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Soil erosion by water affects soil organic carbon (SOC) migration and distribution, which are important processes for defining ecosystem carbon sources and sinks. Little has been done to quantify soil carbon erosion in the three major basins in China, the Yangtze River, Yellow River and Pearl River Basins, which contain the most eroded areas. This research attempts to quantify the lateral movement of SOC based on spatial and temporal patterns of water erosion rates derived from an empirical Unit Stream Power Erosion Deposition Model (USPED) model. The water erosion rates simulated by the USPED model agreed reasonably with observations ([R.sup.2] = 0.43, P < 0.01). We showed that regional water erosion ranged within 23.3-50 Mg [ha.sup.-1] [year.sup.-1] during 1992-2013, inducing the lateral redistribution of SOC caused by erosion in the range of 0.027-0.049 Mg C [ha.sup.-1] [year.sup.-1], and that caused by deposition of 0.0079-0.015 Mg C [ha.sup.-1] [year.sup.-1], in the three basins. The total eroded SOC was 0.006, 0.002 and 0.001 Pg [year.sup.-1] in the Yangtze River, Yellow River and Pearl River Basins respectively. The net eroded SOC in the three basins was -0.0075 Pg C [year.sup.- 1]. Overall, the annual average redistributed SOC rate caused by erosion was greater than that caused by deposition, and the SOC loss in the Yangtze River Basin was greatest among the three basins. Our study suggests that considering both processes of erosion and deposition--as well as effects of topography, rainfall, land use types and their interactions--on these processes are important to understand SOC redistribution caused by water erosion. Additional keywords: Pearl River, soil organic carbon, USPED, water erosion, Yangtze River, Yellow River. Received 12 November 2019, accepted 13 May 2020, published online 8 July 2020, Introduction Since the 'missing carbon sink' in the global carbon (C) budget was summarised by Schindler (1999), tremendous efforts have been made to quantify the terrestrial C budget from local [...]

Vegetation restoration influences near soil-surface characteristics and thus likely affects soil erodibility. This study was performed to quantify the effects of vegetation restoration on soil erodibility on steep gully slopes, and to identify the potential influencing factors on the Loess Plateau. Three shrub and four grass types distributed on different gully slopes were selected, and six erodibility indicators and an integrated erodibility index (IEI) were applied to indirectly evaluate the effects of vegetation restoration on soil erodibility. The former included the soil erodibility K factor, aggregate stability (the mean weight diameter, MWD, and the mean number of drop impacts, MND), saturated hydraulic conductivity ([K.sub.s]), cohesion (Coh), and penetration resistance (PR), and the latter was calculated using these indicators and a weighted integration method. The results showed that vegetation restoration on steep gully slopes was effective in reducing soil erodibility on the Loess Plateau, and grasses seemed more effective than shrubs. Compared with the control, the K of vegetation-restored gully slopes decreased by 4.1-24.0%, and MWD, MND, [K.sub.s], Coh, and PR increased by 64.0-284.3, 51.4-269.5, 100.5-417.4, 10.1-172.2, and 63.3-278.9% respectively. Consequently, the IEI of the vegetation-restored gully slopes declined by 33.1-81.9%, and the mean reduction percentage of the four grasses was 1.5 times that of the three shrubs. The variation in soil erodibility was closely related to the changes in the soil organic matter content and root mass density with vegetation restoration. The results will help in understanding the soil conservation mechanisms of vegetation restoration on steep gully slopes.Additional keywords: revegetation, soil erosion, soil physical properties., IntroductionThe Loess Plateau of China is one of the regions in the world with large gullies and suffers from severe soil erosion, with a soil erosion rate of 5000-10000t [km.sup.-2] [...]

Soil organic carbon (SOC) is one of the primary elements required in the functioning of ecosystems. Soil erosion, a major mechanism of land degradation, removes SOC and transfers it to the hydrosphere or the atmosphere, thereby affecting key ecosystem functions and services. The Mediterranean region is highly susceptible to land degradation because of erosion due to heavy rains following long, dry, hot summers. Although the Mediterranean landscape typically has a high altitude and incline, the soil is brittle and soft and is easily washed away by rain. Thus, vast regions in Turkey have been afflicted by this type of soil degradation. This study aimed to (1) estimate the temporal distribution of water erosion in the Seyhan River Basin, (2) assess the spatial distribution of SOC and (3) estimate the depletion of SOC through soil erosion using the Pan-European Soil Erosion Risk Assessment model, a physically based, regionally scaled soil erosion model. The annual amount of soil eroded from the Seyhan River Basin is estimated to be 7.8 million tonnes per hectare (t [ha.sup.-1] [year.sup.-1]). The amount of fertile soil loss from agricultural areas is ~1.2 million tonnes per year. The maximum amount of soil erosion occurs in maintenance scrubland and degraded forest areas, contributing to 68% of erosion, followed by that in agricultural land, contributing to 27% of erosion, with the remaining in forests and urban areas. Additional keywords: Mediterranean environment, PESERA, SOC, soil erosion. Received 23 February 2016, accepted 18 November 2016, published online 15 December 2016, Introduction Soils are major reservoirs for global carbon (C) storage. Soil organic carbon (SOC) is a primary constituent (~2500 Pg) of total soil C, making it the key element in [...]

