scholarly journals Impact of Land Use Changes on the Erosion Processes of a Degraded Rural Landscape: An Analysis Based on High-Resolution DEMs, Historical Images, and Soil Erosion Models

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 673
Author(s):  
Dario Gioia ◽  
Antonio Minervino Amodio ◽  
Agata Maggio ◽  
Canio Alfieri Sabia

Soil erosion is one of the major natural risk factors for developing high-value crops and an accurate estimation of spatial distribution and rates of soil degradation can be crucial to prevent crop degradation. In this paper, we use comparisons between high-resolution DEMs and soil erosion models to uncover the short-term landscape evolution of hazelnut crop yields, which are affected by incipient processes of rill development. Maps of rill initiation and evolution were extracted from the analysis of UAV-based multitemporal DEMs and the application of soil erosion models. A comparison between such a short-term analysis and historical orthophotos was carried out. Such a comparison shows how the USPED model predicts, very reliably, where linear erosion occurred. In fact, a reliable overlay between the linear erosive forms predicted by the USPED model and those captured by the UAV images can be observed. Furthermore, land use changes from 1974 to 2020 are characterized by a transition from abandoned areas (1974) to areas with high-value cultivation (2020), which has a strong impact on the spatial distribution of erosion processes and landslide occurrence. Such data represent a key tool for both the investigation of the spatial distribution of hot-spots of soil degradation and the identification of effective mitigation practices of soil conservation.

2020 ◽  
Author(s):  
Silvia Kohnová ◽  
Zuzana Németová

<p>At present, the occurrence of extreme precipitation events is becoming more and more frequent and therefore it is important to quantify their impact on the landscape and soil degradation processes. Until now a wide range of soil erosion models have been developed and many significant studies performed to evaluate soil erosion processes at local and regional level, but there are still many modeling principles that suffer from a range of problems. The general problem in soil erosion modelling lies in the validation and verification of the methodologies used. The validation of erosion models is a very complicated and complex process due to lack of suitable sites, financial demands and due to the high temporal and spatial variability. The paper points to validate the physically and event-based Erosion-3D model predominantly developed to calculate the amounts of soil loss, surface runoff, and depositions resulting from natural and design rainfall events. In the study two different erosion assessment methods were chosen in order to compare diverse evaluation approaches. Both water erosion assessment methods used have certain advantages and disadvantages, but nowadays the use of physically-based models, which are a younger generation of models, are regarded to be a more innovative and effective technique for the evaluation of complex runoff-erosion processes, deposition and transport processes. The significant contribution of physically-based models is seen in their more precise representation of the erosion and deposition processes, a more proper calculation of the erosion, deposition and sediment yields and the application of more complicated characteristics, including fluctuating soil conditions and surface properties in comparison with empirical models. The validation of the models was performed based on the continuous rainfall events for the period selected (2015, 2016 and 2017). The extreme rainfall events occurring during the period were chosen and their serious impact on the agricultural land was modeled. The modelled sediment data were compared with the measured sediment deposition data obtained by a bathymetry survey of the Svacenicky Creek polder. The polder is situated in the middle of the Myjava hill lands in the western part of Slovakia and the bathymetry measurement were conducted using a hydrographical survey using the EcoMapper Autonomous Underwater Vehicle (AUV) device. The results of the study include a comparison between the modelled and measured data and an assessment of the impact of the intensive rainfall events on the investigated territory.</p><p>Key words: intensive rainfall events, agricultural land, soil degradation processes, hydrological extremes, physically-based model</p>


2020 ◽  
Author(s):  
Lauren Zweifel ◽  
Maxim Samarin ◽  
Katrin Meusburger ◽  
Volker Roth ◽  
Christine Alewell

