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The composition and turnover time (TT) of organic matter in soil fractions with different magnetic susceptibility were studied in a tropical primary forest in Ghana. The starting hypothesis was that soil organic matter (SOM) composition and properties depend on the magnetic susceptibility of the minerals SOM is associated with. Soil samples from 0 to 5, 5–15, 15–30, and 30–50 cm depth intervals were sieved to remove rock fragments (>2.0 mm) and then separated into two size fractions (0.5–2.0 mm and <0.5 mm) that were processed by a High Gradient Magnetic Separator (HGMS) to finally obtain four fractions with different size and/or magnetic susceptibility. All fractions were analysed for their mineral composition, 14C concentration, and spectroscopic properties of SOM (13C CPMAS NMR). From a mineralogical point of view, the magnetic (MA) fractions essentially differed from the non-magnetic (NM) ones for a higher presence of oxides and kaolinite, which per se is non-magnetic. In terms of chemical composition of SOM, the MA fractions showed higher contribution of labile compounds than the NM ones. At all depths, the 14C concentration revealed shortest TT of SOM in the <0.5 mm MA fraction and longest TT in the <0.5 mm NM fraction, while the 0.5–2.0 mm fractions showed intermediate and similar TT's. At depths <5 cm, the fine NM fraction was not significantly influenced by the carbon fixed after the 1950s ("bomb carbon"), having TT of almost 1000 years and suggesting that in this tropical soil some SOM can be stabilized also in relatively superficial horizons. Our findings support the hypothesis that minerals are driving factors of the fate of SOM. As a consequence, soil fractionation based on magnetic susceptibility might be a meaningful procedure for having insight into SOM dynamics. • A soil carbon fractionation based on magnetic susceptibility is applied to a tropical forest. • The procedure is based on the magnetic susceptibility of different soil minerals. • The obtained soil organic carbon fractions show different composition and turnover time. • Minerals are driving factors of the fate of soil organic carbon. [ABSTRACT FROM AUTHOR]

Woody encroachment is a widespread phenomenon resulting from the abandonment of mountain agricultural and pastoral practices during the last century. As a result, forests have expanded, increasing biomass and necromass carbon (C) pools. However, the impact on soil organic carbon (SOC) is less clear. The main aim of this study was to investigate the effect of woody encroachment on SOC stocks and ecosystem C pools in six chronosequences located along the Italian peninsula, three in the Alps and three in the Apennines. Five stages along the chronosequences were identified in each site. Considering the topsoil (0–30 cm), subsoil (30 cm-bedrock) and whole soil profile, the temporal trend in SOC stocks was similar in all sites, with an initial increment and subsequent decrement in the intermediate phase. However, the final phase of the woody encroachment differed significantly between the Alps (mainly conifers) and the Apennines (broadleaf forests) sites, with a much more pronounced increment in the latter case. Compared to the previous pastures, after mature forest (>62 years old) establishment, SOC stocks increased by: 2.1(mean) ± 18.1(sd) and 50.1 ± 25.2 Mg C·ha−1 in the topsoil, 7.3 ± 17.4 and 93.2 ± 29.7 Mg C·ha−1 in the subsoil, and 9.4 ± 24.4 and 143.3 ± 51.0 Mg C·ha−1 in the whole soil profile in Alps and Apennines, respectively. Changes in SOC stocks increased with mean annual air temperature and average minimum winter temperature, and were negatively correlated with the sum of summer precipitation. At the same time, all other C pools (biomass and necromass) increased by 179.1 ± 51.3 and 304.2 ± 67.6 Mg C·ha−1 in the Alps and the Apennines sites, respectively. This study highlights the importance of considering both the subsoil, since deep soil layers contributed 38% to the observed variations in carbon stocks after land use change, and the possible repercussions for the carbon balance of large areas where forests are expanding, especially under pressing global warming scenarios. Unlabelled Image • Woody encroachment over pasture can help mitigate the effects of climate change. • Soil and biomass C pools were estimated in six areas with a chronosequence approach. • Belowground C pools' (soil + belowground biomass) changes lead ecosystem C dynamics. • Winter air temperatures are the best predictors for sites' overall SOC stock changes. • Subsoil omission leads to substantial ecosystem C underestimation. [ABSTRACT FROM AUTHOR]

