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Industrial farming without considering soil biological features could lead to soil degradation. We aimed to evaluate the biochemical properties (BPs) and biological fertility (BF) of different soils under processing tomato cultivation, estimate the BF through the calculation of a simplified BF index (BFIs), determine if the crop was affected by BP and BF. Three farms were individuated in Modena (MO), Ferrara (MEZ) and Ravenna (RA) provinces, Italy. Soil analysis included total and labile organic C, microbial biomass-C (Cmic) and microbial respiration measurements. The metabolic (qCO2), mineralization (qM) and microbial (qMIC) quotients, and BFIs were calculated. Furthermore, plant nutrient contents were determined. The low Cmic content and qMIC, and high qCO2 found in MEZ soils indicate the occurrence of stressful conditions. The high qMIC and qM, and the low qCO2 demonstrated an efficient organic carbon incorporation as Cmic in MO soils. In RA soils, the low total and labile organic C contents limited the Cmic and microbial respiration. Therefore, as confirmed by the BFIs, while MO showed the healthiest soils, RA soils had an inefficient ecophysiological energy state. However, no effects on plant nutrient contents were observed, likely because of masked by fertigation. Finally, BP monitoring is needed in order to avoid soil degradation and, in turn, crop production decline.

The aim of the study was to assess if pedogenic processes such as mineral weathering and lessivage, other than organic matter accumulation, can affect soil microbial population and enzyme activities. This study examines six soil profiles located in a karst region of the North-Eastern Italian Alps and characterized by a vertical textural differentiation due to lessivage. For each soil, four pedological layers were recognized according to the dominant soil forming process: i) the top soil (Tp layer), formed by A and AB horizons, characterized by organic matter accumulation; ii) the subsurface eluviated layer (Elu layer), comprising AE and EB horizons; iii) the layer dominated by the in-situ mineral weathering (Wh layer), made by Bw horizons; iv) the deepest layer (Ls), subjected to clay illuviation and comprised by Bt horizons. In the upper layers (Tp and Elu), because of the low pH, weathering also occurred, as indicated by the presence of disordered smectite and by the high values of pedogenic Fe oxi-hydroxides to pseudo-total Fe ratio. The microbial biomass content and structure, and the enzyme activities significantly differed in the four pedological layers. The amount of microbial biomass was, as expected, most abundant in the Tp layer, where bacteria and actinomycetes abounded. Conversely, in Elu and Wh we observed a fungal-to-bacterial biomass ratio significantly higher than in Tp and Ls; in Elu, also the gram (+)/gram (−) ratio was the highest. In the upper layer, the interaction between enzymes and minerals like disordered smectite and pedogenic Fe-oxides appeared as responsible for the inhibition of the total enzyme activity per unit of organic C, and of the lipase activity. In Ls layer, where clay illuviation and high organo-minerals interaction occurred, the potential hydrolysis of organic matter was low, as revealed by the SEI/TOC ratio, the reduced lipase activity, and the inhibited activity of α-fucosidase and α-mannosidase. Even if the activity of most enzymes depends on the substrate availability, which decreases with soil depth, those involved in lipid degradation displayed the maximum activities in Elu and Wh layers, where a relative increase of the fungal population was observed. In conclusion, our findings showed that the soil functionality, expressed by the microbial community structure and enzymes activity, can vary according to organic matter–mineral interaction following the weathering and lessivage gradients along the soil profiles.

To improve knowledge on salt leaching suitability on different soils, in Arenosols and Cambisols croplands in the coastal area of Ravenna (Italy), soil samples were collected in the non-irrigation winter period and irrigation summer period. Concurrently, waters of the canal network were also investigated. Soil samples were analyzed for pH, carbonate, total organic carbon (TOC), particle size distribution, electrical conductivity (EC), bulk density (BD) and water content at field capacity (FC). Water samples were investigated for pH, EC, biological and chemical oxygen demand, sodium adsorption ratio, phosphorus, nitrogen, sulfates and chlorides. All soils had low TOC concentrations and Arenosols showed the lowest clay content, BD and FC. Soils had similar EC values in winter, but in summer the lowest ones were observed in Arenosols, suggesting that irrigation mitigated salinization in Arenosols, while the high clay content, BD and FC prevented or limited the salt leaching in Cambisols. In summer, the increase of total nitrogen and biological oxygen demand, especially in drainage channels, might suggest the leaching of soluble nutrients and organic matter from soils due to the high irrigation water volumes. Finally, our findings stress the need to consider soil type and properties to contrast soil salinization without negative effects on soil C leaching caused by salt leaching practice.

