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In the National park of Cilento, Vallo di Diano and Alburni (South Italy), a portion of a chestnut forest was converted in 2012 into an agricultural system in order to crop a local variety of bean. We investigated the effect over time of the conversion on the functional diversity of the soil microbial community by two different approaches: the catabolic response profile, based on the short time CO2 evolution induced by 25 simple organic substrates and the Biolog community level physiological profile (CLPP), based on the growth of microorganisms on 31 different substrates. The soils were sampled at 13, 17, 29, 41 and 49 months after the soil use change. The results showed that the soil use change did not produce evident modifications of the substrate utilization patterns, but rather a general decrease in the activity in the agricultural soils, as a consequence of the reduction in organic matter content. The results also showed seasonal effects on the substrate utilization profiles and on the calculated functional diversity indexes. The two approaches appeared to be complementary: Degens catabolic response profile was more able to discriminate between the two systems, whereas the Biolog was more able to highlight the variability among samplings.

Over - fertilization is one of the most relevant issues affecting container-grown nursery plants. The massive application of chemicals results in severe pollution due to nitrogen (N) leaching, and leads to the production of unhealthy plants sensitive to fungal diseases and insect attacks that increase the use of pesticides. The ability of two fluorescence-based sensors (Dualex and Multiplex) for assessing the N-sufficiency of container grown Prunus laurocerasus L. and Ligustrum japonicum L. as test plants was investigated in a two-year long experiment under experimental and commercial growing conditions. An optimal N rate of 450 mg L−1 was identified for both species growing under different N fertilization levels (0 - 1350 mg N L−1). Fluorescence-based indices allowed for reliable estimation of both chlorophyll and nitrogen content at the leaf and canopy level. Absolute and relative sufficiency threshold values were provided and spatially compared under standard nursery conditions. The optimal shoot N concentration of 2.04% (P. laurocerasus) and 1.35% (L. japonicum), and the corresponding non-destructive nitrogen balance index (NBI) values were assessed and used for decision-making on N application and monitoring of the species considered.

The effect of plant cover on soil microbial community structure and activity was investigated in forest ecosystems dominated by holm oak (Quercus ilex), Turkey oak (Quercus cerris) and beech (Fagus sylvatica), in two seasons (autumn and early summer). Microbial community structure was investigated by phospholipid fatty acid (PLFA) profile and ergosterol determination. Microbial community activity was assessed by fluorescein diacetate hydrolisys, β-glucosidase and cellulase activities. The Turkey oak forest showed the lowest soil microbial biomass, both as total and specific PLFA markers. PLFA profile showed a different microbial community structure among forest soils, mainly between the two oak systems. Enzyme activities were affected by soil organic carbon content, with the lowest values measured in Turkey oak. A seasonal effect both on microbial biomass and on enzyme activity was generally observed. Among the investigated forest systems, the beech forest appeared to store more carbon both in aboveground biomass and in soil.

Greenhouse agriculture, a widespread practice in the Mediterranean basin, is prone to impoverishment in soil organic carbon because of crop removal and high decomposition rate. Open-field experimentation has shown that the addition of biochar, a product of thermochemical conversion of biomass, under a limited concentration of oxygen, increases the soil organic C pool, enhances crop productivity and improves C terrestrial sink. The present study investigates the effect of biochar amendment in a greenhouse environment in a Southern Italy organic farm. Two doses (10 or 20 t ha-1) of biochar from conifer pruning wastes were applied immediately before planting 1-week old plants of pepper (Capsicum annuum L.). Plant growth and crop yield were evaluated six months later, at the end of cultivation, in biochar-treated and in control (without biochar) plots. Soil samples were collected in the same plots immediately after biochar addition and six months later and were analyzed for the following parameters: bulk density, water-holding capacity, pH, electrical conductivity, organic carbon, mineral nitrogen, total microbial biomass and fungal mycelium contents, soil respiration, nitrogen mineralization, potential nitrification, soil suppressiveness to Rhizoctonia solani. A single biochar application caused no apparent damage to the crop; on the other hand, no improvement was observed in crop yield or soil suppressiveness to R. solani. In contrast, the single char application positively affected soil respiration, nitrogen mineralization and potential nitrification. These preliminary results suggest that soil amendment with biochar is a potentially useful practice in greenhouse agriculture, yet further experimentation is necessary to assess optimal amounts for better crop productivity and soil quality.

