Granite Substrates Research Articles

Weight and structural considerations of potential green roof growth: Media compositions for the Nigerian building industry

Abstract The principal objective of this paper was to assess the physical properties and weight or structural implications of some potential green roof growth media compositions practicable for use in the Nigerian built environment. The study carried out an essential selection of material constituents of growth media blends mixed in a 3:1:1 ratio of natural stone-based gravels, soil and compost respectively. Six substrate blends based on later-ite stones, ory and empirical field evaluation methods. The results revealed that the granite-based blend is the heaviest sample with 1,713.30 kg/m3 in its saturated state, while the lightest in weight is the pumice blend with 869.30 kg/m3 which is 50.7% less than the granite blend. The heaviest and the lightest outlined models were subsequently subjected to a weight analysis on a proposed reinforced concrete flat-roofed structure. The results showed that all the extensive green roof samples fall within the IBC stipulated range. The heaviest granite substrate obtained a design load of 0.951 kN/m2, while the lightest pumice blend recorded a design load of 0.576 kN/m2. Hence, it stands to offer an optimum alternative in green roof retrofitting projects for existing flat-roofed buildings. The study, therefore, submits that all samples evaluated involve readily available materials in the studied area and can be used with respect to their characteristic properties as presented in this study. It also serves as a reference point for all stakeholders in the research and building construction industry in Nigeria and beyond.

Insight into immobilization mechanism of nuclear waste management by granite: Impact of waste chemical species

Nuclear waste immobilization is one of the ways to alleviate the harm of radioactive waste produced in the nuclear field to human beings and the environment. In the current study, granite was utilized as a substrate material for the immobilization of simulated radioactive waste. Based on the obtained results, the relationship between the waste chemical species and the physicochemical properties, such as solid-solubility of waste, infrared, density and leaching data, was systematically studied as well. The findings indicate that the granite substrate used for the immobilization of the simulated waste (Nd2O3) exhibits a solid-solubility limit of 27 wt%. When the added content of waste is below 27 wt%, all Nd elements are immobilized into the glassy phase. However, when the waste content exceeds 27 wt%, in addition to being immobilized in the glassy phase, the presence of Nd2O3 reacted with Ca3Si3O9 to form Ca2Nd8(SiO4)6O2. As the Nd2O3 content increased from 20 wt% to 25 wt%, the microstructures related to Si-, Al-, and Fe-are more involved in the immobilization of waste. However, the appearance of Ca2Nd8(SiO4)6O2 and Nd2O3 makes the density and Vickers hardness of the matrix not increase further. The maximum density and hardness values are 3.17 g cm−3 and 7.88 GPa, respectively. The leaching results show that the cured body has good anti-leaching performance (LRNd = ∼10−6 g cm−2 d−1). Finally, the comparison of vacancy formation energy of Nd in Nd2O3 and Ca2Nd8(SiO4)6O2 proved that the formation of Ca2Nd8(SiO4)6O2 is beneficial to the immobilization of simulated waste. This study provides a certain reference for the selection of nuclear waste solidification substrates. This kind of granite material from nature has the potential advantages of low cost and better immobilization effect on waste, and may be more suitable for the treatment of radioactive waste in the future.

Synecological response of spring benthic prokaryotes and macroinvertebrates to Paleozoic roof pendant‐derived calcium

AbstractDespite the ecological significance of desert springs, little is known about relationships between spring hydrogeochemistry and ecology, particularly over multiple trophic levels. Here, we surveyed microbial communities (bacteria and archaea) and benthic macroinvertebrate (BMI) communities in springs that recharge through granitoid bedrock in Owens Valley, CA, to determine whether subtle geochemical differences imparted by metamorphosed roof pendant weathering in the source area affect spring ecosystems. Relative to other springs, roof‐pendant‐recharged springs were characterized by elevated (1) Ca2+/Na+, Ca2+/Mg2+, and divalent/monovalent cation ratios, (2) relative abundance of taxa inferred to be benthic aerobes and prosthecate/stalked bacteria, and (3) abundance and diversity of shredder and collector gatherer BMIs. These BMI feeding groups graze on biofilm communities and stimulate bacterial degradation of particulate organic matter, consistent with extensive bacteria–BMI connections in co‐occurrence networks in these springs. Springs not impacted by roof pendants were instead enriched with taxa inferred to be anaerobes, chemolithotrophs, and low‐diversity BMI communities with poor bacteria–BMI network connectivity. We speculate that excess Ca2+ derived from roof pendant weathering plays a key role in biofilm formation on coarse granite substrates, with subsequent trophic interactions between benthic microbial biofilms and diverse BMI shredders/collector gatherers.

