Agricultural Soil Erosion Research Articles

Stratigraphy and age of colluvial deposits indicating Late Holocene soil erosion in northeastern Germany

In the focus of this study are the sedimentary characteristics, chronology, magnitude, and causes of past soil erosion dynamics of an agriculturally intensively used glacial lowland landscape. From the mesoscale Quillow river catchment, sedimentary sections bearing colluvial sediments from different landforms were analysed to explore their geoarchive potential and to establish a local chronology of Late Holocene soil erosion. Sections from footslopes contain a rather simple stratigraphy with one topping colluvial horizon of up to 1 m thickness burying a palaeosol. In contrast glacial kettle holes preserve more complex sequences partly having several colluvial layers with intercalating palaeosols. The most complex stratigraphy is associated with a kettle hole being the ultimate sediment trap for a dendritic gully system, forming a 4 m thick sequence of alternating peat and colluvial layers. Thirty OSL ages and 13 radiocarbon ages are used to reconstruct phases of soil erosion. Potentially human-induced soil erosion, which is corroborated by local archaeological and palynological data, can be traced back to the last c. 4000 years. The oldest colluvial deposits date back to the Late Bronze Age. Most datings, however, cluster within the last 600 years with a peak in the last 200 years, ascribing the main phase of local soil erosion to the recent past. Thus, although numerous archaeological finds are detected in the catchment since the Neolithic, considerable agricultural soil erosion does not occur before the last millennium. A compilation of OSL chronologies based on colluvial sediments from other regions in Central Europe shows a more complex erosion history there with a pronounced two- or three-phased distribution of ages primarily dating into the last c. 4000–5000 years. This study underlines that in northeastern Central Europe human impact on landscapes was effective apparently at a later stage as compared to some adjacent regions.

: Evaluation of agricultural soil erosion control measures in the Nacala Corridor Area, Mozambique

: Evaluation of agricultural soil erosion control measures in the Nacala Corridor Area, Mozambique

Dynamics of agricultural soil erosion in European Russia

Socioeconomic transformation together with climate change in recent decades significantly affected the geography of agricultural erosion in European Russia. Calculations of erosion rate and soil loss from slopes using logical-mathematical erosion models within different landscape zones and administrative regions revealed spatial-temporal regularities in the dynamics of these parameters and made it possible to assess the role of changes in the main natural and anthropogenic factors of erosion. A universal significant reduction in the mass of soil material washed from tilled slopes is revealed on the background of multidirectional changes in erosion rate.

Impacts of vineyard area dynamics on soil erosion in a Mediterranean catchment (1950-2011)

ABSTRACTThe Mediterranean basin has undergone widespread land cover change. Urbanization of coastal areas, land abandonment of steeper slopes, and agricultural intensification in alluvial plains are recurrent themes. The objective of this study was to examine how vineyard land cover changes have affected agricultural soil erosion in a 50 year period (1950–2011). The study area covers a 235 km2 catchment located near the Gulf of St Tropez. Aerial photographs were used to map land cover in 1950, 1982, 2003 and 2011, and the RUSLE soil erosion model was run to estimate soil erosion.Between 1950 and 2011, vineyard went from about 2,426 ha to 1,561 ha. Mean soil erosion increased as vineyard slopes became steeper (11.8 T ha−1, 13.2 T ha−1, 14.4 T ha−1 and 13.5 T ha−1 for 1950, 1982, 2003 and 2011). Total erosion decreased after 1982: 28,621 T y−1 in 1950, 29,030 T y−1 in 1982, 22,848 T y−1 in 2003, and 21,074 T y−1 in 2011. Total soil loss in 2011 is about 75% of values in 1950–1982, so impacts on water pollution and channel dredging have evolved positively over time.

The mineral sediment loading of the modern Mississippi River Delta: what is the restoration baseline?