Sediments were collected from four slow vegetation recovery plots, six fast vegetation recovery plots and five unburned plots at a post-fire site on a rainfall event basis and sorted for size distribution. The aim was to evaluate the effects of vegetation cover, soil aggregate stability, slope and rainfall intensity on sediment size distribution, transport selectivity and erosion processes between the burned and unbumed treatment plots. Sediment detachment and transport mechanisms and the particle size transport selectivity of the eroded sediment were assessed based on enrichment ratios (ER) and mean weighted diameter (MWD) methods. The most eroded particle size class in all treatment plots was the 125-250 µm class and, generally, the percentage of eroded particle sizes did not increase with slope and rainfall intensity. Higher MWD of the eroded sediment was related to a higher percentage of bare soil exposed and gravel content associated with high soil bum severity and soil disaggregation in the slow vegetation recovery plots. The enrichment of finer clay silt particle sizes increased with varying maximum 30-min rainfall intensity ([I.sub.30]) in the slow vegetation recovery plots, and reflected increased aggregate breakdown and transport selectivity, whereas no good relationship was found in the fast vegetation recovery and unbumed plots with varying [I.sub.30]. A minimum [I.sub.30] of < 3.56 mm [h.sup.-1] and a maximum of 10.9 mm [h.sup.-1] were found to be the threshold rainfall intensity values necessary for aggregate breakdown and transport of finer particles by both rainsplash and rainflow in the slow vegetation recovery plots, whereas the response was weak in the fast vegetation recovery and unburned plots following varying [I.sub.30] dominated only by rainsplash transport closer to the plot sediment collector. The results show that higher vegetation cover in the fast vegetation recovery and unbumed plots reduces erosive rainfall energy by 5.6- and 17.7-fold respectively, and runoff energy by 6.3- and 21.3-fold respectively, limiting aggregate breakdown and transport selectivity of finer particles compared with the slow vegetation recovery plots. Additional keywords: aggregate stability, runoff, soil erosion, soil texture, vegetation recovery. Received 3 May 2016, accepted 10 June 2016, published online 20 September 2016, Introduction In South Korea, forest fires mostly occur in March and April, and the mean annual frequency and intensity of occurrence of forest fires has increased because of human-induced fires [...]

Soil erosion in olive groves is a widespread phenomenon in the Mediterranean Basin. Many studies have investigated the effects of tillage and herbaceous ground cover (spontaneous or seeded) in their effectiveness to reduce soil erosion in a wide range of Mediterranean sites under different pedoclimatic and topographic conditions. The present study was performed in Ferrandina, southern Italy: a small drip-type rainfall simulator was used on square microplots (0.25 x 0.25 m) to evaluate the propensity to erosion of a steep rain-fed olive grove (mean slope ~10%) with a sandy loam soil by measuring runoff and sediment load under extreme rain events. Two types of soil management were compared: (1) spontaneous grasses as ground cover (GC) providing a maximum ground cover close to 100%; and (2) tillage (T). In the tillage treatment, a further distinction was made between runoff and sediment produced 1 day (T1) and 10 days (T2) after tillage in order to assess the temporal evolution of tillage effects. The results show that GC reduced surface runoff to approximately one-third and soil losses to zero compared with T1. T2 microplots, tested 10 days after tillage, produced only one-tenth the sediment compared with T1 microplots that were subjected to rainfall simulations 1 day after tillage. Total runoff between the two tilled microplots was similar, although runoff on T1 microplots increased steadily over time whereas runoff on T2 microplots remained stable over the duration of simulations. Such findings may be useful to direct and strengthen the policy towards measures to prevent further soil degradation, as clearly requested by the European Union via the cross-compliance concept. A further economic recognition to the olive growers for the achievable environmental benefits could convince them to a shift towards alternative soil management strategies. Additional keywords: conservation measures, natural resources, nutrient losses, soil management., Introduction The process of erosion entails two different subprocesses, namely detachment of soil particles from the soil and the subsequent transport of these detached soil particles (Morgan 2005). Studies have [...]

