Monitoring of soil organic carbon and nitrogen stocks in different land use under surface water erosion in a semi-arid drainage basin of Iran

Soil organic carbon (SOC) and soil nitrogen (SN) are the principal components in soil quality assessment, and in mitigation the global greenhouse effect. In Iran, little information exists on the stocks of SOC and SN. SOC and SN stocks are a function of the SOC and SN concentrations and the bulk density of the soil that are prone to changes under land use types and soil erosion. The objective of this study was to evaluate SOC and SN stock in different land use types under surface erosion at catchment scale. In view of this, bulk density, SOC and SN concentration were measured in 39 different sampling sites of three main groups of land use affected by surface erosion namely, rangeland, crop field, and forest land at Taleghani catchment, Khoramabad, Iran. The results showed that SOC and SN stock under all land use types was significantly different (P < 0.01). SOC and SN stocks were greatest in the forest land use. The SOC stock for the 30 cm soil layer in different land uses varied in order forest (66.9 Mg ha 121) > rangeland (63.3 Mg ha 121) > crop field (47.2 Mg ha 121; P < 0.01). Also the SN stock had the same trend in all studied land uses. These results can be useful as a scientific basis for selecting the proper soil management as a simple and low-cost approach to mitigate the SOC and SN loss. \ua9JASE

Assessment of meteorological drought using SPI in West Azarbaijan Province, Iran

Assessment of drought is one of the most important steps in risk management of drought analysis. Drought is mostly the result of a decrease in precipitation in comparison with the mean value and would affect the quantities of soil moisture and water resources. The basis of drought indices is often based on measuring the deviation of precipitation values from long-term mean, during a specific period of time. The standard precipitation index (SPI) can be used for indicating the associated temporal and spatial variations. The aim of this research is the assessment of the characteristics such as intensity, frequency and duration of meteorological drought using SPI with 1, 3, 6, 12 and 24 months time scales in West Azarbaijan Province, Iran. The indices have been computed in various time scales for 38 gauging stations with 32 years record period in the study area and evaluated for the recent drought during 1998-2001. The results indicate that with an increase in return period and time scale, the duration of drought will be increased. Frequency of drought, with an increase in scale, will also be decreased linearly, but their durations show an increase. This index having temporal and spatial variations and is attributed as a suitable tool for analyzing drought for different hydrological purpose

Assessment of meteorological drought using SPI in West Azarbaijan Province, Iran

Assessment of drought is one of the most important steps in risk management of drought analysis. Drought is mostly the result of a decrease in precipitation in comparison with the mean value and would affect the quantities of soil moisture and water resources. The basis of drought indices is often based on measuring the deviation of precipitation values from long-term mean, during a specific period of time. The standard precipitation index (SPI) can be used for indicating the associated temporal and spatial variations. The aim of this research is the assessment of the characteristics such as intensity, frequency and duration of meteorological drought using SPI with 1, 3, 6, 12 and 24 months time scales in West Azarbaijan Province, Iran. The indices have been computed in various time scales for 38 gauging stations with 32 years record period in the study area and evaluated for the recent drought during 1998-2001. The results indicate that with an increase in return period and time scale, the duration of drought will be increased. Frequency of drought, with an increase in scale, will also be decreased linearly, but their durations show an increase. This index having temporal and spatial variations and is attributed as a suitable tool for analyzing drought for different hydrological purpose

Sediment source fingerprinting: benchmarking recent outputs, remaining challenges and emerging themes

Abstract: Purpose: This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international scientists either with track records in the approach or with expertise relevant to progressing the science. Methods: Web of Science and Google Scholar were used to review published papers spanning the period 2013–2019, inclusive, to confirm publication trends in quantities of papers by study area country and the types of tracers used. The most recent (2018–2019, inclusive) papers were also benchmarked using a methodological decision-tree published in 2017. Scope: Areas requiring further research and international consensus on methodological detail are reviewed, and these comprise spatial variability in tracers and corresponding sampling implications for end-members, temporal variability in tracers and sampling implications for end-members and target sediment, tracer conservation and knowledge-based pre-selection, the physico-chemical basis for source discrimination and dissemination of fingerprinting results to stakeholders. Emerging themes are also discussed: novel tracers, concentration-dependence for biomarkers, combining sediment fingerprinting and age-dating, applications to sediment-bound pollutants, incorporation of supportive spatial information to augment discrimination and modelling, aeolian sediment source fingerprinting, integration with process-based models and development of open-access software tools for data processing. Conclusions: The popularity of sediment source fingerprinting continues on an upward trend globally, but with this growth comes issues surrounding lack of standardisation and procedural diversity. Nonetheless, the last 2 years have also evidenced growing uptake of critical requirements for robust applications and this review is intended to signpost investigators, both old and new, towards these benchmarks and remaining research challenges for, and emerging options for different applications of, the fingerprinting approach

Using catchment characteristics to model seasonality of dissolved organic carbon fluxes in semi-arid mountainous headwaters

Prediction of dissolved organic carbon (DOC) based on catchment characteristics is a useful tool for efficient and effective water management, but in the case of arid and semi-arid regions, such predictive capacity is scarce. Accordingly, the main objective of this study was to evaluate the significance of principal components for predicting DOC concentrations and fluxes in nine headwater catchments of the Hiv catchment located in the Southern Alborz Mountains in the west of Tehran, Iran. To achieve this aim, data were assembled on 24 headwater catchment characteristics comprising soil properties, physiography, seasonal rainfall, and flow attributes, as well as estimates of DOC concentrations and fluxes across four seasons. The results revealed a major positive correlation between DOC and soil organic matter parameters related to soil biological processes. Using general linear modelling, an organic matter component related to soil biology, a seasonal component related to the dummy effect of sampling seasons, and a soil physical component related to soil texture were found to be the best predictors for DOC responses in the study area

