Dry Subtropics Research Articles

Ecosystem service research in the dry subtropics: Current state, temporal changes and drivers of regional variability

Dry subtropical (DST) regions that share similar climatic and topographic conditions exhibit today significant disparities in population density, agricultural intensity, wealth and cultural values. In addition, they are also facing increasing pressures on their natural resources. These attributes collectively shape individuals' varying dependence on natural resources and may influence their perception of ecosystem services (ES). In this study, we conducted a systematic literature review, focusing on the DST regions, to address two main questions: 1) What is the current state, temporal trends and regional variability in scientific research on ES and 2) What are the potential drivers of the variability in ES research? Amongst the 471 publications found in our review, 53% focused on provisioning services, followed nearly equally by cultural (33%) and regulating (30%) services. Only 13% addressed more than one ES category and approximately 33% mentioned economic valuation. Our study reveals that research on ES in the dry subtropics experienced a significant increase from 2005 onwards. Approximately 45% of the publications included the term 'ecosystem service' and its frequency has risen substantially over time. Most publications primarily focus on African dry subtropics (over 60%), followed by South and North American ones. Publications from southern Asia and NE Australia were more scarce. Importantly, we found no clear relationship between the number of publications, publication density or representativeness and the variables used as indicators of human pressure (e.g. population density). Consequently, research efforts in the DST regions appear to be influenced by a diverse range of financial and institutional constraints, international research agendas, as well as the personal interests of researchers, contributing to the idiosyncratic nature of this field.

New lines of cauliflower for Dagestan north arid subtropics

Cauliflower Brassica oleracea L. convar. botrytis (L) Alef. var. botrytis is an economically important and widely cultivated vegetable crop. To solve the problems of import substitution, the first priority is to ensure high-quality varietal diversity of cauliflower for agricultural producers in central Russia and the Southern Federal District (SFD). For the first time, such work was carried out in the northern dry subtropics of Southern Dagestan. At the Dagestan ES (it is a branch of VIR), in 2015–2022 lines from crossing two varieties of cauliflower – the early ripening Early Gribovskaya 1355 and the late ripening (winter form) Inca were studied. The paper presents the results of 11 cauliflower lines study, previously identified by early maturity, productivity and commercial qualities. Promising lines of the summer-autumn growing period for cultivation in Southern Dagestan have been identified. Stable early maturity was noted in cauliflower lines 182/4 (121...150 days), 174/1 (121…154), 182/2 (124…154) and 177/4 (124…166 days), the period of mass formation heads – 178/4; 192/4; 177/2; 177/3 (16...19 days), good commercial qualities and productivity – 178/4 (1.15 kg), 182/2 (1.15), 174/1 (0.98), 182/4 (0.94) and 177/3 (0.80 kg), the average weight of the heads is 192/4 (0.73 kg), 177/2 (0.72) and 178/3 (0.65 kg).

Loss of nutrients from meadow-brown soils during irrigation of apple trees in the conditions of the dry subtropics of Azerbaijan

The article presents the results of studies on the effect of water consumption, depending on the length (96, 144 and 192) meters of irrigation furrow with a slope of relief tg = 0.021 on the leaching of nitrogen, phosphorus and humus from irrigated soils of the dry subtropics of Azerbaijan under apple trees. Under conditions of leaching of nutrients, the effect of mineral and organic fertilizer systems on apple yields has also been studied. With a 96-meter furrow and a water consumption of 0.2 l/sec, the content of leached nutrients (N, P) and gross humus with soil was 0.01 % nitrogen and phosphorus, 0.02 % gross humus. Increase in water consumption from 0.2 l/sec. up to 0.4 l/sec. It has a negative effect on the leaching of humus, nitrogen and phosphorus from the soil. With a water consumption of 0.4 l/sec, these indicators increased markedly by 0.01 % for humus, nitrogen and phosphorus. Along the length of the irrigation furrow in both water consumption rates, the leaching of nutrients and humus from the soil increases. It was found that with an increase in the length of the furrow to 192 meters at a water consumption of 0.4 l/sec, the leaching was greater than the 96-meter furrow in humus by 0.22 %, nitrogen by 0.07 % and phosphorus by 0.04 %. The use of an organomineral fertilizer system (Background+ N120P120K90) had a positive effect on the yield of apple trees. Thus, in the non-maneuverable version on a 94–meter furrow, the yield of the apple tree was 274.2 c/ha - when the furrow was lengthened to 192 m, the yield gradually decreased due to the high content of leached nutrients and humus (268.5 c/ha). When using N120P120K90 + 10 t/ha of manure, 278.4 c/ha yield was established at 96 m furrow and 0.2 l/sec of water consumption. Whereas, when the furrow was lengthened to 192 m at the same rate of fertilizers and water consumption, the yield decreased to 278.2 c/ha, that is, furrow lengthening was ineffective at slopes tg = 0.021. It was found that at high slopes, the shorter the furrow, the less nutrients are washed out.

