Andic soils and catastrophic mudflows in Italy: morphological and hydropedological evidences

In Italy rapid landslides are the most frequently occurring natural disasters and, after earthquakes, cause the highest number of victims. In this contribution we attempt to prove that there exist a tight connection between the presence of a specific soil type, namely andic soils, and the occurrence of the main catastrophic mudflows and debris flows occurred in Italy in the last decades. The study was performed by means of an integrated pedological and hydrological analysis on the detachment crowns of some of the most important catastrophic mudflows and debris flows occurred in Italy in the last decades and involving/evolving surface soils. The results at both regional (Campania) and National (Italy) scale clearly show that despite the large variability of the environmental settings of the studied sites there are indeed some striking homogeneous soil features in the detachment crowns including (i) soil morphology, (ii) andic features ranging from high to moderate, (iii) high water retention throughout a large range of pressure heads. Results seem to reveal clear cause-effect evidences between andic soils and the investigated catastrophic mudflows/debrisflows; this must be related to the unique physical properties of these soils inducing high landslide vulnerability

Soils of the Aversa plain (southern Italy)

The Aversa plain is one of the most important agricultural areas of the Campania region, combining the presence of very fertile soils, sites of great archaeological interest and growing residential urbanization. In this paper, the soil map (1:50,000 scale) of the Aversa plain is presented. Three main land systems (coastal, alluvial and foothill plains) characterized by different soil types (Andosols, Phaeozems, Cambisols, Vertisols, Arenosols, Histosols, Luvisols) have been identified. However, Andosols are the most widespread soil type (9768 ha) and, along with part of the Phaeozems and Cambisols, represent the most fertile soils of the Aversa plain (first and second classes of the land capability classification). In order to evaluate recent intense soil sealing, its impact over land capability classes was assessed during the last 60 years. Results show that soil sealing in the Aversa plain affected mainly the most fertile first- and second-class soils

Modelling the Impact on Root Water Uptake and Solute Return Flow of Different Drip Irrigation Regimes with Brackish Water

Water scarcity and quality degradation represent real threats to economic, social, and environmental development of arid and semi-arid regions. Drip irrigation associated to Deficit Irrigation (DI) has been investigated as a water saving technique. Yet its environmental impacts on soil and groundwater need to be gone into in depth especially when using brackish irrigation water. Soil water content and salinity were monitored in a fully drip irrigated potato plot with brackish water (4.45 dSm−1) in semi-arid Tunisia. The HYDRUS-1D model was used to investigate the effects of different irrigation regimes (deficit irrigation (T1R, 70% ETc), full irrigation (T2R, 100% ETc), and farmer’s schedule (T3R, 237% ETc) on root water uptake, root zone salinity, and solute return flows to groundwater. The simulated values of soil water content (θ) and electrical conductivity of soil solution (ECsw) were in good agreement with the observation values, as indicated by mean RMSE values (≤0.008 m3·m−3, and ≤0.28 dSm−1 for soil water content and ECsw respectively). The results of the different simulation treatments showed that relative yield accounted for 54%, 70%, and 85.5% of the potential maximal value when both water and solute stress were considered for deficit, full. and farmer’s irrigation, respectively. Root zone salinity was the lowest and root water uptake was the same with and without solute stress for the treatment corresponding to the farmer’s irrigation schedule (273% ETc). Solute return flows reaching the groundwater were the highest for T3R after two subsequent rainfall seasons. Beyond the water efficiency of DI with brackish water, long term studies need to focus on its impact on soil and groundwater salinization risks under changing climate conditions

Ischia landslides (Italy): a multidisciplinary approach aimed to the knowledge of soil properties

