Semi-desert Zone Research Articles

Dynamics of physical properties of soils and humus reserves in salted soils under desertification

The dynamics of the physical properties and reserves of humus in saline soils of an arid semi-desert zone is presented. The basis for the research was observational data for 2010-2022. in a typical hilly landscape of the Astrakhan region. A grid of 100 × 100 m was laid. Soil studies were carried out at the grid nodes along the sampling layers. We studied the change in physical properties (soil moisture; salt content according to the amount of dense residue; soil density; filtration coefficient; soil porosity; moisture reserve), humus reserves and salt state of saline soils under desertification. Comparative analysis showed that negative changes have taken place in the study area and it can be stated that the processes of soil degradation and desertification are intensively developing. It has been established that in the soil layer of 0–40 cm there was a significant reduction in soil moisture reserves against the background of an increase in maximum air and soil surface temperatures, as well as changes in the hydrological regime because of the embankment of the territory. Dehumification processes are observed. The most clearly negative trend was revealed for meadow solonchaks. The change in the hydrological regime of the territory because of embankment contributes to an increase in the areas of automorphic soils in the landscape and a reduction in the areas of meadow soils. An increase in the degree of salinity and compaction was recorded for automorphic zonal soils. The physical destruction of the Baer's hills exacerbates the processes of degradation and the development of desertification in such conditions.

Analysis of habitats and bioecological composition of communities with the participation of species of the genus Delphinium in the southeast of European Russia

Between 2013 and 2020, 47 communities with seven species of the genus Delphinium were studied on the territory of 12 regions of the southeast of European Russia. The analysis of habitats by vegetation cover using the ecological scales of L. G. Ramensky showed that soils under communities with species of the genus Delpinium are often quite rich and very slightly alluvial.
 D. subcuneatum communities grow in habitats with the highest moisture-meadow-steppe (moist-steppe) and wet-meadow habitats; communities of D. duhmbergii grow in less humid habitats with dry-meadow (and fresh-meadow) moisture; with dry-meadow (and fresh-meadow) and meadow-steppe (moist-steppe) humidification - communities of D. dictyocarpum, D. litwinowii, and
 D. pubiflorum; in meadow-steppe (moist-steppe) humidification, communities of D. sergii. D. puniceum communities grow in the least moisture-provided habitats, with moisture ranging from dry-steppe and middle-steppe to semi-desert (desert-steppe). The biomorphological composition of communities with species of the genus Delphinium is dominated by hemicryptophytes, among which, the most numerous are tap-rooted, short-rhizomatous, and long-rhizomatous. The composition of cenomorphs reflects the confinement of communities with the majority of Delphinium species presented in the study to the forest-steppe zone, and communities with D. sergii and D. puniceum - to the steppe and semi-desert zone. In communities, the first place among trophomorphs is occupied by mesotrophs, and the second by megatrophs. The spectrum of hygromorphs is quite wide and includes species from xerophytes to ultrahygrophytes, however, xerophytes, mesoxerophytes, xeromesophytes, and mesophytes are the predominant groups most often. Judging by the predominance of heliophytes among heliomorphs, communities with all studied species of the genus Delphinium prefer open spaces. The spectrum of thermomorphs of all studied communities is dominated by mesotherms, for which the ecological optimum coincides with a moderate heat supply regime.

Геоинформационный анализ рельефа Астраханского Заволжья

The Astrakhan Trans-Volga region belongs to the dry-steppe and semi-desert zones, in connection with which deflation and desertification pose the greatest danger to this territory. For mapping, the Krasnoyarsk and Kharabalinsky municipal districts of the Astrakhan region were selected, which are located on the territory of the Northern Caspian Sea and are most susceptible to intense desertification processes. In addition, the study area is characterized by thin soils, so the development of desertification processes is a rapidly growing and hardly reversible process. The relevance of the analysis of the relief of the territory is due to the influence of geomorphological characteristics on the magnitude and dynamics of erosive land degradation. The research methodology is based on the use of geoinformation systems for the development of analytical maps based on digital elevation models and geostatistical analysis of the spatial distribution of its structure. Geostatistical analysis is a part of the geoinformation analysis of the relief, thanks to which the description of the physical and geographical scheme of the interaction of landscape components is carried out. Geoinformation analysis of the Astrakhan Trans-Volga region revealed that 63% of the territory has an inclination angle from 0 to 1°, and 90% does not exceed 3.0°. The distribution of the territory by orientation relative to the cardinal points is uneven; the main part of the territory (74.38%) has a southern exposure. The territories with the western, eastern and southeastern exposure (1.21%, 0.05%, and 5.19%, respectively) received the least distribution in quantitative terms. The research results are presented with analytical relief maps, elevation ranges in the study area, and slope steepness. These results make it possible to assess the erosion hazard of such areas and develop measures to prevent their degradation in advance.

