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Throughout Italy, soil sealing has had a significant impact on the landscape and on agricultural land. This issue needs to be analyzed in order to provide the policy maker with strategic information for rational land planning and environmental management. In this context, the purpose of this study is to widen our knowledge about the consumption of agricultural land in Italy, analyzing its dynamics, causes and impact. The analysis considers three specific aspects: design of a territorial model to study the extent of land consumption, qualitativequantitative evaluation and classification of the ways in which sealing areas are extended, and analysis of impact and driving forces. The results have helped identify the extent of soil sealing on a geographical basis and, at the same time, to understand how artificialization morphotypologies are linked to the changes that take place and what impact these changes have in relation to territorial multifunctionality and hydrogeological risk.

This study analyzes soil sealing and its repercussions in the loss of fertile soils, which are more appropriate for agriculture use. Also, soil sealing increases flood risk. The main objective is to estimate soil loss by sealing in the Guadarrama River Basin (Madrid, Spain) between 1961 and 2011. The combination of digital processing (Normalized Difference Vegetation Index (NDVI), principal components and convolution filters) of satellite imagery with the digital terrain model helps to detect risk areas and allows quick updating of sealed soil mapping. The supervised classifications of the images were used to estimate the actual soil loss by sealing (9% in 2011) in the Guadarrama River Basin and the types and agrologic classes that have been lost. Soil loss occurs to a greater extent in highly permeable soils (sands) and in the most fertile soils. The main sealed soil associations are luvisols (alfisols), regosols (entisols) and cambisols (inceptisols).

The present study illustrates a framework to evaluate soil consumption in Mediterranean regions experiencing rapid urban growth. Results indicate that high-quality soils more suitable for agriculture and forestry were mostly consumed by urbanization especially in flat areas. The consumption of these soils was not concentrated in the first observation period (1948-1975) corresponding to the development of compact settlements, but increased significantly in the last period (1975-2010) mainly characterized by discontinuous and low-density urban expansion. The study underlines the urgent need to inform development policies and urban planning with an in-depth quantification of the soil resource base lost by urbanization. [ABSTRACT FROM AUTHOR]

Highlights: [•] We estimated the value of the productive soil lost in the Emilia-Romagna Plain, Italy. [•] The value of the land use changes for the period 2003–2008 at regional scale was 109 euros. [•] The agricultural soil losses mean a vanished food security of 440,000 people equivalent per year. [•] Local land use change produces massive environmental and economical consequences at wider scale. [ABSTRACT FROM AUTHOR]

Soil sealing has negative impacts on ecosystem services since urban green and soil get lost. Although there is political commitment to stop further sealing, no reversal of this trend can be observed in Europe. This paper raises the questions (1) which strategies can be regarded as being efficient toward ecologically sustainable management of urban soil sealing and (2) who has competences and should take responsibility to steer soil sealing? The analyses are conducted in Germany. The assessment of strategies is carried out using indicators as part of a content analysis. Legal-planning, informal-planning, economic-fiscal, co-operative, and informational strategies are analyzed. Results show that there is a sufficient basis of strategies to secure urban ecosystem services by protecting urban green and reducing urban gray where microclimate regulation is a main target. However, soil sealing management lacks a spatial strategically overview as well as the consideration of services provided by fertile soils. [ABSTRACT FROM AUTHOR]

Abstract: Landsat TM images are used to define soil sealing in the Madrid Autonomous Region (Spain) between 1989 and 2010. The comparison of images within this time frame obtains an estimated loss of 42,800ha of agricultural land. Soil sealing mainly occurred in metropolitan areas as well as in the E, SW and NW of the capital. Landsat images overlaid on agrological classification maps and soil association maps show that the most significant losses correspond to agricultural classifications B and C and luvisols associated with cambisols, regosols, calcisols and fluvisols (WRBSR, 2007). [Copyright &y& Elsevier]

In the field of environmental policy, it is widely accepted that the exploitation of the environment in a rapidly urbanising world needs intervention by policy to meet sustainable development. But which laws, incentives, and awareness raising actions support sustainable development? According to the European Environment Agency, policy-effectiveness can be assessed by evaluating changes in driving forces, pressures, states, responses and impacts. However, these changes can only be measured after implementing responses and often cannot be directly related to specific policies or instruments. Therefore, this article argues that a specific framework is necessary which is introduced by a Response-Efficiency-Assessment (REA). For the methodological approach, the framework is developed through a multi-attribute decision method (MADM) using an analytical hierarchy process (AHP). The framework will be presented using the example of soil sealing management including 48 indicators to assess the efficiency of soil sealing management; one main challenge facing the environmental policy. [ABSTRACT FROM AUTHOR]