An integrated approach (chemical, hydrological, mineralogical and micro-tomographic) has been used to study the soils of the landslides occurred in the Ischia island (Italy) on April 2006. The study has been carried out on three soil profiles sampled on representative detachment crowns. The main outcome indicates: (i) presence of volcanic soils, very rich in primary glass, characterised by the presence of poorly ordered kaolinite in all horizons and expandable clay minerals only in the deepest horizons (CBb and Cb), (ii) high values of water content near saturation for all soil horizons, (iii) a relevant vertical discontinuity of soil physical properties. In particular, the deep silty horizon (Cb) retains high amounts of water at low matric potential and shows the lowest value of the saturated hydraulic conductivity than the other horizons. The micro-tomographic analysis of this deep horizon indicates a very complex intra-aggregate pore space, which seems an important factor influencing the specific rheological behaviour of this sliding horizon. In terms of pedogenetic processes, the soils of M. Vezzi northern slope are very different from those described for other catastrophic landslides of the Campania region (Sarno, Quindici, etc.), but they have in common the presence, along the soil profile, of marked physical discontinuities surely contributing to the initiation mechanisms of the landslides

Soil pollution in a decommissioned shooting range: a preliminary survey of the spatial variability of legacy pollutants

Outdoor shooting ranges provide recreational facilities for millions of people in the world. However, there are many negative effects on the environment and public health arising from this activity. In particular, potential risks are mostly associated with the residential or agricultural use of decommissioned outdoor ranges, where bullets and targets have been deposited during the shooting activity. This is the case of an outdoor shooting range in Campania region (Southern Italy), located in an area of historical and naturalistic value, close to the ancient Etruscan village of Suessola (VII century b.C.). Specifically, the study site is located within an agricultural land declared unsuitable for agricultural and forest-pastoral production by the Italian Ministry of Agricultural, Food and Forestry Resources, due to an extensive long term soil contamination associated with Pb, Sb, PAHs, dioxins, PCBs and C> 12 hydrocarbons. With the purpose of planning a detailed site characterization of the shooting range area, a preliminary environmental survey was carried out by means of field investigations (ultrasonic penetrometry, electromagnetic induction - EMI - and gamma spectroscopy) and geochemical prospecting. Cone index data, obtained by ultrasonic penetrometer measurements, indicated the presence of a very dense, hard and impenetrable to hand hauger layer, recognised as travertine rock, from 25 to more than 55 cm of depth, and dipping northward. Continuous EMI data and gamma spectroscopy (K %, eU ppm, eTh ppm) parameters were acquired in the field in order to identify homogeneous zones in which further geochemical investigations should have been focused. In fact, apparent electrical conductivity (ECa) map, consistently with the gamma ray dose rate distribution map, allowed to highlight three separated singularity areas N-S oriented. XRF analyses, carried out through a portable analyzer on soil samples collected along soil profiles digged from topsoil until the travertine layer, showed a high contamination by Pb (greater than 1000 mg/kg) and Sb (greater than 30 mg/kg) in the first 15 cm of depth, at a distance of approximately 90 m from the shooting lanes. Chemical analyses were also performed on 32 topsoil samples collected on the basis of a regular grid across the study area. Concentrations of 13 PAHs compounds were determined and the highest values were found close to the firing lanes where in soil a huge amount of shooting target fragments are present. The preliminary results showed how the contamination due to the previous activity in the area produced a spatial distribution of contaminats differentiated on the basis of their source material and their role in the shooting process

Multi-Sensor Approach Combined with Pedological Investigations to Understand Site-Specific Variability of Soil Properties and Potentially Toxic Elements (PTEs) Content of an Industrial Contaminated Area