Подбор кормовых кустарников для реставрации деградированных полупустынных пастбищных экосистем

Abstract. The purpose. the study is aimed at the introduction and adaptive assessment of perennial fodder plants from the collection of the Uzbek Research Institute of Karakul Breeding and Desert Ecology for use in the restoration of arid degraded pasture ecosystems in the semi-desert zone of southern Russia. Methods. An assessment was made of adaptive capabilities, including: response to drought, frost resistance, productivity, nutritional value of fodder shrubs of the families Chenopodiaceae, Fabaceae, Poaceae, Elaeagnaceae, Polygonaceae, Asteraceae from the collection of the Uzbek Research Institute astrakhan breeding and desert ecology in modern conditions of climate aridization on light chestnut soils of the Astrakhan region. Results. The studies were carried out in arid climatic conditions on infertile soils (humus content – 0.91–1.2 %). In the second year of vegetation, the plant height was 0.82–1.29 m, which will contribute to the retention of snow on the pasture. All studied fodder shrubs had a significantly high energy feed unit index - 0.802–0.972 and a green mass yield of 5.7–38.7 t/ha, respectively, a smaller weight (5.7 t/ha) during the growing season was increased by Haloxylon aphyllum. Scientific novelty. All the studied introduced shrubs showed a high adaptive life potential in the arid semi-desert conditions of the study region, including high drought resistance, undemanding soil fertility, a long growing season (200–230 days) and high energy capacity, which exceeded the energy feed unit of the natural grass stand by 0.07–0.24. The use of these shrubs in the restoration of degraded pastures will increase their species diversity, productivity and nutritional value. All this will make it possible not only to increase the fodder capacity of reclaimed pastures, but also to improve their reclamation state, due to snow retention.

ШЕТ АУДАНЫНЫҢ ГИДРОНИМДЕР ЖҮЙЕСІН ЗЕРТТЕУДІҢ ГЕОГРАФИЯЛЫҚ НЕГІЗДЕРІ

The article studies the system of hydronyms of the Shet district of the Karaganda region, analyzes more than 250 hydronymic names and terms. The significance of hydronyms, which provide extensive information from the natural conditions and landscape features of the territory located on the border of the steppe and semi-desert zones, is comprehensively characterized. Hydronymic names serve as the only sign system that gives a spatial description of the area. In the course of the study, the hydronymic names were grouped and a map of the hydronyms of the territory was compiled based on actual data.

Increasing the Biodiversity of the Dendroflora of Sparsely Wooded Regions by Adapted Representatives of the Genus Robinia L.

Purpose of the study: to substantiate the prospects of using various species, varieties and forms of the genus Robinia in protective afforestation and landscaping of settlements in dry-steppe and semi-desert zones of southern Russia. It is established that the main limiting factors affecting the growth, development and condition of representatives of the genus Robinia in the Volgograd region are winter temperatures up to −37 °C, as well as poor moisture availability and uneven distribution of precipitation during the growing season in combination with extremely low temperatures in the autumn–winter period. All representatives of the generic complex belong to the group of plants that start late and finish the vegetative period late. Phenological atypicity is in the lower half of the normal range, with indicators from +1 °C to 0, which indicates a high level of adaptation to the climatic conditions of the region. In the process of long-term acclimatization, many introduced species have developed a number of genotypic adaptations and are currently able to tolerate extreme winter temperatures up to −37 °C. An assessment of potential drought resistance based on the water-retaining ability of the leaves showed that higher rates of water-resistance capacity (76.8% water loss) are typical of R. neomexicana, which has a natural distribution area in the western arid part of the North American continent. R. viscosa var. hartwegii, with a natural distribution in the areas of the monsoon subtropical climate of eastern North America, is distinguished by low indicators (94.1% water loss), as are clonal decorative forms of R. pseudoacacia: f. pyramidalis and f. umbraculifera (97.6–95.8% water loss), which are common only in culture and characterized by a whole complex of low indicators of bioecological stability. The data obtained by us allow us to recommend the following assortment of species and forms of Robinia for protective afforestation and landscaping in the arid territories of southern Russia: R. pseudoacacia, R. neomexicana var. neomexicana, R. neomexicana var. rusbyi and R. pseudoacacia x R. neomexicana.