Urzhumian Pedocomplexes of the Kazan Volga Region (Eastern Europe): An Example of Paleoclimate and Paleolandscapes of the Subtropics of the Continental Pangea in the Middle Permian

The paleosol profiles of the Urzhumian from the section on the right bank of the Volga River near the village of Grebeni were studied by field and laboratory methods. Two paleosol profiles on red clayey siltstones were identified. They were classified as strongly developed Vertic Calcisols based on their pedogenic features such as horizonation, carbonate nodules, slickensides, etc. The climate during their formation was found to be seasonally wet and warm. The mean annual precipitation was calculated from the geochemical indices of the paleosols and amounted to 522 mm/year for the Late Urzhumian. The reddish-brown soils in the dry subtropics of the Mediterranean or Australia can be considered as modern analogs of these paleosols.The upper paleosol profile is a pedocomplex consisting of four single soils separated by nonpedogenic carbonate layers in the middle part. The pedocomplex structure contains one lacustrinepalustrine and two lacustrine-playa sedimentary microrhytms, which indicate the setting of lacustrinealluvial plains and make it possible to estimate the duration of its formation spanning thousands to tens of thousands of years.A pedocomplex with a similar structure was identified in the upper part of the Urzhumian of the reference section in the Cheremushka Ravine. Both pedocomplexes have very similar mineralogical, chemical, and granulometric composition of their siliciclastics, as well as the isotopic composition of pedogenic nodules. The biostratigraphic position of the pedocomplex in the Cheremushka Ravine shows that it is coeval with the pedocomplex of the Grebeni section. The correlation between them is direct, making them a useful pedostratigraphic marker. It is suggested to label this marker horizon as the “Crimson Clay pedocomplex”.

Features of the Development of Tropical Crops in the Conditions of Dry Subtropics of the Southern Coast of the Crimea

Aerva lanata (L.) Juss. and Passiflora incarnata L. are pharmacopoeial medicinal plants, the raw materials of which are included in the list of imported to the Russian Federation. We conducted the complex of ecological and biological studies in order to select the optimal method of culture (long-term or annual) of these crops and assess the prospects of their cultivation in the conditions of the Southern Coast of the Crimea. In accordance with the methods of introduction study, we revealed the features of biology, growth dynamics and development of plants Aerva lanata and Passiflora incarnata in a dry subtropical climate of the Mediterranean type. It was found that for the cultivation of Passiflora incarnata for the long-term type, the required heat resource higher than 10˚С is 2159˚С. Aerva lanata in the open ground of the annual type forms fully valid seeds with heat supply in the 1870˚С. The biologically necessary amount of heat of the open ground culture is provided by the average long-term effective temperatures for Passiflora incarnata at 97% and Aerva lanata – 98-100%. These species are classified as promising species based on the total number of points.

