Mobile Sand Research Articles

Vegetation Growth and Physiological Adaptation of Pioneer Plants on Mobile Sand Dunes

The Hunshandake Sandy Land is one of the largest sandy areas in China and the closest source of sand dust to the Beijing and Tianjing areas. Sand fixation by vegetation is considered the most efficient strategy for sand control and sustainable development, so clarifying the vegetation coverage and plant adaptation characteristics in the Hunshandake Sandy Land is helpful in guiding restoration and improving local sustainability. Here, we investigated the vegetation growth on the mobile sand dunes in the Hunshandake Sandy Land and specified the photosynthesis and stomatal characteristics of the pioneer plants for sand fixation. The vegetation survey showed that the windward slopes of the mobile sand dunes had far lower plant coverage (6.3%) and plant biodiversity (two species m−2) than the leeward ones (41.0% and eight species m−2, respectively). Elymus sibiricus L. and Agriophyllum squarrosum (L.) Moq. were the only two sand-fixing pioneer plants that grew on both the windward and leeward slopes of the mobile sand dunes and had higher plant heights, greater abundance, and more biomass than other plants. Physiological measurements revealed that Elymus sibiricus L. and Agriophyllum squarrosum (L.) Moq. also had higher photosynthetic rates, transpiration rates, and water use efficiency. In addition, the stomata density (151–197 number mm−2), length (18–29 μm), and area index (13–19%) of these two pioneer species were smaller than those of the common grassland species in Inner Mongolia, suggesting that they were better adapted to the dry habitat of the mobile sand dunes. These findings not only help in understanding the adaptive strategies of pioneer plants on mobile sand dunes, but also provide practical guidance for sand dune restoration and the sustainable development of local areas. Pioneer sand-fixing plant species that are well adapted to sand dunes can be used for sowing or aerial seeding in sand fixation during ecosystem restoration.

Fertile island variation depends on species differences in the deserts of Northwest China

Desert ecosystems are extremely arid and nutrient poor. “Fertile islands” formed by mobile sand dunes and perennial desert plants are crucial for maintaining the structure and function of these ecosystems. However, the impacts of fertile islands created by different plant species at various spatial locations on soil physicochemical properties such as soil nutrients remain unclear. This study focused on the legumes (Astragalus flexus Fisch.), and non-legume (Eremurus inderiensis (M. Bieb.) Regel) plants widely distributed in the Gurbantunggut Desert in northwestern China. We analyzed the soil physicochemical properties of fertile islands formed by these two desert plants at different horizontal distances (0–140 cm) and vertical depths (0–15 cm). In addition, we investigated the relationship between plant functional shape and soil physicochemical properties. This study yielded the following results. (1) The fertile island was observed within the 0–140 cm soil layer of Astragalus flexus and Eremurus inderiensis and gradually weakened with increasing horizontal distance and soil depth. (2) The two plants had different nutrient enrichment rates. Eremurus inderiensis had higher TP and AK enrichment rates than Astragalus flexus. In contrast, Astragalus flexus demonstrated significantly higher enrichment rates for TN, NH4+-N, and NO3−-N, especially NH4+-N, highlighting the ability of legumes to fix and uptake N. (3) The correlation between plant height, crown width, and soil nutrient enrichment rate was more significant for Eremurus inderiensis than for Astragalus flexus. In general, both plants formed the fertile islands that gradually decreased with the increasing distance (both horizontal and vertical). Different plants exhibited varying abilities to enrich soil nutrients and form fertile islands, which presented a clear species effect. Therefore, protecting the diversity of desert plants to form stable fertile islands could be crucial for maintaining the soil fertility in desert ecosystems.

Changes in soil bacterial community characteristics in patches of different vegetation types under different stages of restoration in the desert of northern China.