Environment or genetic isolation? An atypical intestinal microbiota in the Maltese honey bee Apis mellifera spp. ruttneri.

Apis mellifera evolved mainly in African, Asian, and European continents over thousands of years, leading to the selection of a considerable number of honey bees subspecies that have adapted to various environments such as hot semi-desert zones and cold temperate zones. With the evolution of honey bee subspecies, it is possible that environmental conditions, food sources, and microbial communities typical of the colonized areas have shaped the honey bee gut microbiota. In this study the microbiota of two distinct lineages (mitochondrial haplotypes) of bees Apis mellifera ruttneri (lineage A) and Apis mellifera ligustica and carnica (both lineage C) were compared. Honey bee guts were collected in a dry period in the respective breeding areas (the island of Malta and the regions of Emilia-Romagna and South Tyrol in Italy). Microbial DNA from the honey bee gut was extracted and amplified for the V3-V4 regions of the 16S rRNA gene for bacteria and for ITS2 for fungi. The analyses carried out show that the Maltese lineage A honey bees have a distinctive microbiota when compared to Italian lineage C honey bees, with the most abundant genera being Bartonellaceae and Lactobacillaceae, respectively. Lactobacillaceae in Maltese Lineage A honey bees consist mainly of Apilactobacillus instead of Lactobacillus and Bombilactobacillus in the lineage C. Lineage A honey bee gut microbiota also harbors higher proportions of Arsenophonus, Bombella, Commensalibacter, and Pseudomonas when compared to lineage C. The environment seems to be the main driver in the acquisition of these marked differences in the gut microbiota. However, the influence of other factors such as host genetics, seasonality or geography may still play a significant role in the microbiome shaping, in synergy with the environmental aspects.

The Kalamoon University Campus: An oasis in the desert

The university campus built in the desert and semi-desert zone in countries with a hot climate is becoming important not only for the sustainable urban development of the region, but also for solving global problems associated with climate change and reducing carbon footprint. The article discusses the history of the creation of the campus of the private Kalamoon University in Syria, which shows how the university has an impact on the urban development of the city of Deir Atiyah and the surrounding areas. Against the backdrop of a difficult geopolitical situation, the Kalamoon University Campus has become an “oasis in the desert” and currently represents a modern university architectural and landscape complex with a comfortable and accessible environment, which is an example of effective development of territories in a hot climate, as well as one of the “anchor elements” of the urban planning system of the Al-Kalamoon region.

Роль пастбищных растений в экологии полупустыни

In the territories of the South of Russia in semi-desert zones, livestock breeders perform one of the important tasks in solving the food program, in particular, the production of meat products, cattle and small cattle. Currently, livestock breeders are experiencing difficulties in pasture fodder production, in connection with this, we have worked out restoration work with the introduction of more resistant and highly productive plants of halophytes (gray teresken - (Eutoria ceratoides (L.), prostrate kochia - Kochia prostrata (L.), Lessing's camphorosma - (Camphorosma lessingii Litv.), etc.), which withstand droughts due to a powerful and deeply penetrating root system. Based on our recommendations, these projects have been put into production in the Republic of Kalmykia and the Astrakhan Region. The Tersko-Kuma lowland of the Chechen Republic also covers semi-desert zones, precipitation during the growing season is limited, on average 300-350 millimeters, summer days are quite hot, evaporation exceeds precipitation, which negatively affects vegetation and ecological condition. zones. It negatively affects pastures, as mentioned above, livestock breeders experience difficulties due to the lack of pasture fodder. To change the existing conditions, it is necessary to restore and improve degraded pastures by reseeding more resistant shrubs, semi-shrubs and herbaceous plants that can consume moisture deep in the soil. Such types of plants were tested at the Caspian Research Institute and the All-Russian Research Institute of Feeds. V.R. Williams. Using these experiences in production, it is possible that we will correct the lack of food supply, the biodiversity of vegetation and improve the ecological state in the Terek-Kuma lowland of the Chechen Republic.

