Subalpine Soils Research Articles

The Radioecological Peculiarities of Soil Cover in Mountainous Areas (Kyrgyzstan)

The article presents the results of a radiological study of mountain soils depending on the height above sea level (740 - 760; 1600-1700 and 2000-2500 m above sea level) on the territory of the Kyrgyz Republic. Mountainous areas are characterized by denudation-erosion processes and humus; total nitrogen, gross phosphorus and potassium in the soil cover in mountainous zones are not uniform; in general, the studied zones are at the level of a natural area with small deviations, this is due to both natural and man-made processes. The content of natural radionuclides in the studied soil samples of mountain dark chestnut soils (tailing ponds and the adjacent territory) is several times higher than the average Clarke values, where a sharp decrease in the content of radionuclides is observed in the lower 20-60 cm layers, compared to mountain meadow-steppe subalpine soils. Radioecological analyzes in the city of Bishkek showed that, in general, the exposure dose is at background levels and below established standards. In the Issyk-Kul Biosphere Territory, the calculated annual doses to the population from all routes of exposure to radionuclides in the conditions of the Issyk-Kul region do not exceed the established norm (1 mSv per year). Mothballed storage facilities and dumps are a dangerous potential source of environmental pollution and therefore require constant monitoring.

Hydrothermal Changes and Physicochemical Characteristics of Subtropical Subalpine Soils under Freezing and Thawing

The soil column samples were collected for indoor simulated freeze-thaw experiments to monitor the soil hydrothermal dynamics and measure the basic physicochemical properties to research the effects of freeze-thaw on the hydrothermal process of peat bog soil and its relationship with physicochemical properties. The results indicate that in the initial phase of freezing-thawing, soil water content decreases and soil temperature changes, respectively. Unfrozen water content in soil in the stable freezing period decreases sharply. Compared with the freezing period, the fluctuation of soil moisture rate during thawing is more moderate with the temperature change. Soil ammonium nitrogen content decreases with decreasing soil temperature and is significantly positively correlated with soil water content after freeze-thaw, while total phosphorus, fast-acting phosphorus, total nitrogen and nitrate have no significant correlation with soil temperature and soil moisture content after freeze-thaw.

Description of Desmonostoc caucasicum sp. nov. (Cyanobacteria) using an integrative taxonomic approach

ABSTRACT A new cyanobacterial species of the genus Desmonostoc is described according to the International Code of Nomenclature for algae, fungi, and plants. The new species Desmonostoc caucasicum sp. nov. is recorded in the mountain meadow subalpine soil from the Greater Caucasus, Russia. The analysis is based on morphological characters, the 16S rRNA gene phylogenetic analysis, and ITS secondary structure. Desmonostoc caucasicum differs from the other species of the genus in colony morphology, size of vegetative cells and heterocytes, and habitat type. The 16S rRNA gene sequence of the new strain displayed 95.3%–97.9% similarities to other species of the genus Desmonostoc. The phylogeny inferred by maximum likelihood and Bayesian inference placed D. caucasicum in the Desmonostoc clade, within the Nostocaceae. The novel strain formed an independent lineage within the clade. The D1–D1ʹ, Box–B and V3 helices obtained from the 16S–23S ITS region didn’t fit those of any described species of Desmonostoc. Amplification of a fragment of the mcy gene involved in microcystin biosynthesis from D. caucasicum confirmed that it has this genetic determinant. An integrative taxonomic approach, based on morphological, 16S rRNA and mcy genes molecular analyses, ITS secondary structure, along with ecological data, is used to delimit this new species.

