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Vincent Chaplot - One of the best experts on this subject based on the ideXlab platform.
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Selective organic carbon losses from soils by Sheet Erosion and main controls
Earth Surface Processes and Landforms, 2016Co-Authors: Daniel Müller-nedebock, Pauline Chivenge, Vincent ChaplotAbstract:Although the impact of Sheet Erosion on the selective transportation of mineral soil particles has been widely investigated, little is yet known about the specific mechanisms of organic carbon (OC) Erosion, which constitutes an important link in the global carbon cycle. The present study was conducted to quantify the impact of Sheet Erosion on OC losses from soils. Erosion plots with the lengths of 1- and 5-m were installed at different topographic positions along a hillslope in a mountainous South African region. A total of 32 rainfall events from a three years period (November 2010 up to February 2013), were studied and evaluated for runoff (R), particulate and dissolved organic carbon (POCL and DOCL). In comparison to the 0–0·05 m bulk soil, the sediments from the 1-m plots were enriched in OC by a factor 2·6 and those from the 5-m long plots by a factor of 2·2, respectively. These findings suggest a preferential Erosion of OC. In addition, total organic carbon losses (TOCL) were incurred mainly in particulate form (~94%) and the increase in TOCL from 14·09 ± 0·68 g C m−1 yr−1 on 1-m plots to 50·03 ± 2·89 g C m−1 yr−1 on 5-m plots illustrated an increase in Sheet Erosion efficiency with increasing slope length. Both TOCL and sediment enrichment in OC correspondingly increased with a decrease in soil basal grass cover. The characteristics of rainstorms had no significant impact on the selectivity of OC Erosion. The results accrued in this study investigating the links between Sheet Erosion and OC losses, are expected to be of future value in the generation of carbon specific Erosion models, which can further help to inform and improve climate change mitigation measures.
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soil carbon losses by Sheet Erosion a potentially critical contribution to the global carbon cycle
Earth Surface Processes and Landforms, 2015Co-Authors: Daniel Mullernedebock, Vincent ChaplotAbstract:Despite soil Erosion through water being a ubiquitous process and its environmental consequences being well understood, its effects upon the global carbon cycle still remain largely uncertain. How much soil organic carbon (SOC) is removed each year from soils by Sheet wash, an important if not the most efficient mechanism of detachment and transport of surficial soil material? What are the main environnemental controls worldwide? These are important questions which largely remain unanswered. Empirical data from 240 runoff plots studied over entire rainy seasons from different regions of the world were analysed to estimate particulate organic carbon (POC) losses (POCL), and POC enrichment in the sediments compared to the bulk soil (ER), which can be used as a proxy of the fate of the eroded POC. The median POCL was 9.9 g C m-2 y-1 with highest values observed for semi-arid soils (POCL = 10.8 g C m-2 y-1), followed by tropical soils (POCL = 6.4 g C m-2 y-1) and temperate soils (POCL = 1.7 g C m-2 y-1). Considering the mean POCL of 27.2 g C m-2 y-1, the total amount of SOC displaced annually by Sheet Erosion from its source would be 1.32 ± 0.20 Gt C, i.e. 14.6% of the net annual fossil fuel induced C emissions of 9 Gt C. Because of low sediment enrichment in POC, Erosion-induced CO2 emissions are likely to be limited in clayey environments while POC burial within hillslopes is likely to constitute an important carbon sink. In contrast, most of the POC displaced from sandy soils is likely to be emitted to the atmosphere. These results underpin the major role Sheet wash plays in the displacement of SOC from its source and in the fate of the eroded SOC, with large variations across the different pedo-climatic regions of the world. Copyright © 2015 John Wiley & Sons, Ltd.