Monitoring of soil organic carbon and nitrogen stocks in different land use under surface water erosion in a semi-arid drainage basin of Iran

Soil organic carbon (SOC) and soil nitrogen (SN) are the principal components in soil quality assessment, and in mitigation the global greenhouse effect. In Iran, little information exists on the stocks of SOC and SN. SOC and SN stocks are a function of the SOC and SN concentrations and the bulk density of the soil that are prone to changes under land use types and soil erosion. The objective of this study was to evaluate SOC and SN stock in different land use types under surface erosion at catchment scale. In view of this, bulk density, SOC and SN concentration were measured in 39 different sampling sites of three main groups of land use affected by surface erosion namely, rangeland, crop field, and forest land at Taleghani catchment, Khoramabad, Iran. The results showed that SOC and SN stock under all land use types was significantly different (P < 0.01). SOC and SN stocks were greatest in the forest land use. The SOC stock for the 30 cm soil layer in different land uses varied in order forest (66.9 Mg ha−1) > rangeland (63.3 Mg ha−1) > crop field (47.2 Mg ha−1; P < 0.01). Also the SN stock had the same trend in all studied land uses. These results can be useful as a scientific basis for selecting the proper soil management as a simple and low-cost approach to mitigate the SOC and SN loss. ©JASE

The Effect of Forest Road Construction on Soil Organic Carbon Stock in Mountainous Catchment in Northern Iran

The main objective of this study was to investigate the effect of forest road construction on the Soil Organic Carbon Stock (SOCS) in Ziarat Catchment. Therefore, soil samples were collected from five land use types including road construction, cultivated area, channel bank, pasture and forest land and soil organic carbon concentration and bulk density were measured in the samples and SOCS were calculated. The results showed that the forest road construction reduce SOCS. SOC stock was greatest in the forest land use and the total SOC stock under different land uses varied in order forest, pasture, cultivate, channel bank and road construction with 143, 136, 128, 36 and 29 Mg ha −1 , respectively (p< 0.001). Therefore, these results can be useful as a scientific basis for selecting the proper soil erosion control methods as a simple and low-cost approach to mitigate the SOC loss

Assessment of meteorological drought using SPI in West Azarbaijan Province, Iran

Assessment of drought is one of the most important steps in risk management of drought analysis. Drought is mostly the result of a decrease in precipitation in comparison with the mean value and would affect the quantities of soil moisture and water resources. The basis of drought indices is often based on measuring the deviation of precipitation values from long-term mean, during a specific period of time. The standard precipitation index (SPI) can be used for indicating the associated temporal and spatial variations. The aim of this research is the assessment of the characteristics such as intensity, frequency and duration of meteorological drought using SPI with 1, 3, 6, 12 and 24 months time scales in West Azarbaijan Province, Iran. The indices have been computed in various time scales for 38 gauging stations with 32 years record period in the study area and evaluated for the recent drought during 1998-2001. The results indicate that with an increase in return period and time scale, the duration of drought will be increased. Frequency of drought, with an increase in scale, will also be decreased linearly, but their durations show an increase. This index having temporal and spatial variations and is attributed as a suitable tool for analyzing drought for different hydrological purpose

Assessment of meteorological drought using SPI in West Azarbaijan Province, Iran

Assessment of drought is one of the most important steps in risk management of drought analysis. Drought is mostly the result of a decrease in precipitation in comparison with the mean value and would affect the quantities of soil moisture and water resources. The basis of drought indices is often based on measuring the deviation of precipitation values from long-term mean, during a specific period of time. The standard precipitation index (SPI) can be used for indicating the associated temporal and spatial variations. The aim of this research is the assessment of the characteristics such as intensity, frequency and duration of meteorological drought using SPI with 1, 3, 6, 12 and 24 months time scales in West Azarbaijan Province, Iran. The indices have been computed in various time scales for 38 gauging stations with 32 years record period in the study area and evaluated for the recent drought during 1998-2001. The results indicate that with an increase in return period and time scale, the duration of drought will be increased. Frequency of drought, with an increase in scale, will also be decreased linearly, but their durations show an increase. This index having temporal and spatial variations and is attributed as a suitable tool for analyzing drought for different hydrological purpose

Estimation of Taleghan river bank erosion risk using BEHI model

Rivers provide water and energy for nature and humans. Thus, water supply is the most important economic role of rivers. Process of erosion sediment transportation is one of the most important hydrodynamic processes which affect a lot of hydraulic systems such as basins, rivers, coasts and harbors, dams, bridges, farms, and construction facilities. Taleghan River is a major river located in the south hillside of Alborz. The river has dynamic behavior affected by various factors including geology, gradient, land use, hydraulic flow condition, and morphological behavior. Analyzing the stability of Taleghan river bank using mathematical and statistical models and comparing its results with field observations is the aim of this research. Therefore, to achieve this aim BEHI model and statistical one-way analysis of variance (ANOVA) is used and then compared with field and visual observations. The results concerning scoring show moderate to high danger of riverbank erosion in upstream sections and high to very high danger of riverbank erosion in downstream sections. According to the results of one-way analysis of variance (ANOVA), the effects of gradient and discharge have been more than the other parameters. In this analysis, the meaningful parameters consist of mean depth; bank full, riverbank high, discharge, and gradient. According to the results, erodible edges were identified