scholarly journals Soil aggregation, erodibility and erosion rates in mountain soils (NW-Alps, Italy)

2015 ◽  
Vol 7 (1) ◽  
pp. 185-212
Author(s):  
S. Stanchi ◽  
G. Falsone ◽  
E. Bonifacio
Keyword(s):  
Soil Erosion ◽  
Erosion Rate ◽  
Agricultural Land ◽  
Aggregate Stability ◽  
Soil Erodibility ◽  
Stability Parameters ◽  
Erosion Rates ◽  
Relevant Effect ◽  
Soil Erosion Rates ◽  
Aggregate Loss

Abstract. Erosion is a relevant soil degradation factor in mountain agrosilvopastoral ecosystems, and can be enhanced by the abandonment of agricultural land and pastures, then left to natural evolution. The on-site and off-site consequences of soil erosion at the catchment and landscape scale are particularly relevant and may affect settlements at the interface with mountain ecosystems. RUSLE (Revised Universal Soil Loss Equation) estimates of soil erosion consider, among others, the soil erodibility factor (K), which depends on properties involved in structure and aggregation. A relationship between soil erodibility and aggregation is therefore expected. Erosion is however expected to limit the development of soil structure, hence aggregates should not only be related to erodibility but also mirror soil erosion rates. We investigated the relationships between aggregate stability and the RUSLE erodibility and erosion rate in a mountain watershed at the interface with settlements, characterized by two different land use types (pasture and forest). Soil erodibility was in agreement with the aggregate stability parameters, i.e. the most erodible soils in terms of K values also displayed weaker aggregation. However, estimating K from aggregate loss showed that forest soils always had negative residuals, while the opposite happened for pastures. A good relationship between RUSLE soil erosion rates and aggregate stability occurred in pastures, while no relationship was visible in forests. Several hypotheses for this behavior were discussed. A relevant effect of the physical protection of the organic matter by the aggregates that cannot be considered in K computation was finally hypothesized in the case of pastures, while in forests soil erodibility seemed to keep trace of past erosion and depletion of finer particles. In addition, in forests, the erosion rate estimate was particularly problematic likely because of a high spatial variability of litter properties. Considering the relevance and extension of agrosilvopastoral ecosystems partly left to natural colonization, further studies might improve the understanding of the relationship among erosion, erodibility and structure.

scholarly journals Soil aggregation, erodibility, and erosion rates in mountain soils (NW Alps, Italy)

Solid Earth ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 403-414 ◽  
Author(s):  
S. Stanchi ◽  
G. Falsone ◽  
E. Bonifacio
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Agricultural Land ◽  
Statistical Tests ◽  
Protective Action ◽  
Aggregate Stability ◽  
Soil Aggregation ◽  
Soil Erodibility ◽  
Erosion Rates ◽  
Soil Erosion Rates

Abstract. Erosion is a relevant soil degradation factor in mountain agrosilvopastoral ecosystems that can be enhanced by the abandonment of agricultural land and pastures left to natural evolution. The on-site and off-site consequences of soil erosion at the catchment and landscape scale are particularly relevant and may affect settlements at the interface with mountain ecosystems. RUSLE (Revised Universal Soil Loss Equation) estimates of soil erosion consider, among others, the soil erodibility factor (K), which depends on properties involved in structure and aggregation. A relationship between soil erodibility and aggregation should therefore be expected. However, erosion may limit the development of soil structure; hence aggregates should not only be related to erodibility but also partially mirror soil erosion rates. The aim of the research was to evaluate the agreement between aggregate stability and erosion-related variables and to discuss the possible reasons for discrepancies in the two kinds of land use considered (forest and pasture). Topsoil horizons were sampled in a mountain catchment under two vegetation covers (pasture vs. forest) and analyzed for total organic carbon, total extractable carbon, pH, and texture. Soil erodibility was computed, RUSLE erosion rate was estimated, and aggregate stability was determined by wet sieving. Aggregation and RUSLE-related parameters for the two vegetation covers were investigated through statistical tests such as ANOVA, correlation, and regression. Soil erodibility was in agreement with the aggregate stability parameters; i.e., the most erodible soils in terms of K values also displayed weaker aggregation. Despite this general observation, when estimating K from aggregate losses the ANOVA conducted on the regression residuals showed land-use-dependent trends (negative average residuals for forest soils, positive for pastures). Therefore, soil aggregation seemed to mirror the actual topsoil conditions better than soil erodibility. Several hypotheses for this behavior were discussed. A relevant effect of the physical protection of the organic matter by the aggregates that cannot be considered in $K$ computation was finally hypothesized in the case of pastures, while in forests soil erodibility seemed to keep trace of past erosion and depletion of finer particles. A good relationship between RUSLE soil erosion rates and aggregate stability occurred in pastures, while no relationship was visible in forests. Therefore, soil aggregation seemed to capture aspects of actual vulnerability that are not visible through the erodibility estimate. Considering the relevance and extension of agrosilvopastoral ecosystems partly left to natural colonization, further studies on litter and humus protective action might improve the understanding of the relationship among erosion, erodibility, and structure.