Urban Dendroflora of Dry Subtropics of the Northwestern Part of The Greater Caucasus on the Example of the City of Gelendzhik

The article presents the results of the analysis of the species composition of the dendroflora of the city of Gelendzhik. The research covered 20 hectares of tree plantations. The route method and the transect method were used. In total, 30 transects were laid with a width of 5-20 m and the total length was 22 km. The routes covered all biotopes of natural (natural forest plantations on the outskirts of the city) and anthropogenic habitats (boarding houses, house territories of private households, spontaneous vegetation of roadsides and wastelands). True census of all tree and shrub species was carried out on the transects. Special attention was paid to rare species for which renewal and undergrowth were taken into account. The arboreal flora of Gelendzhik is represented by 110 species, which belong to 75 genera and 35 families. The predominant part of the dendroflora is represented by angiosperms (82.7%) and gymnosperms (13.7%). The families of Rosaceae, Cupressaceae and Fabaceae are most widely represented in the dendroflora of the city's green spaces (44%). The analysis of the species composition on their share of participation showed that the native fraction of the dendroflora prevails over the cultural one, which indicates its species richness. The analysis of the geographical element of the wild-growing fraction showed the heterogeneity of the dendroflora, in the formation of which 15 geographical elements take part. The largest number of species in the studied dendroflora belongs to the ancient Mediterranean group of geoelements. The significant participation of the Mediterranean and Caucasian geoelements indicates a high degree of autochthonicity in the development of the dendroflora of the city of Gelendzhik. Phanerophytes predominate among the life forms, represented equally by mesophanerophytes, nanophanerophytes and microphanerophytes. It should also be emphasized the significant participation of adventitious tree species (15.4% of the aboriginal fraction). Most of the adventitious species are of North American origin. The leading place in the quantitative spectrum is occupied by rare Mediterranean species Pinus brutia var. pityusa (Stev) Silba) (21% of the total number of studied individuals), Prunus mahaleb (L.) Vassilcz.) (7%), Pistacia atlantica Desf. (2.1%), which reflects the specifics of the dendroflora of the city of Gelendzhik.

Ecological and economic assessment of the dry subtropics territory for cultivating pomegranate cultivars

Ecological and economic assessment of the dry subtropics territory for cultivating pomegranate cultivars

An Analytic Model for the Clear-Sky Longwave Feedback

Abstract Climate models and observations robustly agree that Earth’s clear-sky longwave feedback has a value of about −2 W m−2 K−1, suggesting that this feedback can be estimated from first principles. In this study, we derive an analytic model for Earth’s clear-sky longwave feedback. Our approach uses a novel spectral decomposition that splits the feedback into four components: a surface Planck feedback and three atmospheric feedbacks from CO2, H2O, and the H2O continuum. We obtain analytic expressions for each of these terms, and the model can also be framed in terms of Simpson’s law and deviations therefrom. We validate the model by comparing it against line-by-line radiative transfer calculations across a wide range of climates. Additionally, the model qualitatively matches the spatial feedback maps of a comprehensive climate model. For present-day Earth, our analysis shows that the clear-sky longwave feedback is dominated by the surface in the global mean and in the dry subtropics; meanwhile, atmospheric feedbacks from CO2 and H2O become important in the inner tropics. Together, these results show that a spectral view of Earth’s clear-sky longwave feedback elucidates not only its global-mean magnitude, but also its spatial pattern and its state dependence across past and future climates. Significance Statement The climate feedback determines how much our planet warms due to changes in radiative forcing. For more than 50 years scientists have been predicting this feedback using complex numerical models. Except for cloud effects the numerical models largely agree, lending confidence to global warming predictions, but nobody has yet derived the feedback from simpler considerations. We show that Earth’s clear-sky longwave feedback can be estimated using only pen and paper. Our results confirm that numerical climate models get the right number for the right reasons, and allow us to explain regional and state variations of Earth’s climate feedback. These variations are difficult to understand solely from numerical models but are crucial for past and future climates.

