمود واحد با شیوه معمول وجود ندارد. به همین دلیل در حوزه های آبخیز بدون آمار، تهیه آب نمود ها با استفاده از روش های تجربی و یا مدل های مبتنی بر ویژگی های حوزه آبخیز صورت می گیرد. در این راستا استفاده صحیح از تئوری مربوط به آب نمود واحد لحظه ای در حوزه های آبخیز بسیار کارا می باشد مشروط بر آن که پارامترهای مورد نیاز آن با دقت مناسب تعیین گردند. در این تحقیق اهمیت زمان پیمایش بین خطوط هم زمان تمرکز در تعیین منحنی زمان-مساحت با استفاده از سیستم اطلاعات جغرافیایی و نهایتاً تهیه آب نمود واحد لحظه ای به روش کلارک در حوزه آبخیز جنگلی کسیلیان بررسی شد. نتایج ارزیابی آب نمود های تخمینی مبتنی بر زمان پیمایش های بین 25/0 تا 3 ساعت در مقایسه با نتایج مستخرج از آب نمود های مشاهده ای با استفاده از روش کیفی و شاخص های آماری و هم چنین تأیید تغییرپذیری دقت آب نمود های حاصل از زمان های پیمایش مختلف نشان داد که خطوط هم زمان تمرکز با فواصل زمانی 3 ساعته در تهیه منحنی زمان-مساحت به منظور تخمین سیلاب حاصل از آب نمود واحد لحظه ای کلارک از بالاترین دقت برخوردار بوده است. نتایج به دست آمده بر ضرورت انتخاب و واسنجی پایه ی زمانی مناسب در تهیه ی آب نمود واحد تأکید داشته است.
واژه های کلیدی: آب نمود واحد لحظه ای، حوزه ی آبخیز کسیلیان، روش کلارک، زمان پیمایش، منحنی زمان-مساحت، نقشه هم زمان تمرکز
B. Salavati; H.R. Sadeghi; A.R. Telvari
Abstract
Abstract
Flood is among phenomena which result considerable damages to resources and is a serious issue among hydrologists. The proper estimation of runoff is necessary for designating appropriate approaches for its control or optimal management. Various problems have been reported in application of ...
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Abstract
Flood is among phenomena which result considerable damages to resources and is a serious issue among hydrologists. The proper estimation of runoff is necessary for designating appropriate approaches for its control or optimal management. Various problems have been reported in application of empirical models. The regional analysis of runoff with different return periods by applying watershed characteristics is an alternative with numerous applications. In this study, mean discharge data of 7 hydrometric stations in Kurdistan Province watersheds, Iran, were collected for a period of 30 years and discharges with return periods of 2, 5, 10, 20, 25, 50, 100 and 200 years were consequently calculated using SMADA package. The relationship between mean discharges with different return periods and 26 physiographic and climatic factors were evaluated by using bivariate and multivariate regression models using SPSS 13.5 package and their partial influence were also determined. The results of the study showed that the nonlinear models performed better than linear regression. The main variables include the area, main waterway length and Gravellius factor. Data analysis also revealed the possible change of variables and their importances in determination of monthly mean discharges with different return periods.
Keywords: Kurdistan Province, Physiographic characteristics, Return Period of flood, Flood modeling
K. Mohammadpour; H.R. Sadeghi; Gh.A. Dianati Tilaki
Abstract
Abstract
Quantitative investigation of effects of range management treatments on different soil and water components in rangeland ecosystems has been rarely taken into account. In the present research, the Kodir Summer Rangeland in the Southeast Nowshahr in Mazandaran Province was selected for studying ...
