Tecniche di monitoraggio non invasive per la tutela del paesaggio e la conservazione dei muretti a secco: il caso di studio della Puglia.

Introduction In the climate system, soil is the second carbon sink after the oceans. Several phenomena associated with climate change and anthropogenic activity indirectly affect soils through ecosystem functioning (Gelybó et al. 2018). Climate change is not the only factor that can change the function of soil from a carbon sink to a source of emissions. , the way it is used also plays a role. Among the techniques for monitoring the environment are remote sensing, which is the technical-scientific discipline concerned with the measurement and observation of the physical characteristics of a site from a distance (Chuvieco, 2020). However, it is used in different application areas, such as environmental and agricultural monitoring, water resources, pollutant emission up to the city scale. State of art Dry stone walls are an age-old building technique commonly used in rural environments to improve soil biocapacity - retaining water, buffering wind and maintaining temperatures. The classic Mediterranean landscape is closely linked to dry stone, the walls are made with local stone and are integrated into the landscape (Tarolli, et al. 2019). Among its advantages over other similar techniques are its permeability, plasticity and its environmental role (Ermini, et al. 2022). Among the different existing techniques, dry stone walls are an important element; therefore, the conservation or improvement of the dry stone heritage can also become a mechanism for the sustainability of natural resources. Methodology This paper analyzes how dry stone walling techniques improve the permeability conditions of rural agricultural soils. For this purpose, a study methodology comprising three phases was employed: 1) an initial review of the bibliographic sources on the subject; 2) field research that allowed the direct analysis of the artefacts investigated, for which abundant graphic and textual documentation was collected; and 3) through the use of multispectral vegetation indices such as Normal Difference Vegetation Index (NDVI) and moisture such as Normal Difference Moisture Index (NDMI) attached to the Sentinel-2 optical sensor satellite images to extract metric parameters for the health of the vegetation and soil within the area surrounded by the dry-stone walls. The objective of the work was to verify, in the light of scientific knowledge, whether dry stone walls constitute a construction technique that improves the permeability capacity of soils, based on an analysis of the characteristics and technical functions of the walls and the use of photogrammetric data of the physical conditions of the soil (Srinivasan et al. 2022). This study aims to provide new theoretical and technical approaches for the conservation of this heritage. This work methodology has made it possible to identify the causes and forms of degradation to which these structures are subjected. In general, although dry stone walls share basic construction rules, they are mainly differentiated by the type of stone material used and by the local territorial construction rules. Discussion In order to understand the phenomenon of degradation suffered by these constructive elements, it is necessary to know the technical stresses to which they are subjected, such as: slope disposition, ground thrusts, overloading of the laying surface, water thrusts, structural instability; the fulfilment of these mechanical characteristics determines the functionality of the artefacts investigated according to the field review. The phenomena that affect the form of degradation can be classified into two groups: endogenous and exogenous; where the former depend on the technical characteristics used for the construction of the walls. This phenomenon can appear due to an inadequate dimensioning or an inadequate arrangement of the stone elements (Line eguida per la tutela, il restauro e gli interventi sulle strutture in pietra a secco della Puglia, 2015). On the other hand, exogenous phenomena are the result of the natural weathering process of the stone material used. Conclusion According to the analysis, these two phenomena affect the permeability of the soil, generating water concentration points. The satellite data obtained have made it possible to identify the relationship between the condition of the structures and the permeability of the soils.