A restoration baseline for river deltas establishes a framework for achieving goals that can be thwarted by choosing an improper historical background. The problem addressed here is identify the size of the modern Mississippi River delta that restoration should use as that baseline. The sediment loading to the Mississippi River main stem delta fluctuated over the last 160 years with a consequential dependent plasticity in delta size. A visual time series of the delta size is presented, and the area: sediment loading ratio is calculated. This ratio ranged from 1.8 to 3.9 km2 per Mmt sediment y−1 during the pre-European colonization of the watershed in the 1800s, a maximum size in the 1930s, and then lower after soil conservation and dam construction decades later. This land building rate is similar to the 1.3 to 3.7 km2 per Mmt sediment y−1 for the Wax Lake and Atchafalaya sub-deltas located to the west, which receives some of the Mississippi River sediment and water from the main channel below St. Francisville, LA. The significance to restoration of delta land lost since the 1930s is that the baseline for the 1930s was conditioned on previous sediment loading that has since declined. Most sediment is trapped in the delta, and so the existing situation is close to a zero-sum land balance. The restoration potential should be based on the delta land area that could be built from the current sediment loading, not from those of the era during peak agricultural expansion and soil erosion in the watershed. Sediment diversions upstream will, therefore, deplete sediment supply downstream where delta land will be lost. The choice of which baseline is used can be seen as a choice between unrealistic perceptions that leads to unachievable goals and agency failures, or, the realism of a delta size limited by current sediment loading.

Validating a Basic Assumption of Using Cesium‐137 Method to Assess Soil Loss in a Small Agricultural Catchment

AbstractAlthough the fallout radionuclide 137Cs technique has been widely used to provide soil redistribution estimates in recent decades, some researchers have recently challenged the usefulness of this technique. Thus, it is necessary to evaluate the usefulness of the 137Cs technique to study soil redistribution, especially in areas that suffer from severe soil erosion and where the 137Cs inventory distributions vary. This study analyses the abundance of 137Cs deposited in sediment trapped by a check dam over 31 years in a small agriculture catchment in the Loess Plateau, which has experienced some of the most extensive agricultural soil erosion in the world. The 137Cs inventory and soil loss were evaluated, and the results indicated that the sediment deposition rate behind the check dam was approximately 38 cm/year. The specific soil erosion rate of the catchment is estimated to be 178 t ha−1 year−1. A geochemical properties fingerprinting method indicated that the ratio of the inter‐gully erosion from cropland to gully erosion was 0·46:0·54 during the investigated period of 31‐year period. Our results suggest that the 137Cs technique cannot be directly used in the study catchment. Gully erosion is the main type of soil erosion that occurs in the loess catchment, and the amount of gully erosion changes from year to year. Therefore, the abundance of 137Cs cannot be used to estimate soil redistribution where gully erosion is severe. However, after calibration, the inter‐gully soil loss was consistently related to 137Cs abundance, which means that the 137Cs technique can be used at the plot or slope scale on the Loess Plateau. Our results also reveal the particle‐size selectivity of soil detachment and sediment deposition during runoff‐erosion events. The average 137Cs content of the fine group couplets is 63% greater than the 137Cs content of the coarse group. When the studied section spans more than 15 years, the 137Cs inventory is consistent (R2 = 0·95, p < 0·01) with soil loss, which means that the selectivity may be offset over a long period. Our results confirm that the 137Cs method requires careful planning when applied at the catchment scale. Copyright © 2017 John Wiley & Sons, Ltd.

A Comprehensive Review of Blue-Green Infrastructure Concepts

Climate change is expected to result in more intense and longer-lasting droughts and increase in the frequency and intensity of heavy rainfall events. The combination of drought followed by intense rainfall increases the risk of severe flooding, with impacts on a range of natural and anthropogenic systems, including infrastructure (road washouts, damage to houses), and impacts on agriculture (soil erosion, and loss of crops and livestock). Blue-Green Infrastructure (BGI) is an interconnected network of natural and designed landscape components, including water bodies and green and open spaces, which provide multiple functions such as: (i) water storage for irrigation and industry use, (ii) flood control, (iii) wetland areas for wildlife habitat or water purification, among many others. This paper provides a review of information on the impact of BGI on environments, particularly on water resources, and vegetation. Efforts have been made to review the BGI development situation in different countries. Based on the research reviewed, the authors suggest the following as priorities for future research into the environmental impacts of BGI: determining the feasibility of BGI, and determining the impacts of applying the BGI for major regions where there have been considerable nature-based recreation and tourism resources.