A forest soil located in the “Parco Nazionale del Cilento e del Vallo di Diano”, Salerno, Italy, has been partly converted to a crop field by deforestation and a deep tillage (mouldboard plowing), characterized by an inversion of soil profile at a depth of 1 m, followed by plowing. In this study, we compare soil quality in a crop field and in the adjacent unchanged forest. Soil samples were collected from the two sites few months after the use change and characterized for main chemical (pH, electrical conductivity, organic C, total N, available P, cation exchange capacity) and microbiological (enzyme activities related to cycles of major nutrients, catabolic response profiles, microbial and fungal biomass) properties. We found a depletion of 50 % in soil organic C content in the crop field in comparison with forest, which indicates that the quality of the top layer of the soil decreased, with consequent deep alteration of the C cycle. The drop of organic matter content determined serious effects on soil microbial activity. Microbial and fungal biomass, as well as all enzyme activities, were decreased. The soil catabolic response profiles showed a significant reduction in functional diversity in the cultivated compared to the forest soil. Among the investigated properties, dehydrogenase and β-galactosidase activities, ergosterol content and catabolic evenness showed the highest sensitivity to the soil use change, suggesting that they could be assumed as indicators of the stress induced by this use change.

SUMMARYCompost use is increasingly proposed as a sustainable strategy to restore the fertility of degraded agricultural soils and to reduce landfill disposal or incineration of organic wastes. The effects of compost application on many soil physico-chemical and biological properties, as well as on soil contamination, have been investigated widely, but a model for the ecological interactions among them has never been developed. The aim of the present paper was to provide an integrated view of the causal processes induced by repeated compost amendments on agricultural soil properties. For this purpose, a confirmatory path analysis was performed to enable inferences to be drawn about the causal processes involving compost amendment, soil organic matter content, nutrient concentrations, microbial activity and soil contamination. The path analysis was performed on a dataset derived from a 3-year field trial carried out by the current authors in a Mediterranean intensive agricultural system, where 0, 15, 30 or 45 t/ha of certified compost from municipal solid wastes were annually applied. A script (‘cpa’) was developed using the R programming language and used to test 13 hypothetical models, expressed as directed acyclic graphs, against the observed data. Within the above-mentioned dataset, potassium and zinc available concentrations, microbial respiration and total polycyclic aromatic hydrocarbon (PAH) concentrations were selected as indicative of soil nutrient availability, microbial activity and organic contamination. The applied approach highlights that compost amendment directly influences all the other variables considered in the study and is the main determinant of the observed trends. Other important relationships are those among organic matter, nutrient availabilities, respiration and PAHs, as well as their temporal dynamics.

Chemometric analysis applied to diffuse reflectance spectroscopy is increasingly proposed as an effective and accurate methodology to predict soil physical, chemical and biological properties. Its effectiveness, however, largely varies in relation to the calibration techniques and the specific soil properties. In addition, the calibration of UV-Vis-NIR spectra usually requires large datasets, and the identification of techniques suitable to deal with small sample sizes and high dimensionality problems is a primary challenge. In order to investigate the predictability of many soil chemical and biological properties from a small dataset and to identify the most suitable techniques to deal with this type of problems, we analysed 20 top soil samples of three different forests (Fagus sylvatica, Quercus cerris and Quercus ilex) in southern Apennines (Italy). Diffuse reflectance spectra were recorded in the UV-Vis-NIR range (200-2500 nm) and 22 chemical and biological properties were analysed. Three different calibration techniques were tested, namely the Partial Least Square Regression (PLSR), the combinations wavelet transformation/Elastic net and wavelet transformation/Supervised Principal Component (SPC) regression/ Least Absolute Shrinkage and Selection Operator (LASSO), a kind of preconditioned LASSO. Calibration techniques were applied to both raw spectra and spectra subjected to wavelet shrinkage filtering, in order to evaluate the influence on predictions of spectra denoising. Overall, SPC/LASSO outperformed the other techniques with both raw and denoised spectra. Elastic net produced heterogeneous results, but outperformed SPC/LASSO for total organic carbon, whereas PLSR produced the worst results. Spectra denoising improved the prediction accuracy of many parameters, but worsen the predictions in some cases. Our approach highlighted that: (i) SPC/LASSO (and Elastic net in the case of total organic carbon) is especially suitable to calibrate spectra in the case of small, high dimensional datasets; and (ii) spectra denoising could be an effective technique to improve calibration results.