Effects of soil erosion and cropping on soil organic carbon (SOC) stocks need to be addressed to better understand the processes of SOC loss following the conversion of natural ecosystems to agriculture. The aims of the present study were to: (1) understand the mechanism of SOC and total nitrogen (TN) losses in a small-scale agricultural landscape with sloping terraces; and (2) quantitatively assess vertical changes in SOC and TN of soil profiles at specific landscape positions and the lateral distribution of SOC and TN in areas with different soil erosion and deposition rates. Soil samples from cultivated land were collected at 5-m intervals along toposequences in different parts of hilly areas of the Sichuan Basin, China; uncultivated land was used as a reference for [sup.137]Cs, SOC and TN. The profile shape of SOC and total N depth distribution was markedly different between cultivated and uncultivated soils, with differences in descriptive coefficients of 2.1-3.4- and 2.0-3.2-fold for a, 1.2-2.2- and 1.0-1.8-fold for b, respectively, in the equationy = -aln(x) + b, wherey is the depth SOC or TN concentration and x is the depth from the soil surface. SOC and TN concentrations in the surface soil horizon were significantly higher on uncultivated land (17.5 g [kg.sup.-1]) than on cultivated land (7.06-9.81 g[kg.sup.-1]). In particular, the 0-5cm surface layer of uncultivated soils had 1.3-, 1.7-, and 2.3- fold higher SOC concentrations than that of the depositional, weak erosional and strong erosional areas, respectively, in cultivated soils. However, there were no significant differences in SOC and TN concentrations in subsoil layers between cultivated and uncultivated lands, suggesting that cropping is one of the factors causing SOC and N losses. SOC and TN inventories exhibited an increasing trend from the upper to toe proportions of the cultivated toposequences. In all the cultivated soils, SOC and TN concentrations of the surface soil horizon and inventories of SOC and TN were closely associated with [sup.137]Cs inventories (P Additional keywords: [sup.137]Cs tracer, tillage erosion. Received 13 June 2014, accepted 29 September 2014, published online 12 January 2015, Introduction Organic carbon (OC) is lost from the soil mainly through mineralisation of soil organic matter to C[O.sub.2]; minor losses can also occur by leaching of soluble OC. If farming [...]

Many authors have reported significant soil erosion resulting from the grazing of sheep, rabbit plagues and invasion of the exotic Hawkweed (Hieracium sp.) in the sub humid alpine region of Mackenzie Basin, South Island, New Zealand. In the present study, wc investigated the soil redistribution of four study plots with varying vegetation depletion over historic (54 years) and long (25 ka) time scales. Historic soil loss, quantified by bomb fallout [sup.137]Cs, under plots of depleted short tussock and herbfield vegetation was no more than the adjacent undisturbed reference plot of red tussock (Chionochloa rubra). This indicates the present landscape characterised by soil and vegetation degradation is not due to erosion since 1953. There is no evidence from the present study to suggest that establishment and rapid invasion of Hieracium sp. and major periodic rabbit plagues have accelerated soil erosion over the past 54 years. By contrast, low topsoil thickness under Hieracium sp. indicates that Hieracium sp. is colonising bare ground and may have, at least in the short-term, a stabilising effect. Long-term soil loss was quantified by the profile distribution of volcanic glass originating from Kawakawa-Oruanui tephra (KOT). The peak concentration, and hence the tephra's 25.4 ka isochron, occurred at a depth of 70-85 cm at the reference plot. The degraded plots showed significant decreases in glass concentration and depth to peak concentration with progressively shallower soils and vegetation depletion. This equated to a minimum erosion rate averaged over the past -25.4 k years of 0.020 mm [year.sup.-1] in the most eroded plot. The extent of bare ground and topsoil thickness were poor indicators of soil erosion status. The tephra results show a potentially long history of soil erosion that has predisposed soil and vegetation degradation within the European era. Additional keywords: caesium-137, Hieracium, soil conservation, soil redistribution, tussock grasslands, vegetation change. Received 27 October 2013, accepted 8 September 2014, published online 12 January 2015, Introduction There is increasing concern that anthropogenic soil erosion is a serious threat to the sustainable development and environmental protection of our land resources (Lai 1990; Pimentel et al. 1995; [...]

