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Two pedotransfer functions (PTFs) are available in the literature enabling the soil water retention function (WRF) to be estimated from knowledge of the soil particle-size distribution (PSD), oven-dry soil bulk density (rb), and saturated soil water content (qs): i) the Arya and Heitman model (PTF-AH), and ii) the Mohammadi and Vanclooster model (PTF-MV). These physicoempirical PTFs rely on the hypothesis of shape similarity between PSD and WRF, and do not require the calibration of the input parameters. In the first stage, twenty-seven PSD models were evaluated using 4,128 soil samples collected in Campania (southern Italy). These models were ranked according to the root mean square residuals (RMSR), corrected Akaike information criterion (AICc), and adjusted coefficient of determination (R2adj). In the second stage, three subsets of PSD and WRF data (DS-1, DS-2, and DS-3), comprising 282 soil samples, were used to evaluate the two PTFs using the best three PSD models selected in the first stage. The hypothesis of shape similarity was assumed as acceptable only when the RMSR value was lower than the field standard deviation of the WRFs (s*), which is viewed as a tolerance threshold and computed from the physically based scaling approach proposed by Kosugi and Hopmans (1998). In the first study area (DS- 1), characterized by a fairly uniform, loamy textured volcanic soil, the PTF-AH outperformed the PTF-MV and both PTFs provided reasonable performance within the acceptance threshold (i.e., RMSR < s*). In the other two heterogeneous field sites (DS-2 and DS-3, characterized by soil textural classes that span from clay and clay-loam to loam and even sandy-loam soils), the PTF-MV (with 3% to 6% RMSR surpassing s*) outperformed the PTF-AH (with 8% to 30% RMSR surpassing s*) and the majority of RMSR values were larger than those obtained in the original studies. The mean relative error (MRE) revealed that the PTF-MV systematically underestimates the measured WRFs, whereas the PTF-AH provided negative MRE values indicating an overall overestimation. The outcomes of our study provide a critical evaluation when using calibration-free PTFs to predict WRFs over large areas [ABSTRACT FROM AUTHOR]

Soil acidification and low nutrient availability are two major challenges facing agriculture in most regions of East Africa, resulting in aluminum toxicity and poor crop yields. The amendment of local sediments to cropland can potentially alleviate these challenges, but responses are variable. In this study, we investigated the potential of two different local sediments influenced by volcanic deposits to increase soil pH, Si and P availability and reduce Al toxicity, thereby improve barley yield. Hence, a field experiment was established in Eldoret, Western Kenya, using 1% and 3% addition by weight of two sediments in barley cultivated plots. The Baringo 3% amendment significantly increased soil pH (from 4.7 to 7.0), the available P content (from 0.01 mg g-1 to 0.02 mg g-1) and decreased the Al availability (from 3.03 mg g-1-2.17 mg g-1). This resulted in a barley yield of 4.7 t/ha (+1061%). The Nakuru 3% and Baringo 1% amendments increased yield to 2-3 t/ha, while the Nakuru 1% did not significantly increase yield. These results highlight that, from a biophysical perspective, there are natural and local opportunities to reduce soil acidification and to partly replace mineral fertilizer, but its magnitude depends on the sediment and the amendment rate. [ABSTRACT FROM AUTHOR]

Chemical composition of volcanic soils has been studied in the Southern Kuril Islands (Iturup, Kunashir, Shikotan), which undergo recurrently ash falls of mainly basic composition upon volcanic eruptions. The total content of metals (K, Ca, Mg, Na, Ba, Cu, Co, Cd, Cr, Fe, Mo, Ni, Pb, Sc, Sr, V, and Zn) and the concentrations of their mobile forms extracted by the ammonium acetate buffer at pH 4.80 have been determined. The total contents of Sc, V, Fe, and Zn are 1.5–5 times higher than their natural abundances in the upper layer of the Earth's crust (clarkes), whereas the contents of Cr, Ni, Sr, and Ba are 2–10 times lower. The soils show contrasting pH distribution (3.75–7.81) providing for the mobility of metals. The maximum activity of radial and lateral migration leading to radical differentiation of the genetic soil horizons by their chemical composition in different catenary positions is observed at low pH values; the coefficients of radial and lateral migration can rise up to 12 and 29, respectively. The results of factor analysis have revealed the leading role of soil-forming rocks in the formation of soil chemical composition (about 63% of sample variance); whereas humus formation, transformation of mineral and organic substances in soils, and hydrothermal activity exert a lesser effect. Soils formed on intermediate and mafic rocks of the Cenozoic volcanic massif are characterized by the Ca–Mg–Na paragenetic association; those formed on deposits of liparite–dacite complex are specified by the Ba–K–Pb–Mo association; on gabbroid rocks, by the Ni–Cr–Cu association; and on psammite, by the V–Sc–Fe–Co association. The Mo–Pb paragenesis is typical for the areas of current hydrothermal activity. The influence of placer formation on the chemical composition of soils in the coastal areas of Iturup and Shikotan Islands is shown. The distribution of mobile forms is associated with chelate-formation processes, geochemical barriers of acid–base, sorption, and redox types. Local soil pollution mainly related to the operation of motor vehicles has been identified. The areas of Krabozavodskoe and Yuzhno-Kuril'sk settlements show elevated concentrations of Ba, Sr and K due to the activities of fish processing plants; and the area of Kuril'sk city manifests elevated concentrations of Cr, Ni, Cu, Co, Zn and Pb, the source of which being the repair base. The calculated index of soil toxicity probability (MERMQ), as well as the results of biotesting for Daphnia magna and Chlorella vulgaris attest to the low soil toxicity. This is explained by the low population density and low economic development of the islands. [ABSTRACT FROM AUTHOR]

The objective of this study was to clarify the actual physical and chemical properties of volcanic ejecta immediately after the explosive eruption of Shinmoe-dake, Mt. Kirishima, in Japan. The day after the explosive eruption occurred on March 25, 2018, permeability tests using a cylindrical frame were conducted, and samples collected in the test site were subjected to laboratory soil tests. The real infiltration capacity of the volcanic ejecta showed that the final values were lower (38–92 mm/h) in the talus inside the forest than in the plain outside the forest. This was attributed to the small particle size distribution above 1 mm, regardless of the particle size of the silt/clay particle size segment. The rainfall after the explosive eruption was at most 20–22 mm/h, indicating that the real infiltration capacity value at the end of the eruption was higher than the rainfall value. This was consistent with the fact that no debris-flow was observed at the foot of Shinmoe-dake after the recent eruption. On the other hand, examination of the chemical properties of the volcanic ejecta collected revealed high values of Ca and SO4. These compounds form gypsums by reaction with water, could reduce the infiltration capacity of deposit, possibly contributing generation of mudslide. [ABSTRACT FROM AUTHOR]

On 26th May 2021, an earthquake with a moment magnitude Mw 5.1 hit the densely populated cities of Gisenyi (Rwanda) and Goma (D.R. Congo) which sit on the active East African Rift System. It was one of the largest earthquakes associated with the 2021 Mount Nyiragongo eruption. Although of moderate magnitude, the earthquake substantially damaged manmade structures. This paper presents field observations on the geotechnical impact, building damage, and factors contributing to the heightened destruction caused by this moderate earthquake. The damage pattern observed in the field indicates that masonry structures with inadequate seismic detailing were the most damaged buildings. In addition, the statistical analysis of the damaged buildings indicates most of the damaged structures were located in plains covered by volcanic soil. The intensity of the waves was estimated using the building damage data based on the European Macroseismic Scale (EMS-98). An intensity distribution map was generated for the surveyed area, suggesting EMS-98 intensity of VIII or IX along the eastern basin boundary fault and VII around the cities of Goma and Gisenyi where the land is composed of black cotton soil of volcanic origin. The higher intensity values along the eastern basin-bounding fault indicate that a reevaluation of the seismic hazard for the region is necessary. Since this is the first-ever such damage survey for the region, the developed intensity map can be used to understand the correlation between the intensity of the ground motion and damage severity which contributed to the seismic hazard assessment of the study area. [ABSTRACT FROM AUTHOR]