This article analyses the impact of soil sealing associated with three decades of urban growth in the Mediterranean coastal municipality of Elche (Alicante, Spain) on local soil resources. Geographical Information System (GIS) and remote sensing (RS) techniques were used to obtain and analyse different types of thematic information relating to urban growth and soil resources (soil class, land use capability, and physiographic classes). Map algebra techniques were employed to assess patterns of land occupation by urban growth and to compare maps of urban areas obtained from satellite imagery in 1978, 1992, 2001 and 2005 with thematic maps showing ancillary soil resources. Three different patterns of land occupation were identified in Elche: concentric growth outwards from the city of Elche (1978-1992), dispersed urban growth onto highly productive agricultural soils (1992- 2001), and coastal urbanization (2001-2005). Soils with high land capacity for agricultural use were the ones most severely affected by soil sealing as a result of urban growth. Land use planning should therefore adopt measures to minimize the impact of soil sealing in agricultural areas in orsure the complete environmental functionality of the soil and guarantee food production.Este trabajo analiza el crecimiento urbano durante tres décadas del municipio costero mediterráneo de Elche (Alicante, España), con la finalidad de evaluar el impacto sobre el recurso suelo que ha tenido el sellado del suelo por el crecimiento urbano. Para llevar a cabo el estudio se emplearon métodos combinando un sistema de información geográfica y teledetección para obtener y analizar diferentes fuentes de información temática relativa al crecimiento urbano y al recurso suelo, tales como: clase de suelo, capacidad de usos y clases fisiográficas. Se emplearon técnicas de álgebra de mapas para detectar patrones de ocupación del territorio por el crecimiento urbano, comparando mapas de zonas urbanas obtenidos a partir de imágenes de satélite para 1978, 1992, 2001 y 2005, respecto a mapas temáticos del recurso suelo disponibles. Se identificaron tres patrones diferentes de ocupación del territorio en el municipio de Elche: crecimiento concéntrico desde el núcleo original de la ciudad de Elche (1978-1992), dispersión urbana ocupando áreas de suelo agrícola altamente productivas (1992-2001) y urbanización de la franja litoral (2001-2005). Los suelos con alta capacidad de uso agrícola fueron los más severamente afectados por el sellado del suelo en el crecimiento de las zonas urbanas. Resulta necesario considerar en la planificación territorial medidas para minimizar el impacto del sellado del suelo en las zonas agrícolas con la finalidad de garantizar la funcionalidad ambiental del suelo y la producción de alimentos.Neste trabalho estudou-se o impacto sobre o solo, como recurso natural, do crescimento urbano ocorrido durante três décadas na cidade da costa Mediterrânica de Elche (Alicante, Espanha). Para levar a cabo este estudo recorreu-se a métodos que combinavam um SIG (Sistema de informação Geográfica) e um sistema detecção remota para obter e analisar diferentes fontes de informação temáticas sobre o crescimento urbano e o recurso solo tais como: tipos de solo, usos e classes fisiográficas. Utilizaram-se técnicas de cartografia para detectar padrões de ocupação do território devidos ao crescimento urbano, comparando mapas de áreas urbanas obtidos de imagens de satélite para 1978, 1992, 2001 e 2005, com mapas temáticos do recurso solo disponíveis. Foram identificados três padrões diferentes de ocupação do território no município de Elche: crescimento concêntrico do núcleo original da cidade de Elche (1978-1992), expansão urbana ocupando terrenos agrícolas altamente produtivos (1992-2001) e urbanização do litoral (2001-2005). Os solos com alta capacidade de uso agrícola foram os mais gravemente afectados pela impermeabilização do solo decorrente do crescimento das áreas urbanas. É, pois, necessário pensar em medidas de planeamento e ordenamento territorial que minimizem o impacto da impermeabilização do solo em áreas agrícolas com o objectivo de assegurar a funcionalidade ambiental do solo e produção de alimentos.