The amount of soil organic carbon (SOC) released into the atmosphere as carbon dioxide (CO), which is referred to as heterotrophic respiration (Rh), is technically difficult to measure despite its necessity to the understanding of how to protect and increase soil carbon stocks. Within this context, the aim of this study is to determine Rh in two Mediterranean forests dominated by pine and oak using radiocarbon measurements of the bulk SOC from different soil layers. The annual Rh was 3.22 Mg C ha y under pine and 3.13 Mg C ha y under oak, corresponding to 38 and 31% of the annual soil respiration, respectively. The accuracy of the Rh values was evaluated by determining the net primary production (NPP), as the sum of the Rh and the net ecosystem production measured by eddy covariance, then comparing it with the NPP obtained through independent biometric measurements. No significant differences were observed, which suggested the suitability of our methodology to infer Rh. Assuming the C inputs to soil to consist exclusively of the aboveground and belowground litter and the C output exclusively of the Rh, both soils were C sinks, which is consistent with a previous modeling study that was performed in the same stands. In conclusion, radiocarbon analysis of bulk SOC provided a reliable estimate of the average annual amount of soil carbon released to the atmosphere; hence, its application is convenient for calculating Rh because it utilizes only a single soil sampling and no time-consuming monitoring activities. [ABSTRACT FROM AUTHOR]

In terrestrial biosphere, soil represents the largest organic carbon pool, and a small change of soil organic carbon (SOC) can significantly affect the global carbon cycle and climate. Land use change (LUC) and soil management practices coupled with climate variables can significantly influence the soil organic carbon stocks (SOC–S) and its dynamics; however, our understanding about the responses of SOC in different LUC's (e.g., cropland, grassland and forest land) to mitigate climate change is quite limited at country level like Italy. Thus, the aims of this study were which factors are affecting SOC dynamics in three LUC's over time across Italy; and their relevance in terms of SOC–S in the superficial layer of soil that significantly contributes to the climate change mitigation, using LUCAS soil database. To calculate the SOC–S, it is necessary to have soil bulk density (BD) which is not present in the LUCAS database. Thus, we estimate the soil BD using the pedotransfer function (PTFs); and results shows that the soil BD obtained from fitting of the PTFs were reasonable to estimate the SOC–S for different land use types (R2 ≥ 0.75). Overall, results showed that LUC's and soil management practices can significantly (p < 0.001) influences SOC dynamics and SOC storage from the soil and varied among LUC's but not for over time except grassland. Spatially, the mean SOC–S storage of the different LUC's was in the following order: forest land > grassland > cropland for both years 2009 and 2015. On the other hand, the SOC–S storage increased by 8.33% for cropland, 13.56% for forest land, and 29.79% for grassland during the year of 2009–2015, while SOC–S storage increased significantly (p < 0.001) in grassland over time but not for cropland and forest land which also follow the increasing trend but insignificantly. Our results also reveal that the SOC dynamics negatively correlated with MAT, and positively correlated with MAP for all land uses except forest land. Thus, this research indicates that LUC's and soil management practices coupled with climate variables can significantly influence SOC storage and its dynamics in the superficial layer of soil which have the potential capacity to mitigate climate change. [Display omitted] • Using PTFs for obtaining soil BD was reasonable to estimate the SOC–S for different LUTs. • SOC negatively correlated with MAT and positively correlated with MAP for all LUT except forest land. • Among LUTs, forest land could store highest SOC in both years compared to grassland and cropland. • Over time, SOC–S increased significantly (p < 0.001) in grassland but not for forest land and cropland. [ABSTRACT FROM AUTHOR]