In desert areas, the process of mobile sandy land changing to semi-fixed sandy land and eventually to fixed sandy land after undergoing vegetation restoration is inevitable. The presence of shrub patches and herb patches is common in this restoration process. No relevant studies have reported the soil bacterial community characteristics of different vegetation-type patches (shrub patches and herb patches) under different stages of restoration. Therefore, we utilized long-established experimental plots to collect soil from 0-20 cm soil layer under shrub patches (dominated by Salix psammophila) and herb patches under different stages of restoration (i.e., mobile sand land, semi-fixed sand land, and fixed sand land), by determining soil physicochemical properties, enzyme activities, and soil bacterial communities. Our results found that soil bacterial α-diversity under different restoration stages showed higher shrub patches than herb patches. The dominant bacterial communities (phyla) in shrub patches and herb patches at different recovery stages were Actinobacteria, Proteobacteria, and Bacteroidota. When the mobile sandy land returned to fixed sandy land, the relative abundance of Actinobacteria and Bacteroidota gradually decreased under shrub patches and herb patches, while the relative abundance of Proteobacteria increased significantly. In addition, herb patches significantly increased the relative abundance of bacteria (genus) relative to shrub patches at different stages of recovery. Soil nutrients, soil fine particles, and soil enzyme activities were significantly higher under shrub patches than under herb patches when fixed sandy land due to differences in life form and architecture between shrub patches and herb patches. Based on this, soil bacterial community composition and diversity under shrub patches were driven by more soil properties during the restoration of sandy land. This study complements the dynamic recovery processes and driving mechanisms of soil bacterial community structure under different vegetation patches in sandy areas, especially in the context of global climate change.

Soil Carbon and Nitrogen Stocks and Their Influencing Factors in Different-Aged Stands of Sand-Fixing Caragana korshinskii in the Mu Us Desert of Northwest China

Establishing artificial sand-fixing shrubs is a key measure to curb dune flow and drive changes in the soil stocks and cycling of carbon and nitrogen. But our understanding of these dynamics across years of sand-fixing afforestation and the factors influencing them remains inadequate, making it hard to accurately assess its capacity to sequester carbon. To fill that knowledge gap, this study investigated soil organic carbon (SOC) and soil total nitrogen (STN) stocks in Mu Us Desert under artificial sand-fixing shrub stands of different ages (10, 30, 50, and 70 years old) vis-à-vis a mobile sand dune, to determine whether Caragana korshinskii afforestation improved stock characteristics and whether SOC and STN stocks were correlated during the restoration processes. The results showed that the pattern observed is consistent with an increase over time in the stocks of both SOC and STN. At 10, 30, 50, and 70 years, these stocks were found to be 1.8, 2.3, 3.2, and 5.5 times higher for SOC, and 1.3, 1.6, 2.1, and 2.7 times higher for STN, respectively, than those of the control (mobile sand) dune. Stocks of SOC and STN mainly increased significantly in the 0–10 cm soil layer. The SOC stock was correlated positively with the STN stock as well as the C:N ratio. The slope of the regression for the C:N ratio against stand age was positive, increasing slightly faster with afforestation age. Additionally, our findings suggest that during the establishment of artificial stands of shrubs, the size of the STN stock did not expand as fast as the SOC stock, resulting in an asynchronous N supply and demand that likely limits the accumulation of soil organic matter. This research provides important evidence for the sustainable development of desertified ecosystems.

Short-Term Foredune Dynamics in Response to Invasive Vegetation Control Actions

Efforts to control the spread of invasive alien species (IAS) in coastal dunes are essential to protect biodiversity and maintain the integrity of the ecosystem. However, the timing and extent of these control measures often do not consider their potential impact on dune morphodynamics. This study investigated how IAS control measures can affect sand dune mobility. Research involved monitoring short-term morphological and vegetation changes using close-range remote sensing along with historical wind data. Findings revealed that changes in vegetation cover significantly impacted dune system evolution, notably increasing sand mobility when IAS vegetation was removed. Considering the seasonal wind regime, dominated by offshore winds in the summer, removing vegetation during this period can promote seaward sediment transport, potentially resulting in sediment loss to the beach. These findings highlight the importance of understanding sediment mobility patterns when planning vegetation control actions within dune restoration strategies.