AGRO ECOLOGICAL CONDITIONS OF DARK GREY SOIL IN IMERETI REGION

Georgia, in particular, the dark grey soils of the middle belt of the Imereti mountain-forest zone are widespread. This soil is of bioclimatic type which analogues are found in many regions of the world forest zone and are formed in geographical and landscape conditions similar to Georgia. According to the vertical zoning, forest dark grey soils are spread from 600-900 meters above sea level to 2000-2100 meters. In Imereti, in the lower zone of the distribution of these soils, they border the yellow and red soils, and in the upper zone, the subalpine soils of the mountain-meadow.They, like the relief of the territory of all mountainous countries, the relief strip of forest dark grey soils in Imereti is very difficult in relief. It is fragmented, which in turn is related to the geological structure, lithological composition of rocks, tectonic processes, erosion-denudation occurrences and more.The thickness of the soil changes with the inclination of the slope, gravel, properties, the greater the slope, the less soil moisture, the slower the soil is washed away, and the dryness of the soil is known to be unfavorable for the plant. Under these conditions, a very small amount of humus-accumulation horizon is formed, which is unsatisfactory in terms of soil protection importance and fertility. At the same time it is noteworthy that the soils of the southern exposure are hotter than those of the north.Dark grey soils are developed on the Tertiary and post-Tertiary sandstones, clays and their overcrop products in the southern Imereti region, which includes the northern slopes of the Meskheti Range, within the Zestafoni, Bagdati, Samtredia, Vani districts. Soil-forming rocks are Lower and Middle Eocene sandstones, marls, clay-shales, erupted (andesites, tuffs) rocks.These soils are developed under broadleaf (hornbeam, chestnut, oak) and deciduous-coniferous forest cover.Sandy soils are spread in Khoni, Baghdati, Vani, Tkibuli, Chiatura, Kharagauli, Imereti region.

Soil enzyme stoichiometry is tightly linked to microbial community composition in successional ecosystems after glacier retreat

Soil enzyme stoichiometry has been proposed to reflect microbial resource limitation. However, this view overlooks the profound variations in microbial community composition and soil abiotic properties that may also affect enzyme stoichiometry. In successional subalpine ecosystems after glacier retreat, we found that the stoichiometry of soil carbon-, nitrogen- and phosphorus-acquisition enzymes was strongly associated with the microbial community composition. Soil abiotic properties (pH and soil organic matter quality) may also affect enzyme stoichiometry directly, or indirectly through microbial community composition. In contrast, microbial resource status was weakly related to enzyme stoichiometry. Thus, precautions should be taken when using enzyme stoichiometry as an indicator of microbial resource limitation. The close relationship between microbial community composition and enzyme stoichiometry suggests that genetic potential is linked to the enzyme activity in subalpine soils.

Microbial activity in alpine soils under climate change

Soil enzymatic activity was assessed in the Stelvio Pass area (Italian Central Alps) aiming to define the possible effects of climate change on microbial functioning. Two sites at two different elevations were chosen, a subalpine (2239 m) and an alpine belt (2604–2624 m), with mean annual air temperature differing by almost 3 °C, coherent with the worst future warming scenario (RCP 8.5) by 2100. The lower altitude site may represent a proxy of the potential future situation at higher altitude after the upward shift of subalpine vegetation due to climate change. Additionally, hexagonal open top chambers (OTCs) were installed at the upper site, to passively increase by about 2 °C the summer inner temperature to simulate short term effects of warming before the vegetation shift takes place. Soil physicochemical properties and the bacterial and fungal abundances of the above samples were also considered. The subalpine soils showed a higher microbial activity, especially for hydrolytic enzymes, higher carbon, ammonium and hydrogen (p < 0.001) contents, and a slightly higher PO4 content (p < 0.05) than alpine soils. Bacterial abundance was higher than fungal abundance, both for alpine and subalpine soils. On the other hand, the short term effect, which increased the mean soil temperature during the peak of the growing season in the OTC, showed to induce scarcely significant differences for edaphic parameters and microbial biomass content among the warmed and control plots. Using the manipulative warming experiments, we demonstrated that warming is able to change the enzyme activity starting from colder and higher altitude sites, known to be more vulnerable to the rising temperatures associated with climate change. Although five-years of experimental warming does not allow us to make bold conclusions, it appeared that warming-induced upwards vegetation shift might induce more substantial changes in enzymatic activities than the short-term effects, in the present vegetation context.