Irrigation regimes for drip irrigation of watermelon in mulched and non-mulched fields

In most regions of Uzbekistan, the biological productivity of the climate will decrease by 10-20%, and in some regions by 30-40%, the steppe and semi-desert zones will expand further. Therefore, it is impossible to effectively develop irrigated agriculture without the development and implementation of resource and water-saving technologies aimed at increasing the efficiency of irrigated water use. We carried out our experiments based on the development of optimal irrigation norms for the cultivation of watermelon plants in mulched fields by drip irrigation, keeping the differentiated soil moisture (60...70...60%, 65...75...65%, 70…80...70% and 75…85...75% SAM) in the defined norm. In this case, the soil moisture limit before irrigation is 60...65...70...75% SAM according to the experimental options of 0-20 cm layer in the “planting - shatrik” period and 0-40 cm layer in the “shatrik - bloom” period; The 0-50 cm layer was maintained at 70...75...80...85% SAM during the “bloom - fruit formation” period and the 0-50 cm layer at 60...65...70...75% SAM during the “ fruit formation - ripening” period.

Improvement of the state of degraded pastures by mechanized sowing of shrubs and semibrubs

This article presents the extensive agricultural characteristics of fodder plants growing wild in nature, which are the most promising shrub and semi-shrub fodder plants for the creation and development of cultivated pastures in degraded karakul (sheep) pastures. Also, the fact that out of 17.5 million hectares of land allotted for karakul breeding in the desert and semi-desert zones of the Republic, which up to 40 percent are degraded to one degree or another, their average productivity has decreased by 21 percent. The authors of the article analyzed degraded pastures in desert and semi-desert zones of Uzbekistan and foreign countries and ways to improve their condition. A method is recommended for restoring degraded pastures by mechanizing the sowing of seeds of shrubs and semi-shrubs. Studies on the mechanization of sowing small-seeded and non-flowing seeds show that, firstly, the mechanized sowing of desert fodder plants is largely carried out on the basis of agrotechnical methods in conditions that do not correspond to the specific conditions of deserts, and secondly, shrub and semi-shrub plants and their seeds have physical and mechanical properties that are very different from other crops and seeds. A universal sowing unit is recommended, which consists of a four-sowing machine, which, in one pass of the technological process of work, sows seeds of shrubs and semi-shrub desert fodder plants with relatively close seed sizes. At the same time, the hoppers of the sowing unit are filled with 1, 2, 3 or 4 types of seeds of different plants and the seeds are sown. During the operation of the unit, the first hopper of the sowing machine is filled with shrub seeds (for example, saxaul) and the hoppers of the remaining 2, 3 and 4 sowing machines are filled with one or different types of seeds of semi-shrubby plants (Izen, keiruk, teresken), etc. The universal sowing machine sows seeds in one direction 3.6 m wide, and when returning, it also sows seeds 3.6 m wide, forming a pasture strip with a total width of 7.2 m. In the first row, it sows the seeds of a shrub plant (for example, saxaul seeds) and, in the remaining 2, 3, 4 rows - different types of seeds of semi-shrubs, for example, seeds of izen or seeds of other semi-shrubs, while on both edge rows of the pasture strip, he sows seeds of shrubs between them, sows seeds of semi-shrubs and creates a pasture-protective strip, consisting of shrubs and semi-shrubs. Simultaneous sowing of shrubs along the two edges of the strip provides for the protection of these undersized semi-shrubs from heat, strong wind and dust, as a result of which they develop better. The following parameters of the universal seeding unit were determined: the speed of movement of the unit is 1.38 -2.22 m/s; working width of the universal sowing unit 3.6 m; quantity of the sowing device 4 pieces; distance between sowing units 0.9 m; the number of seed mixture mixers in the lower part of the hopper is 6 pieces; lengths of cone-shaped fingers softeners of the seed mixture 7.0 cm; normalizing drum radius 5.0 cm; number of revolutions of the normalizing drum 26-30 r/min; length of the normalizing drum 7.0 cm; quantity of triangular chute 8 pieces.

