Phosphorus (P) is an important nutrient for plant growth but its availability in soil is limited. Although plants are able to respond to the P shortage, climatic factors might modify the ...soil-plant-microorganisms system and reduce P availability. In this study we evaluated the rhizosphere effect of beech (Fagus sylvatica L.) in forest soils of Apennines mountains (central Italy) at two altitudes (800 and 1000m) and along 1° of latitudinal gradient, using latitude and altitude as proxies for temperature change. Specifically, we tested if 1) soil organic C, total N, and organic and available P decrease with increasing latitude and altitude, and 2) the rhizosphere effect on P availability becomes more pronounced when potential nutrient limitations are more severe, as it happens with increasing latitude and altitude. The results showed that the small latitudinal gradient has no effect on soil properties. Conversely, significant changes occurred between 800 and 1000m above sea level, as the soils at higher altitude showed greater total organic C (TOC) content, organic and available P contents, and alkaline mono-phosphatases activity than the soils at lower altitude. Further, at the higher altitude, a marked rhizosphere effect was detected, as indicated by greater concentration of TOC, water extractable organic C, and available P, and its fulfillment was mainly attributed to the release of labile organics through rhizodeposition. The availability of easy degradable compounds in the rhizosphere should foster the mineralization of the organic matter with a consequent increase of available P. Hence, we speculate that at high altitude the energy supplied by the plants through rhizodeposition to the rhizosphere heterotrophic microbial community is key for fuelling the rhizospheric processes and, in particular, P cycling.
•Rhizosphere effect of Fagus sylvatica L. was evaluated at different altitudes (800 and 1000m).•Mean annual air temperature was about 10°C at 800m, and about 9°C at 1000ma.s.l.•Significant changes in soil properties occurred between 800 and 1000ma.s.l.•A marked rhizosphere effect was found only at 1000ma.s.l.•At the higher altitude, rhizodeposition is key for fuelling the rhizosphere processes and P cycling.
Anaerobic digestion is an environmentally sustainable way to manage organic waste, and it is able to enhance the recovery of organic carbon and nutrients in agricultural soils and to produce ...renewable energy. Solid-state anaerobic digestion (S-SAD) is a technology that permits the treatment of different type of residues, but is characterized by inhibition phenomena, resulting in a low operational stability. An experimental apparatus, equipped with a recirculation system for the digestate liquid fraction (percolate), was used to optimize the S-SAD system. Different frequencies of recirculation, one, two or four per day, were carried out to investigate how recirculation might affect the quality of the liquid fraction as well as the possible effects on biogas production and on the obtained solid digestate quality. Biogas production was positively affected by percolate spreading, especially when recirculation was performed 4 times per day. As shown by percolate chemical analyses, recirculation avoided the accumulation of volatile fatty acids in the liquid fraction, resulting in a better process stability. In addition, recirculation induced a large consumption of readily available compounds in the percolate, as shown by the depletion of water extractable organic C and total reducing sugars. The quality of the digested solid fraction was also improved by percolate recirculation in terms of the C/N ratio and organic N parameters. These findings showed that daily repeated recirculation of the liquid fraction is suitable to avoid inhibition phenomena during S-SAD and to improve the quality of the digestate solid fraction.
•The S-SAD of animal residue permits to obtain renewable energy.•The daily repeated percolate recirculation avoids inhibition phenomena.•The chemical characteristics of WEOM affect the stability of the S-SAD.•The recirculation frequency influences the quality of the final solid digestate.
•The SOMW and its derived-compost spreading, showed a positive feedback as soil amendment.•The spreading of these materials can lead to the reduction of chemical fertilizers.•They increased soil ...fertility, vegetative activity and olive production.•They also showed no negative effects on the soil bacterial community.
A new type of solid oil mill waste (SOMW), produced by latest-generation decanter, and its derived compost were spread on land for three consecutive years in an olive grove to evaluate the soil chemical characteristics, bacterial abundance and community structure, plant growth and production and oil quality. After the third year of the experiment in both treatments, there was no increase in total organic C (TOC) in the upper layer, while a reduction of TOC concentration in the deeper layer was detected. Moreover, in the upper soil layer, the available P increased in both treated soils compared to control while exchangeable K increased only in SOMW treated soil. In both the treated soils, viable counts of different bacteria showed little or no differences compared with the control. Further, PCR-DGGE analysis of the soil bacterial community indicated the presence of a very high biodiversity that was not affected by the long-term treatment with either SOMW and composted-SOMW. The treated soils with both matrices showed an increase in the vegetative activity and olive yield such as a positive effect on oil quality by increasing phenol content. The overall results indicate that both SOMW and its derived-compost can be positively used as soil amendment, thus, contributing to the reduction in the use of chemical fertilizers.