The maintenance of certain levels of old forest represents a cornerstone of the EU’s biodiversity management strategy. A consensus on a single general ecological definition of old‐growth is particularly difficult in Mediterranean Europe. The present paper deals with old‐growth forests and persistent woodlands in the Cilento and Vallo di Diano National Park (PNCVD) to give an ecological understanding of forest complexity and dynamics under a multiscale and multidisciplinary perspective. The multiscale approach ranged from the identification and mapping of potential old‐growth stands at landscape scale to a two‐level field review of forest stand features. Field sampling involved a multidisciplinary team of researchers in forest structure, pedologic environment, soil microbial activity, flora and vegetation and deadwood components. The research provided sound knowledge about old‐growthness features in the PNCVD that constitutes a unique case study in the whole Mediterranean basin. The integration of...

The effects of municipal food waste compost addition and mineral fertilization on selected soil microbiological activities were investigated during 3 years of reiterated treatments on two Mediterranean agricultural soils with different organic carbon content. Compost at 15, 30 and 45 t ha−1 (dry matter), mineral (NPK) fertilizers and combined fertilizers with 15 t ha−1 of compost plus two reduced doses of mineral N were applied to both soils. At both sites, organic amendment increased soil respiration, fluorescein diacetate hydrolysis, phosphatase and arylsulphatase activities. The differences in soil microbial activities among treatments, found after 3 years of repeated treatments, were attributable to the variations of soil organic C content and to the impact of soil tillage. Our results show that, in Mediterranean intensively cultivated agroecosystems, annual organic amendments improve the microbial activity of soil and produce cumulative effects, suggesting the usefulness of repeated high-rate compost applications.

The effect of soil moisture on bacterial growth was investigated, and the effects of rewetting were compared with glucose addition because both treatments increase substrate availability. Bacterial growth was estimated as thymidine and leucine incorporation, and was compared with respiration. Low growth rates were found in air-dried soil, increasing rapidly to high stable values in moist soils. Respiration and bacterial growth at different soil moisture contents were correlated. Rewetting air-dried soil resulted in a linear increase in bacterial growth with time, reaching the levels in moist soil (10 times higher) after about 7 h. Respiration rates increased within 1 h to a level >10 times higher than that in moist soil. After the initial flush, there was a gradual decrease in respiration rate, while bacterial growth increased to levels twice that of moist soil 24 h after rewetting, and decreased to levels similar to those in moist soil after 2 days. Adding glucose resulted in no positive effect on bacterial growth during the first 9 h, despite resulting in more than five times higher respiration. This indicated that the initial increase in bacterial growth after rewetting was not due to increased substrate availability.