<p>Soil erosion in Alpine grassland areas is an ecological threat caused by the extreme topography, prevailing climate conditions and land-use practices but enhanced by climate change (e.g., heavy precipitation events, changing snow dynamics) in combination with changing land-use practices (e.g, more intensely used pastures). To increase our understanding of ongoing soil erosion processes in Alpine grasslands, there is a need to acquire detailed information on spatial extension and temporal trends.</p><p>In the past, we have successfully applied a semi-automatic method using an object-based image analysis (OBIA) framework with high-resolution aerial images (0.25-0.5m) and a digital terrain model (2m) to map erosion features in the Central Swiss Alps (Urseren Valley, Canton Uri, Switzerland). Degraded sites are classified according to the major erosion process (shallow landslides; sites with reduced vegetation cover affected by sheet erosion) or triggering factors (trampling by livestock; management effects) (Zweifel et al. 2019). We now aim to apply a deep learning (DL) model with the purpose of fast and efficient spatial upscaling(e.g., alpine-wide analysis). While OBIA yields high quality results, there are multiple constraints, such as labor-intensive steps and the requirement of expert knowledge, which make the method unsuitable for larger scale applications. The results of OBIA are used as a training dataset for our DL model. The DL approach uses fully-convolutional networks with the U-Net architecture and is capable of rapid segmentation and classification to identify areas with reduced vegetation cover and bare soil sites.</p><p>Results for the Urseren Valley (Canton Uri, Switzerland) show an increase in total area affected by soil degradation of 156 ±18% during a 16-year observation period (2000-2016). A comparison of the two methods (OBIA and DL) shows that DL results for the Urseren Valley follow similar trends for the 16-year period and that the segmentations of eroded sites are in good agreement (IoU = 0.83). First transferability tests to other valleys not considered during training of the DL model are very promising, confirming that DL is a well-suited and efficient method for future projects to map and assess soil erosion processes in grassland areas at regional scales.</p><p> </p><p><strong>References</strong></p><p>L. Zweifel, K. Meusburger, and C. Alewell. Spatio-temporal pattern of soil degradation in a Swiss Alpine grassland catchment. Remote Sensing of Environment, 235, 2019.</p>


2020 ◽  
Vol 79 (15) ◽  
Author(s):  
Qiongfang Li ◽  
Guobin Lu ◽  
Xingye Han ◽  
Zhengmo Zhou ◽  
Tianshan Zeng ◽  
...  

2018 ◽  
Vol 40 (3) ◽  
pp. 1476
Author(s):  
T. Mimides ◽  
E. Psomiadis ◽  
I. Trikili

The present paper focuses on the usefulness of aerial photographs and satellite data in the multitemporal detection of land use changes, soil degradation and erosion. The study was carried out in the watershed of Vathy in the Kalymnos Island, and the study period spanned from 1960 to 1999. Aerial photographs of two different periods of time and satellite SPOT data were used for this purpose. The synergistic use of a Geographical Information System for the manipulation of the data was the key for the Natural monitoring of the soil erosion and degradation. The results revealed many changes in the cultivations and in the land use of the watershed the last decades. These changes supplemented by village expansion and spatial reduction of natural vegetation led to the acceleration of soil erosion, to the degradation of water supplies and generally to an environmental deterioration of the wider area.


Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2973
Author(s):  
Velibor Spalevic ◽  
Goran Barovic ◽  
Dusko Vujacic ◽  
Milic Curovic ◽  
Morteza Behzadfar ◽  
...  

Land use change in all river basins leads to changes in hydrologic response, soil erosion, and sediment dynamics characteristics. Those changes are often viewed as the main cause of accelerated erosion rates. We studied the impact of land use changes on soil erosion processes in one of the watersheds in Montenegro: the Miocki Potok, using this watershed as a pilot river basin for this area. We simulated responses of soil erosion processes by using a process-oriented soil erosion Intensity of Erosion and Outflow (IntErO) model, with different settings of land use for the years 1970, 1980, 1990, 2000, 2010, and 2020. The model provides fast, effective, and affordable insight into the effects of land use change on soil erosion processes. Testing of the applied procedures was important for the further establishment of watershed management methodologies at the national level, for the other 300 river basins of Montenegro. For the current state of land use, calculated peak discharge for the Miocki Potok was 364 m3 s−1 (2020)–372 m3 s−1 (1970) for the incidence of 100 years, and there is a possibility for large flood waves to appear in the studied basin. Real soil losses, Gyear, were calculated at 13680 m3 year−1 (2020) and specific 333 m3 km−2 year−1 (2020). A Z coefficient value of 0.439 (2020) indicated that the river basin belongs to destruction category III. The strength of the erosion process was medium, and according to the erosion type, it was mixed erosion. According to our analysis, the land use changes in the last 50 years influenced a decrease in the soil erosion intensity for 14% in the Miocki Potok River Basin. Further studies should be focused on the detailed analysis of the land use changes trends with the other river basins at the national level, closely following responses of soil erosion to the changed land use structure, and effects of plant-and-soil interaction on soil erosion and sediment dynamics.