The current state of mountain meadow soils of subalpine pasture ecosystems of the Central Caucasus (elbrus altitudinal zonality)

Intensive recreational, agricultural and logistics land use in uplands leads to their transformation and degradation. Subalpine meadow ecosystems of Central Caucasus are traditionally used for grazing and mowing. The work determined the current state of soils on pastures (mountain meadow-steppe subalpine soil and mountain meadow subalpine soil) and the level of changes of their properties under different stages of pasture degradation were defined. The efficacy of 4-stage assessment system for evaluating the pasture degradation of grasslands dominated by Bromus variegatus M. Bieb. was shown for the assessment of soil cover condition. The reduce of estimated soil indicators and degradation of soils under pastures with maximal degradation stage (DS3) of meadow ecosystems was statistically significant.

The influence of environmental factors of the northern and high-mountain territories on the formation of the yield of tubers of early-maturing potato varieties

The aim of the research was to study the yield indicators of 36 early-ripening potato varieties in the northern region (Arkhangelsk) and the highlands of the North Caucasus (altitude 2500m above sea level). Experimental work was carried out in 2015–2020. Features of the northern zone - a light period of up to 21 hours in June - July, contributing to an increase in the duration of interphase periods of plant development. In the highlands, a short daylight hours of 14 hours, a sharp drop in daytime temperatures 15,1 – 25,8°С and night temperatures 7,8 – 15,2°С and intense solar insolation. Peat-podzolic-gley soils of the northern region are characterized by low humus (3,7%) and high - potassium (240 ... 267 mg/kg) in comparison with mountain meadow subalpine soils of high mountains (6,7% and 102 ... 120 mg/kg). Potatoes were planted in the first decade of June, harvesting - in early September. Was planted 25 tubers of each variety according to the scheme 0,7 × 0,3 m, the area of the accounting plot was 5.25 m². Using cluster, discriminant analyzes, the varieties were grouped according to a set of indicators: the multiplication factor, the yield of one plant and the average mass of tubers. In the northern region, the best were the varieties that formed from 8,1 to 11,4 tubers with an average weight of 37,0 ... 67,9 g and a yield of 400 ... 633 g. In the highlands, the varieties that formed 11,8 ... 19,8 pcs., 56,5 ... 70,6 g and 830 ... 1140, respectively, were the most productive. According to the results of the assessment of plasticity of 36 early-ripening potato varieties, they were resistant to extreme environmental conditions in northern and high mountains. zones were characterized by only five varieties: Daryonka, Red Lady, Breeze, Leader, Gulliver.

Biological activity of mountain meadow subalpine soils of Central Caucasus

Indicators of biological activity (humic content and stock, Cmic content and stock, hydrolytic and redox enzymes activity) were measured for the first time in the upper horizons of mountain meadow subalpine soils of Central Caucasus (elbrus altitudinal zonality in Kabardino-Balkaria). The comparative assessment was performed for the biological characteristics together with soil density and acid-base properties for soils of natural and pasture ecosystems. The integral index of ecological and biological soil state (IIEBSS) was calculated to estimate the level of changes in biological activity. It was shown that pasture degradation leads to 30% decrease of IIEBSS compared to the undisturbed soil. The defined biological parameters of natural undisturbed mountain meadow soils could be used as diagnostic indicators for the ecological studies of ecosystems under anthropogenic load.

A cascading influence of calcium carbonate on the biogeochemistry and pedogenic trajectories of subalpine soils, Switzerland

Soil research in temperate to cool and humid regions has typically focused on acidic soils; there has been relatively little investigation of the effects of calcium carbonate (CaCO3) on unamended soil properties or function in these environments. The object of this study was to characterise the effects of small amounts of CaCO3 on pedogenic trajectories and soil biogeochemistry in a humid subalpine valley of Switzerland. To isolate the influence of CaCO3, six profiles were selected that had developed under almost identical conditions for soil formation, i.e. climate, topography, vegetation structure, time since deglaciation, silicate mineralogy and texture. The main difference between the profiles was that three contained a small quantity of CaCO3 (<6.2%; thereafter, ‘CaCO3-bearing’) while the remaining three contained no detectable CaCO3 (thereafter, ‘CaCO3-free’). The presence of CaCO3 was associated with cascading changes in soil biogeochemistry. These changes included higher pH, an order of magnitude higher extractable Ca and twice as much soil organic carbon (SOC). CaCO3-bearing profiles also displayed a higher proportion of poorly crystalline Fe forms. The higher pH at the CaCO3-bearing site was attributable to the weak buffering provided by CaCO3 dissolution, which in turn maintained the relatively higher extractable Ca. Exchangeable Ca (CaExch) and other reactive Ca forms could help stabilise SOC, contributing to its accumulation through processes such as flocculation and subsequent occlusion within aggregates and/or sorption to mineral surfaces. The increased SOC, CaExch and pH at the CaCO3-bearing site could in turn be inhibiting the crystallisation of disordered Fe forms, but further research is required to confirm this effect and isolate the exact mechanisms. Overall, this study shows that the presence of small amounts of CaCO3 in humid environments has a far-reaching influence on soil biogeochemistry and further supports the idea that indicators of Ca prevalence have the potential to improve regional SOC estimates.