Divergent changes of carbon and nitrogen in the density fractions of soil organic matter after revegetation in the Tengger Desert, north China

AbstractRevegetation is an effective measure to enhance soil organic carbon (OC) and nitrogen (N) storage in drylands, but the underlying processes remain poorly understood. Based on density fractionation, the free light fraction (fLF), the occluded light fraction (oLF), and a heavy fraction (HF) were extracted from a chronosequence of revegetated sites aged 10, 22, 34, 48, and 65 years. A mobile sand dune (MSD) was used as the reference site (aged 0 years). The OC and N contents of different fractions and the bulk soils were determined to evaluate the impacts of revegetation and clarify post‐revegetation stabilization mechanisms for the OC and N. The results showed that the dry mass of fLF and oLF in established shrublands were 17.16–31.30 and 17.68–44.87 times greater than those in the MSD, respectively, while the amount of HF decreased by 1.09%–2.51% in 65 years. The contents and stocks of OC and N and C:N ratio in each fraction significantly increased over time but decreased with soil depth, and these three variables decreased sequentially from fLF to oLF to HF. The OC and N contents and their ratios in each fraction were positively and linearly correlated with their corresponding values in the bulk soil. The OC and N percentages contained in the fLF and oLF increased significantly, but those in the HF decreased with increasing site age. Despite this, more than 55.08% of OC and 80.59% of N were remained in the HF across all the sites, indicating that the enhancement of OC and N stocks in SOM following revegetation were mainly derived from an increase in OC and N in protected fractions. Biological and physicochemical factors including microbial biomass C and N, the availability of N, P, and K, bulk density, and clay and silt contents, were the key factors regulating the OC and N dynamics in the density fractions. The initial OC and N accumulation after revegetation occurs mainly in the HF, while vegetation development shifts the OC and N from stable to labile pools. The OC and N accumulation in revegetated soils is attributed to the changes in both the LF and HF whereas OC and N in the light fraction become increasingly important over time. Stabilization by forming aggregates and mineral associations may dominate the long‐term OC and N sequestration in restored ecosystems.

Analysis of the effects of climatic elements on the mobility of wind-blown sand in the west of Lut desert

Analysis of the effects of climatic elements on the mobility of wind-blown sand in the west of Lut desert

Phytosociological analysis of the Sidi Boughaba Biological Reserve, Kénitra, Morocco

Abstract The biological reserve of Sidi Boughaba has a unique plant biodiversity, with many animals, including birds, finding refuge there. Data on this biodiversity is old and incomplete. This phytosociological study was carried out to define the vegetation structure of the area. Stratified sampling was carried out and 124 relevés were recorded. Multivariate statistical analyses (correspondence factorial analysis and hierarchical ascending classification) used to process the relevés revealed the presence of 9 plant groups, including 4 plant associations and 5 subassociations, which belong to 3 phytosociological classes (Ammophiletea, Quercetea ilicis and Querco roboris-Fagetea sylvaticae). Quercetea ilicis is the most widespread in the area, showing several successional stages on grey and consolidated dunes. Vegetation of Ammophiletea can only be found on mobile sand. Vegetation of the class Querco roboris-Fagetea sylvaticae occupies an inter-dunar depression on hydromorphic soil. The association Pterido aquilinum-Populetum albae is newly described as five subassociations of Clematido cirrhosae-Juniperetum lyciae.