The use of stable isotopes to identify surface water–groundwater interaction in the Kruger National Park, South Africa

The role of groundwater, in general, is often overlooked in freshwater ecosystem management policies and in the management of South Africa’s flagship conservation area, the Kruger National Park (KNP). To address this gap, a generalised conceptual model of surface water–ground water (sw–gw) interactions in the southern and central regions of the KNP was developed. To do this, stable isotope ratios (d18O and d2H) of groundwater, rainfall and surface water were used to determine the extent to which the base flow of perennial, seasonal and ephemeral streams on different geologies (granite vs. basalt) is driven by rainfall or groundwater. These results show that the δ18O and δ2H ratios of perennial rivers are similar to that of groundwater, while seasonal and ephemeral rivers on basalts have values closer to rainfall. On granite substrates, however, the isotope ratios of the seasonal and ephemeral rivers have values closer to groundwater than rainfall. The larger seasonal Mbyamiti River had similar isotope ratios to that of groundwater, and the highly ephemeral Nwaswitsontso had episodic interaction with groundwater (i.e. isotopic ratios overlap occasionally). These results show that decisions necessary for the sustainable management of groundwater resources are better informed when the natural interaction, movement, and exchange between groundwater and rivers are understood. This has particular relevance for large conservation areas in southern Africa that are expected to experience more variable climates in the future with both increases in drought and rainfall intensities.

Geophysical survey of the Roman and post-Roman site of Proendos, Ribeira Sacra, Lugo, Spain

We present a geophysical survey work in the Roman site of Proendos, Sober, Lugo, Spain, which has been carried out on 27,000 square meters of surface area. From a methodological perspective, two different techniques have been compared on the same plot, Ground-penetrating radar (GPR) and magnetometry, showing the pros and cons of each one in granite substrate environments. The results of the chosen method (GPR) have shown a complex and long-term urban reality, part of which can be placed in the Roman period.

Deterioration of graffiti spray paints applied on granite after a decade of natural environment

Graffiti spray paints are commonly used in contemporaneous mural paintings in public spaces, contributing to the transformation of sites and urban life. These outdoor artworks are now beginning to show different deterioration forms, such as physical-mechanical alteration (loss of material and cohesion, etc.) and chromatic changes. However, the deterioration has not been formally characterized, and the influence of the paint composition and underlying substrate are not known. In this study, three non-metallic (red, blue and black) alkyd graffiti spray paints and one metallic (silver) polyethylene graffiti spray paint were applied to two granite stones with different mineralogy and texture and exposed to a natural urban-marine environment near Vigo (NW Spain) for one decade (2010−2020). Physical changes were evaluated by stereomicroscopy, colour spectrophotometry, measurements of gloss, surface roughness and static contact angle, and peeling test. Mineralogical changes were determined by x-ray diffraction and molecular changes by Fourier transform infrared spectroscopy. Moreover, micromorphological and chemical characterization of the surfaces was conducted by scanning electron microscopy.Physical-mechanical changes, such as craquelure and paint loss, depended on the texture of the granite. More specifically, paint on the granite with the finest grain size showed most intense cracking and loss of material. Chemical changes, which were not related to the granite substrate, were most intense in the red and silver paint coatings. In the red paint, loss of binder was accompanied by an intense fading of the colour (due to titanium dioxide relative enrichment), while in the silver paint coating, chemical changes occurred in both the organic binder and aluminium particles, thus darkening the colour. Fewer chemical changes were observed in the blue and black paints. Physical and chemical changes detected in these paints were not correlated.