Slow Recovery of Major Soil Nutrient Pools during Reclamation in a Sub-Alpine Copper Mine Area, Southeastern Edge of the Tibetan Plateau, Sichuan Province, SW China

Improvement of soil nutrients is crucial for the long-term development and stability of restored ecosystems in mine areas. However, knowledge about the variation in soil nutrients and their influencing factors during the reclamation of sub-alpine metal mine soil is still scarce. We assess the status of soil organic carbon (SOC), total nitrogen (TN), N fractions, total phosphorus (TP), and available P in reclaimed soil at a copper mine site (2702 m above sea level) in the southeastern edge of the Tibetan Plateau, southwest China. The mine area had been reclaimed by distributing stockpiled topsoil (~15 cm) in 2008, sowing seeds of ryegrass (Lolium perenne L.) in 2009, and planting seedlings of A. ferdinandi-coburgii and Rosa omeiensis f. pteracantha in 2010. We found that, eight years after the reclamation, although the concentrations of SOC (24.3 g kg−1) and TN (2.21 g kg−1) in the reclaimed soil increased by 25% and 29% compared with the stockpiled topsoil, respectively, they only accounted for about half of the levels in the undisturbed topsoil. In contrast, the concentration of TP (498–570 mg kg−1) did not significantly change between the reclaimed and stockpiled topsoil. The concentrations of NH4-N (30.1 g kg−1), NO3-N (17.2 g kg−1), and available P (11.1 mg kg−1) in the reclaimed soil were 2.2, 1.3, and 1.6 times the levels in stockpiled topsoil, respectively, but still lower than those in undisturbed soil. The concentrations of microbial C, N, and P in the reclaimed soil had a similar variation pattern to the available nutrients. The soil C:P and N:P ratios and microbial biomass C:P and N:P ratios in the reclaimed soil were significantly lower than the levels in the undisturbed forest soil. The average accumulation rates of SOC and TN in the reclaimed soil were 85.3 and 11.4 g m−2 year−1, respectively. The rates are much lower than those of reclaimed mine soils with similar reclaim duration but better climate conditions. Relatively slow development of vegetation and soil microorganisms and leaching due to a freeze–thaw cycle controlled by the sub-alpine climate are likely responsible for the slow recovery of soil SOC and TN.

The isolation of the antagonistic strain Bacillus australimaris CQ07 and the exploration of the pathogenic inhibition mechanism of Magnaporthe oryzae.

Biological control as a promising method to combat plant disease has gained public attention in recent years. In the present study, we isolated 12 strains resistant to Magnaporthe oryzae from western Sichuan subalpine soil. Among them, CQ07 exhibited remarkable activity against M. oryzae. The result of 16S rRNA sequence analysis revealed that CQ07 is approximately 99% similar to Bacillus australimaris. The sterilized culture filtrate of CQ07 inhibited the growth of M. oryzae, which motivated us to deduce the influence of CQ07 on the pathogenicity of M. oryzae. As shown by experimentation, sterilized culture filtrate (10 μl/ml) of CQ07 can delay and even suppress the germination of conidia and prevent the formation of appressorium in vitro and in vivo. In addition, by simulative field tests, the spraying of conidia suspension diluted with sterilized culture filtrate of CQ07 reduced infection of rice blast. To better control rice blasts, understanding the infection mechanism of M. oryzae and inhibiting the mechanism of the antagonistic strain is of great importance.