Research and exploration on cymatics in sound visualization

The article reveals the connection between kinematics and music. Cymatics is a process by which sound can be visualized on a physical substance, and then captured in a photograph. For example, a kinematic image can be tracked through the impact of the speaker on the sand scattered on the plate. Thus, a fluctuating frequency expressed in Hertz will show an unusual result on the plate. The sound that propagates from the speaker in the environment provokes the mobility of sand on the plate, moreover, quite peculiar. Sand, as it travels from the area of the vibrating sections of the plate to places where the vibration does not reach, creates interesting forms of a symmetrical nature (lines, ovals, waveforms, ellipses and even straight edges). Those areas of the plate in which the vibration does not fall are called nodal points and lines.

Exploring the complexities of sand dune transformation: the role of anthropogenic degradation and climatic conditions

Introduction: The sandy soils in the arid Southern Balkhash region have experienced anthropogenic degradation, leading to the formation of bare mobile sand dunes. This transformation has created significant challenges for the growth of cattle feed, particularly in areas with high economic activity. As a consequence, the socio-economic situation of the local population has been significantly worsened, and even the development of tourism has not helped. The objective of this study was to investigate the relationship between the seasonal mobility of sand dune landforms and their hydrothermal regimes, as well as the climatic conditions of the region.Methods: To achieve the study objective, we conducted field investigations and collected data on the mobility of sand dunes, hydrothermal conditions, and climatic factors in the region. Measurements were taken during the summer months when dominant North-East, North-North-East winds prevailed, with an average frequency of 20.4–26.7 days per month and wind speeds ranging from 3.0 to 3.7 m/s, occasionally reaching up to 11.90–13.3 m/s. We also analyzed humidity, air temperature, and atmospheric precipitation levels.Results: Our findings revealed that during the summer months, a fresh-sided layer of sand actively supplied the windward part of the sand dune to the leeward one. This process occurred under very low humidity, high air temperature, and slight atmospheric precipitation conditions. Consequently, the moisture content of the surface root layer (0–20 cm) of the sand dune accumulation zone decreased to 0.2% in the middle and at the end of summer.Discussion: The observed relationship between the seasonal mobility of sand dunes and their hydrothermal regimes, along with the climatic conditions, provides valuable insights for the development of effective technologies to rehabilitate anthropogenically degraded desert sandy soils that have transformed into mobile sands. This knowledge can serve as a theoretical basis for addressing the challenges faced by cattle breeding in the region and improving the socio-economic situation of the local population.

Fuzzy-logic indicators for riverbed de-clogging suggest ecological benefits of large wood

Rivers provide dynamic habitats with ecological niches, particularly in their mobile sand, gravel, and cobble riverbed patches that create an active hyporheic zone. Natural or artificial deposition of fine sediment may clog the porous matrix of the hyporheic zone, impairing exchange processes between the subsurface and surface water. Clogging reduces the permeability of the sediment matrix, thus degrading the ecological functionality of the hyporheic zone. Once clogged, the ecological functions may be recovered through active stream restoration, which requires considerate site assessment. To this end, clogging is typically assessed by expert opinion of substrate characteristics including grain size characteristics, porosity, hydraulic conductivity, and interstitial oxygen content. To overcome limitations of expert assessment, such as subjectivity expressed in noisy decision-making, this study introduces a novel fuzzy-logic method based on physically sound rules. The method provides quantitative indicators for clogging and declogging to evaluate the effectiveness of stream restoration. We applied the fuzzy-logic method to test whether the placement of large wood, a common restoration practice, can locally prevent or reduce clogging. Two measurement series from before and after a morphologically effective flood suggested that large wood placements perpendicular to the flow generate elevated amounts of declogging. The tested logs caused a greater amount of declogging within their region of influence than observed at a reference point. The effect was stronger for a log emergent at baseflow. The declogging assessment showed that the novel fuzzy-logic indicators can reasonably overcome subjective judgment by accounting for multi-variate quantitative changes rather than individual parameter trends.