Distribution of soil selenium and its relationship with parent rocks in Chengmai County, Hainan Island, China

Chengmai County of Hainan Island has plentiful Se-rich land resources. The distribution of Se-rich land is thought to be closely related to the geological background. However, the relationship between the Se enrichment in soil and the parent rocks remains unclear. The clarification of the relationship will be helpful for the development, management, and exploitation of Se-rich land. This paper studies the controlling effect of the composition and soil-forming process of parent rocks on Se enrichment. The results indicate that the Se content in metamorphic rocks (Se = 0.15–6.61 mg/kg) of the Tuolie Formation is significantly higher than that of other rocks, while there is a slight difference in the Se content between the granite (Se = 0.03–0.70 mg/kg) and basalt (Se = 0.05–0.77 mg/kg). The Se content in the overlying topsoil of different parent rocks is sorted as follows: Tuolie Formation (S1t) > basalt > granite > Quaternary loose accumulation. The comparison of the Se content in the rock and soil, the correlation of the Se-iodine content in the soil, and the mass balance calculation all imply that the enrichment of Se in the topsoil from the Tuolie Formation substrate is closely related to the high-Se content in the Tuolie Formation, while the Se content in the topsoil of basalt and granite substrate is more affected by the external input. The content of Se in the topsoil of basalt is higher than that of granite, which is attributed to its lower w(SiO2), higher w(TFe2O3), w(Al2O3), and organic matter content. The parent rock can indirectly influence the Se content in the overlying soil by altering the process and degree of soil formation.

Edaphic preference determines the distribution of the island endemic Ferocactus gatesii (Cactaceae) in Bahía de los Ángeles, Mexico

The insular endemic Gates barrel cactus, Ferocactus gatesii (Cactaceae) [syn. Ferocactus gracilis ssp. gatesii], is only found on seven islands in Bahía de Los Angeles (BLA), an International Biosphere Reserve in Baja California, Mexico. The islands have different geologic origins; some formed as a result of lava flows, and others by the cooling of magma within the crust. These rock types give rise to different soil physical properties, with F. gatesii only observed growing in granite substrates. This suggests that F. gatesii is in fact an edaphic endemic, restricted to specific soil lithologies on the small islands. Proposed edaphic properties of the preferred granite substrate include controls on soil porosity, permeability, nutrient availability and geomorphic conditions that may influence plant success. Further research is necessary to evaluate the mechanisms of soil property effects on F. gatesii presence and survival, however, recognizing this general pattern is of critical importance to conservation planning, particularly in the face of intensifying environmental stresses from increased aridity, decreasing precipitation, and illegal harvesting. This new information allows us to improve models for potential habitat in an assisted migration scenario and allows insights into the evolutionary processes that resulted in this narrowly endemic species.

Cohesive and adhesive healing evaluation of asphalt binders by means of the LASH and BBSH tests

Abstract Generally, the cohesive healing within the asphalt composites and the adhesive healing from the asphalt-aggregate interface always occur simultaneously in the asphalt concrete with growing damage. This study aims to investigate the cohesive and adhesive healing behaviors of asphalt binder respectively by utilizing the newly developed linear amplitude sweep based healing (LASH) and binder bond strength based healing (BBSH) tests. Seven unmodified asphalt binders and one styrene–butadienestyrene (SBS) polymer modified binder are selected in this study. A fracture mechanics based crack growth approach is proposed to define the cohesive healing recovery in the LASH test with two percent healing parameters, in terms of the %Ha of the crack length recovery and the %HA of the sample intact area recovery. In pre-failure conditions, the measured %Ha can at least reach beyond 30% while the %HA is normally within 30% for tested binders. Meanwhile, the %Ha results show more consistent trends to the traditional simplified-viscoelastic continuum damage (S-VECD) based LASH data interpretation. Furthermore, the cohesive failure occurrence is verified to significantly impact the healing performance comparison. The cohesive healing behaviors of neat and SBS binders respectively in pre-failure and post-failure conditions are distinguished to each other, which are validated either from S-VECD or crack growth approaches. Regarding to the binder adhesive healing behavior, it is observed that the presence of water and the using of granite substrate generally have positive effects on adhesive healing recovery in the BBSH tests. The SBS modification generally displays lower adhesive healing percentages than the neat binders especially in the wet conditions. Though no clear relationships can be found between the cohesive and adhesive healing behaviors in this study, it is recommended to quantify the binder contribution to the adhesive healing process in the future work.

