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Agricultural terraces are often subject to degradation issues related to water movement. A better understanding of the main hydrological processes that govern surface and subsurface water flow pathways and that are responsible for terrace failure and dry-stone wall collapse is essential for appropriate water resource management and rural landscape maintenance in terraced areas. However, a clear conceptualization of different hydrological functioning related to wall instability issues is still missing. In this study, we monitored a terrace system in a hilly site of central Italy cultivated with vineyards. We adopted a multidisciplinary approach based on soil analysis, different geophysical techniques, hydrological monitoring, high-resolution grid terrain analysis and field experiments (infiltration and flooding tests) aiming to: (i) obtain new information of terrace soil and subsoil structure; (ii) test the hypothesis on wall instability based on the formation of preferential flow and water accumulation behind the wall; and (iii) develop a conceptual model of water circulation in agricultural terraces. Our results indicate that terrace soil was highly heterogeneous, including discontinuities and piping systems that facilitated a rapid infiltration and the development of fast subsurface flow. Groundwater rise did not occur, as observed in other terraced sites, but infiltrated water accumulated behind dry-stone walls, increasing pore water pressure and inducing wall bulging and instability. Our findings provided new field evidences of water circulation and led to the definition of a novel paradigm of hydrological functioning of farming terraced systems for addressing more efficient management and maintenance issues in these vulnerable landscapes.

The accumulation of non-essential heavy metals in agricultural soils and consequent environmental contamination raises concerns over their potential toxic effects on human health. Unfortunately, over the past years, the Campania Region (Southern Italy) has been subjected to illegal dumping of industrial or household waste. Particular attention is devoted toward the National Interest Priority Site (NIPS) Domitian Coast Flegreo and Agro Aversano because it is characterized by a patchy distribution of anthropogenic and geogenic pollutants. Contrary to other heavy metals, Cadmium (Cd) is of considerable environmental concern. Industrial and agricultural applications of cadmium include the production of batteries, alloys, and pigments and chemical fertilizer and pesticides[1]. Poplar is suitable to absorb and accumulate Cd in its roots and is usually used for phytoremediation of contaminated soils [1]. Nevertheless, direct determination of Cd in poplars roots is an expensive, time-consuming and destructive activity. To circumvent the drawbacks of conventional direct approach, scenario-based strategies obtained by using advanced hydrological modelling tools, like the HydroGeosphere (HGS) model, have been developed to examine both contaminants transport in groundwater and solute surficial distribution in a 3D environment. HGS model accuracy is strongly influenced by detailed information on surface topography, commonly described by a Digital Elevation Model (DEM). A high resolution DEM was generated by applying Unmanned Aerial Vehicles (UAVs)that allows to set the flight quotas by adapting the aerial photos resolution to the object under investigation, and to acquire images in flexible date [2]. All in all, UAVs reduce also time and costs in retrieving aerial data [2]. In the present work, the assessment of Cd removal made by phytoextraction of poplars is evaluated by combining the HGS model with a fine resolution DEM, generated by UAV – photogrammetry. To achieve this aim, two different scenarios have been compared: the former is characterized by bare soil (BS), while the latter considers poplar plantation (PP).

ASPETTI CHIAVE: • variazioni spazio-temporali delle principali componenti idrologiche dovute all’abbandono di aree agricole. • impatto del cambio di uso del suolo osservato sui servizi ecosistemici offerti da un ambiente agroforestale mediterraneo. • analisi di futuri scenari di cambio di uso del suolo.

KEY POINTS • An experimental hillslope - Cape Fear - equipped with real-time monitoring sensors for the analysis of runoff generation is illustrated. • First two years of rainfall, runoff, and soil moisture observations are analyzed. • The hydrological balance suggests that surface and subsurface runoff are driven by rainfall-threshold phenomena and that evapotranspiration accounts for more than 70% of rainfall.