Solving the problem of publicly available census data disaggregation has preoccupied numerous researchers intensively. A noteworthy advance in the methodology was made thanks to the contemporary storage and presentation of spatial and socio-economic data in the GIS environment. It is also important that a large number of auxiliary databases (satellite images, theme layers pertaining to land use and land cover, etc.) are publicly available and are periodically supplemented at increasingly shorter time intervals. Soil sealing databases are another class of auxiliary databases that pertain to land areas which have, due to anthropogenic influences, become a water-impermeable layer and indicate the level of spatial development and spatial contents that correlate to the population distribution. The soil sealing database can be a useful tool for dasymetric mapping of population when combined with town planning documentation that describes land use and height of residential buildings. The results of such mapping can help monitor the spatio-temporal dynamics of population trends in periods between two censuses. This study presents a methodology in which a soil-sealing database is combined with auxiliary data in a test area covered by the Master Plan of the Belgrade City, with census data from the year 2002 and the results of the year 2011. The results of the model validation indicate application of the proposed methodology in highly urbanised areas. [ABSTRACT FROM AUTHOR]

Abstract: Dynamics of soil sealing and soil landscape patterns under rapid urbanization were qualified in the Urban Agglomeration around Hangzhou Bay (UAHB), China. Rapid population growth, economic development, and settlement sprawl were identified from 1994 to 2009. Such accelerating urbanization resulted in considerable soil sealing. For the entire region, percentage of sealed soils increased from 2.7% in 1994 to 4.7% in 2003 and to 8.7% in 2009. Paddy soils, especially those of the highest quality, were the first victims. Soil landscapes, at the regional scale, became more fragmented and irregular, but less dominated, diverse and connected as urbanization intensified. Spatial regression uncovered the diverging relationships between landscape metrics with urbanization indicators and measurement period. The dynamics of soil sealing and soil landscape patterns not only reflected common tendencies in China, but represented a global process. Our study provided a practical methodological framework, by integrating remote sensing, geographical information systems, landscape metrics and spatial regression, for monitoring the impacts of urbanization on soil resources. [Copyright &y& Elsevier]

Available land use/cover maps differ in their spatial extent and in their thematic, spatial, and temporal resolutions. Due to the costs of producing such maps, there is usually a trade-off between spatial extent and resolution. The only European-wide, consistent, and multi-temporal land use/cover dataset available is the CORINE Land Cover (CLC) map. Despite the value and usefulness of CLC, its minimum mapping unit (MMU) of 25 hectares considerably limits its applications at large scales of analysis. Our objective was to improve the spatial detail of CLC 2006 by incorporating land use/cover information present in finer thematic maps available for Europe such as the CLC change map, Soil Sealing Layer, Tele Atlas®Spatial Database, Urban Atlas, and Water Bodies Data from the Shuttle Radar Topography Mission. Relevant data from these datasets were extracted and prepared to be combined with CLC in a stepwise approach. Each step increased the level of modifications to the original CLC. This process generated a newly refined version of the CLC 2006 map with an improved MMU of 1 hectare for all types of artificial surfaces and inland waters while keeping constant the original 100 meter cell size. A validation of the new map was carried out using Land Use/Cover Area frame Statistical survey (LUCAS) 2006 sample points. The observed increase in spatial detail was done, however, at the cost of cartographic consistency. [ABSTRACT FROM AUTHOR]

This article discusses the field of agricultural land protection against soil sealing in Slovenia from the perspective of the land development tax applied to land-use changes. In Slovenia, the land development tax for agricultural land use change was introduced in 1970s with the aim to slow-down the then huge interventions in agricultural land and at the same time to get financial resources for investments in agriculture, in particular for the purpose of agrarian operations. In the research, the methodology for calculating the land development tax for conversion of agricultural land to built-up land and the amount of the tax in Slovenia during reference intervals in the study period 1979-2012 is analysed. The results of the research are presented together with the legal framework, which regulated the discussed field in individual time periods. For the study period, an analysis of methodology for calculating the agricultural land development tax was done for three cadastral districts (Novo mesto, Kranjska Gora and Murska Sobota), and an in-depth analysis of actual payments was done in the area of administrative unit of Lendava in the cadastral district of Murska Sobota. It has been shown that the amount of the agricultural land development tax was changing in the study period and that its value in the past had significantly exceeded the amount, which was determined with the change of legislation in 2011, and has been even decreased in 2012. [ABSTRACT FROM AUTHOR]