The use of compost for soil amendment is a promising agricultural practice environmentally and economically viable. In the framework of a wide research project designed to evaluate the effects of soil amendment with municipal solid waste compost in comparison with traditional mineral fertilization practices, 54 different cultivars (Cvs) of potatoes were AFLP (amplified fragment length polymorphism) molecularly fingerprinted. The seven most genetically biodiverse potato Cvs were used to establish an experimental field in southern Italy. The field area was divided into two portions fertilized with compost (20 Mg ha(-1)) or with ammonium sulphate (200 kg ha(-1)). No significant differences in productivity, organoleptic characteristics and element concentrations were observed between the potato tubers obtained with both kinds of soil fertilization, while the tubers grown on compost amended soil showed, on average, higher K concentrations with respect to those grown on mineral fertilised soil. cDNA-AFLP (complementary DNA-AFLP) and MSAP (methylation sensitive amplified polymorphism) analyses were carried out on both leaves and tubers of one selected Cv to estimate if any transcriptome alterations or epigenetic modifications were induced by the two kinds of fertilization, however no variations were detected. Chemical and biological soil qualities (i.e., microbial respiration, FDA hydrolysis, alkaline and acid phosphatase) were assessed on soil samples at the start of the experiment and at the end of potato crop cycle. No significant differences in soil pH and limited ones, in the available fraction of some trace elements, were observed; while conductivity was much higher for the compost amended portion of the experimental field. Microbial respiration, FDA hydrolysis and acid phosphatase activities were significantly increased by compost amendment, in comparison with mineral fertilization. Finally, a sensory panel of potato Cvs detected no significant differences among qualitative descriptors and among potatoes coming from the two differently fertilized soils.

Holm oaks form typical urban woodlands in the Mediterranean region. We aimed at characterizing the enchytraeid communities in these environments and searching for possible correlations with soil parameters, including the traffic contamination. Samples of litter and topsoil were collected at different spatial scales and seasons in Naples and Siena cities and in two suburban stands. Only the co-variation between pollution and other soil chemico-physical factors showed significant effects, whereas no direct effect of soil microbiology was detected. Some thermophilous Fridericia and Achaeta tolerate high concentrations of heavy metals and PAHs and their abundance was mainly determined by Ca bioavailability. Central-European mesophilous species increased significantly under more temperate environmental conditions. Different combinations of soil cohesiveness, grain size composition and moisture regime seem to select species of certain body sizes.

The temporal dynamics of some trace elements in two different types of Mediterranean soils were studied in order to evaluate the possible long-term contamination following compost amendments. Total and available (DTPA-extractable) concentrations of Cd, Cu, Pb and Zn were determined. The study was carried out on two agricultural soils in Campania region (southern Italy), a Sandy Loam Calcaric Cambisol (SG) and a Clay Gleyc Luvisol (CO), during 3 years of organic amendment with compost. The compost, produced from the organic fraction of municipal solid waste and urban yard trimmings, in accordance with the Italian law for agricultural use, was applied at annually rates of 15, 30, and 45 t ha(-1) (on dry weight basis). Wide variations in total and available Cd, Cu, Pb and Zn concentrations were observed over time, but appeared to be in many cases unrelated to the treatments, occurring also in control plots. After 3 years of compost application the amended SG soil showed the highest and significant increase in total Cd and Zn concentrations; in addition, the available Cd, Pb and Zn concentrations increased in accordance with the compost rates. The CO soil, characterized by a higher clay content, lower organic matter content and lower cation exchange capacity, exhibited a lower increase in available metal fractions. Our findings show that compost amendment affects more the available than the total metal concentrations in the two types of soils studied and thus it is important into legislation that metal "bioavailability" may be considered in defining threshold metal values.