Naphthalene exerts substantial nontarget effects on soil nitrogen mineralization processes in a subalpine forest soil: A microcosm study

Naphthalene has been widely used to test the functional roles of soil fauna, but its nontarget effects remain uncertain in various soils. To determine whether there is a potential nontarget effect on soil biochemical properties in subalpine forest soil, soils in a subalpine forest on the western Qinghai-Tibet Plateau were treated by naphthalene in microcosms. The responses of soil microbial activity and nutrients to naphthalene were studied following 52 days of incubation. The results showed that the naphthalene application obviously decreased the microbial respiration rate in the first 10 days of the incubation and then increased the rate in the following days of the incubation. Moreover, the naphthalene application did not significantly affect the microbial activities overall, measured as soil microbial phospholipid fatty acid (PLFA) abundances and biomasses, or most enzyme activities (invertase, nitrate reductase and nitrite reductase) during the whole incubation period. However, naphthalene suppressed increases in the DON, NH4+-N and NO3--N contents and urease activity and led to the net mineralization of inorganic N (NH4+-N + NO3--N), in contrast to the net immobilization result in the controls. These results suggest that naphthalene can exert direct nontarget effects on soil microbial respiration and N mineralization processes in subalpine soils. Caution should be taken when using naphthalene to repel soil animals in field experiments.

Ammonia Emissions from Subalpine Forest and Mountain Grassland Soils in Rocky Mountain National Park.

Atmospheric deposition of NH and NH contributes to eutrophication within sensitive subalpine ecosystems of Rocky Mountain National Park (RMNP) in the United States. However, little is known about the local contribution of NH from soils within the park. Thus, the goal of this study was to quantify and compare NH emissions from intact soil cores sampled from a subalpine grassland and forest within RMNP. Cores were collected at 2-wk intervals from 20 June 2011 to 12 Sept. 2011 and transferred to a laboratory chamber system for NH flux measurements. Additionally, N wet deposition was monitored at the sampling location to investigate possible impacts on NH soil emissions. The average quantifiable NH emissions (with SDs) from intact soil cores analyzed in the laboratory (23°C) were 0.42 ± 0.30 mg NH-N m d for grassland soil and 0.21 ± 0.03 mg NH-N m d for forest soil ( < 0.001). A mechanistic model was developed to estimate the impact of temperature on soil emissions using the chamber data and field-site air temperatures. Average estimated NH emissions from the field site over the study period were 0.21 and 0.082 mg NH-N m d for grasslands and forests, respectively. Ammonium wet deposition was not correlated to short term reemission of NH based on N isotope analysis. This work provides new information on the magnitude of NH emissions from native subalpine soils, indicating that natural emissions are not likely major sources of NH in the RMNP airshed.

Характеристика микробоценоза горных почв Дидойской депрессии Республики Дагестан

The data about the soil cover of mountain Dagestan are scattered. A comprehensive assessment of the biological diversity of mountain soils by such indicators as the degree of humus content, the number and structure of the microbocenosis has not been carried out yet. This article provides the results of the analysis of the quantitative assessment of microbocenosis in mountain soils (Mollic Leptosols Eutric) of Dido-depression in the Republic of Dagestan. The investigations were carried out on the following types of soils differentiated according to altitude marks: Alpine meadow with the elements of steppe formation, Alpine brown weakly podzolized, Alpine meadow typical, Alpine brown podzolized, mountain-meadow subalpine, mountain-meadow alpine. The article describes the characteristic features of soil bacteria and fungi in their dependence on the altitude marks. A variety of soil bacteria and fungi has been identified according to their frequency and the abundance of morphological and cultural types. The minimum and maximum number of prokaryotes and micromycetes is shown and determined. This number varies depending on the site of soil samples selection. Based on the calculated frequency of occurrence there are identified dominant morphological and cultural types, subdominants, frequently occurring, rare, random. According to the Serensen coefficient, bacteriocenoses formed in soils up to a height of 1450 m are similar in their qualitative composition and structure. It has been established that with an increase in the height of the soil location, the number of prokaryotes decreases, and that of the micromycetes increases. The diversity of bacteria and fungi expands in soils which have the highest altitude. It is shown that in the soils located at an altitude of 1450m (the height of the first section), as well as at an altitude of 2350m (subalpine soil height) the bacteriocenosis similar in their quality composition are formed.

