Modelling of soil organic carbon in the Mediterranean area: A systematic map

A general feature of soil health is the sustainment of soil organic carbon (SOC) concentration and its stock. Digital soil mapping (DSM) development allowed for the implementation of soil properties mapping at various spatial and time scales. However, many of these studies were made in temperate or cold environments from central and northern Europe or United States or in stably arid ecosystems of Australia. Geographical information on the SOC are often fragmented, and this does not allow for a comparison on SOC regional variability in contrasting areas. Here a systematic research of peer-reviewed papers in the Web of science (WoS) and Scopus databases was carried out to highlight knowledge gaps in SOC studies in the Mediterranean area. The systematic searches identified 500 articles in WoS and 750 in Scopus, but only few of them were eligible as ad hoc studies. Regarding WoS, after screening, 150 studies were further analysed for inclusion in the map and only 128 included in the final map (1995-2018). From Scopus, only 104 studies were included in the map (1995-2017). Of all the countries around the Mediterranean Basin, report studies on SOC are available for 15 countries, only. Data gaps identified included the absence of long-term monitoring networks in the south of Europe, a scarcity of information from countries on the eastern coast of the Adriatic and Mediterranean sea and almost lack of detailed information on SOC models and maps from north Africa. Model exportation built in neighbourhood countries (e.g. from Sicily, Italy, to northern Tunisia, or Andalusia, Spain, to northern Morocco) are strongly needed.