Land Cover Classification in Complex and Fragmented Agricultural Landscapes of the Ethiopian Highlands

Ethiopia is a largely agrarian country with nearly 85% of its employment coming from agriculture. Nevertheless, it is not known how much land is under cultivation. Mapping land cover at finer resolution and global scales has been particularly difficult in Ethiopia. The study area falls in a region of high mapping complexity with environmental challenges which require higher quality maps. Here, remote sensing is used to classify a large area of the central and northwestern highlands into eight broad land cover classes that comprise agriculture, grassland, woodland/shrub, forest, bare ground, urban/impervious surfaces, water, and seasonal water/marsh areas. We use data from Landsat spectral bands from 2000 to 2011, the Normalized Difference Vegetation Index (NDVI) and its temporal mean and variance, together with a digital elevation model, all at 30-m spatial resolution, as inputs to a supervised classifier. A Support Vector Machines algorithm (SVM) was chosen to deal with the size, variability and non-parametric nature of these data stacks. In post-processing, an image segmentation algorithm with a minimum mapping unit of about 0.5 hectares was used to convert per pixel classification results into an object based final map. Although the reliability of the map is modest, its overall accuracy is 55%—encouraging results for the accuracy of agricultural uses at 85% suggest that these methods do offer great utility. Confusion among grassland, woodland and barren categories reflects the difficulty of classifying savannah landscapes, especially in east central Africa with monsoonal-driven rainfall patterns where the ground is obstructed by clouds for significant periods of time. Our analysis also points out the need for high quality reference data. Further, topographic analysis of the agriculture class suggests there is a significant amount of sloping land under cultivation. These results are important for future research and environmental monitoring in agricultural land use, soil erosion, and crop modeling of the Abay basin.

Field‐Scale Mapping of Soil Carbon Stock with Limited Sampling by Coupling Gamma‐Ray and Vis‐NIR Spectroscopy

Core Ideas Proximal sensors have been used for high‐detail mapping of soil C stock at field scale. Laboratory Vis‐NIR spectroscopy allowed an increase in the number of data points. Topsoil spatial variability maps were obtained using field gamma‐ray spectroscopy. Only conventional laboratory analysis was used to calibrate the model (one sample/ha). High‐precision mapping of important soil services, such as soil organic C stocks, is basic for monitoring the effects of different soil management regimes and the effectiveness of agricultural policies. Proximal soil sensing methods have been often used in the last decades to limit costs, field work, and time and to obtain reliable and accurate maps. We tested the combined use of two proximal sensors, visible–near‐infrared (Vis‐NIR) and passive γ‐ray spectrometers, to obtain highly detailed maps of C stocks of the topsoil (CS30, 0–30 cm) of nine pairs of fields in western Sicily using a limited number of sampling sites per field for traditional laboratory analysis (about one sample per hectare). Laboratory Vis‐NIR diffuse reflectance spectroscopy allowed the number of data points per field to be increased, at the same time reducing the costs for laboratory analysis. The predictive model had a coefficient of determination (R2) of 0.77 and an error (RMSE) of 0.67 kg m−2. Data points predicted by Vis‐NIR on the fine earth (<2 mm) and corrected for gravel content (CS30pred) were interpolated within each field using geographically weighted multiple regression and two sets of covariates: (i) digital elevation model derivatives, such as elevation, slope, plan and profile curvature, and topographic wetness index; and (ii) elevation and γ‐ray total counts maps. Validation of 36 independent data points showed that the second method provided greater accuracy than the first. In particular, residual prediction deviation (RPD) showed a mean value of 2.19; however, three pairs of fields showed high error and low RPD. This methodology provides a cost‐effective tool to interpolate C stocks within arable fields, limiting laboratory analysis. The accuracy of the CS30pred maps allows monitoring of the effects of agricultural management and/or soil erosion on the soil C pool.