Green alder (Alnus viridis) encroachment shapes microbial communities in subalpine soils and impacts its bacterial or fungal symbionts differently.

Since the mid-twentieth century, subalpine grasslands undergo a progressive encroachment by Alnus viridis shrubs. Thanks to its rapid vegetative reproduction, its nitrogen fixing symbiosis with Frankia and its ectomycorrhizal cohorts, green alders are vigorous colonizers that quickly form mosaic of alder patches that evolves into a close canopy shrub community. To better understand how alder encroachment might influence microbial communities in this successional sequence, symbiont distribution, microbial richness and community structure in both soils and nodules were analyzed at three successional stages: grassland, mosaic and forest. Soil analyses were performed in association with measures of nitrification and denitrification, as well as DNA metabarcoding of three bacterial genes (16S rDNA, nifH and amoA) and one fungal gene (ITS1). Our results show that (i) A. viridis encroachment is associated with soil microbial community changes that are in turn, linked to certain soil properties (i.e., pH, C/N ratio and organic matter content), (ii) both taxonomic and N related functional gene structures of bacteria are modified by alder encroachment and (iii) the distribution in soils of its bacterial symbionts (Frankia) is apparently weakly influenced by alder establishment while Alnus-specific ectomyccorrhizae increase with the increase in alder shrub density.

Earlier snowmelt accompanied by warmer soil temperatures in mid-latitude aspen forest and subalpine meadow: Implications for soil carbon

An advance in snowmelt timing in seasonally snow covered ecosystems has a wide range of potential impacts on plant and soil processes. Plants may respond to earlier melt through changes in phenology and altered allocation of resources to growth and reproduction, and earlier snowmelt may impact active pools of soil C such as microbial biomass and dissolved organic C (DOC). In subalpine aspen forests and open meadows in the Wasatch Plateau of the western Rocky Mountains, we manipulated snowmelt timing by adding dust to the snow surface. We obtained a treatment-induced snow-free interval of 6 to 22 days (3% to 11% reduction in snow-covered days). We observed the growth of early and mid-season herbaceous species, measuring above ground biomass, flower and seed counts, and seed mass. We also monitored microbial biomass, DOC, and soil respiration in the days and weeks following snowmelt. We observed generally warmer soil temperatures in the early snowmelt plots compared to controls. However, we found no difference in microbial biomass C or DOC following snowmelt and we found no legacy effect in growing season soil respiration as a result of earlier snowmelt. After three years of repeated treatments, total soil organic C remained unchanged between treatment and control plots. Although earlier snowmelt is likely to have a variety of impacts on subalpine ecosystems, we found no change in plant biomass or reproductive allocation and we found that carbon pools and fluxes were not perturbed by earlier snowmelt. A common expectation is that earlier snowmelt will lead to more frequent freeze-thaw cycles in soils, and studies have shown that freeze-thaw events can have significant but temporary impacts on soil C efflux. This study indicates that subalpine plants and soils may be at least partially buffered from some of the anticipated effects of earlier snowmelt. One direction of continuing research may be to identify adaptive buffers in subalpine ecosystems, an understanding of which may be useful in anticipating and responding to future climate change.

Mineral controls on soil organic C stabilization in alpine and subalpine soils in the Central Pyrenees: Insights from wet oxidation methods, mineral dissolution treatment and radiocarbon dating