Highlights: The pH buffering capacity was higher in volcanic than non-volcanic soils. The sodium concentration increased exponentially in volcanic soils. The sulfate input increased the sulfur mineralization in soils. Reusing the by-products from wood pulp processing can promote the efficient use of resources. In this sense, the objective of this research was to determine the agronomic efficiency of CaCO3 and Na2SO4 by-products from wood pulp processing to establish criteria for their use and avoid undesirable side effects when applying these materials to the soil. Six treatments in proportions of 1; 0.9; 0.75; 0.5, 0.25, and 0, of CaCO3/Na2SO4, respectively, were incubated at a constant temperature and humidity for 15 days. The first proportion consisted of 100% CaCO3, while M1 mixed 90% CaCO3 and 10% Na2SO4, M2: 75% CaCO3 and 25% Na2SO4, M3: 50% CaCO3 and 50% Na2SO4, M4: 25% CaCO3 and 75% Na2SO4, with the last proportion comprised of 100% Na2SO4. Samples of 40 g from two soil series, Licantén (Inceptisol) and San José (Andisol), were used. The rates applied for each treatment were 0, 1, 2, 4, and 8 g of material per kg of dry soil. At the end of the incubation period, pH in water, pH in CaCl2, exchange bases (Ca2+, Mg2+, K+ and Na+) and extractable sulfur were determined. The results showed that the San José soil had a pH buffering capacity three times higher than that of the Licantén soil. The linear increase in pH was thus explained by the soil type in relation to the applied rate of CaCO3. The analysis of the increase in the exchangeable Na percentage (ESP) showed that the soils increased up to about 70% of their ESP with the highest added rate of Na2SO4. The application of a mixture of 25% Na2SO4 and 75% CaCO3 resulted in an increase in the ESP close to 15%; therefore, it is not recommended to use mixtures with a Na2SO4 content higher than 25% in these soils. Finally, we affirm that for M2 the maximum recommended dose for application should be 4 Mg ha−1, i.e., 3 g of material per kg of soil. [ABSTRACT FROM AUTHOR]

Annual top-dressing application of agricultural lime is a common practice in fruit orchards on acidic soils in southern Chile, which could result in surface over-liming and base imbalances. A trial was performed in a cherry orchard with an 8-year history of surface liming to evaluate the effectiveness of lime materials in neutralizing acidity in the soil profile and the effect on the tree nutritional status. No-lime (NL), calcitic (AgL), hydrated (HL), and liquid (LL) lime treatments were applied on soil surface at commercial rates, and soil acidity variables were measured at depths of 0–5, 5–10, and 10–20 cm in samples collected at 0, 15, 30, 60, and 225 days after application. Tree nutritional status was evaluated through foliar analysis. Top-dressing application of AgL was ineffective in ameliorating subsoil acidity at depths >5 cm, even in high-rainfall conditions. HL did not exhibit greater alkalinity mobility compared to AgL, although it had a faster but shorter-lived reaction. At the manufacturer-recommended rates, LL application was ineffective. After 8 years of top-dressing liming with AgL, a significant stratification of soil pH, Al, and Ca was observed. However, foliar concentration of bases did not reflect the surface Ca accumulation in soil, discarding an antagonistic cation competition for tree uptake. [ABSTRACT FROM AUTHOR]

Priming effects of soil organic matter decomposition are critical to determine carbon budget and turnover in soil. Yet, the overall direction and intensity of soil priming remains under debate. A second‐order meta‐analysis was performed with 9296‐paired observations from 363 primary studies to determine the intensity and general direction of priming effects depending on the compound type, nutrient availability, and ecosystem type. We found that fresh carbon inputs induced positive priming effects (+37%) in 97% of paired observations. Labile compounds induced larger priming effects (+73%) than complex organic compounds (+33%). Nutrients (e.g., N, P) added with organic compounds reduced the intensity of priming effects compared to compounds without N and P, reflecting "nutrient mining from soil organic matter" as one of the main mechanisms of priming effects. Notably, tundra, lakebeds, wetlands, and volcanic soils showed much larger priming effects (+125%) compared to soils under forests, croplands, and grasslands (+24...+32%). Our findings highlight that positive priming effects are predominant in most soils at a global scale. Optimizing strategies to incorporate fresh organic matter and nutrients is urgently needed to offset the priming‐induced accelerated organic carbon turnover and possible losses. [ABSTRACT FROM AUTHOR]

The journey of the potato (Solanum tuberosum L.) from South America to the rest of the world has generated a prolific literature regarding the discovery of this crop, its early consumption and cultivation in the Old World. An important part of that literature concerns the Canary Islands. The islands were the only exception to the Spanish trade monopoly with the New World, which reserved Seville as the only port for imports and exports to the colonies. The first potatoes to arrive from America, both from the Andes and the Chiloé archipelago, passed through the Canary Islands, and it is likely that the islands were initially the place where this crop became acclimatised. The orography, the volcanic soils, the climate and the intermediate photoperiods of the islands contributed to the acclimatisation of potatoes that came from various origins of America. The current biodiversity of potatoes in the Canary Islands includes different cultivars, such as local ones that arrived from South America after the conquest, which have evolved on the islands and are taxonomically classified as Solanum ssp. tuberosum, Solanum ssp. andigena and Solanum chaucha. These potatoes have been preserved by farmers, generation after generation, with between 600 and 800 ha being devoted to their cultivation (mainly on the island of Tenerife), in a traditional way, though with low productivity, often due to high virus pressure. This article traces the history of ancient potatoes in the Canary Islands and investigates in depth the introduction of potatoes in Europe through the Canary Islands. It contributes to describing the cultivated plant genetic resources of the Solanum spp. as well as their current situation and cultivation. It also describes traditional cultivation practices, the importance of the in situ conservation of theses varieties and the threats that affect them such as the Guatemalan potato moth. [ABSTRACT FROM AUTHOR]

The contribution of sediment transport and accumulation to soil formation was investigated in an area characterized by continental sedimentary activity since the Late Pleistocene. The area was the north-eastern portion of the large Quaternary graben represented by the Campania Plain, which is rimmed to the north–east–south by the Mesozoic carbonate Apennine nappes. The plain was filled mainly by products generated by eruptions from the Phlegrean Fields, which were also distributed on the slopes bordering the plain and remobilized toward the adjacent surfaces. Five sites were selected in the area in question. They were studied using morphological features and pertinent characteristics of the mineral soil fraction >2.0 mm, such as their volume and lithological description. Soils were compared to selected lithostratigraphic sequences characterizing the studied area, which were collected from literature and reinterpreted in pedological keys. The results showed that soils derived from the emplacement of Phlegrean primary volcanic materials, such as Campania Ignimbrite (~39–40 ky B.P.) and Neapolitan Yellow Tuff (~15 ky B.P.), with the related weathering products, and from volcanic materials reworked and transported by alluvial/colluvial episodes. The latter formed contrasting soil horizons which, differing in both rock fragment content and lithological composition, testified to the presence of lithological discontinuities. The formation of the horizons in question interrupted the genetic sequence derived from the in situ alteration of the volcanic substrata, suggesting that processes of transport and redistribution of sediments from the adjacent mountain slopes contributed to soil formation. The comparison of the pedostratigraphies with the lithostratigraphic sequences indicated a strong relation between geomorphic and pedogenetic events. [ABSTRACT FROM AUTHOR]