For soils and conditions outside the USA, input parameters for physically based soil erosion models, such as the WEPP model, are usually not available, particularly for tropical soils. In a laboratory study, small erosion pans and a programmable rain simulator were used to determine interrill erodibility, whereas in the field, rills were physically allocated in the field as plots of 0.1 by 10 m within a ridge--furrow arrangement and five water-inflow rates were applied sequentially to determine rill erodibility and critical hydraulic shear. During the rain or inflows, runoff samples were taken and flow was characterised. The soils tested were Grey Vertosol, Black Vertosol, and Red Ferrosol. The fall velocity parameter, [V.sub.50], for rill soil and eroded sediment followed the order Red Ferrosol > Grey Vertosol > Black Vertosol, which Black Vertosol was the same order as observed for [V.sub.50] and mean weight diameter (MWD) of aggregates in the interrill erosion experiment and [D.sub.50] of interrill eroded sediment, demonstrating differences between soils in dispersion and aggregate stability. The estimated values obtained by the WEPP model were not comparable to laboratory interrill erodibility values or to field rill erodibility values. Thus, erodibility parameters for physically based erosion models such a WEPP should be determined in the field for tropical soils, and new equations need to be developed to estimate such values based on soil properties for tropical soils. Additional keywords: erosion processes, flow regime, sedimentation, tropical soils, WEPP model., Introduction Tropical soils are thought to be fairly stable with respect to erosion; however, when subjected to extremely high rainfall volumes of short duration, catastrophic erosion can occur. This is [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2010.04.014 Byline: S.J. Rodway-Dyer, D.E. Walling Abstract: There is increasing awareness of the damage caused to valuable and often unique sensitive habitats by people pressure as degradation causes a loss of plant species, disturbance to wildlife, on-site and off-site impacts of soil movement and loss, and visual destruction of pristine environments. This research developed a new perspective on the problem of recreational induced environmental degradation by assessing the physical aspects of soil erosion using the fallout radionuclide caesium-137 (.sup.137Cs). Temporal sampling problems have not successfully been overcome by traditional research methods monitoring footpath erosion and, to date, the.sup.137Cs technique has not been used to estimate longer-term soil erosion in regard to sensitive recreational habitats. The research was based on-sites within Dartmoor National Park (DNP) and the South West Coast Path (SWCP) in south-west England..sup.137Cs inventories were reduced on the paths relative to the reference inventory (control), indicating loss of soil from the path areas. The Profile Distribution Model estimated longer-term erosion rates (ca. 40 years) based on the.sup.137Cs data and showed that the combined mean soil loss for all the sites on 'paths' was 1.41 kg m.sup.-2 yr.sup.-1 whereas the combined 'off path' soil loss was 0.79 kg m.sup.-2 yr.sup.-1, where natural (non-recreational) soil redistribution processes occur. Recreational pressure was shown to increase erosion in the long-term, as greater soil erosion occurred on the paths, especially where there was higher visitor pressure. Author Affiliation: Department of Geography, University of Exeter, Amory Building, Rennes Drive, Exeter, Devon, EX4 4RJ, UK Article History: Received 2 August 2009; Revised 24 March 2010; Accepted 20 April 2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.11.003 Byline: P. Martin (a)(b), A. Joannon (c), N. Piskiewicz (a)(b) Abstract: This article proposes the use of a new model, DIAR (Diagnostic Agronomique du Ruissellement, or Agronomic Assessment of Runoff), for the prediction of the timing of the risk of runoff. DIAR is dedicated to loamy soils which are very sensitive to surface crusting, leading to runoff, soil erosion and muddy flows. The approach is proposed for the north-western European loess belt regions where muddy flows severely impact human activities. The likelihood of runoff is assessed from the sequence of soil surface states generated by cultivation practices. DIAR is based on the calculation of curve number values, for each stage of the soil-surface-state sequence, for calculating runoff for each of these stages. In this study, DIAR is applied to a catchment of 912ha, cultivated by 26 farmers in the Pays de Caux (Normandy, France) where infrastructures located at the outlet have been damaged several times by muddy flows. Local public authorities involved in reducing muddy flows are eager to limit the agricultural upstream runoff by extending the planting of mustard as a winter cover crop. We tested the efficiency of such a policy on the reduction of the mean runoff. We also tested the year-to-year variability of this efficiency using the acreages of four successive years (1999-2000 to 2002-2003). Finally, the cost-efficiency of the policy was also considered. Though we used the same weather scenario, the initial situation (without much mustard cover) showed a wide year-to-year variation in the total runoff. This variation can be associated with the structure of the farms that cultivate the catchment (Utilised Agricultural Area (UAA) of each farm and percentage of this UAA inside the catchment). Our results showed that the widespread planting of winter cover crops could reduce the runoff by 10-20% compared with the initial situation (depending on the year), and also reduce the year-to-year variability of runoff. For each of the 4 tested years, the cost of the infiltrated m.sup.3, due to each ha of mustard cover, decreases with the increase in mustard cover. It indicates that the present siting of the mustard cover is not as efficient as it could be. We should ask why farmers do not sow it elsewhere. Author Affiliation: (a) AgroParisTech, UMR 1048, Paris, France (b) INRA, UMR 1048, Paris, France (c) INRA, UR SAD Paysage, Rennes, France Article History: Received 3 April 2009; Revised 29 October 2009; Accepted 26 November 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.09.025 Byline: Catherine Marina Pickering (a), Wendy Hill (a), David Newsome (b), Yu-Fai Leung (c) Abstract: Hiking, horse riding and mountain biking are popular in protected areas in Australia and the United States of America. To help inform the often contentious deliberations about use of protected areas for these three types of activities, we review recreation ecology research in both countries. Many impacts on vegetation, soils and trails are similar for the three activities, although there can be differences in severity. Impacts include damage to existing trails, soil erosion, compaction and nutrification, changes in hydrology, trail widening, exposure of roots, rocks and bedrock. There can be damage to plants including reduction in vegetation height and biomass, changes in species composition, creation of informal trails and the spread of weeds and plant pathogens. Due to differences in evolutionary history, impacts on soil and vegetation can be greater in Australia than in the USA. There are specific social and biophysical impacts of horses such as those associated with manure and urine, grazing and the construction and use of tethering yards and fences. Mountain bike specific impacts include soil and vegetation damage from skidding and the construction of unauthorised trails, jumps, bridges and other trail technical features. There are gaps in the current research that should be filled by additional research: (1) on horse and mountain bike impacts to complement those on hiking. The methods used need to reflect patterns of actual usage and be suitable for robust statistical analysis; (2) that directly compares types and severity of impacts among activities; and (3) on the potential for each activity to contribute to the spread of weeds and plant pathogens. Additional research will assist managers and users of protected areas in understanding the relative impacts of these activities, and better ways to manage them. It may not quell the debates among users, managers and conservationists, but it will help put it on a more scientific footing. Author Affiliation: (a) International Centre for Ecotourism, Griffith University, Gold Coast, QLD 4222, Australia (b) Environmental Science and Ecotourism, Murdoch University, Murdoch, WA 6150, Australia (c) Department of Parks Recreation and Tourism Management, North Carolina State University, Raleigh, NC 27695-7106, USA Article History: Received 6 July 2009; Revised 15 September 2009; Accepted 21 September 2009