Sustainable agricultural management is needed to promote carbon (C) sequestration in soil, prevent loss of soil fertility, and reduce the release of greenhouse gases. However, the influence of agronomic practices on soil C sequestration depends on the existing pedoclimatic features. We characterized the soils of three farms far away each other in the Emilia-Romagna region (Northern Italy): an organic farm in the Northern Apennines, a biodynamic farm, and a conventional farm on the Po Plain. The total, inorganic, and organic carbon in soil, as well as the distinct humic fractions were investigated, analyzing both the elemental and isotopic (13C/12C) composition. In soils, organic matter appears to be variously affected by mineralization processes induced by microorganisms that consume organic carbon. In particular, organic carbon declined in farms located in the plain (e.g., organic carbon down to 0.75 wt%, carbon stock0-30 cm down to 33 Mg/ha), because of the warmer climate and moderately alkaline environment that enhance soil microbial activity. On the other hand, at the mountain farm, the minimum soil disturbance, the cold climate, and the neutral conditions favored soil C sequestration (organic carbon up to 4.42 wt%, carbon stock0-30 cm up to 160 Mg/ha) in humified organic compounds with long turnover, which can limit greenhouse gas emissions into the atmosphere. This work shows the need for thorough soil investigations, to propose tailored best-practices that can reconcile productivity and soil sustainability.

The purpose of this study was to investigate the in situ characterization of organic matter (OM) within soil macroaggregates, and to assess the relationships between OM characteristics and macroaggregate size indicating different OM stabilization mechanisms. Optical micro-morphological investigations, coupled to SEM-EDS (scanning electron microscopy and energy X-ray spectroscopy) technique, were carried out on thin sections of 1–4 and 0.25–1 mm soil aggregates (coarse and fine macroaggregates, respectively) from 0 to 20 cm soil layer corresponding to A horizon of four different sites in which soil structure were not disturbed by tillage. The intraggregate porosity, measured by image analysis of four different size classes (200 µm), showed that fine macroaggregates were significantly less porous (3.70–6.71% of total porosity) and had higher presence of the finest pore class (

Assessing the spatial variation of soil and crop properties is the basis for site specific management of crop practices in precision agriculture applications. To this aim, proximal and remote spectral vegetation indices are increasingly replacing soil physical-chemical analysis. In this study the spatial variation of soil properties, proximal and remote spectral vegetation indices were compared in a winter wheat ( Triticum aestivum L.) crop grown in a 4.15 ha field in northern Italy. Soil analysis (particle size distribution, pH, carbonates, C, total N, available P, exchangeable cations and electrical conductivity) was geo-referentially carried out; the proximal indices chlorophyll content by N-Tester and normalized difference vegetation index (NDVI) through GreenSeeker were determined in three dates during stem elongation; the remote indices PurePixel TM Chlorophyll Index and PurePixel TM Vegetation Index were determined through the Landsat 8 satellite in three dates during the same wheat stage. Dry biomass yield (DBY), grain yield (GY) and yield components were determined at harvest. Soil, proximal and remote data were submitted to principal component analysis (PCA), and the retained PCs were clustered to delineate areas at low, intermediate and high yield potential, based on soil parameters (CLU sp ), proximal (CLU pi ), and remote vegetation indices (CLU ri ). DBY and GY were significantly correlated with several soil parameters and vegetation indices. Spatial distribution of soil and crop data consistently depicted a low performing area (GY 8 Mg ha -1 ). CLU sp determined a lower GY difference between low and high performing area (+60%), compared to CLU pi and CLU ri (almost + 100%). In CLU sp and CLU pi the low and high performing area were of similar size (25 and 29% for the two respective areas in CLU sp ; 25 and 33% in CLU pi ), whereas in CLU ri they were quite different (16 and 46%). Lastly, yield potential levels determined by vegetation indices (CLU pi and CLU ri ) exhibited a better degree of agreement with DBY and GY levels, than soil parameters (CLU sp ). In exchange for this, the above referred soil parameters are quite consistent in time, allowing soil data to be used for more years. On concluding, PCA followed by clustering resulted in a robust delineation of field areas at different yield potential. This is the premise for developing research driven strategies of practical use.