Volcanic soils are among the most productive soils in the world as they can accumulate large amounts of organic carbon and nitrogen and have good water storage capacity. They are extensively used worldwide for agriculture, which makes it difficult to study the soil‐landscape dynamics under natural conditions. By working in the Galápagos Islands, a UNESCO World Heritage Site, we aimed to constrain soil development over millennial timescales using empirical data. Our monitoring sites on Santa Cruz Island cover a 10 km long NW‐SE transect with an 8‐fold increase in precipitation and associated vegetation changes. By controlling for age and chemical composition of the basaltic parent material, we investigated the influence of precipitation rates on soil weathering. At the landscape scale, soil weathering degree increased with increasing precipitation, as shown by the spatial patterns in soil depth, pH, mass loss coefficients, chemical index of alteration, chemical depletion fraction, and total reserve in bases. In addition to the climatic effect, rock porosity strongly enhanced basalt weathering. Porosity‐enhanced weathering is particularly important in the humid and perhumid precipitation regimes: soils developed on porous scoriae developed weathering mantles that are ∼10‐fold thicker and have 10‐fold higher mass losses due to weathering compared to soils developed on basalt lava flows. Our results demonstrated that variations in rock pore dimensions and distribution can lead to large variations in basalt weathering rates, particularly in humid and perhumid climates where deep leaching can be facilitated by rock porosity. Plain Language Summary: Tropical volcanic islands are global weathering hotspots. Soil weathering is controlled by climate and lithology, as temperature and precipitation facilitate weathering reactions, solute and nutrient fluxes, and CO2 drawdown. By studying soil‐landscape dynamics along a climosequence in Santa Cruz Island (Galápagos Archipelago), we first explored how precipitation facilitates basalt weathering. Then, we investigated whether rock porosity can further enhance weathering rates. Our data showed that soils are largely composed of atmospheric dust in arid regimes. With increasing precipitation, soil development is increasingly being controlled by in situ soil weathering. Soil weathering rates increased with precipitation, in particular in regions receiving more than 1,000 mm of annual precipitation. We also noted marked differences in soil thickness and degree of weathering between soils developed on basalt lava flows and porous scoriae, with soils developed on scoriae being significantly deeper and more weathered. Key Points: Basalt weathering increases with precipitation while temperature plays a secondary roleSoil weathering depth and rate are higher on porous scoria deposits than on basalt lava flowsPorosity‐enhanced weathering is particularly important in humid and perhumid precipitation regimes [ABSTRACT FROM AUTHOR]

The application of urea as a nitrogen fertilizer and herbicide is a common practice in agricultural systems. However, there is no background information on how the soil acidification caused by urea might affect the herbicide bioavailability in volcanic soils. The persistence study was conducted under microcosm incubation conditions in two Andisol soils amended with a field equivalent nitrogen dose of 200 kg N ha−1 and double dose of 400 kg N ha−1. Clopyralid, fluroxypyr, picloram, and triclopyr, acidic ionizable herbicides, were applied at the field equivalent dose. Adsorption studies were also carried out on both soils at pH 4, 5, and 6. Clopyralid and picloram showed the greatest increase in half-life in the range of 20–80%. The application of twice the dose of urea resulted in minor changes. A higher adsorption implies a higher persistence of the herbicides. This was more evident for the Piedras Negras soil (PNS). The conclusion of this work is that soil acidification by urea increases the persistence of ionizable herbicides in Andisol soils and that this effect depends on the acidity of the herbicide and the physico-chemical characteristics of the soil, which are among the most determining factors. [ABSTRACT FROM AUTHOR]

Background Podoconiosis is a non-infectious neglected tropical disease caused by long-term exposure to irritant volcanic soils. It results in severe physical, psychological and financial consequences. Heart and Sole Africa (HASA) is a non-governmental, community-based organization providing management to podoconiosis patients in Rwanda. We sought to analyze the impact of their program on the lives of patients. Methods Quantitative surveys recorded the participants' demographics, adherence to HASA's management recommendations and changes in quality of life (QOL). Qualitative questions were used to gather respondent perspectives on HASA programming. Results We interviewed 127 patients from HASA's Musanze (n=47) and Burera (n=80) clinics. Almost all participants (98.4%) reported statistically significant (p<0.01) improvements in their QOL, and more than one-half (51.2%) had a favorable adherence score of >80%. Qualitative feedback identified specific challenges to adherence and recognition of program success in symptom management. Conclusions Our study demonstrated the value of community-based podoconiosis programming in improving the lives of patients. Practices such as regular feet washing, emollient application, shoe wearing and limb raising can result in a marked reduction of morbidity. Our findings support the argument for scaling up these management practices across Rwanda. [ABSTRACT FROM AUTHOR]

Volcanic rocks, preserving paleorecords of Earth's magnetic field, are essential to constrain the working of the geodynamo, provided their primary signal was not biased. Using a thermomagnetometer, we simulate a situation where a sample's primary record, carried by a thermoremanence (TRM, acquired by cooling in air from 600°C to room temperature), is partly overprinted by a chemical remanence (CRM, acquired by 200 hr of isothermal exposure at 400°C). This situation leads to two directional and intensity components (in the form of linear segments) in the Zijderveld and Arai‐Nagata diagrams. In the case of unstable titanomagnetite grains prior to CRM acquisition, we show that both components can be strongly biased by up to ∼50° for paleodirections and ∼50% for paleointensities. In such a worst‐case scenario, the secondary CRM strongly overprints the primary TRM, rendering the common interpretation of Zijderveld and Arai‐Nagata diagrams in terms of characteristic components invalid. Plain Language Summary: Volcanic rocks, the magnetic minerals of which can acquire a thermoremanent magnetization (TRM) from Earth's magnetic field during their initial cooling, are essential to constrain the working of the geodynamo through Earth's history. However, if the rock is subsequently reheated at moderate temperature in another ambient field, the initial record can be partly overprinted by a chemical remanence (CRM). Starting from a TRM applied on materials of various thermostability, we reproduced in laboratory conditions the acquisition of a CRM by annealing the rock in a controlled ambient field for 200 hr at 400°C. Rock‐magnetic and structural analyses at regular intervals, supplemented by continuous measurements of the remanent magnetization, indicate the creation of new phases as a result of oxidation processes. The paleomagnetic analysis of the final products reveals the existence of two distinct components that can be associated with the initial TRM and the secondary CRM. Whereas the paleomagnetic record of the initial TRM is trustworthy for the most stabilized initial products, directional (up to 50°) and intensity (up to 50%) biases are observed for the least stabilized initial products, illustrating a critical example where the interpretation of characteristic components (linear segments in the interpretation diagrams) is invalid. Key Points: We overprint a thermoremanent magnetization (TRM) by cooling from 600°C with a chemical remanent magnetization by 200 hr exposure at 400°CChemical remanent magnetization was produced by the creation of cation‐deficient titanomagnetite phases, then stabilized by oxyexsolutionPaleodirections and intensities are strongly biased in the worst scenario, making the interpretation of characteristic components invalid [ABSTRACT FROM AUTHOR]

A palynological study of the uppermost Cretaceous–lowermost Paleocene sequences of the Deccan volcanic province in the Mandla Lobe of central India was carried out to understand floral diversity, palaeoecology and palaeoclimate during Deccan volcanic activity (67.4–62.5 Ma). The study involved 17 intertrappean sedimentary beds at 13 stratigraphical levels. The analysis shows the presence of a rich and diverse palynoflora represented by 47 genera and 61 species of pteridophytes, gymnosperms, algae and fungi. Among these, we recognised three new genera and 10 new species. At the lower stratigraphical levels (582–602 m above sea level), Late Cretaceous (Maastrichtian) age marker palynomorphs, namely Azolla cretacea, Farabeipollis minutus, Jiangsupollis striatus and J. intertrappea sp. nov., and the dominance of Gabonisporis vigourouxii and Aquilapollenites bengalensis were recorded. At the higher stratigraphical levels (698–858 m above sea level), Early Paleocene (Danian) age marker palynomorphs, such as Haloragacidites amolosus, Longapertites vaneendenburgii, Mulleripollis bolpurensis, Palmaepollenites nadhamunii and P. eocenicus, were recorded. The palynoassemblages and associated clay minerals indicate the deposition of intertrappean beds in a fluctuating climate, ranging from humid and semiarid to arid, and the prevalence of estuarine to freshwater depositional environments at the time of deposition. The palynofloral assemblages suggest the prevalence of a warm, humid tropical climate with high precipitation during the deposition of the intertrappean beds. [ABSTRACT FROM AUTHOR]