This work is part of a series of studies being carried out within the EU-Life+ project ECOREMED (Implementation of eco-compatible protocols for agricultural soil remediation in Litorale Domizio-Agro Aversano NIPS). The project refers to Litorale Domitio-Agro Aversano that has been identified as National Interest Priority Site (NIPS) and includes some polluted agricultural land belonging to more than 61 municipalities in the Naples and Caserta provinces of the Campania Region. The major aim of the project is to define an operating protocol for agriculture-based bioremediation of contaminated agricultural soils, also including the use of plant extracting pollutants to be used as biomasses for renewable energy production. This contribution specifically address the question of evaluating the effectiveness of phytoremediation actions selected by the project in the pilot area of Trentola-Ducenta and will provide some preliminary results of monitoring and modeling activities. A physical and hydraulic characterization has been carried out in this area where poplar trees were planted. Monitoring of water flow, root water uptake and solute transport in the soil-plant-atmosphere is under way with reference to two trees using capacitance soil moisture and matric potential sensors located at three different soil depths, whereas plant water status and evapotranspiration fluxes are indirectly estimated using fast-responding stem dendrometers.

The Soil Hydrology Laboratory at University of Naples Federico II has been operating for more than 50 years. During these decades, consolidating certain techniques and developing new measurement methods have always been a target for us and represented an excellence in the field of soil hydrology. Many field campaigns have been undertaken during these years with the major aim of supporting the various research activities of the different groups of our Division. All of the data contained in the database that we provided have been measured in our laboratory.

I modelli di bilancio idrologico, se correttamente parametrizzati per quanto riguarda il dominio fisico-biologico di interesse, forniscono informazioni utilizzabili per razionalizzare l’uso dell’acqua irrigua, consentendo l’applicazione funzionale dell’acqua irrigua, rispettando sia i vincoli fisiologici legati alla sensibilità agli stress idrici della coltura, che quelli imposti dalla natura fisica del suolo. Nella definizione più precisa del dominio che è sede dei processi idrologici, è ormai affermato il paradigma che definisce il sistema Suolo Pianta Atmosfera (sistema SPA) come un sistema continuo attraverso cui l’acqua si muove per effetto di gradienti del potenziale totale. All'interno della componente “pianta” del sistema SPA l'acqua traspirata dalle superfici evaporanti presenti nelle camere sottostomatiche viene rimpiazzata dall’acqua attinta dal suolo, attraverso l'apparato radicale, per mezzo del processo di attingimento idrico radicale. Tale processo è stato storicamente studiato e descritto attraverso l'impiego di schematizzazioni matematiche che differiscono per l'approccio concettuale, per la complessità e per la conseguente necessità di parametrizzazione richiesta. Risultati di precedenti ricerche svolte dagli autori, hanno mostrato che in condizioni di apporti idrici sub-ottimali, i diversi modelli radicali non davano risposte significativamente diverse. Resta perciò spazio per la verifica sperimentale della rispondenza di tali schematizzazioni sulle risposte modellistiche in presenza di stress idrici più severi. In questa memoria si è studiato l'effetto di diverse schematizzazioni della funzione di riduzione dell'attingimento radicale sulle stime di variabili colturali e ambientali (traspirazione effettiva, contenuto d'acqua nel profilo di suolo) in risposta a potenziali idrici del suolo limitanti l'assorbimento radicale. Sono stati scelti a questo scopo quattro modelli di attingimento e si sono utilizzati dati sperimentali relativi a due colture irrigue sottoposte a regimi idrici di diversa severità.

L’importanza di quantificare la variabilità spaziale e temporale dello stato idrico dei suoli ha dato impulso alla sperimentazione di diverse tecniche di “remote sensing”, sia nel campo delle microonde, con sensori attivi (SAR) e passivi (radiometri), che nel dominio solare, dal visibile all’infrarosso termico. La difficoltà di interpretare queste osservazioni in presenza di una copertura vegetale ne ha limitato fortemente l'applicabilità. Nel corso di alcune campagne sperimentali condotte in questi ultimi anni, presso il Dipartimento di Ingegneria Agraria ed Agronomia dell’Università di Napoli Federico II sono state sperimentate due metodologie innovative per la stima del contenuto idrico del suolo in presenza di vegetazione: a) analisi della dipendenza della temperatura superficiale della vegetazione dal contenuto idrico del suolo esplorato dagli apparati radicali; b) stima del contenuto idrico superficiale dall’analisi della riflettanza nel campo del visibile e dell’infrarosso. Il primo metodo, applicabile preferibilmente a superfici caratterizzate da copertura pressoché totale del suolo, si basa sull’analisi di relazioni empiriche fra misure contemporanee di temperatura superficiale da sensori aerotrasportati, quindi caratterizzati da elevata risoluzione spaziale e radiometrica; esso si basa sul principio che la temperatura superficiale della vegetazione possa essere considerata un soddisfacente indicatore del contenuto d’acqua medio nella zona del suolo esplorata dagli apparati radicali. Il secondo metodo, diversamente, è applicabile a superfici non completamente coperte da vegetazione (LAI