Topographic variability and the influence of soil erosion on the carbon cycle

AbstractSoil erosion, particularly that caused by agriculture, is closely linked to the global carbon (C) cycle. There is a wide range of contrasting global estimates of how erosion alters soil‐atmosphere C exchange. This can be partly attributed to limited understanding of how geomorphology, topography, and management practices affect erosion and oxidation of soil organic C (SOC). This work presents a physically based approach that stresses the heterogeneity at fine spatial scales of SOC erosion, SOC burial, and associated soil‐atmosphere C fluxes. The Holcombe's Branch watershed, part of the Calhoun Critical Zone Observatory in South Carolina, USA, is the case study used. The site has experienced some of the most serious agricultural soil erosion in North America. We use SOC content measurements from contrasting soil profiles and estimates of SOC oxidation rates at multiple soil depths. The methodology was implemented in the tRIBS‐ECO (Triangulated Irregular Network‐based Real‐time Integrated Basin Simulator‐Erosion and Carbon Oxidation), a spatially and depth‐explicit model of SOC dynamics built within an existing coupled physically based hydro‐geomorphic model. According to observations from multiple soil profiles, about 32% of the original SOC content has been eroded in the study area. The results indicate that C erosion and its replacement exhibit significant topographic variation at relatively small scales (tens of meters). The episodic representation of SOC erosion reproduces the history of SOC erosion better than models that use an assumption of constant erosion in space and time. The net atmospheric C exchange at the study site is estimated to range from a maximum source of 14.5 g m−2 yr−1 to a maximum sink of −18.2 g m−2 yr−1. The small‐scale complexity of C erosion and burial driven by topography exerts a strong control on the landscape's capacity to serve as a C source or a sink.

MORPHOLITHODYNAMIC FACTORS OF RECENT SOIL EROSION IN THE NORTHERN PART OF THE PRIVOLZHSKAYA HIGHLAND

Modern deluvial process – agricultural soil erosion – is the most powerful process of lateral transfer of minerals, chemicals, and pollutants on the plains under development. A significant reduction of arable land in Russia, which was a result of socio-economic reforms of the end of XX century, as well as transformation of tillage into fallows and other soil-protective grounds, have caused a significant decrease in the intensity of modern deluvial processes. These changes are controlled by the geomorphologic and the most important socioeconomic factors. Cartographic and statistical methods were used to estimate the proportion of morpholithological factors’ effect on the spatial distribution of the deluvial processes for the key area in Northern forest-steppe of the Volga region. It was found that the percentage of this effect varies from 17 to 53% of total impact of all factors, and increases proportionally to the complexity of the structure of agricultural land. Erosion potential of arable slopes (LS model RUSLE) in some places reaches 20-40% of the pre-reform value and directly depends on the complexity of agro-landscape and the degree of the transformation. In general, the reduction and transformation of arable land – the area of most active slope processes – is currently ongoing, but with the slow rate.

Global soil resources under stress

Soil Science The future of humanity is intertwined with the future of Earth's soil resources. Soil provides for agriculture, improves water quality, and buffers greenhouse gases in the atmosphere. Yet human activities, including agricultural soil erosion, are rapidly degrading soil faster than it is naturally replenished. At this rate, human security over the next century will be severely threatened by unsustainable soil management practices. Amundson et al. review recent advances in understanding global soil resources, including how carbon stored in soil responds to anthropogenic warming. Translating this knowledge into practice is the biggest challenge remaining. Science , this issue [10.1126/science.1261071][1] [1]: /lookup/doi/10.1126/science.1261071

Soil science. Soil and human security in the 21st century.

Human security has and will continue to rely on Earth's diverse soil resources. Yet we have now exploited the planet's most productive soils. Soil erosion greatly exceeds rates of production in many agricultural regions. Nitrogen produced by fossil fuel and geological reservoirs of other fertilizers are headed toward possible scarcity, increased cost, and/or geopolitical conflict. Climate change is accelerating the microbial release of greenhouse gases from soil organic matter and will likely play a large role in our near-term climate future. In this Review, we highlight challenges facing Earth's soil resources in the coming century. The direct and indirect response of soils to past and future human activities will play a major role in human prosperity and survival.