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Abstract
Quantitative investigation of effects of range management treatments on different soil and water components in rangeland ecosystems has been rarely taken into account. In the present research, the Kodir Summer Rangeland in the Southeast Nowshahr in Mazandaran Province was selected for studying effects of open grazing and exclosure managements on infiltration, runoff and microrelief. Experimental plots in dimension of 0.5×0.5 meters were applied in order to estimate runoff and subjected to rainfall intensity of 1.6 mm.min-1. The infiltration rate was calculated for each plot as the difference between the applied rainfall to and the runoff collected from each plot. The microrelief was also measured by using a wooden ruler graded in 10 cm steps and adjustable to the plot edges. The results were then compared on storm basis with the help of Tukey test. The results showed that there was a significant difference in infiltration, runoff and microrelief in two study treatments at the confidence level beyond 95%. The amount of total infiltration, runoff and microrelief in open grazing treatment were almost 0.97, 1.48 and 1.50 times to those recorded for short time exclosure treatment, respectively.
Keywords: Infiltration Rate, Kodir Summer Rangeland, Microrelief, Open Grazing, Runoff Generation, Short Time Exclosure
H.R. Sadeghi; H. Yaghmaee; S.M. Ghasempour
Abstract
Abstract
Nowadays, measuring water quality is very important for comprehensive management of water resources. Suspended sediment is one of the most important water quality factors which greatly affects environment health. However, its measurement needs too much time and money. It was therefore tried ...
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Abstract
Nowadays, measuring water quality is very important for comprehensive management of water resources. Suspended sediment is one of the most important water quality factors which greatly affects environment health. However, its measurement needs too much time and money. It was therefore tried in the present study to assess the applicability of modelling relationship between suspended sediment concentration and some easily accessible and cheap water quality factors. Towards this attempt, 61 water samples were taken during October 2007 to July 2008 from main outlet of Tarbiat Modares University Forest Watershed as a representative condition governing northern Iranian forest areas. The samples were taken during different hydrological conditions and corresponding lab analyses were consequently made. The results of regression modeling ultimately proved the relationship between suspended sediment concentration and turbidity, alkalinity, and phosphate with correlation coefficient beyond 0.264 (p=0.006), 0.088 (p=0.018), 0.987 (p=0.001) and respective estimation and verification errors of less than 78% in all classified periods, base flow, and flood conditions, respectively. The models obtained during the study can be then used for estimation of suspended sediment concentration in different hydrological situations.
Key words: Suspended Sediment, Forest Watershed, Water Quality Hydrological Modelling, Characteristics
S.H.R. Sadeghi; P. Saeidi
Abstract
Abstract
Suspended sediment resulted from distributed soil erosions facilitates soil nutrients transportation and influences soil depletion. Soil erosion plays a key role in loss of organic matter and therefore study of the relationship between organic matter and soil erosion processes and soil nutrient ...
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Abstract
Suspended sediment resulted from distributed soil erosions facilitates soil nutrients transportation and influences soil depletion. Soil erosion plays a key role in loss of organic matter and therefore study of the relationship between organic matter and soil erosion processes and soil nutrient loss is very important. The present case study was conducted in Kojour Educational Forest Watershed with an area of 13263 ha to determine the relationship between eroded suspended sediment and organic matter through daily sediment sampling and measurement of suspended sediment. The water and suspended sediment sampling was made via depth-integration. The determination of suspended sediment and organic matter contents was made by decantation and loss on ignition methods, respectively. Then the relationship between variables was assessed by bivariate regression method and descriptive statistics. The results of this study showed that there were high variations of organic matter and suspended sediment with respective coefficient of variation of 150 and 107. Similar trend in variation for both variables in different time periods was also proved by developing regression models with correlation coefficients from 0.48 (P
A.R. Vaezi; H.A. Bahrami; S.H.R. Sadeghi; M.H. Mahdian
Abstract
Abstract
In the Universal Soil Loss Equation (USLE), soil erodibility factor K can be estimated by using a regression equation that has been presented based on field erosion plots in relatively non-calcareous soils. Therefore, it seems necessary to determine the estimating error of the regression equation ...