Түркістан облысында агрометеорологиялық жағдайлардың ерекшеліктері

Анализированы тенденции изменения агрометеорологических показателей в Туркестанской области за период с 1991 по 2022 год. Наблюдается тенденция роста суммы температуры воздуха за вегетационный период, тенденция снижения суммы осадков за вегетационный период, тенденция снижения значений коэффициента увлажнения К и индекса засухи ГТК. Такие условия предполагают рост теплообеспеченности вегетационного периода, рост количества жарких дней, снижение влагообеспеченности и усиление засушливости вегетационного периода. Годы с благоприятными погодными условиями имеют повторяемость 30 % в горной полупустынной зоне. Годы с удовлетворительными погодными условиями имеют повторяемость 20% в горной полупустынной зоне и 10 % в горной пустынной зоне. Годы с неблагоприятными погодными условиями имеют повторяемость 100 % в пустынной зоне, 90 % в горной пустынной зоне и 50 % в горной полупустынной зоне.

Distribution of crustaceans (Malacostraca, Arthropoda) in rivers of the semi-desert zone (with the example of the Volgograd reservoir tributes)

As a result of our studies of the macro- and nectozoobenthos of the rivers of the semidesert zone (the Volgograd reservoir basin), 16 Malacostraca species were recorded, most of which are representatives of the Ponto-Caspian complex. Compared to the Volgograd reservoir, there is an increase in the quantitative indicators of mysids and isopods and a decrease in the number of species, abundance and biomass of amphipods and cumaceans in the semi-desert zone rivers. The average abundance and biomass of crustaceans in the surveyed rivers are approximately 2.5 times lower than in the Volgograd Reservoir. Crustaceans of the Ponto-Caspian and PontoAzov complexes, as well as the isopods Asellus aquaticus (Linné, 1758) inhabit fresh and oligohaline waters, while the gammarids Gammarus lacustris (Sars, 1863) live in oligohaline and polyhaline waters. Amphipods are characterized by the largest number of species, which, taking into account their morphology and the type of substrate which they live on, are assigned to three ecomorphs, namely: clingers, crawlers, and diggers. No symbionts in the Yeruslan basin rivers were found. The noted amphipod ecomorphs are distributed relatively evenly with a slight dominance of crawlers (45%). It has been revealed that two types of crustacean cenoses are formed in the surveyed rivers. The first type is formed mainly by consortium interactions of the edificatory mollusks Dreissena with amphipods Chelicorophium curvispinum Sars, 1895, Dikerogammarus haemobaphes (Eichwald, 1841), mysids Paramysis ullskyi Czerniavsky, 1882, P. lacustris (Czerniavsky, 1882), and associated species. The second cenosis in the rivers is represented by a complex of small coastal mysid species Katamysis warpachowskyi Czerniavsky, 1882, Limnomysis benedeni Sars, 1893, and amphipods Chaetogammarus warpachowsky (Sars, 1894), the relationships within which are based on common biotopic conditions and feeding patterns.

Species composition of bone remains of animals from medieval Аspara and Sharuashylyk settlements (according to the results of the excavations of 2021)

New data on the species composition of the late Middle Ages paleofauna (13-15 centuries) are published, obtained from excavation materials on hillforts of Aspara and Sharuashylyk in valleys of the Shu and Talas rivers. The hillfort of Aspara is located on the foothill plain north of the Kyrgyz Alatau, on the left bank of the river. Aspara is the left tributary of the Shu river. The hillfort of Sharuashylyk is located in the lower reaches of the river. Talas, in the semi-desert zone, at the southwestern outskirts of the sandy desert of Moyynkum. A comparative study of the paleofauna of late medieval settlements located in different landscapes of the Shu-Talas interfluve is carried out for the first time. 3047 mammalian bones were studied, 67.1% of which were determined up to the species. Almost all bone remains determined before the genus and species belong to pets (95.9%). Among the bones of mammals and birds from Sharuashylyk, the proportion of pets is 99.3%, and in the hillfort of Aspara - 96.6%. More than half of the sample (51.3%) are small cattle bones. The second place in terms of number belongs to the remains of cattle (30%), in third place – to horses (16.8%). Small numbers of camel bones and dogs are present. The obtained data make it possible to assess the degree of similarity and differences of paleozoological complexes of two simultaneous sites located in different natural and geographical zones. Keywords: Shu-Talas interfluve, later Middle Ages, Aspara, Sharuashylyk, paleozoology, animal husbandry, hunting.