Repair of historic stone pagoda: Flexural behavior of granite reinforced with stainless steel bars

In the stone-made architectural heritage, one of the most widely used stones is granite. Given its superior material properties and abundant reserves, most Korean stone pagodas were built using granite. For the repair and restoration of the ancient stone pagoda made of granite, understanding of the structural behavior of reinforced granite is crucial. In this study, flexure tests for seven simply supported full-scale granite reinforced with stainless steel bars were conducted to investigate the failure mode and load–displacement relationship. Through the experiments, the feasibility of the suggested method for reinforcement of the damaged granite was also explored. Test specimens were manufactured after injecting epoxy resin by inserting stainless steel bars into the drilled holes, and then each granite substrate was bonded with adhesive epoxy resin. The test results showed that the load–displacement relationship of reinforced granite was highly dependent on the presence of the reinforcement, positioning of the reinforcing bars, and bond capacity of the reinforcing bars. Also, reinforcing bars significantly affected the deformation of the reinforced granite. Based on the test results, four distinct flexural responses of reinforced granite are presented.

A comparative study of Epipactis atrorubens in two different forest communities of the Middle Urals, Russia

The objective of this study was to compare eco-physiological and morphological parameters of a regionally endangered orchid species, Epipactis atrorubens (Hoffm. ex Bernh.) Bess., growing in two forest communities (on serpentine and granite outcrops) of the Middle Urals, Russia. Biodiversity, dominance, and phytocoenosis studies showed the colonization of a wide range of plant species on both sites. The physicochemical properties of the soil, chemical composition and morphological features of E. atrorubens, growing under technogenic conditions (asbestos deposits), on serpentine outcrops and in the natural environment of the granite massif were studied for the first time. The serpentine substrate differed from the granite one by its greater stoniness, circumneutral pH and lower contents of available nitrogen and phosphorus. Extremely high concentrations of magnesium were found in the serpentine soil, some 79 times higher than in the granite substrate. High concentrations of nickel (94 times), chromium (59 times), cobalt (17 times), and iron (4 times) were found in the serpentine substrate, higher than in the granite substrate. The differences between the sites for available metal contents and for root and shoot metal contents were significantly less. Concentrations of most of the metals in the roots were higher than in the shoots. Despite higher metal concentrations and lower nitrogen and phosphorus levels in serpentine soils, E. atrorubens had a larger population and greater viability compared to those growing on granite. Plants on serpentine outcrops were characterized by the formation of a larger number of fruits, greater root lengths and thicker leaf blades, compared to plants on granites. The well-developed orchid mycorrhizae contributed to the survival of this species under unfavorable serpentine conditions. Hence, serpentine outcrops formed due to the mining of asbestos could be a suitable substrate for the light-demanding E. atrorubens due to its capacity to adapt to dry, rocky, nutrient-depleted soils and limited competition from other plants.

Lactic acid oligomer (OLLA) grafted gum arabic based green adhesive for structural applications

L-Lactic acid (LA)-grafted-gum arabic (GA) graft copolymer [OLLA-g-GA] was prepared by using microwave heating in which the hydrophilic GA was grafted with insitu grown lactic acid oligomer. The grafting at OH and NH groups in GA backbone with oligo-(l-lactic acid) (OLLA) chains proved with the help of FTIR and NMR analyses. The grafted GA was dispersed uniformly in OLLA due to the formation of amphiphile GA backbone grafted with OLLA chains, which is supported by XRD, SEM and TEM analyses. This synthesized OLLA-g-GA graft copolymer showed adhesive characteristics with various substrates such as glass and granite. The single lap shear joint of two glass and two granite substrates were fabricated and the adhesive properties of these laminated substrates were tested using Universal Testing Machine. The synthesized biobased adhesive showed excellent shear strength with respect to the present biobased adhesives and substrate failure was observed at optimized conditions during the shear test.

