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The BEST (Beerkan Estimation of Soil Transfer parameters) method was used to compare the hydraulic properties of the soils in two Long-term Agroecosystem Experiments (LTAEs) located at the FIELDLAB experimental site of the University of Perugia (central Italy). The LTAE "NewSmoca" consists of a biennial maize-durum wheat crop rotation under integrated low-input cropping systems with (i) inversion soil tillage (INT) or (ii) no-tillage (INT+) and (iii) under an organic cropping system with inversion soil tillage (ORG). ORG and INT+ involve the use of autumn-sown cover crops (before the maize cycle). Pure stand durum wheat was grown in INT and INT+, while a faba bean–wheat temporary intercropping was implemented in ORG. The LTAE "Crop Rotation" consists of different crop rotations and residue management, a continuous soft winter wheat and biennial rotations of soft winter wheat with maize or faba bean. Each rotation is combined with two modes of crop residue management: removal or burial. For INT+, despite the high-bulk density (>1.50 g/cm3), we found that conductivity, sorptivity and available water are comparable to those of INT, probably due to a more structured and efficient micropore system. ORG soils show the highest conductivity, sorptivity and available water content values, probably due to the recent spring tillage occurring in the wheat inter-row with the faba bean incorporation into the soil. For LTAE Rotation, the residue burial seems to influence the capacity-based indicators positively. However, the differences in the removal treatment are minor, and this could be due to the inversion soil tillage, which limits the progressive accumulation of organic matter. [ABSTRACT FROM AUTHOR]

Both altitude and vegetation are known to affect the amount and quality of soil organic matter (SOM) and the size and activity of soil microbial biomass. However, when altitude and vegetation changes are combined, it is still unclear which one has a greater effect on soil chemical and biochemical properties. With the aim of clarifying this, we tested the effect of altitude (and hence temperature) and vegetation (broadleaf vs pine forests) on soil organic carbon (SOC) and soil microbial biomass and its activity. Soil sampling was carried out in two adjacent toposequences ranging from 500 to 1000 m a.s.l. on a calcareous massif in central Italy: one covered only by Pinus nigra J.F. Arnold forests, while the other covered by Quercus pubescens Willd., Ostrya carpinifolia Scop. and Fagus sylvatica L. forests, at 500, 700 and 1000 m a.s.l., respectively. The content of SOC and water-extractable organic carbon (WEOC) increased with altitude for the pine forests, while for the broadleaf forests no trend along the slope occurred, and the highest SOC and WEOC contents were observed in the soil at 700 m under the Ostrya carpinifolia forest. With regard to the soil microbial community, although the size of the soil microbial biomass (Cmic) generally followed the SOC contents along the slope, both broadleaf and pine forest soils showed similar diminishing trends with altitude of soil respiration (ΣCO2-C), and ΣCO2-C:WEOC and ΣCO2-C:Cmic ratios. The results pointed out that, although under the pine forests' altitude was effective in affecting WEOC and SOC contents, in the soils along the broadleaf forest toposequence this effect was absent, indicating a greater impact of vegetation than temperature on SOC amount and pool distribution. Conversely, the similar trend with altitude of the microbial activity indexes would indicate temperature to be crucial for the activity of the soil microbial community. [ABSTRACT FROM AUTHOR]

Abstract This study evaluated soil properties along a small transect in the Apennines chain (central Italy). Using latitude and altitude as surrogates for temperature differences, three locations at different latitudes were selected for the study. At each location, two altitudes were selected (800 and 1000 m). The study was conducted by contrasting chemical and biochemical parameters [microbial biomass-C content, amount of CO 2 evolved during basal respiration (ΣCO 2 –C), and potential enzyme activities] of topsoils (O and A horizons) supporting European beech (Fagus sylvatica L.) forests at different scales of investigation: horizons, altitude, and latitude. Along the topsoil, the trend of all investigated properties was unique to each O and A horizon according to its level of organic matter degradation, availability of substrates, and nutrients. Contrasting the altitudes, the difference of 1 °C of temperature between 800 and 1000 m significantly affected some of the chemical parameters and both microbial and enzyme activities mainly in the mineral horizons, although glucuronidase and phosphodiesterase activities appeared to be mainly controlled by TOC content. Generally, the different enzyme activities were more clearly highlighted when they were expressed per organic C unit, rather than on a soil mass basis. Latitudinal sensitivity was recorded for total N, ΣCO 2 –C, and some enzyme activities, although no difference in mean annual air temperature occurred along the latitudinal transect. In this case, it is plausible that the summer-winter thermal excursion, which was lower for the southernmost location and increased going north, might have indirectly affected these parameters through changes in the plant-soil relationships, composition of the macro- and mesofauna population, and microbial activity. Considering all the investigated aspects, an increase of 1 °C in mean annual air temperature (in the range 9–10 °C) and/or the alteration of summer-winter thermal excursion might affect the actual soil-plant balance in temperate beech forests, with possible greater mineralization of the topsoil organic matter and a major release of CO 2 in the atmosphere. Highlights • Temperature changes affect chemical and biochemical properties of forest topsoils. • Latitude and altitude can be used as proxy for temperature changes. • Chemical and biochemical properties were peculiar for each topsoil horizon. • 1 °C of difference between altitudes affected soil properties. • Summer-winter thermal excursion induces soil changes. [ABSTRACT FROM AUTHOR]