Background: Teide National Park (Canary Islands) is an alpine volcanic ecosystem with shrub vegetation in which legume Spartocytisus supranubius is the most characteristic key species for nitrogen input to the ecosystem. Aims and methods: Bacterial and fungal communities in bulk and rhizosphere soils were analysed through high-throughput sequencing in undisturbed and wildfire-impacted areas to identify key microorganisms in burned and unburned soils. Results: Microbial communities in undisturbed areas exhibited comparable diversity in bulk and rhizosphere soils, but differed in structure and composition. An unusual abundance of non-photosynthetic Chloroflexi from the oligotrotrophic class Ktedonobacteria dominated the bulk soils, surpassing Proteobacteria, Acidobacteria and Actinobacteria. The rhizosphere effect resulted in a microbiome with a more balanced abundance of these four phyla and enriched in potentially plant growth-promoting microorganisms. The impact of a wildfire on the shrub vegetation resulted in a microbial community, especially the fungal community, reduced in diversity and changed in structure and composition, with many of the most characteristic rhizosphere genera becoming vanished, while others took advantage of the postfire conditions and became predominant. Conclusion: The microbial communities of Teide National Park in fire-affected soils, particularly in the rhizosphere environment of the legume shrubland are significantly altered two years after a wildfire, remaining far from unburned scenarios, suggesting a slow recovery in alpine ecosystem with dry volcanic soils. Pseudarthrobacter (Actinobacteria) and Coprinellus (Basidiomycota), the two most fire-favoured genera, are good indicators of fire severity and are proposed as bioindicators to monitor the recovery of the soil ecosystem. [ABSTRACT FROM AUTHOR]

Granulites and eclogites are useful for revealing the thermal and tectonic evolution of orogens. Early Palaeozoic granulites and associated eclogites in the East Kunlun Orogenic Belt (EKOB) display contrasting metamorphic age. Such asynchronous granulite–eclogite associations have rarely been reported, and the geological significance of their existence remains to be further explored. In this study, petrological and geochronological techniques were used to investigate two felsic and two mafic granulites collected from the Qingshuiquan area in the eastern section of the EKOB. These rocks record similar P–T paths, which are characterized by a peak stage within suprasolidus and high‐pressure (HP) granulite facies conditions (750–832°C and 10.1–12.0 kbar), followed by an initial decompression and cooling stage to subsolidus conditions (600–748°C and 6.5–8.6 kbar), and then a stage of further retrogression under greenschist facies conditions. The protoliths to these granulites are of volcanic and sedimentary origin and suggested to be a component of the continental basement unit. Metamorphic P–T paths indicate that these rocks experienced peak metamorphism at a depth of ~40 km, then cooling and uplift to a depth of ~25 km, and eventually experienced low‐grade retrogression at shallow crustal levels. Cathodoluminescence images and compositional data demonstrate that the zircons in these rocks are of metamorphic origin and they crystallized at or near peak conditions. SIMS U–Pb dating of representative zircon grains yield concordant metamorphic ages of c. 490–520 Ma, with a peak value of 505 Ma on the probability density curve. These ages are similar to other 480–530 Ma ages typically retrieved from EKOB granulites and associated rocks, and are markedly older than the 400–450 Ma ages retrieved from eclogites and their host rocks. The HP granulites and eclogites of the EKOB do not show overprinting relationships. Such asynchronous characteristics imply that the two rock types formed in distinct tectonic settings and at different stages of a protracted subduction–collision process. The studied granulites are suggested to have formed in the root of a continental arc during a stage of Proto‐Tethys Ocean subduction. The formation of the eclogites could be attributed to subsequent deep continental subduction. [ABSTRACT FROM AUTHOR]

The late Quaternary paleoclimate of the North Atlantic region has been widely studied, but the local terrestrial response to broader climatic variations remains underexplored. The Azores Archipelago, influenced by the North Atlantic Oscillation (NAO) and the Azores High, is a strategic target to investigate such interactions. Here, paleosols developed in equilibrium with the atmosphere recorded environmental variations in their geochemistry, and volcanic units sealing those paleosols allow for their precise dating. Clay mineralogical transfer functions from paleosol geochemistry and geochronological data were used to track paleoclimatic and paleoecological changes in this region over the past 1.3 Myr. Mean annual precipitation and air temperature reconstructions range from 620 to 1,520 mm yr−1 and 14–26°C, with the latter tightly coupled with previous reconstructions of sea surface temperature. New K‐Ar ages evidence pulsed soil formation periods under weathering‐favorable wet and warm conditions, suggesting periods of a persistent negative NAO with a weakened or more southern Azores High after glacial Terminations I, II, IV, V, IX, and X. Our humidity province reconstructions indicate a prevailing moist to wet forest under cool temperate to subtropical conditions, with less variability than continental Europe. A rapid paleoecological shift occurred at ∼430 ka in São Miguel Island, probably associated with the high amplitude of Termination V. Paleoecological changes younger than 430 ka could be related to local, not large‐scale, climate changes. Average past precipitations were ∼170 mm yr−1 lower than in the present, which suggests that modern weathering rates are higher than observed in our record. Plain Language Summary: In this work, we studied the local climate of the Azores volcanic islands in response to broader climatic changes over the past 1 million years. By studying the chemistry of paleosols–ancient soils incorporated into the geological record–we reconstructed the conditions of precipitation and temperature at the time of their formation. Air temperature reconstructions are similar to previous reconstructions of sea surface temperatures, suggesting a close relationship between atmospheric and sea surface temperatures in the North Atlantic region. The age determination of volcanic units allowed us to constrain the ages of paleosols. We observed that most paleosols developed quickly after the end of glacial periods, under wet and warm conditions that favored the fast transformation of volcanic products into soils. This indicates periods over which the Azores High–an atmospheric high‐pressure system that impacts the Azores' climate–was weakened or centered farther to the south of its current position. The chemistry of the paleosols registered fast environmental changes and suggests that the present annual precipitations are higher than over the past million years, which could impact the local economic activities and even the global climate, due to the capture of atmospheric CO2 through the weathering of volcanic rocks. Key Points: Precise K‐Ar geochronology revealed pulses of soil formation over the past 1 Myr in the Azores, Central North AtlanticPaleosols' geochemistry recorded paleoclimatic conditions and revealed fast environmental changesWet and warm climate resulted from persistent negative North Atlantic Oscillation conditions, favoring fast weathering of volcanic rocks [ABSTRACT FROM AUTHOR]

The Golan Heights plateau in northern Israel is underlaid by volcanic rocks ranging in age from ~5.5 to 0.1 Ma. Throughout the Golan Heights, these rocks are covered by shallow soils that rarely exceed 0.5 m in depth. The soils are generally assumed to form a chronosequence, in which their ages correspond to those of the basalts they cover. Such age correspondence would imply that the soils have been slowly accumulating over hundreds of thousands to a few million years, suggesting a generally stable system. The ages of these soils and their temporal correlation to the basalts, however, have never been determined or tested. Here, we present age constraints for the soils of the Golan Heights. Soils were surveyed and sampled with their corresponding basalt bedrock. Mass balance calculations based on conservative immobile elements, coupled with 36Cl-based basalt denudation rates, suggest that the soil ages are decoupled from the ages of the underlying basalts, and represent up to a few thousand years of soil production, at most. This time frame is orders of magnitude shorter than the basalt age, challenging the prevalent assumption that the soils form a chronosequence. Our findings strongly suggest that erosion is a significant factor controlling soil formation and accumulation on the plateau, despite the generally flat morphology of the Golan Heights. The erosion is associated with tectonic activity along the Dead Sea transform, with the development of the Kinarot and Hula valleys, and with the consequential development of drainage systems of various sizes on the plateau. Throughout the Golan Heights, the timing of volcanic activity in relation to the development of the valleys and drainage systems also appears to strongly affect soil development and accumulation. [ABSTRACT FROM AUTHOR]

AbstractThe Canary Islands are a Spanish archipelago of volcanic origin in the Atlantic Ocean near the Saharan coast. The extensive intricacy and multitude of variables inherent in the Canary Islands winemaking tradition have posed a substantial challenge, preventing comprehensive research on the main factors contributing to the character of local wine, thus, far. This challenge arises from a convergence of factors including the presence of 14 different grape varieties, and radically different climatic, soil and geographic conditions. This investigation sought to start unraveling this complexity by discerning the impacts of various geographical (specifically, island-related) and management factors (namely, organic vs. conventional practices) on soils and wines within the Canary Islands. Additional variables, such as wine type (red and white) and island of origin, were explored and correlated with the chosen management system. Pairs of organic and conventional wine and soil samples, possessing similar characteristics, were systematically collected from each of the seven wine-producing islands in the Canary archipelago. An examination of elemental composition, oenological attributes and fertility parameters was conducted, followed by comprehensive statistical analysis. Among the variables examined, only the island of origin emerged as statistically significant within the sample. Concerning soil fertility, organic samples exhibited elevated levels of organic matter compared to their conventional counterparts. No notable disparities were observed between the two production methods in terms of soil metal composition and other fertility parameters. However, it is noteworthy that four soil samples surpassed the legally permissible limits for Nickel (Ni) and Mercury (Hg), with three of these instances originating from Lanzarote.