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impact of Sheet Erosion mechanisms on organic carbon losses from crusted soils in the sahel
Catena, 2015Co-Authors: Pauline Chivenge, S Maigayaleu, Hamma Yacouba, I Guiguemde, Harouna Karambiri, Olivier Ribolzi, A Bary, Vincent ChaplotAbstract:article i nfo Soil surface crusting influences water infiltration and runoff but its impact on soil organic carbon (SOC) losses by Sheet Erosion is largely unknown. Because there are different mechanisms of Sheet Erosion, from raindrop detachment and transport by raindrops interacting with flow (RIFT), to detachment and transport by flow, that require a certain slope length to be operative, this study examined the impact of slope length on SOC and nutrient losses. Field experiments were conducted on crusted soils in the Sahel region of Africa. Three replicates of micro-plots (1 m × 1 m), plots (10 m long × 5 m width) and long plots (25 m × 6 m) were installed for each crust type in the area (structural, STRU; desiccation, DES; gravel, GRAV; and Erosion, ERO) and followed for each rainfall event in the 2012 rainy season. Sediment, SOC content in sediments and selected nutrients (NO3 � ;P O4
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controls on a scale explicit analysis of Sheet Erosion
Earth Surface Processes and Landforms, 2012Co-Authors: E G M Oakes, J C Hughes, G P W Jewitt, S A Lorentz, Vincent ChaplotAbstract:Although the impact of Sheet Erosion on the evolution of soils, soil properties and associated ecosystem services across landscapes is undisputed, there are still large uncertainties in the estimation of Sheet Erosion, as the results obtained are highly scale dependent. Consequently, there is a need to develop a scale-explicit understanding of sediment Erosion yields, from microplot to hillslope through to plot, to surmount actual Erosion modelling flaws and to improve guidance for Erosion mitigation. The main objective of this study was to compare sediment yields from small and large plots installed under different environmental conditions and to interpret these results in terms of the main mechanisms and controlling factors of Sheet Erosion. Fifteen 1 × 1 m² and ten 2 × 5 m² plots were installed on a hillslope in the foothills of the Drakensberg, South Africa. Data of runoff, sediment concentration (SC), soil loss (SL) and rainfall characteristics obtained during the 2009–2010 rainy season at the two spatial scales and from different soils, vegetation cover, geology and topographic conditions were used to identify the main controlling factors of Sheet Erosion. Scale ratios for SC and SL were subsequently calculated to assess the level of contribution of rain-impacted flow (RIF) to overall Sheet Erosion. The average runoff rate (n = 17 events) ranged between 4.9 ± 0.4 L m-2 on 1 m2 and 5.4 ± 0.6 L m2 on 10 m2, which did not correspond to significant differences at P < 0.05 level. Sediment losses were significantly higher on the 10 m2 plots, compared with the 1 m2 plots (2.2 ± 0.4 vs 1.5 ± 0.2 g L-1 for SC; 9.8 ± 1.8 vs 3.2 ± 0.3 g m-2 for SL), which illustrated a greater efficiency of Sheet Erosion on longer slopes. Results from a principal component analysis, whose two first axes explained 60% of the data variance, suggested that Sheet Erosion is mainly controlled by rainfall characteristics (rainfall intensity and amount) and soil surface features (crusting and vegetation coverage). The contribution of RIF to Sheet Erosion was the lowest at high soil clay content (r = 0.26) and the highest at high crusting and bulk density (r = 0.22), cumulative rainfall amount in the season and associated rise in soil water table (r = 0.29). Such an explicit consideration of the role of scale on sediment yields and process domination by either in situ (soil and soil surface conditions) or ex situ (rainfall characteristics and antecedent rainfall) factors, is expected to contribute to process-based modelling and Erosion mitigation. Copyright © 2012 John Wiley & Sons, Ltd.
