Franco Previtali

Improved plant resistance to drought is promoted by the root‐associated microbiome as a water stress‐dependent trait

Although drought is an increasing problem in agriculture, the contribution of the root-associated bacterial microbiome to plant adaptation to water stress is poorly studied. We investigated if the culturable bacterial microbiome associated with five grapevine rootstocks and the grapevine cultivar Barbera may enhance plant growth under drought stress. Eight isolates, over 510 strains, were tested in vivo for their capacity to support grapevine growth under water stress. The selected strains exhibited a vast array of plant growth promoting (PGP) traits, and confocal microscopy observation of gfp-labelled Acinetobacter and Pseudomonas isolates showed their ability to adhere and colonize both the Arabidopsis and grapevine rhizoplane. Tests on pepper plants fertilized with the selected strains, under both optimal irrigation and drought conditions, showed that PGP activity was a stress-dependent and not a per se feature of the strains. The isolates were capable of increasing shoot and leaf biomass, shoot length, and photosynthetic activity of drought-challenged grapevines, with an enhanced effect in drought-sensitive rootstock. Three isolates were further assayed for PGP capacity under outdoor conditions, exhibiting the ability to increase grapevine root biomass. Overall, the results indicate that PGP bacteria contribute to improve plant adaptation to drought through a water stress-induced promotion ability.

Mitigating land degradation in Mediterranean agro-silvo-pastoral systems: a GIS-based approach

Agro-silvo-pastoral systems were studied in central–eastern Sardinia (Italy) to assess their environmental impact in marginal Mediterranean areas. Land cover changes between 1955 and 1996 were assessed by using multitemporal aerial coverages. The shift from extensive to semi-extensive production systems resulted in a decrease in woodland and in a marked increase in artificial pastures. Related field surveys highlighted widespread land degradation processes in areas where pasture amendment actions on land characterised by steep or fairly dissected morphology had been carried out. Starting from a past land suitability classification developed at farm level, a scheme for the evaluation of the land suitability to the creation of new pastures at regional scale was developed by using GIS methodologies. The scheme classifies the land into five land suitability classes as defined in the FAO Framework for Land Evaluation (highly suitable, moderately suitable, marginally suitable, currently not suitable, permanently unsuitable). The land suitability classification performed by the GIS model showed high accuracy if compared to the traditional procedure. The comparison between the land suitability and current land uses allows the identification of areas sensitive to land degradation where land resource conservation programmes can be proposed.

Land Suitability for Crop Options Evaluation in Areas Affected by Desertification: The Case Study of Feriana in Tunisia

The study was carried out in the Tunisian site of a Cooperation Project, aiming to implement techniques for combating desertification. The approach of the project is based on promoting drought-resistant fodder shrubs as an alternative crop, in areas where the expansion of traditional cereal and olive trees in not suited rangelands constitute a land degradation factor. A land evaluation procedure was implemented based on a Map of Pedo-morphologic Units purposely created and on GIS based suitability models specifically adapted to the local conditions. The suitability maps obtained showed that about 18% of present rainfed cereal crops and 12% of olive plantations are located in not suited areas. The results also highlight the areas where further crop development could be more or less advisable and fodder shrubs could be introduced as an alternative and sustainable income generating option.

Seismipedoturbations in Volcanic Soils in North-Eastern Ecuador

Abstract Two earth tremors caused topsoil and turf overturning, cracks in the ash mantle, and probably also cracks in soil profiles. In seismically active regions such episodic events may substantially influence soil profile development.

Assessing Impacts of Climate Change, Ski Slope, Snow and Hydraulic Engineering on Slope Stability in Ski Resorts (French and Italian Alps)

Climate change and increased skier density is increasing ski run reworking, use of artificial snow and snow grooming. Few studies are available on these engineering impacts on slope stability. Therefore, the soil properties, compaction and infiltration characteristics were investigated on ski slopes and compared to natural sites for three different ski resorts (Les Menuires, La Rosiere and Foppolo) in the French and Italian Alps. The results show that soil properties differ substantially, with lower nitrogen and carbon content and higher pH on ski runs. Soil compaction is up to three times higher and infiltration takes up to four times longer on ski slopes compared to natural sites. Some new ski slopes were even 100 % impermeable. This explains why ski slopes are more prone to landslides, sheet, rill and gully erosion and have a distinct vegetation cover.

Challenges in Assessing and Managing Geo-hydrological Risk Related to Natural and Anthropogenic Pressures in Alpine Ski Resorts

Alpine ski resorts attract large temporary populations at relatively high altitudes, causing both urban and ski infrastructure development in ecologically vulnerable regions frequently subject to geo-hydrological risk. This study deals with the impacts of urbanization comprising housing, roads, parking and heliports, impacts of ski runs such as slope grooming and drainage and impacts of artificial snow production for example snow grooming, water storage reservoirs and water pipelines in the French and Italian Alps. Ski resort infrastructure is both at risk from natural hazards including landslides, rockfalls, avalanches and floods and from artificially induced hazards related to artificial snow infrastructure and ski slope manipulation for instance landslides, debris flows and erosion. Managing such risks is often only partially successful after 4–5 decades, however many impacts are irreversible. Climate change and intensification of ski resort development is likely to increase geo-hydrological risks in future.

The geomorphologic and pedo-morphologic maps of Skhirat (Feriana, Tunisia) at the 1:50,000 scale

Land planning and land restoration in drylands affected by desertification require a good understanding of the active geomorphic processes, their intensities and spatial patterns. Traditional Soil and Land Suitability maps do not incorporate this information and may be partially inadequate in that regard, because they necessarily give a ‘static’ representation of the land. The geomorphology of the study area (Feriana district, Central Western Tunisia) is complex, including relict landforms, such as Quaternary pediments, fossil sand dunes, and the evidence of ancient endorheic systems. On the other hand the area is characterized by active and intense geomorphic processes: water and wind erosion, aeolian deposition, and localized present-day endorheism accompanied by water logging and salt accumulation processes. The soils reflect the imprints of multiple past and present pedogenic and geomorphic processes. In this study a Geomorphologic and a Pedo-morphologic Map were produced to provide the local decision makers with cartographic tools to best plan land use options and land restoration. The Maps were drawn at the 1:50,000 scale based on detailed photo-interpretation and on dedicated field surveys.