At many dormant volcanoes, magmatic gases are not channeled through preferential degassing routes as fumaroles and only percolate through the flanks of the volcano in a diffuse way. This type of volcanic gas emission provides valuable information, even though the soil matrix contains an important atmospheric component. This study aimed to demonstrate that chemical ratios such as He/CO2 in soil gases provide excellent information on the evolution of volcanic unrest episodes and help forecast the volcanic eruption onset. Before and during the occurrence of the October 2011–March 2012 submarine of El Hierro, Canary Islands, more than 8500 soil He analyses and diffuse CO2 emission measurements were performed. The results show that the soil He/CO2 emission ratio began increasing drastically one month before eruption onset, reaching the maximum value 10 days before. During the eruptive period, this ratio also showed a maximum value several days before the period with the highest magma emission rate. The He/CO2 ratio was also helpful in forecasting the eruption onset. We demonstrate that this tool can be applied in real-time during volcanic emergencies. Our results also encourage a reevaluation of the global He emission from the subaerial volcanism. [ABSTRACT FROM AUTHOR]

Volcanic lava is an excellent model of primary succession, in which basalt-associated microorganisms drive the cycling of different elements such as nitrogen, carbon, and other nutrients. Microbial communities in volcanic soils are of particular interest for study on the emergence and evolution of life within special and extreme conditions. The initial processes of colonization and subsequent rock weathering by microbial communities are still poorly understood. We analyzed the soil bacterial and fungal communities and diversities associated with lava (LBL) and kipuka (BK) sites in Wudalianchi using 16S and ITS rRNA Illumina Miseq sequencing techniques. The results showed that soil physical and chemical properties (pH, MC, TOC, TN, TP, AP, DOC, and DON) significantly differed between LBL and BK. The Shannon, Ace, and Pd indexes of fungi in the two sites showed a significant difference (p < 0.05). The dominant bacterial phyla forming communities at LBL and BK sites were Acidobacteria, Proteobacteria, Actinobacteria, and Basidiomycota, and their differences were driven by Gemmatimonadetes and Verrucomicrobia. The dominant fungal phyla of LBL and BK sites were Ascomycota, Zygomycota, and Rozellomcota, which differed significantly between the two sites. The microbial communities showed extremely significant differences (p < 0.05), with MC, pH, and nitrogen being the main influencing factors according to RDA/CCA and correlation analysis. Microbial functional prediction analysis across the two sites showed that the relative abundance of advantageous functional groups was significantly different (p < 0.05). The combined results drive us to conclude that the volcanic soil differences in the deposits appear to be the main factor shaping the microbial communities in Wudalianchi (WDLC) volcanic ecosystems. [ABSTRACT FROM AUTHOR]

Mineral preservation and microbial residue production are vital for the accumulation of mineral‐associated organic carbon (MAOC) in soils. However, their relative importance and interactive effects remain unclear. Here MAOC content and composition are analyzed in tandem with soil mineral and microbial attributes along a weathering gradient on a volcanic soil sequence. We find that MAOC content increases with increasing mineral weathering states, accompanied by increasing microbial contribution to MAOC. Mineral attributes rather than microbial physiological traits are strongly related to MAOC contents, suggesting that weathering‐enhanced mineral preservation capacity overrides microbial residue production in governing MAOC accumulation by increasing reactive minerals. Furthermore, mineral attributes have a strong interactive effect with microbial traits on MAOC accumulation and composition, likely related to increasing fungal abundance in the microbial community with increasing weathering. These findings highlight that mineral weathering may effectively boost persistent SOC in synergy with microbial conversion in the long term. Plain Language Summary: The accrual of mineral‐associated organic carbon (MAOC) is one of the key mechanisms promoting the long‐term sequestration of atmospheric CO2 into soil organic carbon (SOC). Both microbial residue production and mineral preservation are vital for MAOC accumulation. However, their relative importance and interactive effects remain unclear, hampering our ability to understand how to effectively increase this important pool of persistent SOC. Here by analyzing MAOC content and composition in tandem with soil mineral and microbial attributes along a weathering gradient on a volcanic soil sequence (290 years–2.1 million years ago), we find that MAOC content increases with increasing weathering states, accompanied by increasing microbial contribution to MAOC. In contrast to short‐term studies where microbial residue production predominantly influences MAOC accumulation, weathering‐enhanced mineral preservation capacity overrides microbial residue production in governing MAOC accumulation in the long term by increasing reactive minerals. Furthermore, mineral attributes have a strong interactive effect with microbial traits on MAOC accumulation and composition, likely by enhancing the accumulation efficiency of microbial residues via affecting the microbial community composition. Our findings highlight mineral weathering may effectively boost persistent SOC pools in synergy with microbial conversion. Key Points: The relative importance of mineral versus microbial attributes and their interactive effects in MAOC accumulation was comparedWeathering‐enhanced mineral preservation overrode microbial residue production in governing MAOC accumulation over the weathering gradientMineral weathering strengthened microbial contribution to MAOC via affecting microbial community composition [ABSTRACT FROM AUTHOR]

The size and distribution of home ranges reflect how individuals within a population use, defend, and share space and resources, and may thus be an important predictor of population‐level dynamics. Eruptive species, such as the house mouse in Australian grain‐growing regions, are an ideal species in which to investigate variations in space use and home range overlap between stable and outbreaking populations. In this study, we use spatially explicit capture–recapture models to explore if space use and home range overlap among female mice could serve as indicators of changes in population density leading into summer. Additionally, we assess the sensitivity of space use and home range estimates to reduced recapture rates. Our analysis did not reveal variations in the spring spatial organisation of female mice based on existing capture–mark–recapture data. However, our study highlights the need to balance monitoring efforts within regions, emphasising the importance of exploring studies that can improve spatial recaptures by optimising trapping efforts. This is particularly important in Australian agricultural systems, where varying farm management practices may drive differences in population dynamics. [ABSTRACT FROM AUTHOR]

Rajmahal traps are part of the Rajmahal–Bengal–Sylhet (RBS) Province formed during the Early Cretaceous by the magma plume activity of the Kerguelen hotspot. The hills of Rajmahal are famous for their geological features like columnar basalt, intertrappean beds, fossils of a rich diversity of flora, pyroclastic materials, and many other volcanic features associated with volcanic traps and fossilized floral remains common in intertrappean beds of Rajmahal volcanic province. One such popular feature that attracts tourists and researchers is rice and cereal-shaped silica grains common in wells and ponds of the Kathghar and Taljhari areas of Rajmahal. Although commonly mistaken for fossilized floral remains (of rice or cereal), they are amygdaloidal silica occurring as vesicle fillings in pitchstones. The pitchstones are the product of violent volcanic eruptions during the initial phase of Rajmahal volcanism. Here, we propose a hypothesis that elucidates the origin and occurrence of these rice-shaped silica grains. [ABSTRACT FROM AUTHOR]