Hydrogeochemical processes and vulnerability of a typical karst underground river system, southwest China

This study presents an investigation of the hydrogeochemical processes and potential vulnerability of a typical underground river system in southwest China. Physical and chemical data were collected from both traditional manual sampling and continuous automatic monitoring. Analysis of high-frequency monitoring data from the outlet spring, Jiangjiaquan spring (JJQ), of the underground river system suggests the existence of several physico-chemical processes with distinctive characteristic response to storm events. Due to the impacts of sources and migration influencing factors, seasonal variations of major chemical components of the outlet spring are much different. For the entire karst watershed, spatial variability of surface and subsurface water geochemistry was significantly influenced by land use and lithologic characteristics. Principal component analysis (PCA) reveals that agricultural activities, water-rock interactions and soil erosion are potential influencing factors and the main sources for the chemical composition of JJQ spring. Nutrients from agricultural activities can be brought into the underground river by ways of diffuse recharge from leaching of soils, as well as focused recharge from surface flow via sinkholes. Water-rock interactions in the karst aquifer provide the evidence of diffuse recharge that contributed to groundwater quality. Soil erosion mainly causes focused recharge of contaminated water with particulate matters including iron, manganese and aluminum that carried into the underground river from sinkholes via surface flow.

Variation of Water Quality Parameters with Siltation Depth for River Ichamati Along International Border with Bangladesh Using Multivariate Statistical Techniques

River is considered as one of the main sources of freshwater all over the world. Hence analysis and maintenance of this water resource is globally considered a matter of major concern. This paper deals with the assessment of surface water quality of the Ichamati river using multivariate statistical techniques. Eight distinct surface water quality observation stations were located and samples were collected. For the samples collected statistical techniques were applied to the physico-chemical parameters and depth of siltation. In this paper cluster analysis is done to determine the relations between surface water quality and siltation depth of river Ichamati. Multiple regressions and mathematical equation modeling have been done to characterize surface water quality of Ichamati river on the basis of physico-chemical parameters. It was found that surface water quality of the downstream river was different from the water quality of the upstream. The analysis of the water quality parameters of the Ichamati river clearly indicate high pollution load on the river water which can be accounted to agricultural discharge, tidal effect and soil erosion. The results further reveal that with the increase in depth of siltation, water quality degraded.

Post-fire soil erosion mitigation: a review of the last research and techniques developed in Portugal

Post-fire soil erosion risk assessment is not exempt of uncertainties. In many parts of the world post-fire soil erosion can have devastating effects over forest ecosystems, infrastructures and human life. However, in the Mediterranean countries, it has been defined as “low” and it was attributed to a long history of intense land use. This review paper integrates the last research assessing post-fire runoff and soil erosion as well as mitigation techniques focussing inPortugal. In the case of north-centralPortugal, recent research assessing wildfire and ground preparation effects leads to the conclusion that post-fire soil losses was as high as 5-10 Mg ha-1yr-1, while ground preparations soil losses doubled these figures. Since those values are higher than the estimates for tolerable soil losses, further considerations must be taken in order to guarantee a sustainable land use. The advantages of post-fire soil erosion control with straw mulching are well known worldwide. Recently, other treatments were assessed in recently burnt eucalypt and pine plantations in Portugal: 1) the eucalypt chopped bark mulch; 2) the slash logging mulch (unchopped twigs, stems and leaves); 3) the hydromulch, a mixture of water, organic fibres, seeds, nutrients and a surfactant with good performance in cut slopes rehabilitation; and 4) the polyacrylamides (PAM), a chemical agent with good performance in agricultural soil erosion control and high potential due to its low application rate. The more effective treatments were those increasing the ground cover, one of the most important key factors for soil erosion. For this reason, the eucalypt chopped bark mulch and the hydromulch reduced the runoff in 50% and the soil erosion in 80-90%, while the PAM did not achieved the required reduction effect. In areas where the ground cover was high (due to the presence of a needle carpet) the slash logging mulch was not effective since soil erosion was already low in the untreated areas.

Scratching the Critical Zone: The Global Footprint of Agricultural Soil Erosion

Agricultural activities have drastically increased soil erosion rates and it is therefore likely to have important effects on the Earth's Critical Zone. In this paper we first investigate to what extent agricultural soil erosion can be quantified. We then combine this information with our current understanding of Critical Zone processes to assess the impact of agricultural soil erosion on soil functioning (biogeochemical cycling, hydrology, crop productivity) and to identify areas where additional research is needed to complete our understanding of how agricultural soil erosion affects the Earth's Critical Zone at different spatial and temporal scales.