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controlling factors of Sheet Erosion under degraded grasslands in the sloping lands of kwazulu natal south africa
Agricultural Water Management, 2011Co-Authors: Phesheya Dlamini, Vincent Chaplot, G P W Jewitt, S A Lorentz, C Orchard, L W TitshallAbstract:The current increase in the global demand for food and fresh water and the associated land use changes or misuses exacerbate water Erosion which has become a major threat to the sustainability of the soil and water resources. Soil Erosion by rainfall and runoff is a natural and geologic phenomenon, and one of the most important components of the global geochemical cycle. Despite numerous studies on crop lands, there is still a need to quantify soil Sheet Erosion (an Erosion form that uniformly removes fertile upper soil horizons) under grasslands and to assess the factors of the environment that control its spatial variation. For that purpose, fifteen 1 m2 micro-plots installed within a 23 ha catchment under pasture in the sloping lands of KwaZulu-Natal (South Africa) were monitored during the 2007–2008 rainy season to evaluate runoff (R) and sediment losses (SL). Soil losses computed from the 37 rainfall events with soil Erosion averaged 6.45 ton ha−1 year−1with values from 3 to 13 ton ha−1 year−1. SL were significantly correlated with the proportion of soil surface coverage by the vegetation (P < 0.01) whereas the slope gradient, and soil characteristics such as bulk density or clay content were not correlated. R and SL increased as the proportion of soil surface coverage decreased and this trend was used to predict the spatial variations of Sheet Erosion over the 23 ha catchment. Greater Sheet Erosion occurred at the catchment plateau and at the vicinity of gully head cuts probably in relation to regressive Erosion. Mitigating Sheet Erosion would require an appropriate management of the soil cover through appropriate management of cattle grazing, especially at places where “natural” Erosion is likely to occur.
Gifford H Miller - One of the best experts on this subject based on the ideXlab platform.
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ice Sheet Erosion and the stripping of tertiary regolith from baffin island eastern canadian arctic
Quaternary Science Reviews, 2013Co-Authors: Kurt A Refsnider, Gifford H MillerAbstract:Abstract The Erosion of glaciated regions and concomitant changes in ice Sheet dynamics through the Pleistocene are poorly documented. The Baffin Island landscape, which has been shaped by the Foxe Sector of the Laurentide Ice Sheet (LIS), contains a variety of glacial and proximal glaciomarine sedimentary archives spanning the Pleistocene. We examine these records to better understand when Tertiary regolith was stripped from beneath the Foxe Sector of the LIS. Till on the interior plateaux of the island in areas with scoured bedrock have low chemical index of alteration (CIA) values, low meteoric 10 Be ( 10 Be met ) concentrations, and clay mineralogy consistent with Erosion from an unweathered bedrock source. However, in some areas in between fiord onset zones, more weathered till is present, containing considerably higher CIA values, high 10 Be met concentrations, and secondary clay mineral weathering products, implying that the till has persisted on the landscape and weathered during successive glaciations. Using these weathering signatures, we analyze the coastal glaciogenic deposits of the Clyde Foreland Formation (CFF) at two sites for evidence of Tertiary regolith removal from the interior of Baffin Island by LIS Erosion. Provenance indicators within the CFF demonstrate that Pleistocene LIS ice flow lines across Baffin Island have remained generally constant. The oldest CFF glaciogenic unit, likely representing one of the first, if not the first, LIS advances across Baffin Island, had high 10 Be met concentrations at the time of deposition consistent with extensive regolith Erosion. Evidence of notably weathered sediment is absent in all younger units, suggesting that Tertiary regolith was likely largely stripped from the interior of the island by 1.6 ± 0.2 Ma.
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limited ice Sheet Erosion and complex exposure histories derived from in situ cosmogenic 10be 26al and 14c on baffin island arctic canada
Quaternary Geochronology, 2006Co-Authors: Gifford H Miller, Jason P Briner, Nathaniel A Lifton, Robert C FinkelAbstract:Discordant cosmogenic nuclide exposure ages derived from 10 Be, 26 Al, and 14 C extracted from quartz in rocky summits along the eastern rim of the central Baffin Island plateau provide constraints on the efficiency of Erosion by the Laurentide Ice Sheet (LIS) and on the timing and duration of ice-free conditions in the eastern Canadian Arctic. In situ 14 C records the duration of exposure during the present interglaciation; any previously acquired 14 C decayed below detection limits beneath thick LIS during the last glaciation. The in situ 14 C exposure ages for two samples adjacent to a cold-based local ice cap are significantly less than for a nearby ice-free summit,
Zhanli Wang - One of the best experts on this subject based on the ideXlab platform.