Modeling and performance analysis of geothermal energy based air conditioning in building in Iraq

In many desert places, like Iraq, summer lasts a long time, with a mean daily high temperature of 45 °C. Buildings use a lot of electricity to run the air conditioning systems, which is a big part of the total amount of electricity produced. Everywhere in the hot and dry subtropics, a passive method of cooling is a real way to save money on air conditioning. One of these methods, called earth pipe cooling uses the relatively constant temperature of the ground below to cool indoor spaces without using any mechanical equipment. This reduces or eliminates the building's overall energy use and impact on the environment. In a space that was 3 × 3 × 5.5 m, the temperature of the ground and the efficiency of a 31-m-long, 3-m-deep, 6-inch-wide ground heat exchanger were measured. The effect of weather on the temperature of the air coming out of a building depends on the strength of the sun, the temperature of the ocean, and the relative humidity, all of which change depending on where the building is located. Also, the output air temperature and thermal performance change concerning air moving from 4 to 6 m/s. Using MATLAB and ANSYS FLUENT, the researchers carried out the simulations of the cooling system and it was found that the theoretical results were within 1.3% of the actual results. The results showed that climate variables have a big effect on the ground temperature down to a depth of 0.25 m, but at a depth of 3 m, the ground temperature remains the same (21 °C) all year long. Also, the results exhibited that the temperature of the air coming out of the system increased from 23 °C to 32 °C as the air moved faster through the system. Since the geothermal heat exchanger is most effective at cooling at a speed of 4 m/s, slowing the flow speed makes it work better. By using a geothermal heat exchanger, the difference in temperature between the inside and outside air could be cut by 10–16 °C. The data also showed that the speed and diameter of the air leaving the pipe made it hotter, while length, depth, and conductivity made it cooler.

Estimating the Lowest Latitude of Baroclinic Growth

Abstract Midlatitude storm tracks are the most prominent feature of the midlatitude climate. The equatorward boundary of the storm tracks marks the transition from the dry subtropics to the temperate midlatitudes. This boundary can be estimated as the lowest latitude of efficient baroclinic growth. Scaling theories for the lowest latitude of baroclinic growth were previously suggested based on the domain-averaged parameters of the Eady growth rate and supercriticality. In this study, a new estimate for the lowest latitude of baroclinic growth is proposed, based on the assumption that baroclinic growth is limited by the vertical scale of eddy fluxes. An equation for the eddy displacement flux is obtained from which the vertical scale is calculated, given the zonal-mean zonal wind and temperature profiles. It is found that the vertical scale of the eddy displacement flux and the observed baroclinic conversion rate decrease rapidly toward the equator around the same latitude. The seasonal cycle of the lowest latitude of baroclinic growth, calculated from the observed baroclinic conversion rate, is compared with the theoretical estimates. The estimates based on the vertical scale of the eddy displacement flux and supercriticality agree well with the observed lowest latitude of baroclinic growth. In contrast, the estimate based on the Eady growth rate is located around 10°–15° equatorward. The estimate of the lowest latitude of baroclinic growth may be used in future studies for explaining variations in the properties of the storm track, the Hadley cell edge, and the subtropical jet. Significance Statement The lowest latitude of baroclinic growth marks the transition from the dry and stable subtropics to the moist and variable midlatitudes. Estimating this latitude based on mean-flow variables can potentially advance the theoretical understanding of the latitudinal structure of the atmospheric circulation around the subtropics and midlatitudes. This study suggests a new method for estimating the lowest latitude of baroclinic growth, which is found to predict the observed lowest latitude of baroclinic energy conversion relatively well, compared with the traditional prediction based on the Eady growth rate.

Biochemical composition and antioxidant activity of broccoli (Brassica oleracea L. var. italica) during the summer-autumn cultivation period in South Dagestan

Broccoli cabbage Brassica oleracea L. var. italica is an economically important and widely cultivated vegetable crop, consumed both fresh and processed. To solve the problems of import substitution, the provision of high-quality varietal diversity of broccoli for agricultural producers in the middle zone of Russia and the Southern Federal District (SFD) comes first. Our work presents the results of the study of seven varieties and hybrids of broccoli, previously identified by productivity and commercial qualities. For the first time in the conditions of the northern dry subtropics of southern Dagestan, the content of dry matter, water-soluble polysaccharides, organic acids, flavonoids and antioxidant activity in fresh products were determined. The distribution of these substances by plant organs is shown. Broccoli samples with a high content of individual chemicals, as well as a set of characteristics that can be used as sources in breeding for an increased content of dry matter, water-soluble polysaccharides, organic acids, flavonoids and with high antioxidant activity, were isolated.