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1365-2745.2009.01533.x Byline: Ingo Feeser (*), Michael O'Connell Keywords: biogeography; coprophilous fungal spores; environmental change; karst; land use; late Holocene; non-pollen palynomorphs; pollen analysis; soil erosion; vegetation dynamics Abstract: Summary The study focuses on species-rich, upland, heathy vegetation with arctic-alpine floristic affinities and Sesleria grasslands in the karstic Burren region, western Ireland. The investigations aimed at reconstructing the long-term development of these high conservation-value communities and the role of farming in their formation and long-term survival. The methods used included pollen analysis and 14C-dating of short monoliths and investigation of grykes (fissures in karstic limestone) for evidence of soil erosion. Special attention was paid to fossil, coprophilous fungal spores as indicators of local grazing. The strong local character of the pollen records facilitated identification of inter-site differences as well as regional patterns. It is shown that open pine woodland characterized the Cappanawalla uplands between c. 1500 BC and 500 BC. It is proposed that such woodlands, with floristic affinities to Scandinavian open pine woodlands on calcareous soils, provided a suitable environment for the present-day, open heath vegetation with species such as Dryas octopetala, Arctostaphylos uva-ursi, Geranium sanguineum and Empetrum nigrum. Burning of vegetation as a management tool was important in the uplands over most of the last two millennia. Firing seems to have ceased with the onset of more intensive grazing regimes in the 18th century. Synthesis. Upland palaeoarchives, derived from shallow peaty deposits, show that the upland Burren supported mainly plagioclimax Corylus-dominated woody vegetation and grasslands from c. 1500 BC (beginning of present record), until possibly as late as the 17th century AD. In the uplands of the north-western Burren, open, species-rich pinewoods with hazel dominated. The northern-arctic elements in the present-day upland flora survived clearances, involving initially Pinus sylvestris (c. 500 BC) and subsequently Corylus avellana (c. AD 1600). Colluvial material retrieved from grykes supports the idea of considerable soil loss occurring as late as the first and early 2nd millennium AD. The investigations highlight the potential of upland palaeoarchives, consisting of short sequences, for elucidating vegetation and land-use dynamics in karstic environments such as the Burren. Article History: Received 3 February 2009; accepted 9 June 2009 Handling Editor: Richard Bradshaw Article note: (*) Correspondence author. E-mail: ingo.feeser@nuigalway.ie

