Community managed forests dominate the catchment sediment cascade in the mid-hills of Nepal: A compound-specific stable isotope analysis

Upadhayay, Hari Ram; Smith, Hugh G.; Griepentrog, Marco; Bodé, Samuel; Bajracharya, Roshan Man; Blake, William H.; Cornelis, Wim; Boeckx, Pascal

doi:10.1016/j.scitotenv.2018.04.394

Cited by 33 publications

(18 citation statements)

References 57 publications

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“…In particular, shrub land has a high erosion rate (32.52 t ha −1 year −1 ) and the largest area (150 ha), which is the major contributor (55.08%) to soil loss in the catchment. This suggestion is consistent with the finding reported by Upadhayay et al (2018), who showed that the mixed forest (similar to the shrub land in this study) was the dominant contributor to sediment at the catchment outlet. The results indicate that serious soil erosion from shrub land and sloping farmland should be specifically considered during sustainable development planning in the hills of Nepal.…”

Section: Soil Erosion Rate From the Study Catchmentsupporting

confidence: 94%

Using 137Cs and 210Pbex to trace soil erosion rates for a small catchment in the mid-hills of Nepal

Yuan

Xiong

et al. 2020

J Soils Sediments

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Purpose Soil erosion is a major threat to agricultural sustainability in the hills of Nepal. However, little is known about the soil erosion rates at a small catchment scale in this region. Materials and methods In this study, the soil redistribution rates in a typical small hilly catchment in the Ramechhap District of Nepal were evaluated using the 137 Cs and 210 Pb ex tracer techniques. Nine representative slopes under three land uses and a reference site from the gentle sloping forest land within the catchment were selected as sample plots. A downhill transect was built in each sample plot, and soil samples were collected at 5-m intervals along the transects. Results and discussion The results showed that the spatial variations in radionuclide inventory and soil erosion rates measured by 137 Cs measurements were highly consistent with equivalent estimates from 210 Pb ex measurements, suggesting the potential for using 137 Cs and 210 Pb ex measurements to estimate soil redistribution rates. All 137 Cs and 210 Pb ex inventories on the slopes were less than the reference values, indicating that net soil loss has occurred at all of the sampling points. The net erosion rates from sloping farmland (37.08 t ha −1 year −1) and shrub land (32.52 t ha −1 year −1) were significantly higher than those from forest land (14.91 t ha −1 year −1). Furthermore, the soil erosion rates obtained from 210 Pb ex measurements were higher than those obtained from 137 Cs measurements, which implies that soil erosion in the catchment was accelerated during the last two decades. The net soil loss from the study catchment was estimated to be 31.29 t ha −1 year −1 , which is mainly contributed by shrub land (55.08%) and sloping farmland (37.68%). Conclusions These results indicate that shrub land and sloping farmland are vulnerable to erosion, which should be specifically considered in the sustainable management of small agricultural catchments in the mid-hills of Nepal, especially in dry valley regions.

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Section: Soil Erosion Rate From the Study Catchmentsupporting

confidence: 94%

Using 137Cs and 210Pbex to trace soil erosion rates for a small catchment in the mid-hills of Nepal

Yuan

Xiong

et al. 2020

J Soils Sediments

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“…Agriculture is the mainstay of the Nepalese economy as 65.6% of the population is actively engaged in agriculture [8] but the loss of fertile soil by erosion is hindering the agricultural development there. Owing to negative effects on the quality of life on soil and water, soil erosion through water is of great importance to the Nepalese terrains [9]. Being a mountainous country defined by rugged topography and elevation ranging from 60 m to 8848 m, erratic rainfall events mostly concentrated during monsoon, and conventional agricultural practices, Nepal is prone to several forms of soil erosion [10].…”

Section: Introductionmentioning

confidence: 99%

Estimation of Sediment Yield and Maximum Outflow Using the IntErO Model in the Sarada River Basin of Nepal

Chalise

Kumar

Spalević

et al. 2019

Water

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Soil erosion is a severe environmental problem worldwide as it washes away the fertile topsoil and reduces agricultural production. Nepal, being a hilly country, has significant erosion disputes as well. It is important to cognise the soil erosion processes occurring in a river basin to manage the erosion severity and plan for better soil conservation programs. This paper seeks to calculate the sediment yield and maximum outflow from the Sarada river basin located in the western hills of Nepal using the computer-graphic Intensity of Erosion and Outflow (IntErO) model. Asymmetry coefficient of 0.63 was calculated, which suggests a possibility of large floods to come in the river basin in the future whereas the maximum outflow from the river basin was 1918 m³ s−1. An erosion coefficient value of 0.40 was obtained, which indicates surface erosion of medium strength prevails in the river basin. Similarly, the gross soil loss rate of 10.74 Mg ha−1 year−1 was obtained with the IntErO modeling which compares well with the soil loss from the erosion plot measurements. The IntErO model was used for the very first time to calculate soil erosion rates in the Nepalese hills and has a very good opportunity to be applied in similar river basins.

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“…Various approaches have been used to help end-users visualize this component of fingerprinting procedures (e.g. boxplot-based range test (Blake et al 2012 ), point-in-polygon (Brandt et al 2018 ; Bravo-Linares et al 2018 ), point-in-ellipsoid (Upadhayay et al 2018b )). Simple boxplots of source and target sediment sample tracer values provide easily understandable qualitative information on the potential transformation of the tracers being used.…”

Section: The Status Quomentioning

confidence: 99%

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

et al. 2020

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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.

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Community managed forests dominate the catchment sediment cascade in the mid-hills of Nepal: A compound-specific stable isotope analysis

Cited by 33 publications

References 57 publications

Using 137Cs and 210Pbex to trace soil erosion rates for a small catchment in the mid-hills of Nepal

Using 137Cs and 210Pbex to trace soil erosion rates for a small catchment in the mid-hills of Nepal

Estimation of Sediment Yield and Maximum Outflow Using the IntErO Model in the Sarada River Basin of Nepal

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

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