Effects of global warming on soil organic carbon (C) can be investigated by comparing sites experiencing different temperatures. However, observations can be affected by covariance of temperature with other environmental properties. Here, we studied a thermal gradient in forest soils derived from volcanic materials on Mount Taranaki (New Zealand) to disentangle the effects of temperature and reactive minerals on soil organic C quantity and composition. We collected soils at four depths and four elevations with mean annual temperatures ranging from 7.3 to 10.5 °C. Soil C stocks were not significantly different across sites (average 162 MgC ha−1 to 85 cm depth, P >.05). Neither aluminium (Al)-complexed C, nor mineral-associated C changed significantly (P >.05) with temperature. The molecular characterisation of soil organic matter showed that plant-derived C declined with increasing temperature, while microbial-processed C increased. Accompanying these changes, soil short-range order (SRO) constituents (including allophane) generally increased with temperature. Results from structural equation modelling revealed that, although a warmer temperature tended to accelerate soil organic C decomposition as inferred from molecular fingerprints, it also exerted a positive effect on soil total C presumably by enhancing plant C input. Despite a close linkage between mineral-associated C and soil organic C, the increased abundance of reactive minerals at 30–85 cm depth with temperature did not increase soil organic C concentration at that depth. We therefore propose that fresh C inputs, rather than reactive minerals, mediate soil C responses to temperature across the thermal gradient of volcanic soils under humid-temperate climatic conditions. [ABSTRACT FROM AUTHOR]

The present study aims to assess soil quality and potential health risks associated with soil pollution of the Batala region of Punjab, India. Physico-chemical parameters such as pH (6.69–7.43), electrical conductivity (0.17–0.33 mS/cm), and total organic carbon (1.01–5.94%) were observed to be within permissible limits. The maximum mean content (mg/kg) of heavy metals in soil was found as Fe (4060.93), Zn (444.33), Mn (278.5), Pb (23.16), Cu (21.78), Ni (20.16), Co (7.14), and Cd (1.85) which were below the prescribed limits but beyond the geochemical background limits of world soil. For rice grain samples, metal content (mg/kg) was seen as Fe (307.01) > Zn (12.41) > Mn (7.43) > Cu (4.57) and was below the permissible limits. The mean bioaccumulation factor for various metals was in the order as Zn > Cu > Fe > Mn. Single and integrated soil pollution indices revealed that among 18 sites, six were highly contaminated. The ecological risk index (Er) has shown that contamination of soil with Cd, Zn, and Ni was higher than that of other metals studied. The estimated daily intake of metal (EDI), hazard quotient (HQ), and hazard index (HI) were higher for children than those for adults. Spatial variability based on metal pollution load and soil quality was also determined using cluster analysis (CA) and principal component analysis (PCA). During CA, soil samples from 18 sites formed three statistically significant clusters based on the level of metal pollution at the specific site. PCA showed that all variables were reduced into two main components 1 and 2 with eigenvalues as 3.82 (47% variance) and 1.53 (19.7% variance), respectively. Spatial distribution and source identification of metal contaminants in the soil and rice grain samples: a study on exploration of soil quality and risk assessment [ABSTRACT FROM AUTHOR]

To extract climatically relevant chemical signals from the deepest, oldest Antarctic ice, we must first understand the degree to which chemical ions diffuse within solid ice. Volcanic sulfate peaks are the ideal target for such an investigation because they are high amplitude, short duration (~3 years) events with a quasi-uniform structure. Here we present analysis of the EPICA Dome C sulfate record over the last 450 kyr. We identify volcanic peaks and isolate them from the non-sea salt sulfate background to reveal the effects of diffusion: amplitude damping and broadening of peaks in the time domain with increasing depth/age. Sulfate peak shape is also altered by the thinning of ice layers with depth that results from ice flow. Both processes must be simulated to derive effective diffusion rates. This is achieved by running a forward model to diffuse idealised sulfate peaks at different rates while also accounting for ice thinning. Our simulations suggest a median effective diffusion rate of sulfate ions of 2.4 ± 1.7 x 10-7 m2 yr-1 in the Holocene ice, slightly faster than suggested by previous work. The effective diffusion rate observed in deeper ice is significantly lower, and the Holocene ice shows the highest rate of the last 450 kyr. Beyond the Holocene, there is no systematic difference between the effective diffusion rates of glacial and interglacial periods despite variations in soluble ions concentrations, dust loading and ice grain radii. Effective diffusion rates for 40 to 200 ka are relatively constant, on the order of 1 x 10-8 m2 yr-1. Our results suggests that the diffusion of sulfate ions within volcanic peaks is relatively fast initially, perhaps through the inter-connected vein network, but slows significantly after 40 kyr. In the absence of clear evidence for a controlling environmental factor on sulfate diffusivity with depth/age, we hypothesize that the rapid decrease in diffusion rate from the time of deposition to ice of 50 ka age may be due to a switch in the mechanism of diffusion resulting from the changing location of sulfate ions within the ice microstructure. [ABSTRACT FROM AUTHOR]

Environmental monitoring by measuring topsoil's magnetic and electrical properties is one practical, quick, and low-cost approach. This method has been used worldwide as a proxy for the presence of potentially toxic elements. However, additional research must be conducted on diverse soil types, geology, and climates. We determined the magnetic and electrical properties of urban and agricultural topsoils in a volcanic region and analyzed them as possible proxies of potentially toxic elements for environmental monitoring. To identify topsoil characteristics, we employed the measurements of magnetic susceptibility and hysteresis, electrical conductivity, total dissolved solids, power of hydrogen (pH), particle morphology, and element contents that were statistically analyzed to identify relevant properties. The result was able to differentiate volcanic soils from urban, industrial, and agricultural areas as well. The value of low-frequency magnetic susceptibility (χLF) in soils from urban areas is higher than 866.0±249.9 ×10−8 m3 kg−1, while the value of χLF in agricultural areas is 208.0±67.8 ×10−8 m3 kg−1. This is reinforced by the relationship between low-frequency and frequency-dependent magnetic susceptibility (χLF-χFD%) in samples from urban areas that fall within the same cluster dominated by coarse-grained magnetic minerals originating from anthropogenic processes. In contrast, the agricultural area forms a separate cluster primarily influenced by pedogenic processes from acid igneous rock minerals. Caution is required for interpreting the magnetic signal due to the high contents of lithogenic magnetic particles inherited from the parent materials of Andisols. [ABSTRACT FROM AUTHOR]

Double ridges are sprawling features observed globally across the icy surface of Europa. They consist of two topographic highs flanking a trough. The topographic relief of the ridges is approximately 100 m, and the ridges extend up to hundreds of kilometers in length. The interior structure and dynamics of Europa's ice shell are currently poorly constrained. Therefore, accurate models for the formation of these prominent surface features can be useful for determining how the ice shell operates. We hypothesize that double ridges form as a result of incremental ice wedging. We use both analytical and numerical finite element models to quantify the deformation that occurs as an ice wedge grows incrementally within the ice shell. We show that incremental growth of the ice wedge results in surface deformation that matches the size and shape of typical Europan double ridges, including their topographic relief and surrounding troughs. We find that as the depth of the ice wedge increases, double ridges become broader and shorter. We explore the possibility of local and non‐local sources for the liquid water that freezes to produce the wedge and ultimately argue in favor of local sources of liquid water within the ice shell. Plain Language Summary: Europa, the second Galilean satellite, is hypothesized to have a global salt‐water ocean underneath its outer icy shell. Double ridges are a common feature on Europa's icy surface. They consist of a long trough bordered on either side by uplifted hills of ice. The height of the ridges above the surface is approximately 100 m, and the ridges may extend for hundreds of kilometers over the surface of the moon. Models that show how surface features, like double ridges, may form can tell us about characteristics of the ice shell and underlying ocean that are otherwise hard to measure. We use two different techniques to model a process for how double ridges might form. In this process, water, possibly from the subsurface ocean, enters a long vertical crack in the ice shell and freezes along the sides of the crack. Over time as water continues to enter and freeze in the same place, a new wedge of ice grows inside the ice shell and pushes on material around it. The ice wedge forces ice at the surface of the shell to deform into the same size and shape of double ridges that have been observed on Europa. Key Points: Numerical modeling suggests that double ridges are produced by wedges of ice that grow within Europa's ice shellAnalytical and numerical models show that an ice wedge within Europa's ice shell elastically deforms the surface into double ridgesIce wedge material may be sourced from the ocean or locally from cryovolcanic dikes or water reservoirs within the shell [ABSTRACT FROM AUTHOR]