Municipal wastewater management using Vetiveria zizanioides planted in vertical flow constructed wetland

This study investigated wastewater management using Vetiveria zizanioides planted in vertical flow constructed wetland (VFCW). Wastewater from the grit removal chamber and the primary sedimentation tank of Daspoort Wastewater Treatment Works was fed into six-pilot VFCW consisting of 1000-L plastic tanks having 500-mm-deep, 10–15-mm-diameter granite substrate planted with V. zizanioides. Irrigation of macrophytes using effluent from the grit removal chamber and primary sedimentation tanks was done after 3 months of planting and the VFCW monitored. Wastewater samples were collected and analysed using standard procedures. The pollution parameters of the initial sample were total alkalinity 297 ± 27.3 mg/L; COD 627 ± 149.0 mg/L; EC 82.53 ± 5.4 ms/m; free and saline ammonia 36.02 ± 4.1 mg/L, nitrate/nitrite 0.09 ± 0.1 mg/L; pH 7.66 ± 0.4; phosphate 3.07 ± 0.3 mg/L, sulphate 44.57 ± 3.1 mg/L; TDS 551 ± 37.8; TSS 319 ± 34.2 mg/L; and TKN 41 ± 6 mg/L. Percentage removal of 89.57, 98.34% TSS; 98.95, 98.62 free and saline ammonia; 89.87, 91.44% TKN; and 80.65, 58.02% COD for screen and settled wastewater, respectively, was obtained from the VFCW. VFCW using locally available V. zizanioides is a viable alternative for municipal wastewater treatment.

The influence of the SO2 ageing on the graffiti cleaning effectiveness with chemical procedures on a granite substrate

Graffiti are one of the most severe threats to Stone Cultural Heritage and are most of the times removed after long periods of environmental exposure. This research intends to evaluate the influence of the ageing of the graffitis on the effectiveness of their cleaning. So, comparative studies on unaged and on artificially SO2 aged samples were conducted. Four graffiti spray colours were applied on a granite stone and cleaned with two chemical commercial cleaners: a solution of KOH and a solution of n-butyl acetate, xylene and alcohol isobutyl. The spray paints (unaged and aged) and cleaning effectiveness were characterized by stereomicroscopy, colour spectrophotometry, adhesion tests, SEM, μEDXRF, XRD and FTIR. The cleaning effectiveness was also evaluated through surface roughness and static contact angle measurements. The alkyd graffiti paints presented greatest resistance under SO2 rich environments than the polyethylene paint. The aged polyethylene paint showed chemical modifications that resulted in graffiti losses and neo formed mineralogical phases in the surface of the paint. After ageing, the paints became more difficult to clean, showed higher global colour changes and higher residue percentages. No significant roughness variations were detected after chemical cleaning. After the cleaning procedures aged surfaces became more water repellent comparatively to unaged and reference samples. The best cleaning effectiveness was mainly achieved with the potassium hydroxide solution.

Assessment of Low-Temperature Cracking in Asphalt Materials Using an Acoustic Emission Approach

Abstract An acoustic emission (AE)-based approach to evaluate low-temperature cracking susceptibility of both asphalt binders and asphalt mixtures is presented. The AE binder testing approach consists of a thin film of asphalt binder bonded to a granite substrate exposed to decreasing temperatures ranging from 20°C to −50°C. Because of the differential thermal contraction between the granite substrate and the asphalt binder, thermal cracks develop in the asphalt binder. The initiation/propagation of these thermal cracks leads to a release of mechanical elastic energy in the material, i.e., acoustic emission activity that is recorded and used in determining the embrittlement temperature of the binder material. The AE-based embrittlement temperature showed excellent correlations with thermal cracking predictions based upon the binder rheological properties. Similar results were also obtained when asphalt concrete mixture samples were exposed to temperatures ranging from 20°C to −50°C. The AE-based approach for low-temperature characterization of binders and asphalt concrete mixtures is a rapid and reliable testing method that yields results with better repeatability (lower coefficient of variation) than the traditionally used methods based upon the binder rheological properties. Current results using AE source location also indicate that the AE approach could be used to quantitative evaluate the effectiveness of rejuvenators on aged asphalt pavements.