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quantifying Sheet Erosion rate on steep grassland in the loess region of china
Archives of Agronomy and Soil Science, 2020Co-Authors: Qi Guo, Zhanli Wang, Qingwei Zhang, Nan Shen, Qilin Zhang, Naling Tian, June LiuAbstract:Sheet Erosion has been the major Erosion process on steep grassland since the Grain-for-Green project was implemented in 1999 in the Loess Plateau with serious soil Erosion in China. Quantifying sh...
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response of soil detachment rate by raindrop affected sediment laden Sheet flow to sediment load and hydraulic parameters within a detachment limited Sheet Erosion system on steep slopes on loess plateau china
Soil & Tillage Research, 2019Co-Authors: Zhanli Wang, Qingwei Zhang, Nan Shen, June LiuAbstract:Abstract The response of soil detachment rate by raindrop-affected sediment-laden Sheet flow to sediment load and hydraulic parameters was investigated within a detachment-limited Sheet Erosion system on steep slopes to understand Sheet Erosion processes fully and derive an accurate experimental model. An experiment was conducted at slopes of 12.23%, 17.63%, 26.8%, 36.4%, 40.4% and 46.63% under rainfall intensities of 48, 60, 90, 120, 138 and 150 mm h−1, respectively, by using simulated rainfall. Results showed that the soil detachment rate by raindrop-affected sediment-laden Sheet flow decreased as the sediment load by Sheet flow increased, and the decrease was a power function of sediment load by Sheet flow with NSE = 0.58, MSE = 0.0099 and R2 = 0.58. In addition, the soil detachment rate by raindrop-affected sediment-laden Sheet flow increased as a linear function of shear stress, stream power and unit stream power. Shear stress and stream power could be used to predict the soil detachment rate by raindrop-affected sediment-laden Sheet flow accurately through a linear equation. Stream power (R2 = 0.87, MSE = 0.003 and NSE = 0.87) was a better predictor of soil detachment rate by raindrop-affected sediment-laden Sheet flow than shear stress (NSE = 0.83, MSE = 0.004 and R2 = 0.83). However, prediction based on unit stream power (NSE = 0.43, MSE = 0.01 and R2 = 0.43) was poor. These findings can improve our understanding and modelling of Sheet Erosion processes on steep slopes in the loess region of China.
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modelling Sheet Erosion on steep slopes in the loess region of china
Journal of Hydrology, 2017Co-Authors: Zhanli Wang, Qingwei Zhang, Nan Shen, June LiuAbstract:Abstract The relationship of Sheet Erosion rate ( SE ), slope gradient ( S ) and rainfall intensity ( I ), and hydraulic parameters, such as flow velocity ( V ), shear stress ( τ ), stream power ( Ω ) and unit stream power ( P ), was investigated to derive an accurate experimental model. The experiment was conducted at slopes of 12.23%, 17.63%, 26.8%, 36.4%, 40.4% and 46.63% under I of 48, 60, 90, 120, 138 and 150 mm h −1 , respectively, using simulated rainfall. Results showed that Sheet Erosion rate increased as a power function with rainfall intensity and slope gradient with R 2 = 0.95 and Nash–Sutcliffe model efficiency ( NSE ) = 0.87. Sheet Erosion rate was more sensitive to rainfall intensity than to slope gradient. It increased as a power function with flow velocity, which was satisfactory for predicting Sheet Erosion rate with R 2 = 0.95 and NSE = 0.81. Shear stress and stream power could be used to predict Sheet Erosion rate accurately with a linear function equation. Stream power ( R 2 = 0.97, NSE = 0.97) was a better predictor of Sheet Erosion rather than shear stress ( R 2 = 0.90, NSE = 0.89). However, a prediction based on unit stream power was poor. The new equation (i.e. SE = 7.5 × 10 12 S 1.43 I 3.04 and SE = 0.06 Ω - 0.0003 and SE = 0.011 τ - 0.01 ) would improve water Erosion estimation on loess hillslopes of China.