Assessment of soil redistribution and spatial pattern for a small catchment in the black soil region, Northeastern China: Using fallout 210Pbex

Soil erosion greatly reduces soil fertility. Quantification of soil erosion is required to effectively implement soil conservation practices. This study used the 210Pbex measurements to assess long-term rates and spatial pattern of soil redistribution in an agricultural catchment in the black soil region, Northeastern China. A total of 61 sampling cores were collected from the catchment, where 137Cs has been previously used to study medium-term soil redistribution rates. The potential use of 210Pbex was validated through using 137Cs measurements in our previous study and other methods. 210Pbex-based soil redistribution rates ranged from −106.5 to 166.9tha−1yr−1 with a mean value of −3.9tha−1yr−1. The net erosion rate for the entire catchment was −8.3tha−1yr−1, which is much higher than the tolerable soil erosion rate. The spatial pattern of soil redistribution was investigated based on the 210Pbex measurements. The correlations between the rates of soil redistribution and slope gradient and curvature were not significant at the 0.05 risk level. Although the shelterbelts could greatly affect spatial pattern of soil redistribution, ca. 78% of the eroded soils were lost per year from the agricultural catchment and soil erosion has accelerated in the last few decades. Integrated soil conservation measures are urgently required to effectively control soil loss in the black region of Northeastern China.

Human alteration of groundwater–surface water interactions (Sagittario River, Central Italy): implication for flow regime, contaminant fate and invertebrate response

Many rivers worldwide are undergoing severe man-induced alterations which are reflected also in changes of the degree of connectivity between surface waters and groundwater. Pollution, irrigation withdrawal, alteration of freshwater flows, road construction, surface water diversion, soil erosion in agriculture, deforestation and dam building have led to some irreversible species losses and severe changes in community composition of freshwater ecosystems. Taking into account the impact of damming and flow diversion on natural river discharge, the present study is aimed at (i) evaluating the effects of anthropogenic changes on groundwater/surface water interactions; (ii) analyzing the fate of nitrogenous pollutants at the floodplain scale; and (iii) describing the overall response of invertebrate assemblages to such changes. Hydrogeological, geochemical and isotopic data revealed short- and long-term changes in hydrology, allowing the assessment of the hydrogeological setting and the evaluation of potential contamination by nitrogen compounds. Water isotopes allowed distinguishing a shallow aquifer locally fed by zenithal recharge and river losses, and a deeper aquifer/aquitard system fed by surrounding carbonate aquifers. This system was found to retain ammonium and, through the shallow aquifer, release it in surface running waters via the hyporheic zone of the riverbed. All these factors influence river ecosystem health. As many environmental drivers entered in action offering a multiple-component artificial environment, a clear relationship between river flow alteration and benthic and hyporheic invertebrate diversity was not found, being species response driven by the combination of three main stressors: ammonium pollution, man-induced changes in river morphology and altered discharge regime.

Génesis y consecuencias erosivas de las lluvias de alta intensidad en la región mediterránea

Erosive processes of soil by water have always showed serious problems, mainly in those areas such as the Mediterranean environment, where the vigour of the surface, frequently low resistence of materials, little vegetation cover or bare ground, hard rainfalls and deficient management of resources, have led to favourable conditions for soil degradation. In the Mediterranean area of Spain agricultural andforest soil erosion is one ofthe most serious environmental problems. 
 The erosivity of Mediterranean rainfalls highly depends both on the intensity and on the volume of precipitations. Rainfalls in the Mediterranean area are characterized by their fortuitousness and their concentration in a few days, particularly in Autum. Rainfalls of 100, 200 and even 300 mm, registered by pluviometers in a few hours period, release hígh amounts of energy whose consequencies are visible everywhere: heavy soillosses, gullying, undermining, landsliding, piping, bulky sedimentations, flooding ... The evaluation of erosion rates generated by rainfalls, which constitutes the basisfor the determination offactor R of the U.S.L.E., presents some problems. However, the results of the erosive elficacy of heavy rainjaUs are evident all over the Mediterranean area.