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.earscirev.2009.02.003 Byline: F.G.A. Verheijen (a)(b), R.J.A. Jones (b), R.J. Rickson (b), C.J. Smith (b) Keywords: erosion tolerance; soil formation; climate change; soil protection; monitoring; dust deposition Abstract: Erosion is a major threat to soil resources in Europe, and may impair their ability to deliver a range of ecosystem goods and services. This is reflected by the European Commission's Thematic Strategy for Soil Protection, which recommends an indicator-based approach for monitoring soil erosion. Defined baseline and threshold values are essential for the evaluation of soil monitoring data. Therefore, accurate spatial data on both soil loss and soil genesis are required, especially in the light of predicted changes in climate patterns, notably frequency, seasonal distribution and intensity of precipitation. Rates of soil loss are reported that have been measured, modelled or inferred for most types of soil erosion in a variety of landscapes, by studies across the spectrum of the Earth sciences. Natural rates of soil formation can be used as a basis for setting tolerable soil erosion rates, with soil formation consisting of mineral weathering as well as dust deposition. This paper reviews the concept of tolerable soil erosion and summarises current knowledge on rates of soil formation, which are then compared to rates of soil erosion by known erosion types, for assessment of soil erosion monitoring at the European scale. A modified definition of tolerable soil erosion is proposed as 'any actual soil erosion rate at which a deterioration or loss of one or more soil functions does not occur,' actual soil erosion being 'the total amount of soil lost by all recognised erosion types.' Even when including dust deposition in soil formation rates, the upper limit of tolerable soil erosion, as equal to soil formation, is ca. 1.4 t ha.sup.-1 yr.sup.-1 while the lower limit is ca. 0.3 t ha.sup.-1 yr.sup.-1, for conditions prevalent in Europe. Scope for spatio-temporal differentiation of tolerable soil erosion rates below this upper limit is suggested by considering (components of) relevant soil functions. Reported rates of actual soil erosion vary much more than those for soil formation. Actual soil erosion rates for tilled, arable land in Europe are, on average, 3 to 40 times greater than the upper limit of tolerable soil erosion, accepting substantial spatio-temporal variation. This paper comprehensively reviews tolerable and actual soil erosion in Europe and highlights the scientific areas where more research is needed for successful implementation of an effective European soil monitoring system. Author Affiliation: (a) European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via E. Fermi, 2749 (TP280), I-21027 Ispra (Va), Italy (b) National Soil Resources Institute, Natural Resources Department, Cranfield University, Cranfield, MK43 0AL, UK Article History: Received 13 March 2008; Accepted 19 February 2009

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1745-5871.2008.00554.x Byline: LEA WITTENBERG (1), MOSHE INBAR (1) Keywords: forest fire; soil erosion; vegetation recovery rates; Mediterranean ecosystems Abstract: Abstract The Mediterranean ecosystem of Mt. Carmel, Israel, is subjected to an increasing number of forest fires of various extents and severities. The impacts of forest fires on runoff and erosion are widely documented and include increased peak flows and soil loss until the return of a vegetation cover. Most studies, however, treat fire as a single event, whereas the present study is aimed at exploring the long-term effects of repeated forest fires on eco-geomorphic processes. The study integrates the results of plot-based, detailed analysis of post-fire runoff and erosion with vegetation recovery analysis, at a temporal-spatial scale which includes the effect of reburning. Our results indicate that forest fires lead to a significant increase in runoff and sediment yields, particularly during the first two years following the disturbance, up to five orders of magnitude higher than from the adjacent unburnt control plots. Author Affiliation: (1)Department of Geography and Environmental Studies, University of Haifa, Haifa, Israel, 31905. Article History: Received 15 January 2007; Revised 29 October 2007; Accepted 27 August 2008 Article note: (*) Corresponding author. Email: leaw@geo.haifa.ac.il

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1745-5871.2008.00555.x Byline: BINGQI ZHU (1), XIAOPING YANG (1) Keywords: chemical weathering; detrital sediments; CIA; geomorphology; desert; China Abstract: Abstract Based on the analysis of major-element compositions of detrital sediments from the Taklamakan Desert of northwestern China, this paper aims to study chemical weathering in a hyper-arid desert environment. The major-element compositions are basically similar to the Upper Continental Crust but show a clear enrichment of CaO and depletion of [Na.sub.2]O and [K.sub.2]O, indicating the enrichment of carbonates and the decomposition of sodium and potassium silicates. The indexes of chemical alteration are relatively low and correlate negatively with the content of [Na.sub.2]O, implying that the degree of chemical weathering is weak and mainly controlled by the weathering of sodium feldspars. An A-CN-K model demonstrates that the detrital sediments from the Taklamakan Desert have a high homogeneity in the trend of chemical weathering. They are weathered less than sands and soil in many other Chinese deserts, and also less than similar detrital sediments in many other countries. This evidence suggests a low degree of mineralogical maturity in the Taklamakan Desert. The aeolian sediments of different ages have similar indexes of chemical weathering, suggesting that the degree of chemical weathering was consistent in the Taklamakan Desert throughout the period of aeolian deposition. The low degree of chemical weathering is caused principally by extreme aridity, rapid rejuvenation of detrital sediments associated with strong aeolian processes, and an intensive input of fluvial deposits, as well as a lack of vegetation. Due to the high concentration of erodible minerals, the desert is quite vulnerable to soil erosion and land degradation. Author Affiliation: (1)Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS), P.O. Box 9825, Beijing 100029, China. Article History: Received 13 January 2008; Revised 2 August 2008; Accepted 8 September 2008 Article note: (*) Corresponding author. Email: xpyang@263.net.cn