The contribution of sediment transport and accumulation to soil formation was investigated in an area characterized by continental sedimentary activity since the Late Pleistocene. The area was the north-eastern portion of the large Quaternary graben represented by the Campania Plain, which is rimmed to the north–east–south by the Mesozoic carbonate Apennine nappes. The plain was filled mainly by products generated by eruptions from the Phlegrean Fields, which were also distributed on the slopes bordering the plain and remobilized toward the adjacent surfaces. Five sites were selected in the area in question. They were studied using morphological features and pertinent characteristics of the mineral soil fraction >2.0 mm, such as their volume and lithological description. Soils were compared to selected lithostratigraphic sequences characterizing the studied area, which were collected from literature and reinterpreted in pedological keys. The results showed that soils derived from the emplacement of Phlegrean primary volcanic materials, such as Campania Ignimbrite (~39–40 ky B.P.) and Neapolitan Yellow Tuff (~15 ky B.P.), with the related weathering products, and from volcanic materials reworked and transported by alluvial/colluvial episodes. The latter formed contrasting soil horizons which, differing in both rock fragment content and lithological composition, testified to the presence of lithological discontinuities. The formation of the horizons in question interrupted the genetic sequence derived from the in situ alteration of the volcanic substrata, suggesting that processes of transport and redistribution of sediments from the adjacent mountain slopes contributed to soil formation. The comparison of the pedostratigraphies with the lithostratigraphic sequences indicated a strong relation between geomorphic and pedogenetic events.

The evolution of multifractal structures in physical processes, for instance, climatology, seismology or volcanology, contributes to detecting changes in the corresponding phenomena. The evolution of the multifractal structure of volcanic emissions of low, moderate, and high energy (Colima, México years 2013-2015) contributes to this research to detect quite evident signs of the immediacy of possible dangerous emissions of high energy close to 8.0x108 J. These signs are manifested by the evolution of six multifractal parameters: the central Hölder exponent (α0), the maximum and minimum Hölder exponents (αmax, αmin) the multifractal amplitude (W= αmax-αmin), the multifractal asymmetry (γ = [αmax-α0]/[α0- αmin]) and the complexity index, CI, which is defined as the addition of normalised values of α0, W and γ. The results of the adapted Gutenberg-Richter seismic law to volcanic emissions of energy, as well as the corresponding skewness and standard deviation of the volcanic emission data, also contribute to confirming the results obtained using multifractal analysis. The obtained results, based on multifractal structure, adaptation of Gutenberg-Richter law to volcanic emissions, and basic statistical parameters, could be assumed as relevant to prevent a forthcoming volcanic episode of high energy, which could be additionally quantified by an appropriate forecasting algorithm. [ABSTRACT FROM AUTHOR]

Crop rotations with residue incorporation can be beneficial to the sustainability of agriculture, however as long-term studies are required to determine effects on soil properties, farmers usually don't practice crop rotations. The objective of this study was to evaluate the effects of crop rotations with residue incorporation (0%, 50%, 100%, and 200%) on soil chemical properties of a volcanic soil after 4 years of cultivation. The evaluated rotations were canola (Brassica napus L.)-bread wheat (Triticum aestivum L.), canola-durum wheat (Triticum turgidum L.), canola-corn (Zea mays L.), bean (Phaseolus vulgaris L.)-bread wheat, bean-durum wheat, and bean-corn. The experiment consisted of six crop rotations, four levels of residue incorporation, and four replicates, analyzed as split-plot design. Samples were taken from the topsoil, and the following soil chemical properties were evaluated: pH, organic matter, electrical conductivity, nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), aluminum (Al), and sulfur (S). The results showed that crop rotations affected all the chemical properties evaluated, whereas the level of residue incorporation only affected the concentrations of exchangeable Mg and K. Most of the evaluated crops rotations had beneficial effects on the soil properties. The canola-durum wheat crop rotation recorded the lowest values in OM, available N and the exchangeable Ca, Mg, and Na. Exchangeable Mg and K had a directly proportional relationship with the level of residue incorporation. In conclusion, the incorporation of residues in different doses during 4 years of crop rotation in this volcanic soil had little effect on its chemical properties. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are a significant threat to soils. However, there is scarce information on the impact of MPs on soil properties, particularly in volcanic ashderived soils. The objective of this study was to evaluate the impact of polyamide (PA) and low-density polyethylene (LDPE) MPs on the biological and chemical characteristics of an Andisol from central Chile. Twenty-one parameters were evaluated, including pH, electrical conductivity (EC), total organic carbon (TOC), dissolved organic carbon (DOC), total phosphorus (TP), available phosphorous (AP), available nitrogen (AN), inorganic nitrogen forms (NH4 +, NO2 - and NO3), carbohydrates (CHO), polyphenols (POLs), humic substances, soil basal respiration (SBR) and activities of soil enzymes such as dehydrogenase, ß-glucosidase, phosphatase and urease. For this, a microcosm was set up in clay pots in an incubation chamber at 21°C and 60% soil moisture, with the addition of PA and LDPE at doses of 1% and 3% w/w; a control treatment consisting of microcosm without MPs was also included. After 6 weeks of incubation, PA addition resulted in an increase in TOC and NH4 + by up to 32% and 26%, respectively, and a decrease in NO3 - by 22%. AP decreased by 15%-19% with the addition of PA and LDPE. Similarly, acid phosphatase and ß-glucosidase activities decreased by 15% and 26% with PA and LDPE, respectively. The distance-based linear model (DistLM) was used to analyse relationships in chemical and biological datasets. The analysis revealed that TOC and TP were primary components in the best model for predicting microbiological changes (R2 = .469, AICs = 16.026), indicating that MPs accumulation affects soil carbon cycling and P content. Overall, the results show that MPs addition alters soil chemical and microbiological properties in Andisols, with varying effects depending on the type and dose of MPs, with the highest dose (3%) producing the most marked negative effects. [ABSTRACT FROM AUTHOR]

Debris flow disasters were caused by surface erosion with high rainfall, especially in mountain villages on the island of Bali. This research aims to understand the stability behavior of volcanic soil due to physical and mechanical conditions based on numerical analysis with Plaxis 3D software. The experiment was used by planting in a test box in the form of a steel frame and equipped with a rainfall simulator to determine slope stability due to planting a combination of elephant grass and vetiver. Numerical results for volcanic soil conditions without vegetation show a soil tension of 0.6854 kN/m2. Model results after four days, there was a decrease of 0.0001m, and after 33 days there was a decrease of 0.0000064 m for the slope 45°. The safety factor of slopes without vegetation is 0.8, so this condition has the threat of landslides and surface erosion. Experimental results show that adding elephant grass combined with vetiver grass can reduce erosion by 94.6% on slope 45o and 92.67% on slope 60o. The effectiveness of the resulting runoff reaches 55.48% on slope 45o and 53.89% on slope 60o. This increase in effectiveness was caused by the development of elephant grassroots, which spread horizontally, thereby increasing the bond with the top layer of soil. [ABSTRACT FROM AUTHOR]

The progressive influx of engineered nanoparticles (ENPs) into the soil matrix catalyses a fundamental transformation in the equilibrium dynamics between the soil and the edaphic solution. This all-encompassing investigation is geared towards unravelling the implications of an array of ENP types, diverse dosages and varying incubation durations on the kinetics governing Cd2+ sorption within Ultisol soils. These soils have been subjected to detailed characterizations probing their textural and physicochemical attributes in conjunction with an exhaustive exploration of ENP composition, structure and morphology. To decipher the intricate nuances of kinetics, discrete segments of Ultisol soils were subjected to isolated systems involving ENP dosages of 20 and 500 mg ENPs·kg−1 (AgNPs, CuNPs and FeNPs) across intervals of 1, 3 and 6 months. The comprehensive kinetic parameters were unveiled by applying the pseudo-first-order and pseudo-second-order models. At the same time, the underlying sorption mechanisms were studied via the intra-particle diffusion model. This study underscores the substantial impact of this substrate on the kinetic behaviours of contaminants such as Cd, emphasizing the need for its consideration in soil-linked economic activities and regulatory frameworks to optimize resource management. [ABSTRACT FROM AUTHOR]