In mountain areas, water erosion plays an important role on soil structure and can strongly affect its functions. Suitable management practices, namely choice of crops, may be able to improve aggregate stability and reduce soil loss by surface runoff. To study the effects of cover crops on aggregation in mountain soils, we investigated a soil planted with wheat (site C) compared to two soils under alfalfa (sites A and B). All investigated soils were Typic Ustorthents. The soil aggregates were isolated by a physical-functional procedure defined on the basis of aggregates resistance against specific breakdown mechanisms such as slaking and water abrasion. One year after alfalfa plantation, its effect on wet aggregate stability and the amount of organic carbon (OC) and nutrients retained by the isolated aggregates were measured. In the less degraded soils (site B) organic matter decomposition was stimulated, and after 1 year the TOC and TOC/N declined. Consequently a reduction in aggregate stability and ability to preserve elements occurred, as shown by the decrease of wet aggregate stability indexes and total nutrients (e.g. N, P and K) retained by stable aggregates. In more degraded soil (site A), alfalfa generally positively affected the investigated properties. The effect of alfalfa in the studied crop rotation depends on the degree of land degradation due to water erosion. As regards the investigated breakdown mechanisms, our data showed that the aggregate resistance to water abrasion was related to TOC, while the resistance against fast wetting breakdown is correlated to the microbial biomass.

Maintaining multiple ecological functions (“multifunctionality”) is crucial to sustain viable ecosystems. To date most studies on biodiversity-ecosystem functioning (BEF) have focused on single or few ecological functions and services. However, there is a critical need to evaluate how species and species assemblages affect multiple processes at the same time, and how these functions are interconnected. Dung beetles represent excellent model organisms because they are key contributors to several ecosystem functions. Using a novel method based on the application of 15N-enriched dung in a mesocosm field experiment, we assessed the role of dung beetles in regulating multiple aspects of nutrient cycling in alpine pastures over appropriate spatial (up to a soil depth of 20 cm) and temporal (up to 1 yr after dung application) scales. 15N isotope tracing allowed the evaluation of multiple interrelated ecosystem functions responsible for the cycling of dung-derived nitrogen (DDN) in the soil and vegetation. We also resolved the role of functional group identity and the importance of interactions among co-occurring species for sustaining multiple functions by focusing on two different dung beetle nesting strategies (tunnelers and dwellers). Species interactions were studied by contrasting mixed-species to single-species assemblages, and asking whether the former performed multiple functions better than the latter. Dung beetles influenced at least seven ecological functions by facilitating dung removal, transport of DDN into the soil, microbial ammonification and nitrification processes, uptake of DDN by plants, herbage growth, and changes in botanical composition. Tunnelers and dwellers were found to be similarly efficient for most functions, with differences based on the spatial and temporal scales over which the functions operated. Although mixed-species assemblages seemed to perform better than single-species, this outcome may be dependent on the context. Most importantly though, the different functions were found to be interconnected sequentially as reveled by analyzing 15N content in dung, soil and vegetation. Taken together, our current findings offer strong support for the contention that the link between biodiversity and ecosystem functions should be examined not function by function, but in terms of understanding multiple functions and how they interact with each other.