The overall aim of this study is to develop a set of indicators for assessing the efficiency of instruments to steer urban soil sealing. To set up a framework for an efficient approach to soil sealing socio-demographic driving forces of soil sealing and constraints of soil sealing management were analyzed by statistical methods, expert interviews and through a literature review. Leipzig and Munich (Germany) as shrinking and growing cities were used as case studies. Results showed that it is not the increased number of residents that drive further sealing but rather their life style through an increase in space per capita and lack of soil awareness. The reduction of sealing is hampered moreover by an economic orientation of local authorities which leads to an under-weighting of ecological impact caused by soil sealing. Therefore, an efficient soil sealing approach involves instruments which support environmental and ecological sustainable development and which are economically and fiscally functional, politically-institutionally compatible and which promote environmental competence and high living quality. Within these categories 48 indicators are presented which can be used for an efficiency assessment of soil sealing management instruments. Such an assessment should include management authorities and addressees on a macro- (state government, federal state, regions), meso- (local authorities in cities) and microscale (investors, residents). [ABSTRACT FROM AUTHOR]

An approach to assess the soil organic carbon (SOC) pools in megapolises and in small settlements with due account for the natural, economic, and historical heterogeneity of urban territories; the degree of the soil sealing; and the specific features of their functional use is discussed. Cartographic information, satellite imagery, geoinformation systems, and field and literature data have been applied to adapt this approach for Moscow and for the town of Serebryanye Prudy in Moscow oblast. The pool of SOC has been calculated for the topsoil horizons (0-10 cm) and for the total thickness of the cultural layer (habitation deposits) in these urban areas. The total SOC pool comprises 13 833.0 × 10 t (with an error of 30-40%) for Moscow and 2 996.6 × 10 t (with an error of 50-70%) for Serebryanye Prudy. The specific carbon pools for these territories reach 128 and 810 t/ha, respectively. The cultural layer of Moscow concentrates about 75% of the total SOC pool; in Serebryanye Prudy, it contains about 95% of the total SOC pool. The SOC pools in the urban soils are comparable with or exceed the SOC pools in the corresponding natural zonal soils. [ABSTRACT FROM AUTHOR]

This article presents a literature review that explores the challenges for planning in urban regions in connection with the preservation of ecosystem services. It further presents some best practice examples for meeting these challenges. The demand for the provision of ecosystem services within urban regions changed during the transition from a largely agrarian society to an industrial society and, most recently, to a service society. Although in the past, provisioning services such as food production or the provision of raw material were decisive for urban development, today cultural services, e.g., clear views or nearby recreation areas, have become increasingly important. According to the literature, soil sealing is the greatest threat urbanization poses toward ecosystem services, as it compromises all of them. Spatially extensive cities with a high building density particularly inhibit regulating services like the regulation of temperature or water surface runoff. Conversely, scattered settlement patterns may lead to very small remnants of open space that cannot reasonably serve as natural habitat, agricultural land, or recreation area. The challenges for planning in urban regions are: 1) specifying regulations that define outer limits to the development of each settlement unit, 2) comprehensive planning with focal points for development, and limiting access and development at other places, and 3) compensating for new soil sealing by restoring nearby sealed areas. The article presents 3 best-practice examples that support these principles: designating areas with a particular soil quality that should not be built over, offering incentives for corporate planning in urban regions, and restoring a country road in connection with a motorway construction. Integr Environ Assess Manag 2013; 9: 243-251. © 2013 SETAC [ABSTRACT FROM AUTHOR]

Abstract: The United Nations Convention to Combat Desertification (UNCCD) does not distinguish between natural and human drivers, and between active and inherited desertification. Partly as a result of these ambiguities the UNCCD has attracted a low level of international attention. As the Spanish case study shows, this vagueness hinders the implementation of effective strategies to combat this global challenge. Unsustainable agricultural land management is the most blamed desertification agent in Spain but as land use changes trends demonstrate, desertification phenomena are fueled by a push–pull dynamics. Our data indicate that agriculture, rather than being a desertification agent, is a victim of a set of social and economic conditions leading to its abandonment and/or transformation in urban land, becoming irreversibly degraded by soil sealing. From 1975 to 2008, half a million ha of former agricultural land has been made available for development. Urban sprawl has become the most active desertification agent in Spain. [Copyright &y& Elsevier]

Population figures are usually collected by national statistical institutes at small enumeration units (e.g. census tracts or building units). However, still for many countries in Europe, data are distributed at coarser geographical units like municipalities. This level of resolution is insufficient for analysis in many fields. In addition, the heterogeneity of the size of the geographical units causes great distortions in analysis, i.e. the Modifiable Areal Unit Problem (MAUP). Dasymetric mapping techniques have long been applied world-wide to derive finer (and MAUP-free) depictions of the population distribution. These techniques disaggregate population figures reported at coarse source zones into a finer set of zones using ancillary geographical data. Previous attempts to map the European population at high resolution have used CORINE Land Cover (CLC) as the main source of ancillary data. In this article, we test new geographical datasets to produce an updated and improved European population grid map. It is tested whether using more detailed ancillary data in the dasymetric mapping significantly yields higher accuracies. As final outcome of this cartographic exercise, a European population grid map for the reference year of 2006, with a spatial resolution of 100 × 100 meters, is presented and validated against reference data. Resident population reported at commune level, a refined version of CLC and information on the soil sealing degree are used as the main inputs to produce the final map. [ABSTRACT FROM AUTHOR]