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2008.10.004 Byline: Nathaniel D. Olive (a), Jeffrey L. Marion (b) Abstract: Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding 'fall-line' alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes. This research also sought to develop a more efficient Variable Cross-Sectional Area method for assessing soil loss on trails. This method permitted incorporation of CSA measures in a representative sampling scheme applied to a large (24%) sample of the park's 526km trail system. The variety of soil loss measures derived from the Variable CSA method, including extrapolated trail-wide soil loss estimates, permit an objective quantification of soil erosion on recreational trails and roads. Such data support relational analyses to increase understanding of trail degradation, and long-term monitoring of the natural and recreational integrity of the trail system infrastructure. Author Affiliation: (a) Warnell School of Forestry and Natural Resources, Recreation and Tourism program, University of Georgia, Athens, Georgia 30601, USA (b) Virginia Tech Field Station, Forestry Department (0324), USGS Patuxent Wildlife Research Center, Blacksburg, Virginia 24061, USA Article History: Received 9 March 2006; Revised 10 September 2008; Accepted 7 October 2008

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1745-5871.2008.00533.x Byline: J.P. TERRY (1), R. LAL (2), S. GARIMELLA (3) Keywords: floodplains; accretion rates; Cs-137 method; Labasa River; Fiji Abstract: Abstract The 137Cs (caesium-137) method was used to investigate medium-term rates of sediment deposition on the floodplain of the Labasa River, on Vanua Levu island in northern Fiji. The Labasa basin is commercially important for sugarcane farming, which provides much revenue and sustains the economy in the greater Labasa area. Alluvium was sampled at three riverbank sites in vertical increments of 30 mm. Measured net vertical accretion rates, based on analysis of depth-profiles of 137Cs activity, ranged from 10 mm yr.sup.-1 at a low-lying site near a tributary confluence with the main river, to 60 mm yr.sup.-1 on a levee that was elevated slightly above the adjacent floodplain. These rates of accretion are high, but in general agreement with rates recorded using similar methods in other tropical Pacific island river systems. Soil erosion under sugarcane on hilly parts of the lower Labasa basin is an important factor in rapid floodplain development. Observations made during Cyclone Ami, which traversed Vanua Levu island in early 2003, illustrate the major contribution of severe storm events to floodplain sediment supply, by triggering numerous landslides on catchment slopes and in-channel debris floods, and by generating large-magnitude overbank floods. Author Affiliation: (1)Department of Geography, National University of Singapore, 1 Arts Link, Singapore 117570. (2)Division of Physics, The University of the South Pacific, Private Mail Bag, Suva, Fiji Islands. (3)School of Engineering and Physics, The University of the South Pacific, Private Mail Bag, Suva, Fiji Islands. Article History: Received 14 September 2007; Revised 9 November 2007; Accepted 29 November 2007 Article note: (*) Corresponding author. Email: geojpt@nus.edu.sg

This study was conducted to evaluate the overall performance of the Precision Agricultural-Landscape Modeling System (PALMS) for calculating runoff and soil loss under cropped conditions. The PALMS model uses a lognormal distribution of saturated hydraulic conductivity across the fields to simulate typical soil heterogeneity within soil texture classes. Runoff and soil loss data were collected in three farm fields for a total of 75 runoff events during 2 yr under six cropping scenarios (alfalfa [Medicago sativa L.] and corn [Zea mays L.] no-tilled, corn and soybean [Glycine max (L.) Merr.] moldboard plowed, and alfalfa and corn chisel plowed). For individual storms, calculated runoff and sediment loss from PALMS were compared with corresponding measurements for each farm during the entire cropping season. The coefficient of determination ([r.sup.2]) between runoff calculations and measurements was 0.84. The [r.sup.2] between soil loss calculations and measurements with the storm-by-storm simulations during both seasons was 0.78. Based on these continuous simulation results, the PALMS calculations appear to have lower relative errors with large events than small events, a desirable result because large events are most important in assessing the environmental consequences of management practices. Abbreviations: DEM, digital elevation model; EPIC, Erosion Productivity Impact Calculator; ME, model efficiency; PALMS, Precision Agricultural-Landscape Modeling System; RUSLE, Revised Universal Soil Loss Equation; USLE, Universal Soil Loss Equation; WEPP, Water Erosion Prediction Project