Approaches to the development of environmental standards for the content of petroleum hydrocarbons and Pb, Cr, Cu, Ni in soils of Greatest Caucasus

<p>The development of tourism and leisure infrastructure results in a continuous increase of anthropogenic impact on soils of wet and dry subtropics of the Greatest Caucasus. It is very important for the region to preserve the sustainable functions of soils and ecosystems, maintain a comfortable life and recreation environment create environmentally friendly agricultural products. It is conducted studies to determine the limits of resistance of soils in wet and dry sub-tropics to priority pollutants, especially petroleum hydrocarbons and heavy metals (Pb, Cr, Cu, Ni). It was found that the soils of wet and dry subtropics for resistance by Pb, Cr, Cu, and Ni are located as follows: south-ern chernozem > typical sod-carbonate soil ≥ brown typical soil ≥ brown carbonate soil = brown leached soil ≥ leached sod-carbonate soil = yellow soil >acid brown forest soil ≥ acid brown forest podzolized soil. In terms of the degree of resistance to oil pollution, studied soils create certain series: brown carbonate ≥ brown typical = sod-carbonate leached ≥ sod-carbonate typical > southern chernozem ≥ yellow soil ≥ brown leached soil > acid brown forest soil = acid brown forest podzolized soil. Heavy metals by ecotoxicity to the soils of wet and dry subtropics from the following series: Cr> Cu ≥ Ni = Pb. Based on the degradation of ecological functions of soils, we offer regional standards of the maximum permissible content of Pb, Cr, Cu, and Ni for the main soils of wet and dry subtropics.</p>

Dependence of productivity and quality of pomegranate cultivars on meteorological conditions in dry subtropics

Dependence of productivity and quality of pomegranate cultivars on meteorological conditions in dry subtropics

The Effect of Pesticides on Soil Biogenicity

This article presents the results of a study of the effect of pesticides on the biogenicity of gray-earth soils of the dry subtropics of Azerbaijan. The soils were examined from the location of the pesticide storage base in the Zardob area. It was revealed that in this territory about 12 thousand cubic meters of soil are polluted to a very strong degree and the content of pesticides (including DDT) exceeded the MPC by tens to hundreds of times. Microbiological studies of soil samples showed that, unlike the background clean soil, soil biogenicity was suppressed in all soil samples contaminated with pesticides, and this indicates a negative impact of soil contamination with pesticides on the structure and activity of microbiocenosis, which was confirmed by a high degree of phytotoxicity of these samples. All this indicates a very limited assimilation potential and a low ability of these soils to self-purify from organic pollutants. The results obtained can be used in the zoning of the soil cover of the country according to the rate of self-purification from pesticides, their assimilation capacity.Ключевые слова: почва, пестициды, ассимиляция, фитотоксичность.Keywords: soil, pesticides, assimilation, phytotoxicity.

Holocene Multi‐Centennial Variations of the Asian Summer Monsoon Triggered by Solar Activity

AbstractSolar activity affects Asian summer monsoon (ASM) at various time scales. However, it remains unknown if and how solar activity can influence ASM on the centennial time scale. Using the Community Earth System Model, we conduct a solar activity forced Holocene transient simulation with an acceleration factor of 10 and show that during the middle–late Holocene ASM precipitation exhibits a significant 300–600‐year periodicity under solar forcing. This model‐produced multi‐centennial variation is also suggested by proxy data. The leading mode of the multi‐centennial ASM variation shows a “wet tropics–dry subtropics” pattern, which lags the corresponding solar activity by about a quarter cycle. The western North Pacific (WNP) circulation system is responsible for the multi‐centennial ASM variation, through enhancing the climatological south Asia–WNP monsoon trough. We suggest that solar activity modulates the zonal SST gradients of the tropical Pacific, inducing the anomalous WNP cyclone and enhancing ASM precipitation in a delayed mode.