Influences of temperature and load on the dry friction behaviour of tire tread compounds in contact with rough granite

The temperature and load dependence of the sliding friction behaviour of a racing tire tread compound on coarse and fine rough granite substrates is analysed by experimental and theoretical techniques. Based on dry friction measurements at different temperatures, friction master curves are constructed by shifting the data horizontally on the velocity axis using the same shifting factors as found from viscoelastic master curves. The obtained isothermal friction curves increase rapidly with increasing sliding velocities and show a more or less pronounced plateau over a broad velocity range, which decreases with increasing load. For analysing this behaviour, the Klüppel and Heinrich theory of rubber friction and contact mechanics is applied, which considers the multi-scale contacts and excitations of the rubber sliding on rough surfaces in the frame of a linear viscoelastic approach. The extension of this theory to more realistic surfaces with two or more scaling ranges is described in some detail. It takes adhesion and hysteresis contributions into account referring to the viscoelastic response of the rubber on different frequency scales. The theory predicts that under isothermal conditions the coefficient of friction decreases with load, which is more pronounced for the adhesion than for the hysteresis contribution. This result is found to be in fair agreement with the measure friction curves confirming the contact mechanical approach of the theory.

Municipal wastewater treatment using sequential activated sludge reactor and vegetated submerged bed constructed wetland planted with Vetiveria zizanioides

This study investigated a sequential system consisting of Biological Nutrient Removal Activated Sludge (BNRAS) and Vegetated Submerged Bed Constructed Wetlands (VSBCW). The BNRAS/VSBCW combination removing pollutants from municipal wastewater in a developing country was examined. Wastewater from the anaerobic, anoxic and aerobic zones of the BNRAS was fed into 12 pilot VSBCW consisting of 1000L plastic tanks having 500mm deep 10–15mm diameter granite substrate planted with Vetiveria Zizanioides. Irrigation of macrophytes using effluent from the BNRAS was done after 3 months of planting and the VSBCW effluent analyzed. Wastewater samples were collected and analyzed using standard procedures. Percentage removal of 96.6, 96.93, and 97.21% of COD; 33.33, 85.71, and 92.48% of Nitrate/Nitrite; 53.51, 46.45, and 88.78% of Sulphate; and 98.34, 99.72, and 99.6% of TSS were obtained from the anaerobic, anoxic and aerobic zones respectively. Removal efficiency from the anaerobic zone effluent was highest during the study period. VSBCW using locally available macrophytes V. Zizanioides in combination with BNRAS was found efficient in municipal wastewater treatment.

Determining the effects of aging on halloysite nano-tube modified binders through the pull-off test method

Aging changes the chemistry of bitumen and this adversely affects bitumen’s adhesion with aggregate. For this reason, the use of pull-off test was proposed to evaluate bitumen’s adhesion during different aging stages. In this study, the pull-off test method is used to evaluate the effects of aging on a 60/70 penetration grade bitumen and binders modified with 2 and 4% halloysite nano-tube (HNT). The short-term aging (STA) and long-term aging (LTA) of unmodified and modified bitumens were simulated using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) tests respectively. The pull-off test was conducted using the universal testing machine (UTM). Stainless steel and granite substrates moulds were designed and fabricated for this purpose. Dry and wet conditions were simulated to evaluate the loss of bonding strength due to aging. Additionally, consistency tests, namely penetration test, softening point test, and viscosity test, were conducted on all binders. The activation energy (AE) for unaged and aged binders were also evaluated. The results for the consistency test; the pull-off test for stainless steel substrate; and the values for AE showed that the addition of the HNT decreased the effect of aging, which means that modified binders showed decreased temperature susceptibility and this is reflected in improved aging resistance. The result of the pull-off test on granite substrate showed that binders modified with HNT performed better under dry and wet conditions. It can be concluded that HNT is an anti-aging as well as anti-striping agent.

