Quantification of soil erosion (using 239+240Pu) on periglacial chronosequences reveals the importance of vegetation cover in soil stabilisation

2021 ◽  
Author(s):  
Alessandra Musso ◽  
Michael E. Ketterer ◽  
Konrad Greinwald ◽  
Clemens Geitner ◽  
Markus Egli
Keyword(s):  
Soil Erosion ◽  
Vegetation Cover ◽  
Swiss Alps ◽  
Vegetation Coverage ◽  
Vegetation Development ◽  
Erosion Rates ◽  
Fallout Radionuclides ◽  
Soil Stabilisation ◽  
Soil Erosion Rates ◽  
Chemical Soil

<p>High mountainous areas are are strongly shaped by redistribution processes of sediments and soils. Due to the projected climate warming and the continued retreat of glaciers in the 21<sup>st</sup> century, we can expect the area of newly exposed, highly erodible sediments and soils to increase. While soil and vegetation development is increasingly well understood and quantified, it has rarely been coupled to soil erosion. The aim of this study was to assess how soil erosion rates change with surface age. We investigated two moraine chronosequences in the Swiss Alps which were situated in a siliceous and calcareous lithology and spanned over 30 – 10’000 yrs and 110 – 13’500 yrs, respectively. We used <sup>239+240</sup>Pu fallout radionuclides to quantify the average soil erosion rates over the last 60 years and compared them to physico−chemical soil properties and the vegetation coverage. At both chronosequences, the erosion rates were highest in the young soils. The erosion rates decreased markedly after 3−5 ka of soil development to reach a more or less stable situation after 10−14 ka. This decrease  goes hand in hand with the development of a closed vegetation cover. We conclude that depending on the relief and vegetational development, it takes up to at least 10 ka to reach soil stability. The establishment of a closed vegetation cover with dense root networks appears to be the controlling factor in the reduction of soil erodibility in periglacial areas.</p>

How spatial vegetation distribution affects soil erosion and sediment transport

2021 ◽  
Author(s):  
Malte Kuegler ◽  
Thomas Hoffmann ◽  
Jana Eichel ◽  
Lothar Schrott ◽  
Juergen Schmidt
Keyword(s):  
Soil Erosion ◽  
Vegetation Cover ◽  
Vegetation Pattern ◽  
Vegetation Coverage ◽  
Future Research ◽  
Initial Increase ◽  
Vegetation Patterns ◽  
Erosion Rates ◽  
Catchment Areas ◽  
The Impact

<p>There are a multitude of factors that affect soil erosion and the process of sediment movement. One particular factor known to have a considerable impact is vegetation coverage within catchment areas.  Previous studies have examined the impact of vegetation cover on erosion. However, there is a lack of research on how the spatial distribution of vegetation influences erosion rates.</p><p>A greater understanding of hillslope erosion is fundamental in modelling previous and future topographic changes under various climate conditions. Here, the physical based erosion model EROSION 3D © is used to evaluate the impact of a variety of vegetation patterns and degrees of vegetation cover on sediment erosion and transport. The model was applied on a natural catchment in La Campana (Central Chile). For this purpose, three different vegetation patterns were created: (i) random distribution, (ii) water-dependent distribution (TWIR) and (iii) banded vegetation pattern distribution. Additional to this, the areas covered by vegetation generated in the first step were expanded by steps of 10% [0...100%]. The Erosion3D © model then was applied on all vegetation patterns and degrees of cover.</p><p>Our results show an initial increase of soil erosion with increasing plant coverage within the catchment up to a certain cover threshold ranging between 10 and 40%. At larger vegetation cover soil erosion rates decline. The strength of increase and decline, as well as the cover-threshold is strongly conditioned by the spatial vegetation pattern. In the light of this, future research should pay particular attention to the properties of the plants and their distribution, not solely on the amount of biomass within catchment areas.</p>

scholarly journals Soil erosion risk assessment: a case study of the Jos Plateau, Nigeria

2021 ◽  
pp. 109-117
Author(s):  
Ayodele Owonubi
Keyword(s):  
Soil Erosion ◽  
Vegetation Index ◽  
Vegetation Coverage ◽  
Anthropogenic Factors ◽  
Rainfall Erosivity ◽  
Entire Area ◽  
Jos Plateau ◽  
Erosion Rates ◽  
Erosion Processes ◽  
Soil Erosion Rates