A combination of indirect soil investigation by proximal soil sensors (PSS), based on geophysical (ARP, EMI), physical (Cone Index –CI– by ultrasound penetrometry) and spectrometric (γ-rays) techniques, as well as pedological surveys, was applied in the field to assess the spatial variability of soil pollution and physical degradation in an automobile-battery recycling plant in southern Italy. Five homogeneous zones (HZs) were identified by the PSS and characterized by soil profiles. CI measurements and field analysis showed clear features of physical (i.e., soil compaction, massive structure) degradation. XRF in situ (on profiles) analysis using portable equipment (pXRF) showed Pb, Cd and As concentrations exceeding the contamination thresholds provided by the Italian regulation for industrial land use up to 20 or 100 cm of depth. Hence, a validation procedure, based on pXRF field survey, was applied to the PSS approach used for the HZs identification. High consistency was found between the HZs and the PTEs in the most contaminated areas. Significant negative Pearson correlation coefficients were found between γ-rays dose rate and Pb, Cu, Zn, As and Ni; positive ones were found between γ-rays and autochthonous lithogenic elements (V, Ti, Mn, K, Sr, Nb, Zr, Rb, Th), confirming that higher radionuclide activity correlated with lower pollution levels

Assessing the dynamics of soil salinity with time-lapse inversion of electromagnetic data guided by hydrological modelling

Irrigated agriculture is threatened by soil salinity in numerous arid and semi-arid areas of the world, chiefly caused by the use of highly salinity irrigation water, compounded by excessive evapotranspiration. Given this threat, efficient field assessment methods are needed to monitor the dynamics of soil salinity in salt-affected irrigated lands and evaluate the performance of management strategies. In this study, we report on the results of an irrigation experiment with the main objective of evaluating time-lapse inversion of electromagnetic induction (EMI) data and hydrological modelling in field assessment of soil salinity dynamics. Four experimental plots were established and irrigated 12 times during a 2-month period, with water at four different salinity levels (1, 4, 8 and 12 dSm􀀀1) using a drip irrigation system. Time-lapse apparent electrical conductivity (a) data were collected four times during the experiment period using the CMD Mini-Explorer. Prior to inversion of time-lapse a data, a numerical experiment was performed by 2D simulations of the water and solute infiltration and redistribution process in synthetic transects, generated by using the statistical distribution of the hydraulic properties in the study area. These simulations gave known spatio-temporal distribution of water contents and solute concentrations and thus of bulk electrical conductivity (b), which in turn were used to obtain known structures of apparent electrical conductivity, a. These synthetic distributions were used for a preliminary understanding of how the physical context may influence the EMI-based a readings carried out in the monitored transects as well as being used to optimize the smoothing parameter to be used in the inversion of a readings.With this prior information at hand, we inverted the time-lapse field a data and interpreted the results in terms of concentration distributions over time. The proposed approach, using preliminary hydrological simulations to understand the potential role of the variability of the physical system to be monitored by EMI, may actually allow for a better choice of the inversion parameters and interpretation of EMI readings, thus increasing the potentiality of using the electromagnetic induction technique for rapid and non-invasive investigation of spatio-temporal variability in soil salinity over large areas

Le frane d’Ischia (Italia): un approccio integrato finalizzato alla protezione ambientale

Un approccio integrato (chimico, idrologico, mineralogico e microtomografico) è stato usato per studiare i suoli delle frane (colate rapide di fango) avvenute ad Ischia nell’aprile del 2006. Lo studio è stato condotto su campioni di suolo prelevati da tre profili pedologici rappresentativi descritti nelle nicchie di distacco delle frane. Il principale risultato indica: (i) presenza di suoli vulcanici, molto ricchi di vetro primario, caratterizzati dalla presenza di caolinite a basso ordine cristallino in tutti gli orizzonti e minerali argillosi a reticolo espandibile negli orizzonti più profondi (2CB e 2C), (ii) elevata capacità di ritenzione idrica in tutti gli orizzonti del suolo, (iii) una discontinuità verticale delle proprietà fisiche del suolo. In termini di processi pedogenetici, i suoli del versante nord del M. Vezzi sono molto diversi da quelli descritti per le altre frane catastrofiche della regione Campania (Sarno, Quindici, ecc), ma hanno in comune la presenza, lungo il profilo del suolo, di una marcata discontinuità fisica che certamente contribuisce ai meccanismi di innesco delle frane