Soil sealing is one of the most serious environmental problems today regarding its impact on cities. This article presents an analysis of the different urban practices currently used to mitigate the effects of soil sealing in urban areas. The main typologies, characteristics, differences, similarities and objectives have been considered. The practices analyzed were SuDS (Sustainable Drainage Systems), LIDs (Low Impact Developments), BMPs (Best Management Practices), WSUD (Water Sensitive Urban Design), GI (Green Infrastructure), and NbS (Nature-based Solutions). To understand the impact of these terms, an analysis of their presence in the scientific literature over the last 10 years is carried out. The results indicate that the trend in the use of these terms is increasing, with the number of articles having doubled in the last 10 years. This indicates the importance that the problem of soil sealing has acquired in the world, and the relevant environmental benefits of addressing it.

Lichens are sensitive to pollution and have therefore been used as air quality indicators. While the distribution of lichens within cities may reflect the distribution of traffic pollution, other factors affecting urban lichens are correlated with this pollution - particularly moisture and the presence of lichen colonization sources., Our objective was to determine the relative importance of these three factors - vehicle pollution, moisture and colonization sources - in determining lichen distribution within a city. We surveyed macrolichen richness and cover on 420 trees within 84 sites across urban Ottawa, Canada. The sites were selected to minimize correlations among vehicle pollution, moisture and colonization sources. Model-averaged standardized regression coefficients were used to compare the relative effects of these three variables on macrolichen richness and cover., We found that macrolichen cover was most strongly related to vehicle pollution and that this effect occurred within 300 m of a site., However, macrolichen species richness responded more strongly to both moisture (at the site centre) and colonization sources (within 1000 m of the site) than to vehicle pollution., Synthesis and applications. Our results suggest that macrolichen cover, but not macrolichen species richness, can be used as an indicator of urban traffic pollution. Our results also suggest that, to promote urban macrolichen diversity, it would be more effective to increase the availability of lichen colonization sources (nearby trees) than to control traffic pollution. [ABSTRACT FROM AUTHOR]

Abstract: Spatial analyses of cropland productivity levels and land use data from 2000 and 2006 were performed to assess the loss of cropland resources for biomass production of the European Union due to land take. Productivity loss in administrative regions was calculated on the basis of the extent and quality of agricultural land resources converted to artificial surfaces. Data show that while all EU member states experience constant decrease of their production capacity, there are also considerable differences among countries and regions. Based on the analysis of 24 member states, the EU lost 0.27% of its cropland and 0.26% of its crop productive potential in the period between 2000 and 2006 due to land take. The loss of agricultural land during the study period was the highest in the Netherlands, which lost 1.57% of its crop production potential within six years. The figures are quite alarming for Cyprus (0.84%), Ireland (0.77%) and Spain (0.49%) as well. In metropolitan areas of Barcelona, Berlin, Bratislava, Bucharest, Copenhagen, Hamburg, Milan, and Vienna infrastructural investment occurred on the higher quality cropland while Budapest, Paris, and Warsaw spread their urban growth to areas of less productive cropland. Denmark had to face the largest loss of its food production capacity for each citizen, exceeding the equivalent of 4kgcapita−1 year−1 of wheat, followed by Ireland with more than the equivalent of 3kg wheat and Spain, Netherlands, Hungary, Cyprus and France all above 2kg loss per capita, annually. The EU lost an amount of cropland production potential equal to approximately 700,000t of wheat grain, annually, in the study period. Results highlight the following general trends: (i) land conversion from different land cover types to artificial surfaces follows the historic trends in Europe with continuing consumption of more productive areas from its land resources; (ii) the conversion rate of croplands to artificial surfaces is growing with increased population growth; (iii) with the growing rate of population increase, increasingly higher quality croplands are converted to artificial surfaces, while with faster rates of population decline increasingly poorer quality croplands are converted; (iv) countries with more developed economies generally convert cropland at a higher speed; and (v) there is a negative correlation between annual economic growth and the rate of cropland conversion. [Copyright &y& Elsevier]