Background and aims: In the Jomoro district in Ghana, tree plantations were the first cause of deforestation in the past, drastically reducing the area occupied by primary forests. The aim of this study was to quantify soil organic carbon (SOC) losses due to a change in land use from primary forest to tree plantations (cocoa, coconut, rubber, oil palm) on the different substrates of the district. Secondary forests and mixed plantations were also included in the study. Methods: Soils were sampled at different depths up to 100 cm along a series of chronosequences in each of the three substrates (Granite, Lower Birrimian and Tertiary Sands) present in the area. Results: The highest SOC losses in the 0-30 cm layer were caused by the conversion of primary forests to tree plantations: cocoa −61 % of the original SOC stock, coconut −55 %, rubber −35 % and oil palm 28 %, while mixed plantations and secondary forests showed a loss of 23 % and 21 % of the original SOC stock, respectively. C losses were less apparent from the entire profile (to a depth of 100 cm). Conclusions: All conversions to tree plantations caused substantial SOC losses, comparable to the conversion of forests to agricultural systems. Secondary forests and mixed plantations were the only sustainable land uses that restricted SOC losses considerably. [ABSTRACT FROM AUTHOR]

The aim of this work was to quantify the soil organic C (SOC) stock in the top 30 cm of mineral soil for the whole Italian territory, according to the different land use types of the Intergovernmental Panel on Climate Change (IPCC) cropland category (arable land, agroforestry, vineyards, olive groves, orchards and rice fields), as a basis for future land use scenarios and to address mitigation policy at country level. A database for SOC stock was created with the data from the national project denominated SIAS and partly from regional map reports. All data were referred to the year 2000 since they were derived from surveys conducted from 1995 to 2005. The data were stratified according to the Italian climatic regions, the landscape position and the IPCC cropland subcategories. Taking into account the uncertainty in the estimate, the mean SOC stock values of the different subcategories show significant differences ( p < 0.05) among climatic regions and landscapes, ranging from 41.9 ± 15.9 Mg C ha in the vineyards to 63.3 ± 27.9 Mg C ha in the rice fields. Generally, a small decrease of the SOC stock from the temperate regions toward the Mediterranean ones is observed. Taking into account the mean value of each subcategory and the country area they occupied in 2000, the total C stored in the upper 30 cm of soil was estimated at 490.0 ± 121.7 Tg C. The resulting estimate represents the 17% of the value reported by another study for the soil of the whole country down to 50 cm depth, suggesting the importance of preserving this large C pool. Considering the cropland category as a whole, the estimated mean SOC stock is 52.1 ± 17.4 Mg C ha, similar to that reported for other European countries, 50-60 Mg C ha. In conclusion, the assessment of the mean SOC stock of the different cropland land uses, landscape position and climate regions could notably help when assessing the impact of different agricultural practices and future stock change evaluation. [ABSTRACT FROM AUTHOR]

The contribution of decomposing soil organic carbon (SOC) to total annual soil respiration (SR) was evaluated by radiocarbon measurements at a Scots pine stand growing on a plaggen soil in the Belgian Campine region. Two approaches were used to estimate the contribution of different C pools to SR. In the first approach, the variations in C content of soil CO efflux were monitored during one year (2003) and compared to the atmospheric and SOC C signatures to determine the contribution of 'fast' (root respiration and fast decomposing SOC) and 'slow' cycling C pools to total SR. In the second approach an estimate of the total heterotrophic soil respiration (Rh), comprising the slow cycling C and the heterotrophic part of the fast-cycling C pools, was derived applying a box model based on the amount of the bulk SOC pool and its C-derived mean residence time (MRT). The quantification of the Rh and the decomposition rate of the slow-cycling SOC allows to indirectly determining the contribution of the heterotrophic C that decompose within a year. Measurements of total SR performed in the field allowed assessing the contribution of the different C pools to total soil C efflux. On an annual basis, the fast-cycling C was the main contributor to SR, about 85%, while the contribution of the slow-cycling C (with MRT >1 yr) to total SR was 15%. Total annual Rh was 36% of total SR, which is in the lower range reported for temperate coniferous forests. The comparison of Rh with other estimates for the same site (47-50% of total SR) suggest a possible underestimation of the C flux from the mineral soil. In fact, the 'very old' C contained in the plaggen horizon strongly affects the signature of the mostly young C leaving the soil. In conclusion, our results indicate that the contribution of SOC decomposition to total soil CO flux in this forest is less than 40%, and at least half of it comes from organic compounds less than 1 year old. [ABSTRACT FROM AUTHOR]