STABILITY OF BURIED SCOUR PROTECTION IN SHALLOW COASTAL WATERS

Physical model tests were conducted to verify the stability of a conceptual scour protection design placed around monopiles in varying water depth and under combined wave and current load. The tests were performed in a 3D wave-current basin at Ludwig-Franzius-Institute, Leibniz University Hannover in a model scale of 1:35. As a unique boundary condition compared to previous studies, the scour protection around the monopile was placed below a mobile sand bed. Before waves and current could act on the scour protection, the overlaying sand layer had to be eroded. The scouring process of this sand layer was evaluated, and the stability of the armour layer of the underlying scour protection quantitatively assessed. The characteristics of the scour development and the damage of the armour layer were described as a function of several wave-current load combinations and different morphodynamic stages of the beach.

Sand-fixing vegetation regulates deep percolation and soil water dynamics in semiarid sandy land: Evidence from a deep percolation recorder and in-situ test

Deep percolation (DP) determines the sustainable utilization of regional groundwater resources and provides large hydrological benefits to ecosystems in semiarid sandy regions. However, studies involving DP variability have rarely conducted in-situ tests with different vegetation coverages (VC) and vegetation types using direct measurements. This study measured soil moisture and DP for four years in five plots, with DP measured using a deep percolation recorder: mobile sand (MS) as the control group; Artemisia ordosica semifixed (AOSF) with VC of 30%–35% and Artemisia ordosica fixed (AOF) with VC of 70%–75% (AOSF and AOF stand ages: 30–40 years), representing different vegetation coverages; and Salix psammophila fixed (SPF) and Pinus sylvestrix var. Mongolica fixed (PSMF) with the same VC of 45%–50% (SPF and PSMF stand ages: 30 years), representing different vegetation types. The effects of sand-fixing vegetation on DP and soil water were evaluated using the relative extractable soil water (RESW) and soil water storage deficit metrics. DP occurrence in MS was closely related to rainfall amounts of > 10 mm and high-intensity rainfall rather than the total annual rainfall. Increases in vegetation coverages and forest selection significantly reduced DP and RESW compared with MS. DP in the shrub plot (SPF) was significantly higher than that in the forest plot (PSMF). Plants utilized water from different sources among the sandy land types: the shallow (0–80 cm) and deep layers (80–200 cm) in PSMF and AOF, and only from the shallow layer in AOSF and SPF. However, compared with MS, soil water storage deficit occurred to varying degrees in each plot. This study can provide a scientific reference for the restoration of the ecology and water cycle in sandy regions.

A Salt Tolerant Native plants as a Solution for Mobile Sand and Dust in Kuwait

In this study, a coastal research site north of Kuwait Bay faces sand encroachment, floods, and wave erosion. The plantation project’s infrastructure was improved by fencing 1.2 km2 with barbed wire. The heavily deteriorated environment has coppice dunes of Nitraria retusa and Lycium shawii around single, double, or triple plants. To manage mobile sand and dust and protect the research centre, 21,500 Nitraria and Lycium were planted and irrigated with brackish water (around 7000 TDS). In order to aerodynamically shift and/or trap mobile aeolian sediments, the vegetation was planted in a V-shape facing the north-westerly wind. A closer gap (about 1m between plants) on the side facing the primary wind and widened toward the inner edges of the gated area controls mobile sand and dust. This projected design stabilizes the soil, protects against floods and wave erosion, enhances flora and animals, and controls aeolian activity. Mobile sand and dust yearly rates in the downwind traps were reduced by 94% and 64.5%, respectively. Native vegetation can control mobile sand and dust, according to this. Such systems can be more efficient with proper design and plant spacing.