La distribuzione spaziale e temporale dei prelievi nei sistemi irrigui con esercizio alla domanda dipende da due componenti principali. La prima componente è legata in maniera deterministica all’evoluzione dei diversi processi fisici che regolano il funzionamento del sistema, la seconda è invece una componente puramente stocastica che dipende dalle modalità di distribuzione irrigua scelte da ciascun agricoltore. Nell’analisi del funzionamento di un sistema irriguo alla domanda che prenda in considerazione intervalli di tempo di uno o più giorni per la valutazione dei prelievi dalla rete, la prima componente è prevalente sulla seconda componente di natura stocastica (che prevale invece nelle analisi condotte su intervalli temporali subgiornalieri). Sulla base di queste considerazioni, il presente studio intende dimostrare come, attraverso una caratterizzazione della variabilità spaziale e temporale di clima, suolo e vegetazione, sia possibile identificare alcuni parametri che descrivono in maniera sintetica il funzionamento di tutto il sistema irriguo. L’impiego di modelli distribuiti di simulazione del moto dell’acqua nel sistema suolo-pianta-atmosfera e di modelli idraulici delle reti in pressione, unitamente ad avanzate metodologie di caratterizzazione del suolo e della vegetazione, ha consentito di identificare, con riferimento ad un sistema irriguo in pressione con esercizio alla domanda i seguenti parametri caratteristici: -volume irriguo specifico fisso o variabile in funzione del contenuto idrico nel suolo; -volume massimo giornaliero a disposizione dell’intero sistema irriguo in esame; -valore minimo dell’altezza piezometrica alla consegna. Detti parametri definiscono in maniera concisa il funzionamento del sistema irriguo e possono essere utilizzati per la simulazione di scenari di gestione, per l’ottimizzazione dell’uso delle risorse idriche disponibili. La procedura illustrata è stata sviluppata e testata con riferimento ad un distretto irriguo di 3000 ha nella Piana del Sele, con riferimento a due stagioni irrigue nel corso delle quali erano disponibili serie temporali di misure dei prelievi.

L'impiego congiunto di modelli di simulazione del bilancio idrologico e delle tecniche di telerilevamento può risultare di notevole utilità nella valutazione dell'efficienza degli interventi irrigui di vasti comprensori. Integrando anche strumenti per il controllo automatico delle quantità erogate, è oggi pensabile lo sviluppo di sistemi di supporto alle decisioni nella gestione di un comprensorio irriguo.

In the framework of its Earth Observation Envelope Programme the European Space Agency (ESA) carries out a number of ground-based and airborne campaigns that includes activities in support of the EC Water Framework Directive (WFD) EO projects for the improvement of protection and management of Europe’s water resources. The integration of algorithms for biophysical parameters determination from remote sensing and mathematical modelling of soil water balance is a crucial point to face with for arid zone agriculture management. Both an advanced application of precision farming and a parsimonious use of scarcer water resources require detailed spatial and temporal data retrievals on vegetation and soil. This spatial information can be obtained by means of Earth Observation, integrated necessarily with ground data and modeling techniques of soil water dynamics.