Soil erosion is a treat to global food security. The objective of this study was to evaluate factors influencing erosion on the arable lands of the Jos Plateau; and to estimate the extent of soil erosion in the area. Universal Soil Loss Equation (USLE) model was used to evaluate soil erosion processes in the study area. This was facilitated with the aid of Geographic Information System Both for Interpolation and Geospatial analysis. Soil data from field survey was the primary source of data for analysis of soil erodibility. Topographic factor was determined from 90-meter elevation data. Rainfall erosivity was determined from rainfall data at 1 kilometer resolution. Whereas vegetation cover factor was determined from Normalized Difference Vegetation Index. Results of the study indicate that rainfall erosivity values were remarkably high and have mean values of 5117MJ.mm/ ha.h.y. Analysis of percent areal coverage indicate that the entire area had 52, 34, 7, and 7% low, moderate, high and very high topographic factors respectively. Further analysis indicate that anthropogenic factors had severely affected vegetation coverage of the Jos plateau, especially on the arable lands. Furthermore, during this research, the mean annual actual and potential soil erosion rates were estimated spatially over the Jos Plateau area. Soil erosion rates were far more than tolerable rates thereby affecting soil fertility and productivity.

Rapid decrease of soil erosion rates with soil formation and vegetation development in periglacial areas

2020 ◽  
Vol 45 (12) ◽  
pp. 2824-2839 ◽  
Author(s):  
Alessandra Musso ◽  
Michael E. Ketterer ◽  
Konrad Greinwald ◽  
Clemens Geitner ◽  
Markus Egli
Keyword(s):  
Soil Erosion ◽  
Soil Formation ◽  
Rapid Decrease ◽  
Vegetation Development ◽  
Erosion Rates ◽  
Soil Erosion Rates

Impact of plant roots on the resistance of soils to erosion by water: a review

2005 ◽  
Vol 29 (2) ◽  
pp. 189-217 ◽  
Author(s):  
G. Gyssels ◽  
J. Poesen ◽  
E. Bochet ◽  
Y. Li
Keyword(s):  
Soil Erosion ◽  
Vegetation Cover ◽  
Root Length ◽  
Root Length Density ◽  
Water Erosion ◽  
Root Density ◽  
Plant Roots ◽  
Rill Erosion ◽  
Erosion Rates ◽  
Soil Erosion Rates

Vegetation controls soil erosion rates significantly. The decrease of water erosion rates with increasing vegetation cover is exponential. This review reveals that the decrease in water erosion rates with increasing root mass is also exponential, according to the equation SEP e b RP where SEP is a soil erosion parameter (e.g., interrill or rill erosion rates relative to erosion rates of bare topsoils without roots), RP is a root parameter (e.g., root density or root length density) and b is a constant that indicates the effectiveness of the plant roots in reducing soil erosion rates. Whatever rooting parameter is used, for splash erosion b equals zero. For interrill erosion the average b-value is 0.1195 when root density (kg m 3) is used as root parameter, and 0.0022 when root length density (km m 3) is used. For rill erosion these average b-values are 0.5930 and 0.0460, respectively. The similarity of this equation for root effects with the equation for vegetation cover effects is striking, but it is yet impossible to determine which plant element has the highest impact in reducing soil losses, due to incomparable units. Moreover, all the studies on vegetation cover effects attribute soil loss reduction to the above-ground biomass only, whereas in reality this reduction results from the combined effects of roots and canopy cover. Based on an analysis of available data it can be concluded that for splash and interrill erosion vegetation cover is the most important vegetation parameter, whereas for rill and ephemeral gully erosion plant roots are at least as important as vegetation cover.

scholarly journals Tracing erosion rates in loess landscape of the Trzebnica Hills (Poland) over time using fallout and cosmogenic nuclides

2021 ◽  
Author(s):  
Aleksandra Loba ◽  
Jarosław Waroszewski ◽  
Dmitry Tikhomirov ◽  
Fancesca Calitri ◽  
Marcus Christl ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Temporal Trends ◽  
Short Term ◽  
Undisturbed Soil ◽  
Erosion Rates ◽  
Erosion Processes ◽  
Fallout Radionuclides ◽  
Soil Erosion Rates