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Remote sensing products have proven an effective tool for the study of urban areas, from city management to environmental monitoring. This work focuses on the mapping of urban areas in the Province of Milan, Northern Italy, using mid-resolution remote sensing data covering the last 20 years. The methodology consists of three main steps: (i) a pixel-based classification tree, (ii) object-based filtering of agricultural terrain, and (iii) joining of land cover classes into two (urbanized and non-urbanized) ,adding post-classification editing. The final derived urban maps were validated and demonstrated to reach very good accuracy (error: 7-13%), thus providing reliable thematic information for urban planning of local and regional authorities. [ABSTRACT FROM AUTHOR]

The combined effects of areal heterogeneity of the soil hydraulic properties and the surface seal formation dominate the hydrological response of arid and semiarid water catchments. Here these two phenomena were simulated to study their mutual role in runoff generation in small bare catchments. Seal formation during rainfall was simulated applying the dynamic model of Assouline and Mualem (1997). Areal heterogeneity of the soil was represented by a lognormal distribution of the saturated hydraulic conductivity of the initially undisturbed soil, K s, and by related distributions of the other soil parameters. The runoff hydrograph, at the outlet of a hypothetical bare catchment of 0.5 km2, was calculated using the cell model of Diskin et al. (1984). Two water catchments types, homogeneous and heterogeneous, with two different soil surface states, unsealed (mulched) and ongoing dynamic sealing, were considered. Four spatial organizations of the 10 cells in the heterogeneous catchment, all representing the same discrete distribution of K s, were studied. Rainfall events of two rainfall intensities, 20 and 40 mm h−1, of different durations ranging from 10 to 120 min, were applied uniformly over the catchments to study the effect of rainfall intensity and duration on runoff characteristics under the different soils and catchments conditions. The state of the soil surface seal was found to be a dominant factor with regard to runoff generation. Relative to the runoff produced in the homogeneous unsealed catchment under a (40 mm h−1, 45 min) rainfall, the runoff was augmented by a factor of 10 during soil surface sealing and still more, by a factor of 20, when the soil surface was already sealed. On a relative basis the impact of soil sealing on runoff is much more important than that of soil heterogeneity. The effect of areal heterogeneity on runoff seems to depend on both the soil surface condition and the rainfall intensity and duration. When the soil is unsealed, the total runoff and the discharge peak are higher for the heterogeneous catchment. When the soil surface undergoes a sealing process, the total runoff and the discharge peak are higher for the heterogeneous catchment for the lower rainfall intensity of 20 mm h−1. For the 40 mm h−1 rainfall the catchment relative response was found to depend on the rainfall duration. A higher peak was obtained in the homogeneous catchment for rainfall durations above 60 min, and more runoff was produced for rainfall durations above 90 min. The spatial pattern of the cell organization in the heterogeneous catchment is an additional factor affecting the hydrological response. The hydrographs corresponding to each of four patterns representing the same areal heterogeneity displayed differences regarding concentration time (which varied between 7 and 28 min), timing of the peak runoff (varying between 77 and 146 min), and the peak discharge (varying between 0.41 and 0.57 m3 s−1). [ABSTRACT FROM AUTHOR]

Abstract: Soil erosion during rainfall is strongly affected by runoff and slope steepness. Runoff production is drastically increased when a seal is formed at the soil surface during rainfall. Therefore, a complex interaction exists between soil erosion and surface sealing. In this study, the dynamics of interrill erosion during seal formation is studied under different simulated rainfall and slope conditions. A sandy soil was exposed to 70mm of rainfall at two intensities, 24mm h−1 and 60mm h−1, and five slope gradients, from 5% to 25%. Infiltration, runoff and soil loss rates were monitored during rainfall. Final infiltration rates increased with slope gradient at both rainfall intensities, this effect being stronger for the higher intensity. Cumulative runoff at the end of the rainfall event was lower as slopes were steeper, while an opposite trend was obtained for soil loss. For the 5% and the 9% slopes, the sediment concentration in runoff reached quickly a stable value during the whole rainfall event, while it reached a peak value before declining for the higher slopes. The peak value and its timing were rainfall intensity dependent. Soil erodibility during seal formation was evaluated using two empirical multiplication-of-factors type models. It seems that slope and rainfall erosivity are accounted for only partly in these models. For mild slope gradients below 9%, the value of K i estimated by means of the two expressions becomes practically constant shortly after runoff apparition. Consequently, the estimates resulting from this type of expressions remain valuable from the practical point of view. [Copyright &y& Elsevier]