Approaches to the development of environmental regional standards for the content of lead in the soils of the Black Sea coast of the Caucasus on the basis of an integral indicator of the biological state of the soil

Introduction. The Black Sea coast of the Caucasus is an actively developing region with a progressively growing tourism and recreation infrastructure. However, there are rare and unique soils, such as southern chernozems (chestnut), brown soils of dry subtropics, yellow soils. Lead (Pb) is a priority group of toxicant metals. However, the use of uniform, common standards of Pb content in all types of soils is impractical, since local regional ecological and geochemical features of soils are not taken into account when calculating them. Materials and methods. Soil contamination of 100, 1000, 10,000 mg Pb per 1 kg of soil was modelling, corresponding to 1, 10 and 100 MPC of this element in Germany and several other countries. After 30 days, changes in biological parameters (the number of bacteria, the activity of soil enzymes and length of roots of radish) were evaluated. To combine the values of the studied biological indicators with different units of measurement into one common indicator, an integral indicator of the biological state (IIBS) of the soil was used. Results. In most cases, there was an inhibition of the biological properties of the studied soils. According to the resistance to Pb pollution, the soils of the Black Sea coast of the Caucasus form the series including southern chernozems (Haplic Chernozems Pachic) (85) > cinnamonics typical (Haplicisols Eutric) (79) ≥ soddy-carbonate typical (Rendzic Leptosols Eutric) (77) ≥ cinnamonics leached (Haplic Cambisols Eutric) (76) ≥ cinnamonics carbonate (Haplic Cambisols Eutric) (74) = sod-calcareouses leached (Rendzic Leptosols Eutric) (74) = yellow soils (Albic Luvisols Abruptic ) (74) > brown forest weakly-unsaturated (Haplic Cambisols Eutric) (67) ≥ brown forest acid (Haplic Cambisols Eutric) (65) > brown forest acid podzolized (Haplic Cambisols Dystric) (59). On the base of the analysis of the degree of failure of environmental functions of soils, regional values of maximum permissible concentrations (rMPC) of Pb in soils of the Black Sea coast of the Caucasus are established. Regional values of maximum permissible concentrations of Pb for southern chernozem is 120 mg/kg, for cinnamonics typical, cinnamonics leached, cinnamonics carbonate, sod-calcareouses leached, sod-calcareouses typical soils and yellow soil - 100 mg/kg, for brown forest acid, brown forest weakly-unsaturated - 70 mg/kg, 65 mg/kg for brown forest acid podzolized. Limitations. The proposed maximum permissible concentrations of Pb in soils are applicable primarily to the territory of the Black Sea coast of the Caucasus. Conclusion. The proposed maximum permissible concentrations of Pb in the soils of the Black Sea coast of the Caucasus can be used by environmental, agricultural and scientific institutions.

Fine-grain beta diversity in Palaearctic open vegetation: variability within and between biomes and vegetation types