International audience; In the soil thematic strategy of the European Union Commission, a soil organic carbon content of 2% is indicated as a threshold below which a reduction in soil chemical, biological and physical fertility, and increase in erosion can be observed. Composting of organic matter 'exogenous' to soil (such as from municipalities, industries and agriculture sources) is recommended as an effective way to ensure the return of biomass to soil and the return of the soil organic matter losses. The composting of municipal solid wastes is seen as a strategy to divert organic waste materials from landfills. A municipal source-separated solid waste compost was used in a study carried out during 2003-2006 in Southern Italy. An annual tomato-snap bean-lettuce rotation was planted on a sandy loam soil with 26 g kg−1 organic carbon under greenhouse conditions. Different rates of compost (15-30-45 t ha−1 on a dry weight basis) and combinations of compost at a rate of 15 t ha−1 with reduced doses of mineral N fertilizer (1/2 or 1/4 of optimal supply) were compared with an untreated control and a N, P, K fertilized control. We found that: (1) increasing compost rates produced increasing positive soil organic carbon balances. The C conversion efficiency was 23 and 36% with 15 and 30 t ha−1, respectively, but declined to 28% with the highest rate of compost. Indeed, the higher the compost amounts applied, the higher the soil organic carbon losses. (2) Under tunnel-greenhouse conditions, all the fertilization strategies, except compost at a rate of 15 t ha−1, increased soil nitrate concentrations by up 100 to 400 mg kg−1 dry weight of soil, particularly in the spring-summer seasons. In the same period, nitrate contents in the untreated control reached 100 mg kg−1. (3) The average yield of marketable tomato for the four-year period was 114 t ha−1 and did not vary significantly among treatments. No differences in snap bean yields were detected among the fertilization treatments. In lettuce cultivation, however, 30 and 45 t ha−1 of compost yielded more than other treatments. In the tunnel-greenhouse environment, a high initial content of soil organic matter resulted in high vegetable yields over all four years, even without mineral or organic fertilizer supply. However, among the various fertilization strategies, the best solution able to restore annual soil carbon mineralization was the supply of 15 t ha−1 of compost. In addition, this rate reduced the hazards linked to the high release of nitrates in soil caused by 30 and 45 t ha−1 rates of compost or mineral fertilization.

Stone pine (Pinus pinea L.) has been widely introduced for afforestation in Mediterranean areas. Despite its wide distribution and its presence since ancient time, it is mostly considered as non-native to the Italian peninsula. Plantation of non-native species may have a strong impact on the soil microbial community and, consequently, on nutrient cycling and soil functions. The effect of stone pine on soil microbial community structure and biomass, as revealed by phospholipid fatty acid (PLFA) analysis and fungal biomass indicators, was investigated in two Mediterranean areas in south Italy, where the climax tree species was holm oak (Quercus ilex L.) and some patches were afforested with stone pine. We studied soils from two sites with different parent material, volcanic lava and limestone (calcareous soil). The soil pH range was wider in the calcareous than in the volcanic soils. At both sites, the soils under stone pine had lower pH and higher organic matter content than under holm oak. Microbial biomass was, on average, 1.3-1.4 fold higher in the soils under holm oak than under stone pine. The PLFA composition was different in soils under stone pine compared with holm oak, while the changes in PLEA composition induced by the different tree species were comparable at the two sites. The changes in the PLFA composition were significantly correlated to soil pH and relative concentrations of PLFA indicators (mol%) previously demonstrated to indicate pH effects were also correlated to pH. Thus, both in the volcanic and the calcareous soils, stone pine plantation affected soil microbial community structure and the mechanism for this change appeared to be soil pH changes. (C) Elsevier B.V. All rights reserved. (Less)

Surface volcanic soils (0–5 cm) were analysed for 8 trace elements (Cd, Cr, Cu, Fe, Mn, Pb, V, Zn) and 27 PAHs. Soils were collected every four months at five urban sites in Naples and at a control site in the Vesuvius National Park from May 2001 to May 2002. Cr, V and Fe were more abundant in the control soils while Pb, Zn and ΣPAH were higher in the urban soils. Pb was 2–4 and ΣPAH 2–20 fold higher in urban than in control soil, whereas V was 2 fold higher in the control than in urban soils. Among the urban soils, both trace element and PAH accumulations also differed. Atmospheric deposition is responsible for trace element and PAH accumulation in urban soils. Phenanthrene, fluoranthene, pyrene, benzo[ a ]pyrene, benzo[ b + k + j ]fluoranthene and benzo[ g , h , i ]perylene were the most abundant PAHs both in control and urban soils. Naphthalene was also high in the control soil. Coronene was the most abundant at the urban site near the highway. The accumulation of PAHs in soils appeared to be affected by soil organic matter and microbial metabolism.

In order to evaluate the influence of air pollutants influx on leaf elemental composition, the concentration of N, S, Cu, Fe and Pb were analyzed in the surface deposit and tissue of Quercus ilex L. leaves from 8 sites of the urban area of Naples. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total contents of N and S and for available contents of Cu, Fe and Pb. In the leaf surface deposit S content was high though significantly (P