The review of soil legacy data as a first step for the construction of a soil health monitoring system in the Mediterranean Region

In the Mediterranean region and particularly in the Near East and North Africa Mediterranean (NENA) countries, the soils and landscapes are extensively degraded, due to long-term unsustainable anthropogenic pressure and the effects of climate change. The average level of health of the soil resources is low and already inadequate to support economic development and food security targets. In the context of the sustainable management and protection of soil resources, considering the specificities of Mediterranean environmental conditions, there is an urgent need to make soil data and soil information (SDI) data understandable and usable for the purpose of monitoring soil health and assessing soil ecosystems in the region. Steps toward this aim are being taken within the PRIMA-funded SOIL4MED project, which focuses on monitoring soil health and developing information systems to promote sustainable soil management in Mediterranean region, aligning with the Global Soil Partnership aims and approaches. The project starts with a comprehensive review of legacy soil point data provided by partner countries, i.e. Italy, Lebanon, Spain, France, Tunisia, Greece, Egypt, Jordan, Turkey, and Morocco. A total of almost 9,000 soil profiles data were collected, thanks also to the contributions of some research institutes (i.e., IAO, CREA, IRD/ORSTOM). These were then subjected to detailed analysis in order to ascertain the types of survey methods employed, the different soil classification systems used and the type of data available for each country (e.g., field data, lab data). The systematic collection of data has revealed several key findings. Firstly, that legacy data are frequently old, in non-digital format and lack homogeneity in terms of soil classification systems, field and lab methods, and data formats. Secondly, that if properly processed, such data are able to provide an overview of soil characteristics and properties in the Mediterranean area. Therefore, to use these data systematically and effectively, they must be harmonized and digitized in order to develop an easily accessible and standardized database of soil information. The process of collecting, evaluating, integrating multiple types of soil legacy data, homogenizing them using a single classification system (WRB, 2022), and their subsequent inclusion in a database, provides a more robust and complete view of the evidence available about soil health in the MR. It is a key step in the selection of soil health indicators and provides useful information to define past and present soil health conditions. This collaborative effort represents a crucial preparatory step for the future realization of the Soil Atlas of the Mediterranean Region.