scholarly journals Estimation of soil loss using remote sensing and GIS-based universal soil loss equation in northern catchment of Lake Tana Sub-basin, Upper Blue Nile Basin, Northwest Ethiopia

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Veera Narayana Balabathina ◽  
R. P. Raju ◽  
Wuletaw Mulualem ◽  
Gedefaw Tadele
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Soil Erosion ◽  
Soil Loss ◽  
Erosion Rate ◽  
Soil Erodibility ◽  
Lake Tana ◽  
Erosion Rates ◽  
Soil Erosion Rate ◽  
Soil Loss Equation

Abstract Background Soil erosion is one of the major environmental challenges and has a significant impact on potential land productivity and food security in many highland regions of Ethiopia. Quantifying and identifying the spatial patterns of soil erosion is important for management. The present study aims to estimate soil erosion by water in the Northern catchment of Lake Tana basin in the NW highlands of Ethiopia. The estimations are based on available data through the application of the Universal Soil Loss Equation integrated with Geographic Information System and remote sensing technologies. The study further explored the effects of land use and land cover, topography, soil erodibility, and drainage density on soil erosion rate in the catchment. Results The total estimated soil loss in the catchment was 1,705,370 tons per year and the mean erosion rate was 37.89 t ha−1 year−1, with a standard deviation of 59.2 t ha−1 year−1. The average annual soil erosion rare for the sub-catchments Derma, Megech, Gumara, Garno, and Gabi Kura were estimated at 46.8, 40.9, 30.9, 30.0, and 29.7 t ha−1 year−1, respectively. Based on estimated erosion rates in the catchment, the grid cells were divided into five different erosion severity classes: very low, low, moderate, high and extreme. The soil erosion severity map showed about 58.9% of the area was in very low erosion potential (0–1 t ha−1 year−1) that contributes only 1.1% of the total soil loss, while 12.4% of the areas (36,617 ha) were in high and extreme erosion potential with erosion rates of 10 t ha−1 year−1 or more that contributed about 82.1% of the total soil loss in the catchment which should be a high priority. Areas with high to extreme erosion severity classes were mostly found in Megech, Gumero and Garno sub-catchments. Results of Multiple linear regression analysis showed a relationship between soil erosion rate (A) and USLE factors that soil erosion rate was most sensitive to the topographic factor (LS) followed by the support practice (P), soil erodibility (K), crop management (C) and rainfall erosivity factor (R). Barenland showed the most severe erosion, followed by croplands and plantation forests in the catchment. Conclusions Use of the erosion severity classes coupled with various individual factors can help to understand the primary processes affecting erosion and spatial patterns in the catchment. This could be used for the site-specific implementation of effective soil conservation practices and land use plans targeted in erosion-prone locations to control soil erosion.