Features of the population dynamics of larks (Alaudidae, Aves) in the semi-desert zone of the Saratov Trans-Volga region

The paper presents the results of our long-term monitoring of the family of larks (Alauda arvensis L., Melanocorypha calandra L., M. leucoptera Pallas, M. yeltoniensis J. R. Forster and Calandrella rufescens Vieillot) in the semi-desert zone of the Saratov Trans-Volga region. Bird censuses were carried out at 4 key sites on permanent routes during the nesting period, the total length of the census transects was 792 km. Statistical indicators of population dynamics were calculated, namely: the growth rates (Tnp.) and average density values (ind. / 100 ha) of each lark species. A statistical multivariate factor analysis (F-test) was carried out, with the help of which we were able to reveal the influence of a whole range of factors on the lark density dynamics. Changes in habitat conditions at the key areas (Fcrit. = 1.30, p = 0.003), as well as weather factors (Fcrit. = 1.39, p = 0.004) of particular years, have a significant impact on the density dynamics of larks. Evaluation of the variance showed heterogeneity of the sample (St = 0.119, p = 0.006), therefore, the average densities of larks differs significantly from each other. Thus, the structure of the lark community and the annual density of each species are the result of the environmental conditions of the habitats at each key site, and the weather conditions of particular years.

Mongolian Marmot (<i>Marmota sibirica</i>) Ecosystem Engineering Effects on Herpetofauna

The Mongolian marmot (Marmota sibirica) is a relatively large-bodied, social rodent that lives in colonies across the Mongolian steppes and adjacent parts of China and Russia. Marmots serve as ecosystem engineers that display multiple functions on the steppe environments they inhabit. Mongolian marmots experienced a 75% decline across Mongolia in the 1990s that led to their listing as endangered globally. The decline of marmots likely affected other species given their importance to the ecosystems they inhabit. To examine the role of marmots on herpetofauna, we established drift fence arrays with associated pitfall and funnel traps on active marmot colonies, inactive colonies, and control sites in the forest-steppe and semi-desert zones of Mongolia. In total, we identified 555 individuals representing 5 species of reptiles in Ikh Nart Nature Reserve (semi-desert) from 2010 – 2011 and 22 individuals of 3 species of reptiles and one amphibian species in Hustai National Park (forest-steppe) in 2014 and 2016. We found significantly higher species abundance and some diversity indices on active and inactive colonies compared to control sites in Hustai. Vegetation height and cover significantly affected the abundance and species richness of reptiles in Ikh Nart. In Ikh Nart, we found that under conditions of higher vegetation cover and height, reptiles were distributed more widely across the landscape, but with lower vegetation cover and height, reptiles associated more strongly with marmot burrows. Burrows likely provide shelter from extreme climatic conditions and refugia from predation. Our research provides insights into how marmots create important habitats for associated fauna. This and similar experimental approaches will allow us to better understand the biodiversity patterns in and around marmot burrows.

Evaluation of productivity and biochemical composition of fruits of promising apple varieties, grown in the arid zone

Relevance. The list of imported varieties and rootstocks is often determined by the marketing policy of the producing countries ; they had not been tested for specific conditions. For the first time in the arid conditions of the Astrakhan region a comprehensive assessment of new introduced apple varieties of autumn and winter ripening period was carried out to select a modern adaptive assortment for arid conditions.Methods. The experiment was laid in 2012 in the experimental orchard of the Caspian Agrarian Federal Scientific Center of the Russian Academy of Sciences. The purpose of the research is a comprehensive assessment of apple varieties by economic and biological indicators to optimize the regional assortment and selection of the best varieties for cultivation using intensive technologies in the Astrakhan region. The article presents the results of the study of 9 new apple varieties by productivity components in the semi-desert zone of the Northern Caspian Sea.Results. It was found that in the conditions of the arid zone, the most rapid-fruiting varieties are Renet Simirenko, Prikubanskoe, Pamyati esaulu and Renet Kubansky, who fructified in the second year of vegetation (0.2–0.5 kg/tree). Prikubanskoye (31.0 t/ha), Galakub (31.1 t/ha) and Pinovo (28.7 t/ha) varieties have been characterized by high yields over the past five years. The harmonious taste of apple fruits distinguished varieties Prikubanskoe, Pamyati esaulu, Renet Kubansky (16.7–20.0). Varieties Zolotaya korona, Paskhalnoe, Galakub, Red Chief and Pinovo had sweeter fruits (21.0–35.8).