Tropical primary rainforests of Africa are an enormous reservoir of carbon (C), most of which, in the common perception, is stored in the biomass. We studied one of these forests, Ankasa, in the south-western part of Ghana, in terms of quantity and 14C activity of soil organic carbon (SOC) to elucidate the little known important role of soil in storing carbon in such biomass-rich environments. The stock of carbon in the mineral soil to a depth of 1 m was measured to be 151 ± 20 Mg C ha−1, a similar value in magnitude to the one of the aboveground biomass being 138–170 Mg C ha−1, including live and dead wood. Surface litter C is roughly 10% (15 ± 9 Mg C ha−1) of the C in the biomass and soil. The radiocarbon measurements indicate that SOC was significantly affected by “bomb C” enrichment, so that “Modern C”, namely with a mean radiocarbon age lower than 200 years, is present also deeper than 45 cm in the Bo2 horizon. The mean residence time (MRT) estimated from radiocarbon content are of the order of a few decades in the topsoil and a few centuries in the deeper horizons. Altogether, the MRT values indicate a fast recycle of C compared to temperate or boreal forests, but not as fast as usually believed for tropical forest soils. Making a pondered mean, in the Ankasa forest the time an atom of C resides in soil is not much different from one atom of C in the woody aboveground biomass. Hence, the contribution of soil in storing C is substantial, implying that in primary rainforests it is mandatory to determine the SOC stock and its dynamics, too often neglected or underestimated. [ABSTRACT FROM AUTHOR]

• Forest die-off decreases C and N content in soil. • Forest die-off positively affected C stability. • Responses of soil C and N content and C stability vary along the soil profile. Drought-induced forest die-off is occurring worldwide and is projected to increase in coming decades. However, if and to what extent this phenomenon affects the content of carbon (C) and nitrogen (N) in soils as well as its stability is far from clear. In a Mediterranean oak forest, we found that forest die-off negatively affected soil C and N contents, and positively affected C stability. We also found that the effect of forest die-off on soil C and N content was more pronounced at the 0–5 cm than at the 5–10 cm soil layer, while the opposite was found for soil C stability. Our results highlight the importance of considering both, soil organic matter quantity and stability, along the soil profile to fully understand the effects of environmental changes on the global C and N cycle. [ABSTRACT FROM AUTHOR]

Aims: The majority of research on the diversity-productivity relationship has utilized aboveground plant biomass as a measure of overall ecosystem productivity and investigated successions with species-poor early stages. During this study we modelled patterns of plant diversity and carbon pools along a succession from pasture abandonment to submediterranean Quercus cerris woodland and investigated ecosystem productivity using biomass and soil carbon. Study area: The hilly-mountainous area of Tolfa in Central Italy. Methods: We used chronosequences to analyse changes in vascular plant species richness and composition across successional stages and along a gradient of productivity (i.e. of increasing carbon stocks). To test possible differences across successional stages species richness and carbon pool data were analysed through analysis of variance. Mixed model regression analyses were used to test the effect of the amount of the carbon stocks on the variation in plant species richness and composition. Results: We found a high variation in plant species richness along the succession, with grasslands and newly formed woods showing the highest values. The amount of carbon in biomass and soil increased along the succession, even if soil carbon did not differ significantly among successional stages. Plant species richness was not dependent on the variation in the carbon pools (i.e. biomass and soil carbon) along the succession, while plant species composition significantly responded to this variation. Conclusions: Our results strongly support the need to manage semi-natural ecosystems through a multi-functional perspective that values both carbon sequestration and biodiversity. [ABSTRACT FROM AUTHOR]