Advances in techniques to assess soil erodibility

2021 ◽  
pp. 175-214
Author(s):  
R. J. Rickson ◽  
◽  
E. Dowdeswell Downey ◽  
G. Alegbeleye ◽  
S. E. Cooper ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Test Procedure ◽  
Aggregate Stability ◽  
Analytical Techniques ◽  
Soil Biology ◽  
Soil Erodibility ◽  
Erosion Rates ◽  
Erosion Processes ◽  
Assessment Techniques ◽  
Soil Erosion By Water

Soil erodibility is the susceptibility of soil to the erosive forces of rainsplash, runoff and wind. It is a significant factor in determining present and future soil erosion rates. Focusing on soil erosion by water, this chapter shows that erodibility is determined by static and dynamic soil properties that control a range of sub-processes affecting soil erosion, but there is no standardised test procedure, making comparison of erodibility assessment techniques and their results challenging. Most researchers agree that aggregate stability is the best indicator of soil erodibility. Selection of techniques to measure aggregate stability need to consider the type of disruptive forces and breakdown processes to which field aggregates are subjected. New indices must incorporate spatial and temporal variabilities in erodibility; the different erosion processes operating; the impact of climate change; and the role of soil biology. New analytical techniques such as computer aided tomography show promise in considering soil erodibility as a dynamic continuum operating over 3 dimensions.

scholarly journals Pendugaan Erosi Tanah dan Arahan Rehabilitasi Lahan berbasis SIG di DAS Wai Ela Negeri Lima Jazirah Leihitu Pulau Ambon

2020 ◽  
Vol 16 (1) ◽  
pp. 11-20
Author(s):  
Sisilia Wariunsora ◽  
Rafael M Osok ◽  
Silwanus Talakua
Keyword(s):  
Soil Erosion ◽  
Correction Factor ◽  
Cover Crops ◽  
Agricultural Land ◽  
Survey Method ◽  
Observation Distance ◽  
Land Rehabilitation ◽  
Erosion Rates ◽  
Study Results ◽  
Soil Erosion Rates

The occurrence of soil erosion in Wai Ela Watershed is related to natural factors such as geology, soil types, slope steepness, and land uses. This study aimed to estimate soil erosion rates and their spatial distribution in Wai Ela watershed, and the results were used to establish land rehabilitation practices. The study used a survey method with a flexible grid observation distance, and field data collection was conducted on 15 sampling areas representing 72 land units. The annual soil erosion rates of Wai Ela watershed were estimated by using RUSLE and GIS, and the results were corrected with 0,2547 (Talakua and Osok’s correction factor). The proposed land rehabilitation practices were established based on the tolerable soil erosion (T) values and CP maximum. The study results showed that the average annual erosion rates in Wai Ela watershed vary from light erosion (8,14 t/ha/yr) to very heavy erosion (381,70 t/ha/yr), while the tolerable soil erosion rates range from 4,60 t/ha/yr to 24t/ha/yr. The proposed land rehabilitation practices include enrichment of the existing unprotected areas (bare lands) with forest and fruit trees, planting cover crops and grasses, and mulching on agricultural land. Keywords: correction factor 0,2547, land rehabilitation practices, RUSLE, Wai Ela watershed   ABSTRAK Erosi pada DAS Wai Ela terjadi akibat faktor alam yaitu geologi, jenis tanah, panjang dan kemiringan lereng dan penggunaan lahan. Tujuan penelitian adalah menduga besarnya erosi di DAS Wai Ela, dan menetapkan arahan rehabilitasi lahannya. Metode yang digunakan adalah survei dengan tipe observasi fleksible grid dan pengumpulan data lapangan dilakukan pada 15 sampel area yang mewakili 72 satuan lahan. Besarnya erosi dihitung menggunakan metode RUSLE dan hasilnya dikoreksi dengan factor 0,2547, dan dipetakan menggunakan program SIG. Hasil penelitian menunjukkan bahwa rrosbi di DAS Wai Ela berkisar dari sangat ringan (8,14 ton/ha/thn) hingga erosi sangat berat (381,70 ton/ha/thn), sedangkan erosi yang dapat dibiarkan atau nilai T berkisar dari 4,6 ton/ha/thn hingga 24 ton/ha/thn. Arahan rehabilitasi lahan yang disarankan adalah melakukan pengkayaan pada lahan-lahan yang terbuka dengan tanaman hutan dan buah-buahan, menanam tanaman penutup tanah dan rumput pada lahan yang miring dan penggunaan mulsa serasah/jerami, pada lahan-lahan pertanian. Kata kunci: DAS Wai Ela, faktor koreksi 0,2547, usulan rehabilitasi lahan, RUSLE

scholarly journals Within-Storm Rainfall Distribution Effect on Soil Erosion Rate