Studies on the mineral stabilization of soil organic carbon (SOC) and the radiocarbon age of Pyrenean mountain soils have not been conducted to date. This study assessed the SOC concentrations, the interaction of SOC with the mineral phase (stabilization), the radiocarbon age and the relationships between SOC and dithionite-, oxalate-, and pyrophosphate-extractable Fe, Al and Si contents on four summits in Ordesa National Park (Central Pyrenees, Spain). The selected summits represented a gradient in plant community composition from subalpine (2242ma.s.l.) to nival (3022m) environments. Soil samples (0–10cm) were physico-chemically fractionated and exposed to Na2S2O8 and H2O2 oxidation and to mineral dissolution with HF. The average SOC concentration in the <20μm fraction decreased with increasing elevation (from 80.1 to 15.0gCkg dry soil−1 at 2242 and 3022m, respectively). The H2O2- and Na2S2O8-resistant SOC fraction increased with elevation, and was mainly controlled by oxalate-extractable Si (Sio), i.e., 69.3 and 66.7% of the variability was explained by the Na2S2O8persulfate- and H2O2-oxidation fractions, respectively. The oxalate-extractable Al (Alo), dithionate-extractable Al (Ald), pyrophosphate-extractable Al (Alp), and indicators Alp/Alo and Alo+Feo were more important for SOC stabilization on the two lower summits (2242m and 2519m) than on the two higher summits (2800m and 3022m). In contrast, the HF-soluble SOC fraction was not correlated with the mineral indicators. The largest percentages of Na2S2O8- and H2O2-resistant SOC fractions were found in one of the higher summits, where the greatest 14C age was measured. The radiocarbon analyses indicated that the 14C age of the mineral-associated SOC ranged from 825 and 830yr BP on the two lower summits to 10,500 and ca. 16,000yr BP on the two higher summits. Multivariate analysis, i.e., non-multidimensional scaling (NMDS) analysis, highlighted the relationship between plant community composition at the different summits and the facing slopes and the analysed soil variables. A clear detailed description of SOC and stabilization in mountain ecosystems is needed to enable further predictions of soil C gains and losses related to the expected global changes, i.e., T increase, precipitation regime and land use changes.

The composition of organic phosphorus in soils of the Snowy Mountains region of south-eastern Australia

Few studies have considered the influence of climate on organic phosphorus (P) speciation in soils. We used sodium hydroxide–ethylenediaminetetra-acetic acid (NaOH–EDTA) soil extractions and solution 31P nuclear magnetic resonance spectroscopy to investigate the soil P composition of five alpine and sub-alpine soils. The aim was to compare the P speciation of this set of soils with those of soils typically reported in the literature from other cold and wet locations, as well as those of other Australian soils from warmer and drier environments. For all alpine and sub-alpine soils, the majority of P detected was in an organic form (54–66% of total NaOH–EDTA extractable P). Phosphomonoesters comprised the largest pool of extractable organic P (83–100%) with prominent peaks assigned to myo- and scyllo-inositol hexakisphosphate (IP6), although trace amounts of the neo- and d-chiro-IP6 stereoisomers were also present. Phosphonates were identified in the soils from the coldest and wettest locations; α- and β-glycerophosphate and mononucleotides were minor components of organic P in all soils. The composition of organic P in these soils contrasts with that reported previously for Australian soils from warm, dry environments where inositol phosphate (IP6) peaks were less dominant or absent and humic-P and α- and β-glycerophosphate were proportionally larger components of organic P. Instead, the soil organic P composition exhibited similarities to soils from other cold, wet environments. This provides preliminary evidence that climate is a key driver in the variation of organic P speciation in soils.

Methane flux in montane and subalpine soils of the Central and Northern Alps

Aerobic soils are generally known as potent sinks for the atmospheric greenhouse gas methane (CH4). However, uptake rates vary greatly depending on the soil site, and hence estimation of the global soil sink is difficult. Here, we measured the in situ CH4 flux of 15 forests and 14 grasslands on siliceous or calcareous parent materials in summer 2013. To cover the topography of North Tyrol (Austria), sampling sites were distributed over four typical altitudes (500, 1000, 1500, and 2000m above sea level). Twenty-three of the soils were net sinks for CH4, whereas net CH4 emission occurred at four grassland sites and two sites neither showed net removal nor emission. Flux rates ranged between −3.2 and 2218.2μgCH4-Cm−2h−1 for grasslands, and between −3.2 and −45.0μgCH4-Cm−2h−1 for forests, thus showing that forest soils are significantly more efficient sinks than grassland soils. Soils derived from siliceous parent material were significantly more effective sinks than those derived from calcareous parent material, when only negative flux rates were considered. Multiple regressions indicated that soil dry mass and NH4+-N shaped CH4 flux of grasslands, whereas CH4 flux of forest soils was regulated by soil pH and NO3−-N. Our results provide insights into the CH4 turnover of the so far scarcely studied Central European alpine regions and thus add to the knowledge on this relevant topic.