Sustainable agricultural and food processing practices are often proposed as attractive strategies enabling food systems to respond to the challenges posed by climate change in terms of adaptation and mitigation. However, information on the actual contribution to climate change provided by sustainable food production systems is lacking in literature. With the intention to contribute to a more informed debate, this study aims at quantify the actual impact on climate of sustainable practices applied to a grape-to-wine system in Italy. The overall budget of greenhouse gas (GHG) fluxes is assessed at wine farm level, from the vineyard to the final bottle of wine, through an integration of methods, including the eddy covariance technique, the life cycle assessment (LCA) and the IPCC guidelines. All the components of the GHG budget have been considered: the (a) biogenic GHG fluxes and the (b) anthropogenic GHG emissions generated for the grape production as well as the (c) carbon stock change due to the vineyard management and the (d) anthropogenic GHG emissions generated by the transformation of grape into wine. At the vineyard level, the overall GHG budget resulted to be close to zero, showing a potential carbon neutrality of sustainable viticulture: the sum of biogenic GHG fluxes (a) and the carbon stock change (c) resulted in a net carbon sink with a potential contribution to climate change mitigation of −0,27 ± 1,11 Mg CO 2 eq year−1 per hectare; while the anthropogenic GHG emissions (b) for the sustainable vineyard management accounted for 0,24 ± 0,05 Mg CO 2 eq ha−1 year−1. The total carbon footprint (b + d) of sustainable wine is 0,79 ± 0,14 kg CO 2 eq per bottle, with 15% attributable to the agricultural phase and 85% to the transformation of grape into wine. These findings indicate that sustainable wine production has in general a lower contribution to climate change. In particular, sustainable practices applied to viticulture can turn the system into a net carbon sink able to totally compensate the anthropogenic emissions for the vineyard management. Therefore, sustainable viticulture allows food production with a potential carbon neutrality without exacerbating climate change. • Sustainable viticulture allows food production with a potential carbon neutrality without exacerbating climate change. • Sustainable viticulture generates biogenic GHG fluxes that turn the agrosystem into a net carbon sink. • Anthropogenic GHG emissions in sustainable vineyard are low and can be totally compensate by the net carbon sink. • The carbon footprint (CF) of sustainable wine is 0,79 ± 0,14 kg CO 2 eq per bottle. • Sustainable wine production has in general a lower contribution to climate change. [ABSTRACT FROM AUTHOR]

Questions To what extent have semi-natural grassland plant species composition and functional traits changed during the past five decades? Which are the main directions of change? Which environmental, management and landscape factors have determined these changes? Location Central and southern Apennines of Italy. Methods In 2013-2014, we used a stratified random sampling design to revisit 132 semi-natural grasslands originally sampled between 1966 and 1992. The exact locations of the historical plots were not available but they were associated with detailed vegetation maps. Plots were divided in 17 groups based on study area and original community type. To assess changes in species composition we ran PERMANOVA and RDA. The extent of change was estimated by comparing each new plot with the quantitative species pool of the corresponding historical group; species composition changes were calculated using Bray-Curtis coefficient, and shifts in functional traits were quantified as differences in community-weighted means. These measures of change were used as response variables in mixed effects models including climate, topography, management and landscape metrics as explanatory variables. Results The largest changes were related to successional dynamics, which occurred mainly in grasslands developing at low altitude and in the flattest sites where the soil organic horizon was relatively thick. Colonization by shrubs and trees was facilitated by high soil pH and amount of adjacent forests. Also, management factors affected the patterns of shifts in species composition and functional traits: grazing intensity was negatively related to the degree of compositional change as well as to the abundance of woody species, whereas the increase of species associated with frequent grazing disturbance was found at sites with higher values of soil salinity. Conclusions Apennine semi-natural grasslands have undergone substantial changes in species composition and functional traits during recent decades. Compositional changes mainly indicated successional dynamics, likely following a decrease in grazing intensity, whereas some more accessible grasslands experienced an increase in disturbance-tolerant species. The combination of the re-visitation approach with functional traits allowed us to clarify different directions of changes in species composition, adding information on the ecological processes related to these changes. [ABSTRACT FROM AUTHOR]