The DMAPS upgrade of the Belle II vertex detector Babeluk, M.; Barbero, M.; Baudot, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2024, Letnik:
1064
Journal Article
Recenzirano
The Belle II experiment at KEK in Japan considers an upgrade for the vertex detector system in line with the accelerator upgrade for higher luminosity at long shutdown 2 planned for 2028.
One ...proposal for the upgrade of the vertex detector called VTX aims to improve background robustness and reduce occupancy using small and fast pixels. VTX accommodates the OBELIX depleted monolithic active CMOS pixel sensor (DMAPS) on all five proposed layers. OBELIX is specifically developed for the VTX application and based on the TJ-Monopix2 chip initially developed to meet the requirements of the outer layers of the ATLAS inner tracker (ITk).
This paper will review recent tests of the TJ-Monopix2 chip as well as various design aspects of the OBELIX-1 chip currently under development.
The application of municipal waste compost (MWC) and other organic materials may serve to enhance soil fertility of earthen materials and mine spoils used in land reclamation activities, particularly ...in the recovery of degraded areas left by exhausted quarries, mines and landfill sites among others. The long-term distribution, mobility and phytoavailability of heavy metals in such anthropogenic soils were studied by collecting soil samples at different depths over a 10 y chronosequence subsequent to amendment of the top layer of a landfill covering soil with a single dose of mechanically-separated MWC. Amendment resulted in a significant enhancement of the metal loadings in the amended topsoils particularly for Cu, Zn and Pb, which were also the predominant metals in the compost utilised. Although metals were predominantly retained in the compost amended soil horizon, with time their vertical distribution resulted in a moderate enrichment of the underlying mineral horizons, not directly influenced by compost amendment. This enrichment generally resulted from the leaching of soluble organo-metal complexes and subsequent adsorption to mineral horizons. However, in the course of the 10-y experimental period, metal concentrations in the underlying horizons generally returned to background concentrations suggesting a potential loss of metals from the soil system. Analysis of the tissues of plants growing spontaneously on the landfill site suggests that metal phytoavailability was limited and generally species-dependent.
Summary
Compared with annual crop cultivation, tree groves might represent a relevant land‐use system to improve C sequestration, but few data are available to support this hypothesis. To evaluate ...the potential of olive tree (Olea europaea L., 1753) cultivation to store soil organic C (SOC), we assessed (i) the distribution of organic C in active (water‐extractable and particulate organic C, WEOC and POC, respectively), intermediate (organic matter associated with stable sand‐size aggregates and silt‐ and clay‐size aggregates, SSAs and SCAs, respectively) and passive (organic matter resistant to oxidation, rSOM) pools, (ii) the phenol content of the C pools, (iii) the humic‐C distribution of the intermediate C pool and (iv) the stocks of SOC pools in two olive groves of different age (7 years (OG7) and 30 years (OG30)) compared with a nearby site with cereal crops (arable soil, AS). In OG30 the organic C stock of the olive grove was no different from that of the AS, but the distribution of SOC pools changed with the age of the olive groves. The WEOC and POC increased in the Ap horizon of OGs, probably because of the herbaceous cover and distribution of chipped prunings on the soil. There were fewer SSAs in OG7 than AS, possibly because of pedoturbations from deep tillage before the olive trees were established, but they increased in OG30. The increase in SSAs and SCAs in the Bw and BC horizons of OG30 was associated with humic‐C and unextractable‐C and a smaller phenol content than AS. This suggested that the olive tree roots had a positive role through rhizodeposition and root turnover, which favoured the stabilization of organic matter into aggregates at depth. In contrast to the active and intermediate C pools, the passive C pool did not vary following the change in land use from arable to olive grove.
Highlights
Effects of land‐use change from arable to olive grove on soil organic C pools and stocks.
Soil organic C stock increased from 7‐ to 30‐year‐old olive orchard.
Olive tree cultivation affected active and intermediate C pools, but not the passive C pool.
After 30 years, the olive grove stored an amount of SOC similar to that of the arable system.