Shyshatska sand arena: History, current state, and prospects of afforestation

Non-afforested lands in Ukraine are the primary instrument for increasing the forest cover of the territory The issue of sand afforestation is relevant in the context of climate change. Treeless sand arenas are a source of dust storms, and deflationary processes that occur lead to negative consequences that are quite difficult to correct in the future. The purpose of this study was to summarise the experience and achievements of the branch “Myrhorod Forest Enterprise” of the State Specialised Commercial Enterprise “Forests of Ukraine” in afforestation of mobile sands in the conditions of the Forest-Steppe of Ukraine. Forest stands are established using one-year-old Scots pine seedlings on sandy soils to achieve the set goal. Testing is conducted using planting material grown under various conditions – in the open ground and in a greenhouse. Extended periods for establishing forest stands beyond agrotechnical terms are examined during the late spring and summer periods using rejuvenated planting material with partially damaged root systems. The current state of plantings within the Shyshatska sand arena is analysed. It is established that in general, the territory of the arena is represented by the entire range of types of forest conditions ranging from bors to mixed broad-leaved forests. The prevailing types of forest-growing conditions are given, among which dry and fresh forests are distinguished. Subors and su-deciduous forests are represented on small areas. Deciduous types of conditions are located mainly in the drained areas of the Psel River floodplain. The main forest-forming species on the territory of the arena is Scots pine, which occupies more than 60% of the territory. Also in the lowlands and floodplains of the Psel River stands of Black Alder and Common Oak grow. In the conditions of bors, Scots pine grows in III – Va bonitet class. In richer conditions, subor and su-deciduous forest cultures have better indicators and have a class I-II bonitet, but there are not many of them. The results of this study can be used in the afforestation of sandy lands in the Forest-Steppe of Ukraine and adjacent regions

A new aeolian activity proxy based on analysis of the grain size characteristics of surface soils across the Tengger Desert, northwest China, and its application to a Quaternary aeolian succession

The arid regions of northwestern China are dominated by extensive areas of mobile sand dunes. These features cause environmental problems and exert global climatic impacts; however, due to the lack of systematically-applied indicators of aeolian activity, direct evidence of past changes in aeolian activity is unreliable, especially for aeolian sand source regions. In this paper, we analyze the end-member (EM) distributions of various types of surface soil across the Tengger Desert in northwestern China, and devise a sensitive proxy for aeolian activity using a spatio-temporal substitution approach. This proxy is then used to evaluate a Quaternary aeolian succession and to understand the response of aeolian activity to regional climate change. Our results suggest that gradual increases in the coarse-grained EM components 3–5 reflect enhanced dune mobility and reduced vegetation coverage, which are a direct function of the intensity of regional aeolian activity. In the aeolian section, coarse- and medium-grained sand layers resemble modern semi-mobile and mobile dunes, whereas fine-grained sand layers are analogous to vegetated fixed/semi-fixed or semi-mobile dunes. Combining this record with independent multi-proxy evidence from the same section leads us to conclude that strong aeolian activity coincided with a dry climate, sparse vegetation cover, and strong surface winds during the Last Glacial Maximum, and that these conditions gradually attenuated at the beginning of the Last Deglacial. These inferences are in accord with independent paleoclimate records from this region, confirming that the intensity of aeolian activity in the southeastern Tengger Desert is closely associated with large-scale climate change. Our findings show that our EM proxy can be used to infer the intensity of aeolian activity and to reliably reconstruct the evolution of deserts in northwestern China.

Sandy beach dynamics by constrained wave energy minimization

This paper focuses on a new approach to describe coastal morphodynamics, based on optimization theory, and more specifically on the assumption that a sandy beach profile evolves in order to minimize a wave-related function, the choice of which depends on what is considered the driving force behind the coastal morphodynamic processes considered. The numerical model derived from this theory uses a gradient descent method and allows us to account for physical constraints such as sand conservation in wave flume experiments. Hence, the model automatically adapts to either wave flume or open sea settings and only involves two hyper-parameters: a sand mobility and a critical angle of repose. The ability of OptiMorph to model cross-shore beach morphodynamics is illustrated on a flume configuration. Comparison of the beach profile changes computed with OptiMorph with experimental data as well as the results from the coastal morphodynamic software XBeach demonstrates the potential of a model by wave energy minimization.