Algorithms for quantitative estimation of canopy biophysical variables from remote observation enable continuous crop status monitoring. Mediated by root apparatus, a link exist between crop water content and soil water availability. Previous research has evidenced the existence of a robust relationship between the water status of vegetated surfaces, their canopy development and the corresponding surface temperature. Although it is very difficult to determine with accuracy the soil water content of vegetated surfaces from surface temperature, this latter can be taken –under given circumstances– as a proxy of soil water status. This information, together with other observations in the solar range needed to determine land surface parameters, can be of great usefulness for the validation of hydrological distributed models, and possibly for a definition of data assimilation schemes. So doing, it is possible to increase the reliability of distributed hydrological numerical models, widely used as operative tools in a large number of applications dealing with water management problems.

analysed to evaluate the spatial distribution of Leaf Area Index and soil water content in different types of crops. To this end, regular grids of measurements of soil water content have been acquired in coincidence to the flight acquisitions in two fields. LAI has been measured in distinct locations within the fields by means of the Licor LAI-2000 optical analyser and maps of LAI have been derived from CASI data by using an inversion procedure of the PROSAILH canopy radiative transfer code. The resulting map has been used to assess the correlation between the LAI estimated by using optical data and the surface backscattering in bands X, C and L of AGRISAR. Diversely, in the case of soil water content, the analysis has been performed by using a grid of approximately 80 measurements taken by using an FDR sensor to detect the volumetric water content in the upper 6-7 cm of soil in a vegetated field. SAR data in bands C and L have been considered to verify the possibility of detecting soil water content in presence of a vegetation cover. Successively, the application of semi-empirical models for LAI (X-band) and for soil water content (C and L bands) has been evaluated with and without on-site calibration.

The main objective of the present work was to compare different functions for describing water stress based on the “macroscopic” approach (reduction coefficient for root water uptake as function of soil water pressure head) and to calibrate root water uptake parameters, as implemented in the different models employed.

In this work we evaluated the effect of the choice between various parametric relations for the description of the hydraulic conductivity in order to verify the impact that they exert on the estimation and on the spatial variability of the hydraulic conductivity.

This research deals with scale-dependency effects on the calibration of parameter in the Arya and Paris method for estimating the soil water retention function from textural data.

This study examines how well PTFs perform that use both basic soil physical and chemical properties and topographical attributes for a hillslope in Southern Italy.

Basic soil properties have long been used to predict unsaturated soil hydraulic properties with pedotransfer function (PTFs). Implementation of such PTFs is usually not feasible for catchment-scale studies because of the experimental effort that would be required. On the other hand, topographical attributes are often readily available. This study therefore examines how well PTFs perform that use both basic soil properties and topographical attributes for a hillslope in Basilicata, Italy. Basic soil properties and hydraulic data were determined on soil samples taken at 50-m intervals along a 5-km hillslope transect. Topographical attributes were determined from a digital elevation model. Spearman coefficients showed that elevation (z) was positively correlated with organic carbon (OC) and silt contents (0.62 and 0.59, respectively) and negatively with bulk density (ρ b ) and sand fraction (−0.34 and −0.37). Retention parameters were somewhat correlated with topographical attributes z, slope (β), aspect (cosϕ), and potential solar radiation. Water contents were correlated most strongly with elevation (coefficient between 0.38 and 0.48) and aspect during “wet” conditions. Artificial neural networks (ANNs) were developed for 21 different sets of predictors to estimate retention parameters, saturated hydraulic conductivity (K s ), and water contents at capillary heads h = 50 cm and 12 bar (103 cm). The prediction of retention parameters could be improved with 10% by including topography (RMSE = 0.0327 cm3 cm−3) using textural fractions, ρ b , OC, z, and β as predictors. Furthermore, OC became a better predictor when the PTF also used z as predictor. The water content at h = 50 cm could be predicted 26% more accurately (RMSE = 0.0231 cm3cm−3) using texture, ρ b , OC, z, β, and potential solar radiation as input. Predictions of ANNs with and without topographical attributes were most accurate in the wet range (0 < h < 250 cm). Semivariograms of the hydraulic parameters and their residuals showed that the ANNs could explain part of the (spatial) variability. The results of this study confirm the utility of topographical attributes such as z, β, cosϕ, and potential solar radiation as predictors for PTFs when basic soil properties are available. A next step would be the use of topographical attributes when no or limited other predictors are available.