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
S. I. Ahmed ◽  
R. P. Rudra ◽  
B. Gharabaghi ◽  
K. Mackenzie ◽  
W. T. Dickinson
Keyword(s):  
Soil Erosion ◽  
Erosion Rate ◽  
Rainfall Intensity ◽  
Silica Sand ◽  
Rainfall Erosivity ◽  
Rainfall Distribution ◽  
Erosion Rates ◽  
Soil Erosion Rate ◽  
Soil Erosion Rates ◽  
Loam Soil

This study investigates the effect of rainfall temporal distribution pattern within a storm event on soil erosion rate and the possibility of using rain power type model for rainfall erosivity. Various rainfall distribution patterns, simulated by rainfall simulator, were used on 1.0 m2 plot of silica sand and loam soil with a minimum of three replications. The results show that the soil erosion rates spiked following every sharp increase in rainfall intensity followed by a gradual decline to a steady erosion rate. Transient effects resulted in the soil erosion rates for an oscillatory rainfall distribution to be more than two fold higher than those obtained for a steady-state rainfall intensity event with same duration and same average rainfall intensity. The 3-parameter and 4-parameter rain power models were developed for a process-based measure of rainfall erosivity. The 4 parameter model yielded better match with the observed data and predicted soil erosion rates more accurately for silica sand under all rainfall distributions, and good results for loam soil under low intensity rainfall. More research is necessary to improve the accuracy of soil erosion prediction models for a wider range of rainfall distributions.

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.

scholarly journals The Impact of Land Use and Land Cover Changes on Soil Erosion in Western Iran

2021 ◽  
Author(s):  
Hadi Eskandari Damaneh ◽  
Hassan Khosravi ◽  
Khalil Habashi ◽  
Hamed Eskandari Damaneh ◽  
John P. Tiefenbacher
Keyword(s):  
Soil Erosion ◽  
Land Cover ◽  
Agricultural Land ◽  
Land Cover Changes ◽  
Lulc Changes ◽  
Erosion Rates ◽  
Soil Erosion Rates ◽  
Maximum Likelihood Methods ◽  
Landsat Satellite ◽  
The Impact

Abstract Estimates of long-term change and land cover changes using satellite imagery update data about effects erosion on the destruction. This is relevant on semi-arid land where soil resources are scarce, and proper management requires matching LULC to the conditions to achieve sustainability. This study evaluates the impact of LULC changes on soil erosion using Landsat satellite images and the RUSLE model on plains around the Jarahi River and Shadegan International Wetlands. The maps of LULC were prepared with supervised classification and maximum-likelihood methods applied to pre-processed TM, ETM, and OLI images for 1989, 2003, and 2017. This study investigated the impacts of LULC changes on soil erosion. Based on the results, we observe that an assessment of LULC changes from 1989 to 2003 revealed diminishing bare land and wetland vegetation with increases in agricultural land and water features. The areas of agricultural lands and wetlands decreased from 2003 to 2017, while bare lands increased in the area. The areas with soil erosion rates < 1 Mg ha-1 y-1 have diminished, and areas having rates >1 Mg ha-1 y-1 increased in extent. We conclude that LULC changes led to increased soil erosion in Shadegan International Wetlands. Our study highlights the need to plan LULC changes to reduce soil erosion rates to achieve sustainable management. We argue that nature-based solutions can effectively reduce soil losses.

scholarly journals Impacts of oak deforestation and rainfed cultivation on soil redistribution processes across hillslopes using 137Cs techniques

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shamsollah Ayoubi ◽  
Nafiseh Sadeghi ◽  
Farideh Abbaszadeh Afshar ◽  
Mohammad Reza Abdi ◽  
Mojtaba Zeraatpisheh ◽  
...  
Keyword(s):  
Land Use ◽  
Magnetic Susceptibility ◽  
Soil Erosion ◽  
Erosion Rate ◽  
Land Use Changes ◽  
Soil Samples ◽  
Natural Forest ◽  
Oak Forests ◽  
Erosion Rates ◽  
Rainfed Farming