Degradation, a reduction of the ecosystem's capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions. [ABSTRACT FROM AUTHOR]

Soil quality is fundamental for ecosystem long term functionality, productivity and resilience to current climatic changes. Despite its importance, soil is lost and degraded at dramatic rates worldwide. In Europe, the Mediterranean areas are a hotspot for soil erosion and land degradation due to a combination of climatic conditions, soils, geomorphology and anthropic pressure. Soil organic carbon (SOC) is considered a key indicator of soil quality as it relates to other fundamental soil functions supporting crucial ecosystem services. In the present study, the functional relationships among SOC and other important soil properties were investigated in the topsoil of 38 sites under different land cover and management, distributed over three Mediterranean regions under strong desertification risk, with the final aim to define critical SOC ranges for fast loss of important soil functionalities. The study sites belonged to private and public landowners seeking to adopt sustainable land management practices to support ecosystem sustainability and productivity of their land. Data showed a very clear relationship between SOC concentrations and the other analyzed soil properties: total nitrogen, bulk density, cation exchange capacity, available water capacity, microbial biomass, C fractions associated to particulate organic matter and to the mineral soil component and indirectly with net N mineralization. Below 20 g SOC kg−1, additional changes of SOC concentrations resulted in a steep variation of all the analyzed soil indicators, an order of magnitude higher than the changes occurring between 50 and 100 g SOC kg−1 and 3–4 times the changes observed at 20–50 g SOC kg−1. About half of the study sites showed average SOC concentration of the topsoil centimetres <20 g SOC kg−1. For these areas the level of SOC might hence be considered critical and immediate and effective recovery management plans are needed to avoid complete land degradation in the next future. • SOC was an important indicator of soil quality in areas under desertification risk. • A critical limit of 20 g SOC kg−1 was found for soil quality in the analyzed areas. • Soil properties rapidly changed for a variation of 1% SOC below critical limit. • MAOC represented most of the organic C pool <50 g SOC kg−1. [ABSTRACT FROM AUTHOR]

The measurement of soil CO 2 fluxes and their isotopic composition is increasingly used to study and distinguish respiration sources in the soil profile. The influence of non-steady state processes on soil respiratory δ 13 CO 2 values, such as diffusive fractionation, remains unclear but is suggested to be strong, especially in arid ecosystems. In this study, an in situ Fourier transform infrared spectrometer was coupled to automated soil flux chambers and installed in an arid grassland in Italy. Hourly flux and concentration measurements of CO 2 and its isotopic composition were taken over bare soil and senescent grass material. CO 2 fluxes were stable at night (∼1 μmol m −2 s −1 ), and showed peak emissions during the day (up to 10 μmol m −2 s −1 ). Respiratory δ 13 CO 2 values showed a diel pattern. Daytime respiratory δ 13 CO 2 values were on average −24.8‰ and nighttime values were on average −26.9‰, but showed significantly more depleted values during nights with strong increase in atmospheric CO 2 . We hypothesize that the observed diel variation in respiratory δ 13 CO 2 values was a consequence of the non-steady state process “diffusive fractionation” induced by the increasing atmospheric CO 2 concentrations at night. [ABSTRACT FROM AUTHOR]

Highlights: [•] We developed a model able to simulate the growth of a mixed oak forest in Italy. [•] We examined the contribute of each layer and cohorts on GPP, NPP and ET. [•] We compared the models’ results for LAI against the MODIS LAI-NDVI data. [•] We validated a series of models’ results against measured independent data. [•] We showed the effects on models’ results of a series of simplified model runs. [Copyright &y& Elsevier]