Accurate prediction of ground-surface settlement adjacent to an excavation is often difficult to achieve without using accurate representation of small-strain nonlinearity in a soil model within finite-element analyses. In this paper a simplified semiempirical model is proposed for predicting maximum wall deflection, maximum surface settlement, and surface-settlement profile due to excavations in soft to medium clays. A large number of artificial data are generated through finite-element analyses using a well-calibrated, small-strain soil model. These data, consisting of wall displacements and ground-surface settlements in simulated excavations in soft to medium clays, provide the basis for developing the proposed semiempirical model. The proposed model is verified using case histories not used in the development of the model. The study shows that the developed model can accurately predict maximum wall deflection and ground-surface settlement caused by braced excavations in soft to medium clays. DOI: 10.1061/(ASCE)1090-0241(2007)133:6(731) CE Database subject headings: Finite-element method; Excavation; Settlement; Deflection; Walls; Clays.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2006.04.019 Byline: David A. Lobb (a), Edward Huffman (b), Donald C. Reicosky (c) Keywords: Tillage; Soil management; Environmental indicators; Soil erosion; Tillage erosion; Crop residue cover Abstract: Tillage has been and will always be integral to crop production. Tillage can result in the degradation of soil, water, and air quality. Of all farm management practices, tillage may have the greatest impact on the environment. A wide variety of tillage equipment, practices and systems are available to farmers, providing opportunities to enhance environmental performance. These opportunities have made tillage a popular focus of environmental policies and programs such as environmental indicators for agriculture. This paper provides a very brief examination of the role of tillage in crop production, its effect on biophysical processes and, therefore, its impact on the environment. Models of biophysical processes are briefly examined to demonstrate the importance of tillage relative to other farm management practices and to demonstrate the detail of tillage data that these models can demand. The focus of this paper is an examination of the use of information on tillage in Canada's agri-environmental indicators initiative, National Agri-environmental Health Analysis and Reporting Program (NAHARP). Information on tillage is required for several of the indicators in NAHARP. The type of data used, its source, and its quality are discussed. Recommendations regarding the collection of tillage data and use of tillage information are presented. Author Affiliation: (a) Soil Science, University of Manitoba, Winnipeg, Canada (b) Research Branch, Agriculture and Agri-Food Canada, Ottawa, Canada (c) Agricultural Research Service, United States Department of Agriculture, Morris, MN, USA Article History: Received 30 October 2004; Revised 21 April 2006; Accepted 27 April 2006

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.05.019 Byline: Shu-Kuang Ning (a), Ni-Bin Chang (b), Kai-Yu Jeng (c), Yi-Hsing Tseng (d) Abstract: Soil erosion associated with non-point source pollution is viewed as a process of land degradation in many terrestrial environments. Careful monitoring and assessment of land use variations with different temporal and spatial scales would reveal a fluctuating interface, punctuated by changes in rainfall and runoff, movement of people, perturbation from environmental disasters, and shifts in agricultural activities and cropping patterns. The use of multi-temporal remote sensing images in support of environmental modeling analysis in a geographic information system (GIS) environment leading to identification of a variety of long-term interactions between land, resources, and the built environment has been a highly promising approach in recent years. This paper started with a series of supervised land use classifications, using SPOT satellite imagery as a means, in the Kao-Ping River Basin, South Taiwan. Then, it was designed to differentiate the variations of eight land use patterns in the past decade, including orchard, farmland, sugarcane field, forest, grassland, barren, community, and water body. Final accuracy was confirmed based on interpretation of available aerial photographs and global positioning system (GPS) measurements. Finally, a numerical simulation model (General Watershed Loading Function, GWLF) was used to relate soil erosion to non-point source pollution impacts in the coupled land and river water systems. Research findings indicate that while the decadal increase in orchards poses a significant threat to water quality, the continual decrease in forested land exhibits a potential impact on water quality management. Non-point source pollution, contributing to part of the downstream water quality deterioration of the Kao-Ping River system in the last decade, has resulted in an irreversible impact on land integrity from a long-term perspective. Author Affiliation: (a) Department of Civil and Environmental Engineering, National University of Kaohsiung, Kaohsiung, Taiwan, ROC (b) Department of Civil and Environmental Engineering, University of Central Florida, Orlando, FL 32826, USA (c) Department of Environmental Engineering, National Cheng-Kung University, Tainan, Taiwan, ROC (d) Department of Surveying Engineering, National Cheng-Kung University, Tainan, Taiwan, ROC Article History: Received 15 November 2004; Revised 20 March 2005; Accepted 24 May 2005