Abstract Background As one of the main components of land-use change, deforestation is considered the greatest threat to global environmental diversity with possible irreversible environmental consequences. Specifically, one example could be the impacts of land-use changes from oak forests into agricultural ecosystems, which may have detrimental impacts on soil mobilization across hillslopes. However, to date, scarce studies are assessing these impacts at different slope positions and soil depths, shedding light on key geomorphological processes. Methods In this research, the Caesium-137 (137Cs) technique was applied to evaluate soil redistribution and soil erosion rates due to the effects of these above-mentioned land-use changes. To achieve this goal, we select a representative area in the Lordegan district, central Iran. 137Cs depth distribution profiles were established in four different hillslope positions after converting natural oak forests to rainfed farming. In each hillslope, soil samples from three depths (0–10, 10–20, and 20–50 cm) and in four different slope positions (summit, shoulder, backslope, and footslope) were taken in three transects of about 20 m away from each other. The activity of 137Cs was determined in all the soil samples (72 soil samples) by a gamma spectrometer. In addition, some physicochemical properties and the magnetic susceptibility (MS) of soil samples were measured. Results Erosion rates reached 51.1 t·ha− 1·yr− 1 in rainfed farming, whereas in the natural forest, the erosion rate was 9.3 t·ha− 1·yr− 1. Magnetic susceptibility was considerably lower in the cultivated land (χhf = 43.5 × 10− 8 m3·kg− 1) than in the natural forest (χhf = 55.1 × 10− 8 m3·kg− 1). The lower soil erosion rate in the natural forest land indicated significantly higher MS in all landform positions except at the summit one, compared to that in the rainfed farming land. The shoulder and summit positions were the most erodible hillslope positions in the natural forest and rainfed farming, respectively. Conclusions We concluded that land-use change and hillslope positions played a key role in eroding the surface soils in this area. Moreover, land management can influence soil erosion intensity and may both mitigate and amplify soil loss.

scholarly journals The application of137Cs and210Pbexmethods in soil erosion research of Titel loess plateau, Vojvodina, Northern Serbia

2020 ◽  
Vol 12 (1) ◽  
pp. 11-24
Author(s):  
Kristina S. Kalkan ◽  
Sofija Forkapić ◽  
Slobodan B. Marković ◽  
Kristina Bikit ◽  
Milivoj B. Gavrilov ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Alternative Methods ◽  
Delivery Ratio ◽  
Undisturbed Soil ◽  
Migration Model ◽  
Erosion Rates ◽  
Soil Erosion Rates ◽  
Profile Distribution ◽  
And Migration

AbstractSoil erosion is one of the largest global problems of environmental protection and sustainable development, causing serious land degradation and environmental deterioration. The need for fast and accurate soil rate assessment of erosion and deposition favors the application of alternative methods based on the radionuclide measurement technique contrary to long-term conventional methods. In this paper, we used gamma spectrometry measurements of 137Cs and unsupported 210Pbex in order to quantify the erosion on the Titel Loess Plateau near the Tisa (Tisza) River in the Vojvodina province of Serbia. Along the slope of the study area and in the immediate vicinity eight representative soil depth profiles were taken and the radioactivity content in 1 cm thick soil layers was analyzed. Soil erosion rates were estimated according to the profile distribution model and the diffusion and migration model for undisturbed soil. The net soil erosion rates, estimated by 137Cs method range from −2.3 t ha−1 yr−1 to −2.7 t ha−1 yr−1, related to the used conversion model which is comparable to published results of similar studies of soil erosion in the region. Vertical distribution of natural radionuclides in soil profiles was also discussed and compared with the profile distribution of unsupported 210Pbex measurements. The use of diffusion and migration model to convert the results of 210Pbex activities to soil redistribution rates indicates a slightly higher net erosion of −3.7 t ha−1 yr−1 with 98% of the sediment delivery ratio.

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