In this study, we assess the possibility of using ground penetrating radar (GPR) and electrical resistivity tomography (ERT) as indirect non-destructive techniques for root detection. Two experimental sites were investigated: a poplar plantation [mean height of plants 25.7m, diameter at breast height (dbh) 33cm] and a pinewood forest mainly composed of Pinus pineaL. and Pinus pinasterAit. (mean height 17m, dbh 29cm). GPR measures were taken using antennas of 900 and 1500MHz applied in square and circular grids. ERT was previously tested along 2-D lines, compared with GPR sections and direct observation of the roots, and then using a complete 3-D acquisition technique. Three-dimensional reconstructions using grids of electrodes centred and evenly spaced around the tree were used in all cases (poplar and pine), and repeated in different periods in the pine forest (April, June and September) to investigate the influence of water saturation on the results obtainable. The investigated roots systems were entirely excavated using AIR-SPADE Series 2000. In order to acquire morphological information on the root system, to be compared with the GPR and ERT, poplar and pine roots were scanned using a portable on ground scanning LIDAR. In test sections analysed around the poplar trees, GPR with a high frequency antenna proved to be able to detect roots with very small diameters and different angles, with the geometry of survey lines ruling the intensity of individual reflectors. The comparison between 3-D images of the extracted roots obtained with a laser scan data point cloud and the GPR profile proved the potential of high density 3-D GPR in mapping the entire system in unsaturated soil, with a preference for sandy and silty terrain, with problems arising when clay is predominant. Clutter produced by gravel and pebbles, mixed with the presence of roots, can also be sources of noise for the GPR signals. The work performed on the pine trees shows that the shape, distribution and volume of roots system, can be coupled to the 3-D electrical resistivity variation of the soil model map. Geophysical surveys can be a useful approach to root investigation in describing both the shape and behaviour of the roots in the subsoil. [ABSTRACT FROM AUTHOR]

Alpine grasslands are the products of thousands of years of interaction between humanactivity and mountain harsh environmental conditions. Together, they inhibit development ofwoody vegetation, promoting meadow communities and short life cycles. Current trend in theland use in Italy is characterized by an intensification of the agricultural practices inthe lowlands and abandonment of traditional pastoral activities in the mountains.According to the scientific literature, the last results in the loss of C from soil at least inthe first decades after the pasture conversion to other land use types or completeabandonment. In this study we attempted to unravel the causes of soil C depletion with grazingabandonment. The study site, Brocon, is a mountain alpine grassland located 1700 m abovethe sea level in the eastern Alps (Cinte Tesino, Italy). The site is historically usedfor the summer cattle grazing, alpeggio. Here, the local farmers apply differentmanagement regimes: short and more intensive grazing; long and less intensivegrazing; and no grazing, where a portion of pasture has been fenced from cattle since2002. Soil and all plant species were sampled in the end of July in managed and abandonedplots. Diversity of plant species was assessed through Shannon and Simpson indices andspecies richness. Soil quality was evaluated by analyses of the following biochemicalparameters: enzymes involved in C, N, S and P cycles, microbial C and N, microbial basalrespiration and ecophysiological quotients: qmic, qCO2 and qN. Microbial functionaldiversity was assessed by means of Shannon index. Plant and soil samples were analyzed fortheir δ13C and δ15N in order to quantify changes in nutritional status, water and carbon useefficiency. Changes in soil structure were evaluated by means of aggregate stability and sizedistribution. The results demonstrated considerable changes in plant nutritional status and plantspecies richness with loss of numerous plant species in plots excluded from grazing. Changesin ecosystem C and N cycles were confirmed at the soil biochemical level. 15 years ofgrazing abandonment resulted in the deterioration of the soil chemical and physical propertieswith ongoing and future tendency to loss of C from the system. Lowering of the labile Cinputs combined with soil acidification affected negatively the microbial biomass pool inabandoned plots. On one hand, it slackened the biochemical cycles, on the other hand, itshifted microbial community to decomposition of older and more protected SOM.Impoverishment of the area and accumulation of the nitrogenous forms favored thedevelopment of nitrophilous and synanthropic species, not allowing for more demandingplant species to colonize the area. Prolonged and less intensive grazing appeared to be themost appropriate management practice for both, vegetation compartment and soil. [ABSTRACT FROM AUTHOR]