Aims: To quantify how fine-grain (within-plot) beta diversity differs among biomes and vegetation types. Study area: Palaearctic biogeographic realm. Methods: We extracted 4,654 nested-plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database spanning broad geographic and ecological gradients. Next, we calculated the slope parameter (z-value) of the power-law species–area relationship (SAR) to use as a measure of multiplicative beta diversity. We did this separately for vascular plants, bryophytes and lichens and for the three groups combined (complete vegetation). We then tested whether z-values differed between biomes, ecological-physiognomic vegetation types at coarse and fine levels and phytosociological classes. Results: We found that z-values varied significantly among biomes and vegetation types. The explanatory power of area for species richness was highest for vascular plants, followed by complete vegetation, bryophytes and lichens. Within each species group, the explained variance increased with typological resolution. In vascular plants, adjusted R2 was 0.14 for biomes, but reached 0.50 for phytosociological classes. Among the biomes, mean z-values were particularly high in the Subtropics with winter rain (Mediterranean biome) and the Dry tropics and subtropics. Natural grasslands had higher z-values than secondary grasslands. Alpine and Mediterranean vegetation types had particularly high z-values whereas managed grasslands with benign soil and climate conditions and saline communities were characterised by particularly low z-values. Conclusions: In this study relating fine-grain beta diversity to typological units, we found distinct patterns. As we explain in a conceptual figure, these can be related to ultimate drivers, such as productivity, stress and disturbance, which can influence z-values via multiple pathways. The provided means, medians and quantiles of z-values for a wide range of typological entities provide benchmarks for local to continental studies, while calling for additional data from under-represented units. Syntaxonomic references: Mucina et al. (2016) for classes occurring in Europe; Ermakov (2012) for classes restricted to Asia. Abbreviations: ANOVA = analysis of variance; EDGG = Eurasian Dry Grassland Group; SAR = species-area relationship.

Ecological Safe Concentrations of Oil in the Soils of the Black Sea Coast of the Caucasus

Environmentally safe concentrations of oil in the soils of wet and dry subtropics of the Black Sea coast of the Caucasus (Black Sea Coast) have been established according to the degree of violation of their ecological functions. The indicators of the number of bacteria, the activity of soil enzymes, plant growth and development were determined. Based on the analysis of the degree of disruption of the ecological functions of soils, regional values of the maximum permissible concentrations of oil in the soils of the Black Sea Coast have been established.

Eucalyptus bakeri: a potential source species for eucalyptus oil production in the subtropics

ABSTRACT There is a paucity of eucalypt species in tropical Australia that produce a foliar essential oil in high concentration and rich in 1,8-cineole, the sought-after component of medicinal eucalyptus oils. Eucalyptus bakeri, a mallee from the dry subtropical parts of northern New South Wales and Queensland, is an exception, with limited earlier studies reporting that this species produced foliar oil with commercial characteristics. The aim of this study was to determine the variation in foliar oil characteristics throughout the natural range of E. bakeri as a precursor to the more intensive field-testing of the species as a commercial source of eucalyptus oil. Mature leaves and, when available, coppice leaves for comparison were collected over three separate field trips in 2020 from individual trees representing each of 17 provenances throughout the natural range of E. bakeri in Queensland. Foliar oil concentrations on a fresh-weight basis throughout the provenances sampled were relatively high, averaging 2.3% for mature leaves and 2.8% for coppice leaves, with an individual tree high of 4.1% for both leaf categories. 1,8-Cineole was the dominant compound in all foliar oils sampled, averaging 89.3% (range 70.2–94.6%) in oils from mature leaves and 87.6% (range 79–92.5%) from coppice leaves. Sabinene levels, restricted to a maximum of 0.3% in some oil standards, averaged 0.3% (range trace – 1.5%) in oils from mature leaves and 0.4% (range trace – 0.7%) from coppice leaves. The high foliar oil concentrations and consistency in oil qualities mark this species as a potential candidate as a eucalyptus oil source species for the dry subtropics. Provenance/progeny trials are now needed to determine which provenances produce adequate growth rates and the silviculture required to manage the species as an oil-producing crop, as well as to investigate variations in oil characteristics, including sabinene levels, when all sources are grown at a common site.

Растительность и ее значение в формировании лугово-коричневых почв

The studied meadow-brown soils of moderately dry subtropics of Azerbaijan are formed under thinned forest-bush and lacustrine — grass vegetation. In meadow-brown and other types of meadow soils, vegetation development and phytomass formation are influenced by soil and surface moistening. Aboveground phytomass which plays an important role in humus formation of natural and cultural cenoses of meadow soils creates plant biomass of 32–60–76 cwt/ha and 55–110–119 cwt/ha.