Purpose: Canal dredging and shaping produce considerable amounts of sediments whose reuse on- and off-site depends on their pollution level. This study explores the potential of a calcium chloride washing to remove potentially toxic elements (PTEs) from a freshly dredged calcareous sediment and to affect the aggregate stability of the washed sediment. Materials and methods: The ability of 0.5-M CaCl2 washing to restore the sediment samples polluted with Cu and Zn dredged from a freshwater canal was assessed. The distribution of the two metals among the sediment geochemical phases, the potential availability to plants (DTPA), and the water aggregate stability of particles were evaluated on the washed samples and compared to control. Results and discussion: In the most polluted sample (similar to 200 and 500mgkg(-1) of Cu and Zn, respectively), the washing decreased the amount of Cu by 26%, mainly in the sulfide/organic fraction, and of Zn by 10%, mainly in carbonates. A decrease in the dispersivity of clay fraction was observed due to the well-known effect of Ca2+ ions on flocculation of colloidal clay particles. At large scale, the aggregates formed by the interaction between large particles and flocculated clay showed lower water stability with respect to the control, thus suggesting the need to improve the physical properties of the treated material. Noteworthy, after 1 year of dry storage from washing, the average percentage of potentially bioavailable (DTPA) Cu and Zn (23 and 13% of pseudo-total amount, respectively) dropped with respect to the control (40 and 19%) and a concomitant carbonate increase (+33%) was observed. Conclusions: The CaCl2 washing is a promising method to reduce Cu and, to a minor extent, Zn in wet calcareous sediments dredged from freshwater canals. However, there is still room for improvement. The PTE fractions remaining in carbonates and organic component of washed sediment clearly indicate the potential of combining mild acidic pH values with calcium chloride in the washing to enhance the PTE removal.

A Fragipan (Bx) is a soil horizon hard when dry and brittle when moist, that undergoes slaking upon water immersion, forming a barrier to roots and limiting land use. Brittleness and slaking depend on soil porosity and particle arrangement, but still no agreement exists on the inorganic components responsible for such arrangement. We hypothesized that the same kind of particle arrangement may originate from different soil components, ultimately depending on the lithology of parent material, and evaluated the soil and clay characteristics that best differentiate Bx from B horizons. Thirty-six samples were taken from Typic Fragiudalfs developed on the two sides of an alluvial fan characterized by different amounts of ultramafic materials. Discriminant Analysis evidenced that pedogenic Fe oxides were fundamental in discriminating Bx from B horizons on pure ultramafic parent material, while clay mineralogy was more important in soils with less ultramafic materials. In the first case, the association between clay minerals and self-assembling oxides systems may lead to brittleness, while in the second case the higher abundance of kaolinite may contribute to weak associations between pH-dependent sites and negatively charged surfaces. The only common feature to fragipans on both river sides was a higher degree of weathering.

Chestnut plantations are worldwide distributed and they are often subjected to intensive management practices such as the removal of the organic residues from the soil surface. The present study aimed to investigate the effect of such practices on soil properties at different depths and on nutrient contents in chestnut leaves. To reach our goal, 6 pits down to 30 cm soil depth were dug in European chestnut (Castanea sativa Mill.) stands where the organic residues such as burrs, leaves and pruned materials are yearly removed (REM), and 9 pits in stands where the organic residues are chopped and left on soil surface (CONS). Both practices began about 30 years ago. The nutrient contents in leaves were assessed on chestnut trees close to each pit. Our findings showed a more intense soil development in CONS than in REM. At soil surface, CONS had thicker mineral horizon than in REM probably due to the protection acted by the organic residues against erosion. In subsoil, organic residues conservation promoted the organic C (soil organic C, water–extractable organic C, fulvic–like C and soil organic C stock) accumulation which further promoted horizon development. Since the role of soil organic matter (SOM) as source of nutrients, the subsoil of CONS study sites had a greater stock of Ca, P and S and a higher exchangeable Ca content than REM. Furthermore, the higher SOM and nutrient contents in CONS subsoil compared to REM promoted the microbial respiration. The organic residues conservation effects on the surface soil horizon properties were, instead, negligible. Despite the generally better soil conditions in CONS than in REM, no differences were observed for the leaf nutrient contents likely due to the chestnut trees adaptability also to the scarcely fertile soils. Overall, our findings highlighted the importance of organic residues conservation for the improvement in deeper soil horizons of the chemical and biological fertility in chestnut plantations. Furthermore, this research pointed out to pay more attention on subsoil since it is a good indicator of the changes caused by external factors.