Promising cultivars of winter triticale for grain production in the north-west of the Astrakhan region

Triticale, due to its specific properties to form stable grain yields in the zones with risky agriculture, should find wider application in acutely arid conditions. Therefore, the use of highly productive cultivars of winter triticale in semi-desert zone of the north-west of the Astrakhan region is relevant. The aim of the research was a comprehensive assessment of promising winter triticale cultivars of different ecological and geographical origin for adaptability to stressful meteorological factors in semi-desert zone of the northwestern Astrakhan region. To determine the main indicators of adaptability (winter hardiness, plasticity, stability, stress tolerance, genetic flexibility), six promising winter triticale cultivars (Tribun, Interes, PRAG 152, Khleborob, Zhnets and Uragan) were studied. Field agroecological tests were conducted on rainfed fields of Precaspian Agrarian Federal Scientific Center of the RAS with different moisture level in 2018-2020. Nelli cultivar was used as a control. The methods of Selyaninov G.T., Zhivotkov L.A., Eberhart S.A., and Rassell W.A. were used for calculations. During periods of active vegetation of winter triticale, Selyaninov hydrothermal coefficient varied from 0.3 to 0.5 (zone of strong and very strong drought); environment index was from -0.67 to 0.66. According to the data obtained, cv. Khleborob showed the greatest adaptive potential and consistently high yield under various meteorological conditions of the season compared to the other tested winter triticale varieties. Moreover, the cultivar had good winter hardiness (5 points) and survival (90.8 %). On the average for the years of research it showed high adaptability coefficient (1.43), and the indicators of its plasticity and genetic flexibility were 0.77 and 1.40, respectively. Therefore, cv. Khleborob can be recommended for use in the acutely arid conditions in semi-desert zone of the northwestern part of the Astrakhan region.

Comparative assessment of the resistance of introduced spring oat varieties to arid climate of the Astrakhan region

In the semi-desert zone of the north of the Astrakhan region, a comparative assessment of spring oat varieties from the world collection of VIR was carried out. The 2019-2021 studies included 57 variety samples. Based on the results of the study, the most resistant samples were identified, capable of producing a stable crop, regardless of the climatic conditions of the current years. These samples are distinguished by: high field germination, early maturity, high levels of plant productivity elements, and, consequently, high genetic potential of variety samples. Selected varieties: Leo, Scorpion and Borets (Moscow region) with a yield of 3.48, 3.00 and 2.70 t/ha, respectively.

Evaluation of apple varieties of winter ripening period according to the rate of fertility and the strength of growth in the arid region

For the first time in the conditions of the Northern Caspian Sea, a comprehensive assessment of new introduced apple varieties of winter ripening period is carried out to select a modern adaptive assortment for arid conditions. The experience was laid in 2018 in the experimental orchard of the Caspian Agrarian Federal Scientific Center. The article presents the results of studying the indicators of growth and development, fertility and fruiting of 14 new varieties of apple trees of winter maturity in the semi-desert zone of the Northern Caspian. It was found that during the study period, no significant damage to the trees of the studied varieties was observed in winter. The survival rate of the studied varieties was high and amounted to 64.6–100.0%. More restrained growth of trees in height was characterized by the varieties Winespur, Red Chief, Reinet painted and Korey. The varieties Golden Delicious, Prikubanskoe, Pinova, Memory of Yesaulu, Red Chief, Painted and Ligol were the most fertile, in which 15.6–64.8% of trees bloomed and formed fruits. The maximum productivity was recorded in the variety Renet Kuban (7 kg /tree Varieties Starkrimson and Prikubanskoye have complex resistance to scab, brown spot and rust.