Experiments in Earth surface process research Manuel Seeger a, ⁎, John Quinton b , Nikolaus J. Kuhn c a Land Degradation and Development, Wageningen University. P.O. Box 47, NL-6700 AA Wageningen, The Netherlands b Environmental Science, Lancaster University, Bailrigg, LA1 4YQ Lancaster, United Kingdom c Geography, University of Basel, Klingelbergstr. 27, CH-4056 Basel, Switzerland abstract article info Article history: Received 15 September 2011 Received in revised form 5 October 2011 Accepted 26 October 2011 Keywords: Soil erosion Geomoephology Editorial Experimental methods Earth sciences Within this Editorial, we put the articles included in the Special Issue into a historical and actual context of experimental research in Earth system sciences. © 2011 Elsevier B.V. All rights reserved. Experiments have been an important part of hydrological, geo- morphologic and soil erosion research for decades. In the late 19th century Ewald Wollny carried out systematic experiments on soil physics (Wollny, 1878–1898), which identified the quality of the soil substrate and the consequences of soil management for the agri- cultural productivity. In the 1920s, different reactions of soils to ero- sional processes were formally recognised for the first time by Bennett (1926) when attempting to identify the properties which control resistance to erosion of Cuban Latosols. While this early work focused on soil properties and erosion processes, increasing soil and land degradation problems initiated, under the influence of Bennett, a more stochastically-designed applied erosion research, most notably in the USA, in the 1930s. A large body of plot observa- tion data was collected by the US Soil Conservation Service, which, while of limited use for understanding erosion processes, enabled the development of the Universal Soil Loss Equation (USLE) (Wischmeier and Smith, 1978). Both data and concept of the USLE have been applied outside the USA and are, modified and revised, still in use today. The shortcomings of the USLE led to the develop- ment of complimentary research activities focused on the under- standing of erosion processes and the interaction between form and process on larger spatial and long-term temporal scale. For example, in the 1950s Hudson carried out pioneering experimental work which demonstrated the importance of rainsplash for sediment pro- duction (Hudson and Jackson, 1959). Further benchmark experimen- tal research evolved during the 1960s and 1970s, most notably in Australia, Belgium, Canada, France, Germany, Great Britain, Israel, Italy and Spain (reviewed by Bryan, 1991), with field sites expanding into Africa and across Europe. Monitoring and experiments have also served as starting points for the development of erosion models, for example the work of (e.g. Carson and Kirkby, 1972; Govers et al., 1990) provided the basis for the transport capacity equations included in the EUROSEM model (Morgan et al., 1998). In addition, the simula- tion of rainfall and wind has played an important role in surface process research, especially for understanding the processes associated with soil erosion, sediment transfer and, in combination with monitoring and numerical modeling, landform formation (e.g. Dunne and Aubry, 1986). Most recently, experiments are also used to study the movement of individual particulate substances through landscapes, most notably Carbon (e.g. Polyakov and Lal, 2004). With this special issue we want to illustrate the current develop- ment of new methods and applications of experiments in soil erosion and geomorphological research. To do so, a selection of papers pre- sented within specific sessions at the European Geoscience Union's General Assembly and the Deutscher Geographentag (German Geogra- phers Meeting), both held Vienna in 2009 has been collated. The pa- pers demonstrate that questions ranging from the role of soil erosion on global geochemical cycles to the relevance of the combined action of wind, rainfall and runoff on soil surfaces can be studied using ex- periments. The papers broadly fall into two groups: (i) those which describe new methods and techniques for soil erosion experiments, and (ii) those which explore processes either using innovative tech- nology or addressing new questions, or both. Laboratory experiments and methods for precise replication of real soil characteristics in the laboratory are presented as well as field experiments and their com- bination with different monitoring techniques. Both types of studies Catena 91 (2012) 1–3 ⁎ Corresponding author. Tel.: + 31 317 486617; fax: + 31 317 419000. E-mail addresses: manuel.seeger@wur.nl (M. Seeger), J.Quinton@Lancaster.ac.uk (J. Quinton), nikolaus.kuhn@unibas.ch (N.J. Kuhn). 0341-8162/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.catena.2011.10.003 Contents lists available at SciVerse ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena