Mapping Soil Water-Holding Capacity Index to Evaluate the Effectiveness of Phytoremediation Protocols and ExposureRisk to Contaminated Soils in a National Interest Priority Site of the Campania Region (Southern Italy).

Abstract:

Soil moisture is an important state variable that influences water flow and solute transport in the soil-vegetation-atmosphere system, and plays a key role in securing agricultural ecosystem services for nutrition and food security. Especially when environmental studies should be carried out at relatively large spatial scales, there is a need to synthesize the complex interactions between soil, plant behavior, and local atmospheric conditions. Although it relies on the somewhat loosely defined concepts of “field capacity” and “wilting point”, the soil water-holding capacity seems a suitable indicator to meet the above-mentioned requirement, yet easily understandable by the public and stakeholders. This parameter is employed in this work to evaluate the effectiveness of phytoremediation protocols funded by the EU-Life project EcoRemed and being implemented to remediate and restore contaminated agricultural soils of the National Interest Priority Site Litorale Domizio-Agro Aversano. The study area is located in the Campania Region (Southern Italy) and has an extent of about 200,000 hectares. A high-level spotted soil contamination is mostly due to the legal or outlaw industrial and municipal wastes, with hazardous consequences also on groundwater quality. With the availability of soil and land systems maps for this study area, disturbed and undisturbed soil samples were collected at two different soil depths to determine basic soil physico-chemical properties for the subsequent application of pedotransfer functions (PTFs). Soil water retention and hydraulic conductivity functions were determined for a number of soil cores, in the laboratory with the evaporation experiments, and used to calibrate the PTFs. Efficient mapping of the soil hydraulic properties benefitted greatly from the use of the PTFs and the physically-based scaling procedure developed by Nasta et al. (2013, WRR, 49:4219-4229).