Abstract Soil magnetic properties are sensitive indicators of pedogenetic processes. Although many of the processes that increase soil magnetism are well documented, the role of microbial communities and the metabolic characteristics of Fe-reducing bacteria are still largely unknown. For this work, two soils with contrasting magnetic properties were identified in a beech forest on Monte Zuccarello (central Italy). Samples of bulk soil and rhizosphere were obtained from A (0–7 cm), AB (7–16 cm), Bw1 (16–22 cm) and Bw2 (22–29 cm) horizons of both soils, and were analysed for their physicochemical characteristics, the amount of magnetic minerals, and the composition of total and culturable bacterial communities, focusing on siderophore-producing bacteria (SPB). Analyses confirmed that the magnetic soil (MS) have a higher content of maghemite and magnetite association, compared to non-magnetic soil (NMS). Since the formation of maghemite can occur through different processes, we investigated on the possible role of soil bacteria in the formation of this magnetic mineral. As soil maghemite generally contains small amounts of Fe2+, the formation of which has been attributed to the combustion of organic matter, SPB have been isolated and identified. MS samples showed the highest number of SPB (mainly Micrococcaceae , Bacillaceae , and Pseudomonadaceae), suggesting a significant increase in Fe-reducing bacteria. High-throughput sequencing analysis revealed a separation in terms of the total composition of the bacterial community between bulk and rhizosphere of both MS and NMS, dominated by Proteobacteria , Actinobacteria , Acidobacteria , and Verrucomicrobia phyla. Interestingly, Gamma and Delta Proteobacteria , as well as Nitrospirae , were usually more abundant in MS than in NMS, confirming that the MS was predominantly characterized by groups of magnetotactic bacteria and SPB, and potentially contributing to enhance the soil magnetic properties. Highlights • Magnetic and non-magnetic paleosols selected for different bacterial communities. • Magnetic soils were enriched in maghemite and Fe-reducing bacteria. • Rhizosphere did not promote the accumulation of magnetic minerals. • Magnetotactic and siderophore-producing bacteria increased in magnetic soils. [ABSTRACT FROM AUTHOR]

In forest ecosystems, a variety of abiotic and biotic soil forming factors drives soil organic matter (SOM) and nutrients cycling with a profitable outcome on climate change mitigation. As a consequence, type and intensity of forest management, through its impact on carbon (C) and nutrient soil stocks, can be considered as an additional soil forming force. In this study, we investigated the influence of the coppice conversion into high forest on pedogenesis and on soil C and nutrient (N, P, Ca, Mg, and K) stocks, fifty years later the beginning of the conversion-cycle. The trial was established in a Turkey oak forest historically managed under the coppice system in central Italy. Specifically, we considered tree population density (natural evolution – control, moderate thinning, heavy thinning) where soil samples were collected according to genetic horizon to estimate C, N, and P stocks both in the forest floor and at fixed depth intervals (0–30, 30–50 and 50–75 cm). Further, the stocks of exchangeable Ca, Mg, and K were also assessed for the mineral layers. The results showed that litter and the upper layer of mineral soil (0–30 cm) contained a similar quantity of C (about 74–83 Mg ha-1), independently of the trials and no differences were observed also in the whole soil stocks (about 192–213 Mg ha−1). The comparison of the mean stocks calculated per 1-cm of thickness of organic (O), organo-mineral (OM), and mineral (M) layers, although it did not display any difference among trials (excepted for P and Mg), showed a similar capability of the organo-mineral horizons to store C and nutrients compared with the organic ones (e.g., about 6–12 Mg ha−1, 0.3–0.5 Mg ha−1 and 0.5–1.5 kg ha−1 for C, N and P, respectively). Our findings showed that thinning operated on Turkey oak coppice did not affect soil capacity to store C and nutrients. These results suggested that the forest ecosystem itself is the main soil forming force and this is consistent with the target of adopting forest management able to control the global C cycle through the storage of SOM in the mineral soil rather than in forest floor, where SOM turnover is faster. • Thinning of Turkey oak forest has negligible effect on soil C and nutrients stock. • Genetic horizons are fundamental in determining soil C and nutrient stock. • Mineral horizons of forest soils are able to store high amount of organic C in depth. • The multi millennial forest cover is the main soil forming factor. [ABSTRACT FROM AUTHOR]