Research challenges on gully erosion control in EU and China

Trabajo presentado en la EGU General Assembly (Annual Meeting of the European Geosciences Union), celebrada online deñ 4 al 8 de mayo de 2020.Gully erosion is a soil degradation process widely present across the world. Permanent gullyerosion has usually soil erosion rates one order of magnitude higher than hillslope water erosionin conventional agriculture, e.g. 2.1 vs 0.6 mm year-1 (Castillo and Gómez, 2016). It remains a majorprocess of soil degradation worldwide. This work attempts to investigate recent trends of published research on gully erosion in relationto gully erosion control since 2000. A review in Web of Science (core collection, 2000-19 by title)reported 401 documents, produced mainly in the European Union (52.1%), China (22.7%), USA(16.0%) and Australia (8.7%). Approximately 17% of all these articles covered restoration or controlof gully erosion as their main topic. When screened most of these 68 articles deal with specificsituations and techniques with a limited number devoted to a comparative review of effectivenessof different techniques, one of the few exceptions was Liu et al. (2019a). To provide perspective,there were a similar proportion of articles devoted to the study of gully erosion processes, a and amuch larger number of articles devoted to the description of gully development and erosion ratesin specific situations. It is apparent that the subject of gully erosion control is not a dominant onein the scientific indexed literature. This review was complemented with an analysis in WOCAT(WOCAT, 2019), a comprehensive international databases of soil conservation technologies. Itshowed with 27 entries of gully erosion restoration techniques over a total of 1098 descriptions(2.5% approximately). This might be explained, partially, because most of the information on gullyerosion control appears in documents outside scientific, or technical, international databases,many times in local languages. Overall, two of the major barriers frequently noted bystakeholders, particularly farmers, for effective gully erosion control, their high costs and thecomplexity of controlling expansion of very large gullies (e.g. Liu et al.2019b) are not major majorsubjects in the international scientific literature on gullies in the last decades