Sergio Vacca

Zeolitized tuffs in pedotechnique for the reclamation of abandoned quarries. A case study in the Campania region (Italy).

The present study aims to assess the evolution of different proto-horizons as embryonic soils built by pedotechnologies for the reclamation and management of derelict and damaged lands, such as abandoned quarries. The model proto-horizons were assembled by utilizing coarse limestone gravel or zeolitized Phlegraean Yellow Tuff (PYT) as mineral components and commercial compost-amendments or a phosphorite-poultry manure mixture as organic matrices for growth of a pasture-grass under controlled conditions. The evolution of the model proto-horizons was followed by an evaluation of the stability and modification of the organic matter (OM) with reference to plant development. The results suggest that the natural carbonatic substrate occurring in limestone quarries was unable to sustain significant plant growth, while the PYT was suitable and efficient as a pedogenic substrate because it supported plant growth and induced a conspicuous accumulation of OM due to root activity. In particular, OM, including humic and non-humic components, greatly increased in the PYT treatment with the phosphorite-poultry manure mixture showing a concurrent trend toward humification. Conversely, an overall tendency toward degradation of OM was detected in the PYT model proto-horizon treated with commercial compost. Feasibility estimates show that quarry restoration costs appear reasonable where environmental impacts are high.

Ethnopedology in the study of toponyms connected to the indigenous knowledge on soil resource

In taking an integrated ethnopedological approach, this study aims to investigate the meaning of the distribution of the toponyms used in traditional and recent cartography of Sardinia (southern Italy). It is particularly, but not only, focused on those related to soil resources. Sardinia is particularly interesting in this respect, as its unique history, geography, and linguistic position makes it one of the Italian and Mediterranean regions with the greatest number of toponyms. This research investigated the toponyms belonging to an important sub-region of Sardinia, called Ogliastra (central-eastern Sardinia). The research was conducted through the following integrated approach: i) toponymy research and collection from different sources; ii) database creation and translation of toponyms from the Sardinian language (SL); iii) categorization of toponyms; and iv) graphical, statistical, and cartographic data processing. Distribution and diversity of toponyms were assessed using the compiled database, coupled with a geographical information system (GIS). Of around 7700 toponyms collected, 79% had already been reported in SL, while just 21% were in Italian. Of the toponyms in SL, 77% are of known meaning and 54% of these toponyms were characterized by a meaning directly and/or indirectly connected to specific environmental features. On the whole, morphology would appear to be the primary environmental factor able to explain the complex, articulated presence, distribution, and typology of the investigated toponyms. A least squares regression analysis of pedodiversity vs. topodiversity shows a very closed distribution, with an impressive high correlation index (R2 = 0.824). The principal factor analysis (PFA) shows that such a connection may be morphologically based, thereby confirming that pedodiversity and topodiversity are strongly linked each other. Overall, the research shows that an integrated ethnopedological approach, combining indigenous and scientific knowledge may be of great interest in order to mitigate the impressive phenomena of the indigenous knowledge lost.

Zeolitized tuffs in pedotechniques to improve soil resilience against the impact of treatment by municipal sewage: balance of nutrient and noxious cations

Abstract Two zeolitized tuffs (ZTs), viz. a Neapolitan yellow tuff (NYT) and a clinoptilolitebearing tuff (ZCL), were tested as pedotechnical materials to improve soil resilience against the impact of treatment by a ‘dirty’ municipal sewage system (DSW). Soils (surface horizon) were a sandy, alkaline Entisol (Typic Xeropsamment), and a sandy-loam, sub-acidic Alfisol (Ultic Palexeralf). Results showed that the presence of ZTs resulted in several favourable effects. Electrical conductivity (EC) decreased and pH was buffered. Ammonium was selectively taken up from the DSW, making the zeolitized tuffs almost saturated by NH4+, by exchanging both beneficial cations, such as K+ and Ca2+, thus improving their potential availability to plants, and undesirable cations such as Na+, thereby hindering the exchangeable sodium percentage (ESP) increase and concurrent soil salinization-alkalinization. At the same time, NH4+ was stored as a potentially slow-release nitrogen fertilizer. The mobility of Pb, Cu and Zn dropped off to a large extent. NYT produced the best effects, and the Entisol gained the greatest benefit from treatments.

Biochemical performance of degraded soil recovered by lake-dredged materials (LDM) as pedotechnomaterials

PurposeThe increasing need for disposal of lake-dredged material (LDM) as a consequence of intensified natural and/or anthropogenically mediated erosion processes has lead the scientific community to find new strategies for its reuse. The aim of this study is to investigate the effect of LDM use on the biochemical and functional performance of a degraded soil affected by erosion and entisolization processes.Materials and methodsAs a paradigmatic case study, a hydrographic basin located in Sardinia (Italy) was investigated. Severe soil degradation processes affect this area and have resulted in intensive sheet and rill water erosion. In contrast, an increase in sedimentation has been recorded on the bottom of an artificial lake. A degraded soil, collected in this area, were treated by co-utilization of LDM, other mineral matrices (a zeolitized tuff), organic amendment (a commercial manure), and mineral fertilizer (urea, triple superphosphate, and potassium sulfate) for the growth of a pasture grass under controlled (pot) conditions. The evolution of nine different model proto-horizons (MPH) was monitored through a series of biochemical parameters and techniques (total/extracellular enzymatic activity, isoelectric focusing, and gas chromatography) to assess the potential of LDM in soil biochemical recovery.Results and discussionOn the whole, treatments containing LDM resulted in good recovery of degraded soils, as shown by a general enhancement in biochemical functionality. Application of LDM increased the more stable fraction of organic matter and its active biochemical fraction, showing the highest stable humic carbon content and humic activity. Such outcomes seem to represent a long-term beneficial effect on soil functionality.ConclusionsThis study demonstrates that LDM could be a useful pedotechnomaterial (PTM) for improving the biochemical functionality of extremely degraded soils. Additionally, the use of LDM as a PTM has the ecological advantage of recycling what is often considered as a “waste material.” From a socioeconomic point of view, the reuse of LDM in pedotechnique could represent a new low-cost alternative to the complex and expensive management and disposal of this material.

Urban Wastewater Effects on Water Flow and Solute Transport in Soils

Abstract This article aims mainly to verify the consequences of urban wastewater reuse in irrigation practices on hydrological behavior of soils. Herein the effects on both the hydraulic and dispersive properties of characteristic soils in South Sardinia are illustrated. The study was carried out at the Ente Autonomo del Flumendosa (EAF) laboratory. Ten undisturbed soil monoliths, 120 cm height and 40 cm diameter, were collected from plots, the locations of which were preliminarily individuated through a prior pedological study. An experimental facility was set up and sensors for monitoring both soil water and solute concentrations were inserted horizontally in each column at different depths. A disturbed layer at the soil surface, which expands in depth with time, was observed, characterized by reduced soil porosity, translation of pore size distribution towards narrower pores and consequent drastic decrease of permeability. It will be shown that these changes occurring in the disturbed soil layer, although local by nature, affect the mean hydrological behavior of the whole soil profile.