Abstract Purpose Loess landscapes are highly susceptible to soil erosion, which affects soil stability and productivity. Erosion is non-linear in time and space and determines whether soils form or degrade. While the spatial variability of erosion is often assessed by either modelling or on-site measurements, temporal trends over decades to millennia are very often lacking. In this study, we determined long- and short-term erosion rates to trace the dynamics of loess deposits in south-western Poland. Materials and methods We quantified long-term (millennial) erosion rates using cosmogenic (in situ 10Be) and short-term (decadal) rates with fallout radionuclides (239+240Pu). Erosion processes were studied in two slope-soil transects (12 soil pits) with variable erosion features. As a reference site, an undisturbed soil profile under natural forest was sampled. Results and discussion The long-term erosion rates ranged between 0.44 and 0.85 t ha−1 year−1, whereas the short-term erosion rates varied from 1.2 to 10.9 t ha−1 year−1 and seem to be reliable. The short-term erosion rates are up to 10 times higher than the long-term rates. The soil erosion rates are quite consistent with the terrain relief, with erosion increasing in the steeper slope sections and decreasing in the lower parts of the slope, while still maintaining high values. Conclusions Soil erosion rates have increased during the last few decades owing to agriculture intensification and probably climate change. The measured values lie far above tolerable erosion rates, and the soils were found to be strongly imbalanced and exhibit a drastic shallowing of the productive soils horizons.

Effects of soil and vegetation development on surface and subsurface hydrological properties and processes on moraines in the Swiss Alps

2021 ◽  
Author(s):  
Fabian Maier ◽  
Ilja van Meerveld
Keyword(s):  
Vegetation Cover ◽  
Landscape Evolution ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
Swiss Alps ◽  
Runoff Generation ◽  
Vegetation Development ◽  
Soil Aggregate Stability ◽  
Erosion Rates ◽  
The Impact

<p>Overland flow (OF) and subsurface flow (SSF) are key processes that determine the streamflow response to precipitation, as well as water quality, but are affected by the land surface and soil characteristics. They can also modify the shape of our landscape. However, our understanding of the evolution of OF and SSF characteristics and the feedback mechanisms between hydrological, pedological, biological and geormorphological processes that affect OF and SSF during landscape evolution is still limited.</p><p>We used a space-for-time approach and studied 3 plots (4m x 6m each) on four different aged moraines (several decades to ~13.500 years) on the Sustenpass near the Steinglacier and in the karstic glacier foreland of the Griessfirn near Klausenpass (total of 24 plots) to determine how OF & SSF change during landscape evolution. We used artificial rainfall experiments with high rainfall intensities to determine runoff ratios, peak flow rates, timing and duration of OF & SSF. The addition of tracers (<sup>2</sup>H and NaCl) to the sprinkling water and sampling of soil water allowed us to determine the degree of mixing of the applied rainfall with water in the soil. Measurements during natural rainfall events helped to determine the impact of the rainfall volume and intensity on the runoff generation. In addition, the runoff samples and sensor-based turbidity measurements of OF provide an estimate of the erosion rates during extreme events. In order to link the differences in runoff generation with the pedological and biological characteristics of the slopes, vegetation cover, root density, soil texture, soil aggregate stability, and the saturated hydraulic conductivity (K<sub>sat</sub>) were measured as well.</p><p>The results show that K<sub>sat</sub> at both study areas decreases with moraine age and soil depth and is mainly driven by the increase in silt and clay content. Despite the high K<sub>sat</sub> values, local OF occurs frequently on the youngest moraines due to the large rock and stone cover. Sediment flux and the related erosion rates are largest for the young moraines, since vegetation cover and soil aggregate stability are small. Soil and vegetation development change major OF and SSF characteristics during landscape development, such as the mixing processes and the pre-event water fraction in OF & SSF, which both increase for the older moraines. However, the rate of these changes during landscape evolution is controlled by the parent material. These results can be used to inform landscape evolution models and help us to understand processes within the critical zone during the first millennia of soil development.</p>

scholarly journals Deforestation effects on soil erosion rates and soil physicochemical properties in Iran: a case study of using fallout radionuclides in a Chernobyl contaminated area