Impact of the Former Vineyard Land Use on the Productivity of Secondary Forest Herb Layer in the Little Carpathians (SW Slovakia)

Abstract The Little Carpathians Mountains include a vineyard region with long tradition that dates back up to the Roman Empire period (and according to some opinions, even earlier). In the late 19th century, it was strongly impacted by the phylloxera epidemic, and the vineyard area has significantly reduced here. Large areas of the former vineyards are covered by forests, which mostly have formed spontaneously, but some of them were also planted. This contribution is focused on the impact of the former vineyard land use on the productivity (aboveground, belowground, and total biomass) of such forest herb layer. Research included also the forests, which occupy rocky mounds formed by rock gathering and their placement on the vineyard borders. There were sampled by following four stands, mostly differed by tree composition, origin, age, and succession stage: (i) up to 100 years old spontaneously formed thermophilous acidophilous oak forest on the former vineyard on the granite substrate, (ii) up to 100 years old spontaneously formed oak-dominated forest on the rocky (granite) mounds (borders between the former vineyards formed by rock gathering), (iii) 40–60 years old planted ash stands on the gneiss bedrock, and (iv) 40–60 years old planted ash-dominated stands on the rocky (gneiss) mounds. According to our results, the former land use modified original relief, where the former vineyards have modified soil profile and new relief forms rocky mounds were created. These mounds with no or just shallow soils are usually much less covered by vegetation, thus production of herb layer biomass is lower here than in the adjacent former vineyards. Moreover, rocky mounds show a higher ratio of synanthropic species and apophytes than the adjacent former vineyards, and same as for ratio of therophytes. The younger the stands on the former vineyards, the higher is the ratio of synanthropic species, apophytes, and therophytes. On the other hand, when estimating the production quantity, the values of herb layer production on the former vineyards are similar to those in natural oak-hornbeam forests found in the Little Carpathians Mts. and the adjacent regions, except for the rocky mounds covered by old oak forests, which are less productive. In other words, the former vineyard land use affects the herb layer production quality rather than quantity.

Using isotopes to determine the contribution of volcanic ash to Sr and Ca in stream waters and plants in a granite watershed, Mt. Tsukuba, central Japan

Strontium (Sr) isotope ratios of soils, stream water, plants, and atmospheric precipitation were used to trace calcium (Ca) and to determine the influence of volcanic ash in soils on Ca cycling in forest ecosystems in a small forested watershed on Mt. Tsukuba, central Japan. The 87Sr/86Sr ratios of soils on steep slopes and the valley floor ranged from 0.7110 to 0.7139, which indicates that the major source of Sr was the granite substrate (87Sr/86Sr ratio 0.7120–0.7131). Soils on a ridge had lower 87Sr/86Sr ratios (0.7068–0.7072), indicating that they were mainly composed of volcanic ash materials released around 30,000 years ago from Mt. Akagi (0.7069). The 87Sr/86Sr ratio decreased and the concentrations of Sr (and Ca) increased in stream water with increased elevation from the valley bottom to the ridge, indicating that volcanic ash was the dominant source of both cations in the upstream area. The contributions of volcanic ash-derived Sr to upstream and downstream water were 50 and 0–1 %, respectively. The 87Sr/86Sr ratios of plants were between those of the soils in which the plants were growing and those of atmospheric precipitation (0.7100). More than 74 % of the Sr in plants on the ridge, but <17 % in plants in the valley bottom, was volcanic ash-derived. The origin of Sr (and thus Ca) in stream waters and plants varied depending on the volcanic ash content in soils, which was significantly influenced by the site elevation.