J M Bodoque - One of the best experts on this subject based on the ideXlab platform.
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laboratory and field protocol for estimating Sheet Erosion rates from dendrogeomorphology
Journal of Visualized Experiments, 2019Co-Authors: J M Bodoque, Juan Antonio Ballesteroscanovas, J M Rubiales, Markus StoffelAbstract:Sheet Erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to severe environmental impacts. The understanding of Sheet Erosion is, consequently, a worldwide issue with implications for both environment and economies. However, the knowledge on how Erosion evolves in space and time is still limited, as well as its effects on the environment. Below, we explain a new dendrogeomorphological protocol for deriving eroded soil thickness (Ex) by acquiring accurate microtopographic data using both terrestrial laser scanning (TLS) and microtopographic profile gauges. Additionally, standard dendrogeomorphic procedures, dependent on anatomical variations in root rings, are utilized to establish the timing of exposure. Both TLS and microtopographic profile gauges are used to obtain ground surface profiles, from which Ex is estimated after the threshold distance (TD) is determined, i.e., the distance between the root and the sediment knickpoint, which allows defining the lowering of the ground surface caused by Sheet Erosion. For each profile, we measured the height between the topside of the root and a virtual plane tangential to the ground surface. In this way, we intended to avoid small-scale impacts of soil deformation, which may be due to pressures exerted by the root system, or by the arrangement of exposed roots. This may provoke small amounts of soil sedimentation or Erosion depending on how they physically affect the surface runoff. We demonstrate that an adequate microtopographic characterization of exposed roots and their associated ground surface is very valuable to obtain accurate Erosion rates. This finding could be utilized to develop the best management practices designed to eventually halt or perhaps, at least, lessen soil Erosion, so that more sustainable management policies can be put into practice.
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source of error and uncertainty in Sheet Erosion rates estimated from dendrogeomorphology
Earth Surface Processes and Landforms, 2015Co-Authors: J M Bodoque, Juan Antonio Ballesteroscanovas, Ana Lucia, Andres Diezherrero, Jose F MartinduqueAbstract:Dendrogeomorphology has been used since the 1960s to estimate Sheet Erosion rates. To date, most efforts have focused on accurately determining the first year of root exposure. However, an adequate methodological approach that takes into consideration the microtopography of the ground surface when estimating Sheet Erosion rates using dendrogeomorphology has not been proposed. In this study, terrestrial laser scanning (TLS) was used for the first time to examine how changes in microtopography determine the level of certainty in estimates. To this end, highly accurate TLS-based digital elevation models representing exposed roots and their immediate vicinity were analysed using geographic information system tools. The results indicate that Erosion rates calculated using the standard dendrogeomorphic method have been underestimated by up to 29% because the method does not take into account changes to the microtopography caused by the axial and radial pressure of the roots. Another source of uncertainty, which we estimate to be 50%, was also found and is the result of changes in the ground surface microtopography caused by variations in soil roughness. These findings do not invalidate the usefulness of dendrogeomorphology for assessing soil Erosion, although they do show the need for correct characterization of the microtopography to guarantee reliability. Copyright © 2015 John Wiley & Sons, Ltd.