Soil aggregation and organic matter (OM) conservation are important in the prevention of land degradation. Aggregation processes and OM turnover influence each other and depend on the characteristics of both minerals and organic pools. We assessed the relative importance of the organic and mineral phases at the macroaggregate and colloidal scale in two soils (CHL and SRP, chlorite and serpentine-rich, respectively) where Mg-silicates dominated, by incubating them with a relatively degraded and oxidized organic fraction, that is the humic acids (HAs) extracted from the organic horizons of both CHL and SRP. The HA from SRP were more aromatic and richer in phenolic groups, whereas HA from CHL were N-richer, more aliphatic and richer in carboxyl groups. The SRP soil formed larger amounts of macroaggregates, more stable than in CHL. At the colloidal scale, SRP was more flocculated and clay had a lower electrophoretic mobility than CHL. HA enhanced aggregate formation in both samples but improved aggregate stability only in CHL. In CHL, slight differences in electrophoretic mobility were visible, while in SRP, differences were more pronounced, with a point of zero charge at lower pH and larger hydrodynamic diameter. The abundance of Mg in SRP may have favoured the formation of weaker outer-sphere interactions and the release of clay-HA associations upon water dispersion, while in CHL Ca formed more stable bonds with HA. In SRP, ligand exchange reactions can be ruled out, conversely to the dominant bonding mechanism occurring in Al-silicate dominated soils, with important consequences on the release of OM-loaded clay particles. Copyright © 2016 John Wiley & Sons, Ltd.

Soil needs a long time for its development, and traces of the past effects of climate, vegetation cover, and human activity can persist through time. Thus, paleosols are widely studied for paleo-environmental reconstructions, so to understand the effects of climate changes and/or human activities that for millennia transformed the land and interacted with soil formation. The aim of this work was to assess the influence of both ancient and modern environmental conditions on the pedogenesis at Mt Cimone, Northern Apennines, Italy. In particular, we compared buried paleosols and the overlying modern soils separated by a charcoal enriched horizon (Aub) along an altitudinal (climatic) sequence from 1553 to 1939 m above sea level. The radiocarbon age of the Aub horizon was 3040-2940 calibrated years before present, therefore it was taken as a chronological marker for the beginning of soil formation of the modern soil unit. The horizons thickness of the modern soil varied among the sites, suggesting the occurrence of accumulation/erosion processes, with a differential redistribution over the Aub horizon of the soil material transported by surface water runoff. The soil horizon sequence in the paleosol at lower altitudes (1553–1700 m) was rather simple (Bw-C horizons), indicating the occurrence of a moderately intense paleo-pedogenesis. Instead, from 1700 to 1900 m (mostly above the actual tree line) the paleosol showed well-expressed processes of eluviation-illuviation of organic matter and Fe/Al oxyhydroxides, which led to the formation of E-Bs or Bhs-C horizons sequences (podzols). These findings agree with previous studies dealing with climatic and palynological changes occurred in this area in the last seven millennia. At altitudes >1700 m, the ancient pedogenetic phase occurred during the Atlantic climatic period, with a cryic soil temperature regime, no permafrost, presence of seasonal snow, and a progressive tree species transition from Abies alba to oaks of warm temperate climate. The modern pedogenetic phase seemed to be affected by local wetter conditions and human induced forest disturbance, as it is testified by the change in the pollen abundance.