Background: There are few reports of crop rotations with high residue incorporation in terms of their effects on indicator crop yields and soil properties, so this study evaluated the effect of two medium-term biannual rotations on wheat yield development and soil chemical properties after six years of rotation. Methods: The experiment was conducted with two biannual rotations (canola–wheat and bean–wheat) and four residue incorporation levels (0%, 50%, 100%, and 200%) in an Andisol in south central Chile. Wheat grain yield and residue production were evaluated during each biannual cycle during three cycles of crop rotation, and soil chemical properties were evaluated at final evaluation. Results: The use of beans as a wheat preculture partially improved grain yield in 7.3%. The chemical properties of the soil showed an increase in pH (0.08 units), organic matter content (15 g kg−1), and concentrations of P (2.8 mg kg−1), S (7.4 mg kg−1), and Al (0.03 cmol+ kg−1) after canola cultivation, while after bean cultivation there was an increase in the available N concentration (3.7 mg kg−1). The use of increasing doses of residue allowed for an increase in the soil pH and decrease in the exchangeable Al concentration. Conclusion: The continuous incorporation of the residues produced within the biannual rotations evaluated in this volcanic soil did contribute to improving some chemical properties of the soil without affecting wheat crop yield. [ABSTRACT FROM AUTHOR]

Volcanic soils are well-known to have a high agronomical value, and in Sumatra, Mt. Kerinci volcanic soils produce one of the highest quality tea and rice. Declining soil organic carbon (C) and high phosphorus (P) retention are two main issues in volcanic soils in the area. Thus, this study aimed to study the dynamic of C) and P content in volcanic soils and to find the main controls of their variation from geochemical signatures. The soils of Mt Kerinci present a unique environment as one part of the area was converted from forest to tea plantation for about 100 years, and a nearby field had been used for paddy rice cultivation for about 200 years. The study was conducted in the Mt Kerinci area covering 5,922 ha in the north comprise of paddy soils (ps) and north tea soils (nts) and the south slope (south tea soils= sts). Soil samples were collected on a grid of 500 × 500 m under tea and paddy (n = 206 samples) at 0–20 and 20–40 cm depth. All soils have similar pH in H2O, but pH in KCl paddy soils (ps) > north tea soils (nts) > south tea soils (sts). The average content of soil organic Carbon (SOC) in paddy soils was 50% less than in the soils of tea plantations. The labile organic carbon content in paddy soils were lower than in soils of tea plantations. Most C was chemically bound to the metal complex. Higher P retention occurred in all soils. The CaO/TiO2 index indicated a weathering sequence of ps > nts > sts. Soil weathering controlled P retention with an increasing P retention as the soils weathered. Overall, the study suggests that cultivation in volcanic soils influenced the geochemical properties of the soils and subsequently their C and P contents. [ABSTRACT FROM AUTHOR]

Pedogenesis of volcanic soils has been studied broadly in humid regions, but very little data are present regarding these soils in arid and semi-arid regions of Turkey. This research aimed to assess the pedological processes and investigate the physical, chemical, and mineralogical characteristics of soil profiles developed from volcanic parent material. The studied soils were not classified as Andisol because they lack andic properties. The results showed that sand and coarse silt fractions exceeded 30%. The bulk density was higher than 0.90 grcm-3 in all profiles. In general, phosphate retention was low, higher than 25% in profiles but lower than 85% in all profiles. The Al + 1/2 Fed percentages were lower than 2% in all profiles. Selective extraction (Na-Pyrophosphate, Ammonium Oxalate, Na-Dithionite) indicated that soils lack noncrystalline minerals, such as allophane, imogolite, and iron humus complexes. The only noncrystalline minerals in high quantities are Al-humus complexes and small amounts of ferrihydrite. X-ray diffraction indicated that smectite, kaolinite and illite were dominant minerals in the clay fraction. Among the studied profiles, profiles 1 and profile 4 are classified as vitrandic Haploxerept, profile 2 as vitrandic haploxerolls, and profile 3 as vitrandic Xerorthent. The results indicated that the dominant soil-forming processes include the following: 1. desilication and the eluviations of base cations and Al from the solum; and 2. transformation of iron and aluminum from the sand and silt-size fractions into secondary clay and crystalline Fe minerals. The major factors determining soil genesis on Mt. Karacadağ appear to be climate and topography affected by the leaching regime and weathering rates. [ABSTRACT FROM AUTHOR]

Phosphorus is a key plant nutrient linked to plant growth during the early stages of primary succession in volcanic soils. Available phosphorus is thought to include soil and atmospheric phosphorus, but it is not well understood. Here, we focused on deposition as a potential phosphorus source. We evaluated the contribution of deposition to phosphorus uptake and growth in Fallopia japonica, a key pioneer species of primary succession. When we experimented with growing F. japonica under field conditions, F. japonica not covered by a roof absorbed more phosphorus than that covered by the roof, suggesting the influence of total (dry + wet) deposition. Furthermore, we tested the effects of deposition by treating F. japonica seedlings with wet deposition or distilled water in six volcanic soils. Plants that received the wet deposition treatment exhibited higher phosphorus contents and growth rates than those treated with distilled water. The phosphorus from wet deposition and the phosphorus from soil contributed nearly equally to F. japonica development. Our findings suggest that F. japonica grows during primary succession and builds up the phosphorus cycle by absorbing a trace amount of phosphorus from deposition and volcanic soils. [ABSTRACT FROM AUTHOR]

The study of effects of particle breakage on the mechanical properties of soil composed of porous particles is challenging due to the heterogeneity of the shape and inner void structure of individual particles, even for an identical soil sample, which imparts a compound effect on the mechanical properties. Advancements in three-dimensional (3D) printing technique have enabled the replication of objects with the same shape but different inner structures. This study investigated the feasibility of replicating porous and non-porous particles with the same particle shape characteristics, such as form, waviness, and texture, using 3D printing technique. The particle shape characteristics were evaluated using image analysis. Single particle crushing and triaxial compression tests were conducted to characterize the mechanical properties of the 3D printed and porous volcanic soil particles. It is observed that the mechanical response in the single particle crushing test varies for volcanic soil, which may be attributed to the heterogeneity in the shape and porosity of the particles. However, for each type of 3D printed particle, the response has a high repeatability and varies based on particle porosity. Furthermore, the effects of porosity on the shear response are demonstrated through triaxial tests on 3D printed particles of different porosities. It is noted that although a quantitative comparison is not possible, a qualitative similarity is observed in the response of the 3D printed porous particles with natural porous volcanic soil. Thus, insights into the mechanical response of porous particles can be gained using 3D printed particles. [ABSTRACT FROM AUTHOR]

The hydrobiological diversity in the basin depends on biotic and abiotic factors. A predictive model of hydrobiological diversity for periphyton and macrobenthos was developed through multiple linear regression analysis (MLRA) based on the physicochemical parameters of water (PPW) and metal content in sediments (MCS) from eight monitoring stations in the Asana-Tumilaca Basin during the dry and wet seasons. The electrical conductivity presented values between 47.9 and 3617 μS/cm, showing the highest value in the Capillune River due to the influence of geothermal waters. According to Piper's diagram, the water in the basin had a composition of calcium sulfate and calcium bicarbonate-sulfate. According to the Wilcox diagram, the water was found to be between good and very good quality, except for in the Capillune River. The Shannon–Wiener diversity indices (H′) were 2.62 and 2.88 for periphyton, and 2.10 and 2.44 for macrobenthos, indicating moderate diversity; for the Pielou's evenness index (J′), they were 0.68 and 0.70 for periphyton, and 0.68 and 0.59 for macrobenthos, indicating similar equity, in the dry and wet seasons, respectively, for both indices. In the model there were three cases, where the first two cases only worked with PPW or MCS, and case 3 worked with PPW and MCS. For case 3, the predicted values for H′ and J′ of periphyton and macrobenthos concerning those observed presented correlation coefficients of 0.7437 and 0.6523 for periphyton and 0.9321 and 0.8570 for macrobenthos, respectively, which were better than those of cases 1 and 2. In addition, principal component analysis revealed that the As, Pb, and Zn contents in the sediments negatively influenced the diversity, uniformity, and richness of the macrobenthos. In contrast, Cu and Cr had positive impacts because of the adaptation processes.