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measuring medium term Sheet Erosion in gullies from trees a case study using dendrogeomorphological analysis of exposed pine roots in central iberia
Geomorphology, 2011Co-Authors: J M Bodoque, Ana Lucia, Jose F Martinduque, J M Rubiales, J A Ballesteros, Mar GenovaAbstract:The assessment of gully Erosion poses a great challenge because of the complexity and connectivity of the geomorphic processes involved. This study focuses on the quantification of Sheet Erosion rates in a set of slope gullies located on the northern piedmont of the Guadarrama Mountains (Spanish Central System). In order to delineate accurately the gully areas in which Sheet Erosion was predominant, the Hydrologic/Erosion Response Unit (HRU/ERU) approach was used and a dendrogeomorphological analysis of exposed tree roots was carried out to quantify Sheet Erosion rates in one selected HRU/ERU. Identification of the first year of exposure by Erosion from anatomical criteria was therefore critical. The 29 samples taken were prepared for anatomical analysis and cross-dated. Anatomical analysis of the samples showed a reduction in the lumen area of earlywood tracheids following root exposure and also, in most cases, a slight increase in growth rings. Moreover, at the end of the ring, latewood tissue and visible annual borders were very clearly defined by several rows of thick-walled tracheids. A non-parametric test was used on the findings derived from this qualitative analysis to objectify determination of the first year of exposure. Estimates of Sheet Erosion were obtained by dividing the height of eroded soil by the number of years that each root was exposed. The mean value of soil Erosion for the entire study site was then determined from statistical inference. Using this procedure, a range of Sheet Erosion rates between 6.2 and 8.8 mm y−1 (125.2 and 177.8 t ha−1 year−1) was obtained for the dominant HRU/ERU of these gullies in central Iberia. These estimates of eroded soil thickness were adjusted based on the recent finding that root anatomical changes occur prior to their exposure by Erosion.
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Response of Pinus sylvestris roots to Sheet-Erosion exposure: an anatomical approach
Natural Hazards and Earth System Science, 2008Co-Authors: J M Rubiales, J M Bodoque, J A Ballesteros, A. Diez-herreroAbstract:Anatomical changes of exposed tree roots are valuable tools to date Erosion events, but the responses of diverse species under different types of Erosion need still to be studied in detail. In this paper we analyze the histological changes that occur in roots of Scots pine (Pinus sylvestris L.) subjected to continuous denudation. A descriptive and quantitative study was conducted in the Senda Schmidt, a popular trail located on the northern slope of the Sierra de Guadarrama (Central Iberian System, Spain). Measurement of significant parameters allowed the moment of exposure of the roots to be identified. These parameters were: a) width of the growth ring; b) number of cells per ring; c) percentage of latewood and d) diameter of cellular light in earlywood. A one-way analysis ANOVA was also carried out in order to establish statistically significant differences between homogeneous groups of measurements in pre-exposed and exposed roots. Based on these analyses, Scots pine roots show a remarkable anatomical response to Sheet-Erosion exposure. Increased growth in the ring is accompanied by a slight reduction of the cell lumina of the earlywood tracheids. At the end of the ring, several rows of thick-walled tracheids define latewood tissue and visible annual borders very clearly. Furthermore, resin ducts often appear in tangential rows, increasing resin density in the tissue. All of these indicators made it possible to determine with precision the first year of exposure and to estimate precisely Sheet Erosion rates.
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Sheet Erosion rates determined by using dendrogeomorphological analysis of exposed tree roots two examples from central spain
Catena, 2005Co-Authors: J M Bodoque, Andres Diezherrero, Jose F Martinduque, J M Rubiales, Andrew E Godfrey, Javier Pedraza, Rosa M Carrasco, M A SanzAbstract:This paper describes the determination of Sheet Erosion rates by using dendrogeomorphological methods on exposed tree roots. Two sites on the northern slope of the Guadarrama Mountains, Central Spain, were studied: a popular trail in a Scots pine forest (Senda Schmidt, Valsain) growing on granites and gneisses, and an open holm-oak forest on granitic slopes (Monterrubio). These sites were selected because they showed high denudation morphologies due to accelerated soil-Erosion processes caused by human influence (trampling by continuous trekking and overgrazing), resulting in exposed roots. The method applied is based on the morphological pattern of roots, defined by the growth-ring series of the sampled roots. In order to confirm the validity of the criteria used and to make the estimations of Erosion more accurate, several anatomical indicators of exposed and non- exposed Pinus sylvestris roots were characterized. The study entailed a statistical analysis of exposure time and Erosion depth. The influence of environmental factors affecting the variation in velocity of the Erosion processes was also examined.