The soil liquid (LL) and plastic limit (PL), and their difference PI (plasticity index) are physical properties related with the soil mechanical behavior, determined on the

Purpose This study investigated a Lateglacial to Holocene sedimentary sequence derived from a small catchment located at San Lazzaro di Savena in the surroundings of Bologna Emilia (Northern Italy), in which different buried soil horizons were investigated in order to delineate the physiographic evolution of the area. Materials and methods Several disciplinary/analytical approaches including pedostratigraphy, geochemistry, radiocarbon dating, archaeobotanical investigation and δ13 stable isotopes analyses were taken into account for the pedosequence characterization. Results and discussion This multidisciplinary approach allowed us to identify the main factors that affected the ancient environment over a prolonged time interval (ca12 ky); starting from 14 ky BP with a palaeosol ascribed to the Bølling period, cold-arid conditions characterized by a steppic vegetation gradually evolved toward a more humid (and slightly warmer) setting. This climatic change allowed the development of a forest constituted by abundant conifers at ca 10 ky BP. Humans also impacted on the environment, at least since 9 ky BP, as indicated by repeated traces of firing (plausibly for deforestation and land clearance). The data allow a comparison with findings provided by other neighbouring sites and contribute to the ongoing debate on the relationships between climatic and anthropogenic impacts on the landscape dynamic. Conclusions The human impact on the landscape has been effective from the Mesolithic, earlier than usually considered in previous studies. Anthropogenic activities caused geomorphological and hydraulic instabilities within the basin, accelerating soil erosion as indicated by the increase of the estimated sedimentation rates and change in the type of geochemical, mineralogical and textural properties of the studied soils.

In a coastal Mediterranean area, the effects of two native [Quercus ilex (Holm), Alnus glutinosa and Fraxinus oxycarpa (Hygro)] and one planted [Pinus pinaster (Pine)] forest species on both content and quality of organic C and total N pools in Arenosols was assessed. Three soil profiles per each forest cover were opened and sampled. Total N in the organic layers was not affected by forest covers, whereas total organic C ranged from 36.1 to 63.2 Mg ha−1, being organic layers under Hygro those with the highest contents. Total organic C in the first 50 cm of mineral soil was 64 Mg ha−1 under Holm and 36.7 and 37.6 Mg ha−1 under Pine and Hygro, respectively. Soil covered by Holm and Hygro stored, respectively, 5.2 and 3.2 Mg ha−1 of total N. Soils under Pine showed the lowest values of total N, extractable C and N, microbial biomass C and N and microbial quotient. Also the quality of the organic layers was lowest under Pine, as evidenced by the highest values of TOC/TN ratio. Forest covers affected size and quality of organic C and total N pools in Arenosols. Arenosols stored from 73.7 to 127.2 Mg ha−1 of organic C and from 3.9 to 7.1 Mg ha−1 of total N. The organic layers could accumulate even the same amount of organic C and up to 50 % of the total N stored in the first 50 cm of mineral soils. Pine cover worsened the quality of soil organic matter.

Transitional systems are complex and fragile ecosystems where the water table oscillation plays a fundamental role in soil and landscape development. Due to global climate change, by the end of the next century a large part of these environments will be affected by water flooding, causing deep changes to soil properties and functionality. Increasing the knowledge on the genesis and properties of these soils can be fundamental for providing useful tools for the correct management of this natural resource. The transition from wetland to hydromorphic interdune system in the coastal area of the S. Vitale park (Northern Italy) represents a unique soil hydrosequence characterized by soils which undergo continuous or partial, permanent or periodic saturation and reduction. These hydrosequences offer a great opportunity to investigate how soil properties change in the transition from subaqueous to hydromorphic soils and to understand which pedogenetic processes mostly characterize the soil development under different water saturation conditions. In this study, the soil transition through the hydrosequence was recognized by the evaluation of some morphological (e.g. Munsell color) and chemical (organic carbon, sulfur ratio, CaCO3 content) soil properties that could trace the extent of sulfidization and decarbonation processes along the soil sequences. The presence of salts of marine origin characterized the subaqueous pedons, while nutrients accumulation (i.e., phosphorous) increased with soil emersion. These hydrosequences represent a soil continuum where the duration of water saturation and the oscillation of the water table along the soil profiles strongly affect some specific soil-forming processes that involve S redox transformation, P accumulation, CaCO3 depletion and salt accumulation.