2021 ◽  
Author(s):  
Maral Khodadadi ◽  
Christine Alewell ◽  
Mohammad Mirzaei ◽  
Ehssan Ehssan-Malahat ◽  
Farrokh Asadzadeh ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Physicochemical Properties ◽  
Land Use Changes ◽  
Aggregate Stability ◽  
Soil Physicochemical Properties ◽  
Sediment Delivery ◽  
Erosion Rates ◽  
Fallout Radionuclides ◽  
Soil Erosion Rates ◽  
The Impact

Abstract. Deforestation for farming and grazing purposes has become a global challenge. To study the impact of deforestation on soil erosion rates and soil physicochemical properties, Zarivar Lake watershed, Kurdestan Province, Iran, was selected. Converting the steep hillslopes naturally under oak forest to rainfed vineyards has been one of the most common land-use changes in the area. We used 137Cs and 210Pbex radionuclides and quantified the Chernobyl-derived 137Cs fallout with 239+240Pu. The soil samples were collected from two adjacent and similar hillslopes, one of which is under natural forest, while the other is under rainfed vineyard. Using 137Cs/239+240Pu rates and a simple unmixing of the 137Cs sources indicated that 50.2 ± 10.0 % of 137Cs was Chernobyl-derived. The mean reference inventory values of 137Cs, 210Pbex, and 239+240Pu were estimated to be at 6152 ± 1266, 6079 ± 1511, and 135 ± 31 Bq m−2, respectively. At the forested hillslope, net soil erosion rates based on 137Cs, and 210Pbex, techniques were estimated to be at 5.0 and 5.9 Mg ha−1 yr−1, respectively, resulting in Sediment Delivery Ratios (SDRs) of 96 and 70 %. However, at the vineyard hillslope, the net soil redistribution rates were at 25.9 and 32.5 Mg ha−1 yr−1 for 137Cs and 210Pbex, respectively, resulting in respective SDRs of around 95 and 92 %. Both 137Cs and 210Pbex indicated that as a result of deforestation, soil erosion has increased by approximately five times. Percolation Stabilities (PS) in forest and vineyard topsoil are about 309 and 160 gr H2O 600 s−1 classified as rapid and moderate PSs, respectively. Rapid PS in forest soil implies high aggregate stability, whereas moderate PS in vineyard soils indicates that they are generally weakly-structured. All in all, the results of the present study revealed that deforestation and converting natural vegetation to cropland prompted soil loss and deteriorated physicochemical properties of the soil.

Analysis of relationship between soil erosion and lake deposition during the Holocene in Xingyun Lake, southwestern China

The Holocene ◽  
2021 ◽  
pp. 095968362110190
Author(s):  
Hongfei Zhao ◽  
Jie Zhou ◽  
Qianli Sun ◽  
Claudio O Delang ◽  
Ali Mokhtar ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Erosion ◽  
Vegetation Cover ◽  
Land Reclamation ◽  
Anthropogenic Impacts ◽  
Lake Basin ◽  
The Holocene ◽  
Erosion Rates ◽  
Soil Erosion Rates ◽  
Xingyun Lake

Quantifying the relative influences of anthropogenic activities and climate change on soil erosion and deposition during the Holocene, when both forces have been interacting is a complex problem. Analysis of long-term patterns in soil erosion and lake deposition in a basin can provide the basis for untangling the complexities of climate and anthropogenic forcings. In this paper, sedimentary sequences from Xingyun Lake are compared with simulated soil erosion rates in the basin to explore the relationship between river basin soil erosion and lake deposition during the Holocene in Yunnan, China. Modern soil erosion rates are calculated using RUSLE, while Holocene soil erosion rates are estimated using modern rates with reconstructed precipitation and vegetation cover sequences. Through this investigation, we found the following results. First, Holocene vegetation in the lake basin was mainly affected by climate change, and the vegetation experienced the same pattern of changes as the climate. Soil erosion and lake deposition rates, along with changes to vegetation cover, were synchronous with precipitation trends during the Holocene. Second, soil erosion and lake deposition have been exacerbated by human activities, such as deforestation and land reclamation in the Xingyun Lake basin. Finally, this study provides new insights into the effects by anthropogenic impacts and climate forcing on the processes of soil erosion and lake deposition on the millennium scale.

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