Anette Eltner - One of the best experts on this subject based on the ideXlab platform.
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high resolution monitoring of diffuse Sheet or interrill Erosion using structure from motion
Geoderma, 2020Co-Authors: Bernardo Moreira Cândido, John Quinton, Mike R James, Marx Leandro Naves Silva, Teotonio Soares De Carvalho, Wellington De Lima, Adnane Beniaich, Anette EltnerAbstract:Abstract Sheet Erosion is common on agricultural lands, and understanding the dynamics of the erosive process as well as the quantification of soil loss is important for both soil scientists and managers. However, measuring rates of soil loss from Sheet Erosion has proved difficult due to requiring the detection of relatively small surface changes over extended areas. Consequently, such measurements have relied on the use of Erosion plots, which have limited spatial coverage and have high operating costs. For measuring the larger Erosion rates characteristic of rill and gully Erosion, structure-from-motion (SfM) photogrammetry has been demonstrated to be a valuable tool. Here, we demonstrate the first direct validation of UAV-SfM measurements of Sheet Erosion using sediment collection data collected from Erosion plots. Three Erosion plots (12 m × 4 m) located at Lavras, Brazil, with bare soil exposed to natural rainfall from which event sediment and runoff was monitored, were mapped during two hydrological years (2016 and 2017), using a UAV equipped with a RGB camera. DEMs of difference (DoD) were calculated to detect spatial changes in the soil surface topography over time and to quantify the volumes of sediments lost or gained. Precision maps were generated to enable precision estimates for both DEMs to be propagated into the DoD as spatially variable vertical uncertainties. The point clouds generated from SfM gave mean errors of ~2.4 mm horizontally (xy) and ~1.9 mm vertically (z) on control and independent check points, and the level of detection (LoD) along the plots ranged from 1.4 mm to 7.4 mm. The soil loss values obtained by SfM were significantly (p
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multi temporal uav data for automatic measurement of rill and interrill Erosion on loess soil
Earth Surface Processes and Landforms, 2015Co-Authors: Anette Eltner, Philipp Baumgart, Hansgerd Maas, Dominik FaustAbstract:The fragile landscape of the north European loess belt is prone to soil Erosion due to soil properties and intense land use of the fertile region. Exact measurement of surface changes with high temporal and spatial resolution over large areas is necessary to quantify and understand rill and interrill Erosion processes. High resolution aerial imagery, acquired by an unmanned aerial vehicle (UAV), is used to automatically generate precise digital surface models (DSMs) of high spatial resolution by applying structure-from-motion image processing tools. During an investigation period of ten months, a 600 m2 field plot is observed during four field campaigns. A stable reference system is established for multi-temporal comparison. The overall accuracy of the DSMs generated from UAV images is less than 1 cm, verified by comparison with terrestrial laser scanner (TLS) data. Furthermore, a method for automatic rill extraction and rill parameter calculation is developed, which enables objective rill description with cm-accuracy and -resolution. Soil surface roughness and rill development as well as volumetric quantifications are analysed for multi-temporal change detection. Surface changes during winter season are controlled by soil consolidation, crusting and Sheet Erosion. During rainy spring season Sheet Erosion and rill incision occur. Two thunderstorms in summer season cause dominant rill Erosion. Erosion rills are more dominantly deepening than widening (from to 2 to 4 cm depth and from 17 to 23 cm width), resulting in average per rill Erosion values of 0.03 and 0.07 m3 respectively. An orientation dependent lateral rill shift is revealed, implying rill widening in eastern direction due to dominant winds from the West. Volumetric quantifications indicate high Erosion volumes, reaching up to 121 tha-1 during the summer events. Highest Erosion volumes are due to rill Erosion rather than interrill Erosion. Copyright © 2014 John Wiley & Sons, Ltd.