Modern relief formation of the northern Aral region under the conditions of the sea regression

The article examines the modern processes of relief formation in the Northern Aral Sea during the period of sea regression and the factors of their formation. The study aims to determine the predominant types of relief formation processes under the conditions of sea regression and the impact of an arid climate. The research methodology combines field observations, interpretation of remote sensing data, digital photogrammetric analysis of aerial photographs, and data processing in GIS. As a result of the study, a map of the modern land cover of the studied area of the Northern Aral Sea region was created. 13 types of cover were identified: wastelands (unused lands), lands occupied by settlements, arable land, wetlands, grasses, steppe with sparse vegetation, water surface, drained bottom of the Aral Sea, fixed sands, shifting sands, saline, and takyrs. The absence of vegetation indicates active gravitational processes and wind erosion. Several villages have been identified that are subject to the adverse effects of mobile sands; these are Kosaman, Akespe, Akbasty, Bogen, etc. In the villages of Akespe and Akbasty, residential houses and household premises of residents are covered with mobile sands. The relative height between the base and the crest of the dune, on average, is 2 meters. The development area of shifting sands in Akespe village is 1.68 km2, and in the village of Akbasty is about 1.62 km2. The values of the load factor of conditional cattle on pastures in the study area, where a high coefficient is noted in the village of Akbasty, are calculated. The development and implementation of environmental management measures in the conditions of adaptation of the environment and human activity to the increasing processes of climate aridization and its consequences become relevant.

<italic>De novo</italic> domestication and preliminary cultivar development of sand rice (<italic>Agriophyllum squarrosum</italic>), a sand dune pioneer species

<p indent="0mm">The comprehensive utilization of desert plants and sandy land resources is of far-reaching significance to the eco-civilization progress and food security in the arid region of northern China. The pioneer species <italic>Agriophyllum squarrosum</italic> is broadly distributed on the mobile sand dunes in the arid and semi-arid areas of northern China. Its seed, also called sand rice, has well-balanced nutritional values and has been consumed for more than <sc>1300 years.</sc> In 2010, our group first initiated the domestication research of sand rice by investigating the various historical literature and food consuming records of sand rice. Genetic modification and breeding are currently dependent on natural populations and artificial mutagenesis. A few modified lines with better agronomic traits have been initially isolated, laying a material foundation for further cultivation evaluation in different areas and cultivar declaration. However, the speed domestication of sand rice still requires systematically analyzing phenotypic variation among different germplasms, the establishment of a genetic transformation system, and isolating elite lines with a synchronous germination rate and strong seedling vigor.

EFFECT OF WIND AND HYDROTHERMAL REGIMES OF SAND DUNE ON MOBILITY OF RELIEF FORMS

The sandy pastures around the world are most often used year-round for cattle breeding. Here, desert sandy soils (Arenosols), which have become widespread, unlike the others, even with a short-term anthropogenic load, easily lose the texture of the surface horizon, which, under conditions of high wind activity, in a short time (5-7 years) turn into mobile sands and, with in the absence of work to fixing them, they quickly expand into hilly dunes. Due to the lack of vegetation in them, the processes of deflation and the appearance of foci of winding are rapidly developing. Such foci were formed in the Southern Balkhash region as a result of the intensive use of woody plants by local residents as a source of fuel and daily cattle passing. They thereby became, on the one hand, the "conductor" of desertification, and on the other hand, its victim. To restore the fertility of such formations, we wanted to understand first of all how dunes are created and how they undergo changes over time. Therefore, we studied the influence of the wind regime on the seasonal changes in their landforms, considering the wind and hydrothermal regimes. It has been established that the bare surface of sand dunes is strongly heated during the summer months, up to 45.0-46.0°С in its windward part and up to 47.2 and 52.0°С in the leeward part. And the humidity of the upper layer of a sand dune at the end of summer drops to a critical level (0.26%), which, under conditions of wind activity and aridity of the local climate, leads to the movement of sand masses by the wind from its windward to leeward part. This, in turn, in combination creates unfavorable conditions for the survival of plants.