2002 ◽  
Vol 6 (2) ◽  
pp. 255-265 ◽  
Author(s):  
Armando Brath ◽  
Attilio Castellarin ◽  
Alberto Montanari

Abstract. The effects of land-use changes on potential annual gross erosion in the uplands of the Emilia-Romagna administrative region, a broad geographical area of some 22 000 km2 in northern-central Italy, have been analysed by application of the Universal Soil Loss Equation (USLE). The presence of an extended mountain chain, particularly subject to soil erosion, makes the estimation of annual gross erosion relevant in defining regional soil-conservation strategies. The USLE, derived empirically for plots, is usually applied at the basin scale. In the present study, the method is implemented in a distributed framework for the hilly and mountainous portion of Emilia-Romagna through a discretisation of the region into elementary square cells. The annual gross erosion is evaluated by combining morphological, pedological and climatic information. The stream network and the tributary area drained by each elementary cell, which are needed for the local application of the USLE, are derived automatically from a Digital Elevation Model (DEM) of grid size 250 x 250 m. The rainfall erosivity factor is evaluated from local estimates of rainfall of six-hour storm duration and two-year return period. The soil erodibility and slope length-steepness factors are derived from digital maps of land use, pedology and geomorphology. Furthermore, historical land-use maps of the district of Bologna (a large portion — 3720 km2 — of the area under study), allow the effect of actual land use changes on the soil erosion process to be assessed. The analysis shows the influence of land-use changes on annual gross erosion as well as the increasing vulnerability of upland areas to soil erosion processes during recent decades. Keywords: USLE, gross erosion, distributed modelling, land use changes, northern-central Italy


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1438
Author(s):  
Snežana Jakšić ◽  
Jordana Ninkov ◽  
Stanko Milić ◽  
Jovica Vasin ◽  
Milorad Živanov ◽  
...  

Spatial distribution of soil organic carbon (SOC) is the result of a combination of various factors related to both the natural environment and anthropogenic activities. The aim of this study was to examine (i) the state of SOC in topsoil and subsoil of vineyards compared to the nearest forest, (ii) the influence of soil management on SOC, (iii) the variation in SOC content with topographic position, (iv) the intensity of soil erosion in order to estimate the leaching of SOC from upper to lower topographic positions, and (v) the significance of SOC for the reduction of soil’s susceptibility to compaction. The study area was the vineyard region of Niš, which represents a medium-sized vineyard region in Serbia. About 32% of the total land area is affected, to some degree, by soil erosion. However, according to the mean annual soil loss rate, the total area is classified as having tolerable erosion risk. Land use was shown to be an important factor that controls SOC content. The vineyards contained less SOC than forest land. The SOC content was affected by topographic position. The interactive effect of topographic position and land use on SOC was significant. The SOC of forest land was significantly higher at the upper position than at the middle and lower positions. Spatial distribution of organic carbon in vineyards was not influenced by altitude, but occurred as a consequence of different soil management practices. The deep tillage at 60–80 cm, along with application of organic amendments, showed the potential to preserve SOC in the subsoil and prevent carbon loss from the surface layer. Penetrometric resistance values indicated optimum soil compaction in the surface layer of the soil, while low permeability was observed in deeper layers. Increases in SOC content reduce soil compaction and thus the risk of erosion and landslides. Knowledge of soil carbon distribution as a function of topographic position, land use and soil management is important for sustainable production and climate change mitigation.


Author(s):  
Hui Wei ◽  
Wenwu Zhao ◽  
Han Wang

Large-scale vegetation restoration greatly changed the soil erosion environment in the Loess Plateau since the implementation of the “Grain for Green Project” (GGP) in 1999. Evaluating the effects of vegetation restoration on soil erosion is significant to local soil and water conservation and vegetation construction. Taking the Ansai Watershed as the case area, this study calculated the soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration, using the Chinese Soil Loess Equation (CSLE), based on rainfall and soil data, remote sensing images and socio-economic data. The effect of vegetation restoration on soil erosion was evaluated by comparing the average annual soil erosion modulus under two scenarios among 16 years. The results showed: (1) vegetation restoration significantly changed the local land use, characterized by the conversion of farmland to grassland, arboreal land, and shrub land. From 2000 to 2015, the area of arboreal land, shrub land, and grassland increased from 19.46 km2, 19.43 km2, and 719.49 km2 to 99.26 km2, 75.97 km2, and 1084.24 km2; while the farmland area decreased from 547.90 km2 to 34.35 km2; (2) the average annual soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration was 114.44 t/(hm²·a) and 78.42 t/(hm²·a), respectively, with an average annual reduction of 4.81 × 106 t of soil erosion amount thanks to the vegetation restoration; (3) the dominant soil erosion intensity changed from “severe and light erosion” to “moderate and light erosion”, vegetation restoration greatly improved the soil erosion environment in the study area; (4) areas with increased erosion and decreased erosion were alternately distributed, accounting for 48% and 52% of the total land area, and mainly distributed in the northwest and southeast of the watershed, respectively. Irrational land use changes in local areas (such as the conversion of farmland and grassland into construction land, etc.) and the ineffective implementation of vegetation restoration are the main reasons leading to the existence of areas with increased erosion.


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