BACKGROUND AND AIMS: The activity of roots and associated microorganisms plays a key-role in soil formation and evolution, but we lack of knowledge on the quality and extent of the “rhizosphere ...effect” in the different soil horizons. The aim of this study was to assess the interactions between rhizosphere processes and genetic horizons in a forest (Quercus ilex L.) soil developed from limestone. Specifically, we tested (a) if the rhizosphere effect was significant in all the horizons of the soil profiles, and (b) if the intensity of the rhizosphere effect was associated to structure, composition and activity of the microbial community. METHODS: Bulk and rhizosphere soils were characterized by physical, mineralogical, chemical and biological (microbial activity and community structure) analyses. RESULTS: Throughout the soil profile, the rhizosphere processes affected properties like particle-size distribution and soil structure, mineralogy, pH, and organic C and total P content. Conversely, amounts of exchangeable Ca, Mg and K, iron oxides, available P, and total nitrogen showed no significant change. As for the microbial community, its structure and metabolic activity differed between rhizosphere and bulk only in the core of the solum (2Bwb and 3Bwb horizons). CONCLUSIONS: The main processes controlling the intensity of the rhizosphere effect on the soil horizons were root activity, soil faunal perturbation and slope dynamics. While root activity impacted the whole soil profile, although to a lesser extent at depth, the influence of fauna and slope was confined atop the profile. It follows that long-term changes due to root activity and associated microbial community were more strongly expressed in the core of the solum, not at the surface, of this limestone-derived soil.
Plant communities, through species richness and composition, strongly influence soil microorganisms and the ecosystem processes they drive. To test the effects of other plant community attributes, ...such as the identity of dominant plant species, evenness, and spatial arrangement, we set up a model mesocosm experiment that manipulated these three attributes in a full factorial design, using three grassland plant species (Anthoxanthum odoratum, Plantago lanceolata, and Lotus corniculatus). The impact of the three community attributes on the soil microbial community structure and functioning was evaluated after two growing seasons by ester-linked phospholipid fatty-acids analysis, substrate-induced respiration, basal respiration, and nitrogen mineralization and nitrification rates. Our results suggested that the dominant species identity had the most prevalent influence of the three community attributes, with significant effects on most of the measured aspects of microbial biomass, composition and functioning. Evenness had no effects on microbial community structure, but independently influenced basal respiration. Its effects on nitrogen cycling depended on the identity of the dominant plant species, indicating that interactions among species and their effects on functioning can vary with their relative abundance. Systems with an aggregated spatial arrangement had a different microbial community composition and a higher microbial biomass compared to those with a random spatial arrangement, but rarely differed in their functioning. Overall, it appears that dominant species identity was the main driver of soil microorganisms and functioning in these model grassland communities, but that other plant community attributes such as evenness and spatial arrangement can also be important.
The silicon vertex detector of the Belle II experiment Gabrielli, A.; Adamczyk, K.; Aihara, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2024, Letnik:
1064
Journal Article
Recenzirano
The silicon vertex detector (SVD) is a four-layer double-sided strip detector installed at the heart of the Belle II experiment, taking data at the high-luminosity B-Factory SuperKEKB since 2019. SVD ...has been operating smoothly and reliably, showing a stable and above-99% hit efficiency, and a large signal-to-noise ratio in all sensors. In June 2022 the data-taking of the Belle II experiment was stopped for the Long Shutdown 1, primarily required to complete the vertex detector (VXD) with the inner two-layer DEPFET detector and to upgrade several components of the accelerator. This article reports on the excellent performance of SVD in terms of the signal-to-noise ratio, the hit position resolution, as well as the hit-time resolution. We briefly describe the challenges and delicate phases of the VXD re-installation and the SVD status for operation starting in early 2024. In SVD layer 3, which is closest to the interaction point, the average occupancy has been less 0.5%, well below the estimated limit for acceptable tracking performance. However, higher machine backgrounds are expected at increased luminosity, and so also increased hit occupancy. To enhance the robustness of offline software in a high-background environment, new algorithms of background suppression using the excellent SVD hit-time information have been developed, which allows a significant reduction of the fake rate, while preserving the tracking efficiency.
With the increasing luminosity also the radiation levels are expected to increase, with possible deterioration of the sensor performance. The SVD integrated dose is estimated by the correlation of the SVD occupancy with the dose rate measured by the diamonds of the radiation monitor and beam-abort system.
The effects of radiation damage are starting and in good agreement with our expectations. So far, no harmful impact due to the radiation damage on the detector performance has been observed.
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