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Abstract
In the Universal Soil Loss Equation (USLE), soil erodibility factor K can be estimated by using a regression equation that has been presented based on field erosion plots in relatively non-calcareous soils. Therefore, it seems necessary to determine the estimating error of the regression equation in calcareous soils of Iran. This study was conducted in an agricultural area with a dimension of 30 km in Hashtrood province, northwest of Iran during March 2005-2006. The studied soils had about 1.1% organic matter and 13% lime (TNV). In order to investigate the soil erodibility, 36 regular grids of 5×5 km were considered on the study area. On each grid, three standard plots with 1.2 m intervals were established in dryland farming area having a 9% south hill slope. The actual soil erodibility value of the plots was determined as the annual soil loss per annual rain erosivity factor under natural rainfall events. The K value was estimated using the USLE regression equation. Soil physical and chemical properties were measured in samples taken from 0 to 30 cm depth. The results indicated that mean actual value of the soil erodibility factor in the study area was 0.004258 Mg.h.MJ-1.mm-1 which is 10.75 times smaller than the estimated K-factor. There was a poor correlation (R2= 0.16) between the actual and estimated soil erodibility factor. The estimating error values of the soil erodibility varied from 3.173 to 39.298 with a mean error of 9.984. There was a significant correlation between the calcareous soil erodibility and the amount of coarse sand, silt, organic matter and lime (TNV) of the soil. Regression analysis showed that the calcareous soil erodibility significantly (R2= 0.80, p
S.H. Sadeghi; M. Boshri Seghaleh; A. Rangavar
Abstract
Abstract
In this study the role of hillside direction and plot length of experimental plots on the accuracy of soil erosion estimation was studied. For this purpose 12 experimental plots with length of 2, 5, 10, 15, 20 and 25 meters were established on the north and south facing hillside of Sanganeh ...
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Abstract
In this study the role of hillside direction and plot length of experimental plots on the accuracy of soil erosion estimation was studied. For this purpose 12 experimental plots with length of 2, 5, 10, 15, 20 and 25 meters were established on the north and south facing hillside of Sanganeh watershed having sandy loam soil texture and mean slope of 30%, located in the northeastern part of Khorasan Razavi province. The sediment of Sanganeh watershed having an area of about 1 ha was collected in concrete ponds and was used for comparison with the test plots. During the research period (November 2006 to June 2007), 12 storms causing runoff occurred and the sediments were collected in metal containers and were analyzed later. The results revealed that the amount of sediment per unit area collected from the south hillside plots was nonlinearly and adversely dependent on the plot length. However, the variation among sediment collected from the north hillside plots was not significant due to difference in crop cover and soil type. In addition, the variation in soil loss was reduced as the plot length increased. According to statistical analyses, the 20 meter plot length was found as the optimal plot length for estimation of soil erosion in the studied watershed.
Key words: Soil erosion, hillside direction, Sediment, Sanganeh watershed, Khorasan Razavi province
L. Gholami; H.R. Sadeghi; A. Khaledi Darvishan; A. Telvari
Abstract
Abstract
Application of empirical models is a must owing to complexity of process, different features, spatial and temporal variation of soil erosion and non-existence or lack of pertaining data. In this study, the efficiency of rainfall and runoff variables of 11 storms during winter 2006 and spring ...
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Abstract
Application of empirical models is a must owing to complexity of process, different features, spatial and temporal variation of soil erosion and non-existence or lack of pertaining data. In this study, the efficiency of rainfall and runoff variables of 11 storms during winter 2006 and spring 2007 in explanation of storm-wise sediment yield in Chehelgazi watershed of Gheshlagh Dam basin in Kurdistan province was evaluated with the help of bivariate and multivariate regression models by using different transformed data. The models’ efficacy was then assessed by using coefficient of determination, error of estimation and verification. The results showed that bivariate regression models, using different transformed data with determination coefficient of beyond 66%, and respective error of estimation and verification of below 40 and 30%, had a better efficiency in estimation of storm-wise sediment yield than multivariate regression models. The results also verified that the rainfall variables could explain storm-wise sediment yield variations better than runoff relating factors with overall contribution of some 80%.
Key words: Sediment yield, regression models, Gheshlagh dam, Chehelgazi watershed, Kurdistan province, Iran