Soil Active Layer Research Articles

Effects of permafrost degradation on soil organic matter turnover and plant growth

Continuous climate warming in northeastern China has intensified the melting of permafrost, leading to its degradation. The thawing of permafrost increases the instability of wetland soil organic matter and accelerates decomposition; this will inevitably have a strong impact on the transformation of soil organic matter and the process of vegetation growth. Therefore, the present study used the Xing’an Mountains in Northeast China as the research area. We selected typical marsh areas and analyzed the thickness of the active layer and seasonal frozen soil at different degrees of permafrost degradation. Soil and plant samples (herbs: Carex schumidtii; shrubs: Vaccinium uliginosum; trees: Betula papyrifera) from foliage, roots, and stems were collected at different depths to determine the carbon and nitrogen stable isotope contents in soil and plants. Analysis of variance and multiple linear regression were used to examine the impact of frozen soil degradation on soil organic matter turnover and vegetation growth. The results showed that the thickness of the active layer is increasing, and the amount of seasonal frozen soil is decreasing in the Xing'an Mountains. The δ13C, δ15N, ɛδ13C, and ɛsoil15N values of different depths of permafrost were significantly different (P < 0.05). The foliage, roots, and stems of C. schumidtii, V. uliginosum, and B. papyrifera under different degrees of permafrost degradation were significantly different (P < 0.05), except for the δ13C value of B. papyrifera roots. Soil isotopic composition, and therefore SOM quality, was dependent on the isotopic composition of incoming biomass (foliage, roots, and stems).

Comparative Metagenomics of the Active Layer and Permafrost from Low-Carbon Soil in the Canadian High Arctic.

Approximately 87% of the Arctic consists of low-organic carbon mineral soil, but knowledge of microbial activity in low-carbon permafrost (PF) and active layer soils remains limited. This study investigated the taxonomic composition and genetic potential of microbial communities at contrasting depths of the active layer (5, 35, and 65 cm below surface, bls) and PF (80 cm bls). We showed microbial communities in PF to be taxonomically and functionally different from those in the active layer. 16S rRNA gene sequence analysis revealed higher biodiversity in the active layer than in PF, and biodiversity decreased significantly with depth. The reconstructed 91 metagenome-assembled genomes showed that PF was dominated by heterotrophic, fermenting Bacteroidota using nitrite as their main electron acceptor. Prevalent microbes identified in the active layer belonged to bacterial taxa, gaining energy via aerobic respiration. Gene abundance in metagenomes revealed enrichment of genes encoding the plant-derived polysaccharide degradation and metabolism of nitrate and sulfate in PF, whereas genes encoding methane/ammonia oxidation, cold-shock protein, and two-component systems were generally more abundant in the active layer, particularly at 5 cm bls. The results of this study deepen our understanding of the low-carbon Arctic soil microbiome and improve prediction of the impacts of thawing PF.

Synergetic variations of active layer soil water and salt in a permafrost-affected meadow in the headwater area of the Yellow River, northeastern Qinghai–Tibet plateau

The coupling effects and mechanisms of water, heat, and salt in frozen soils are considered to be one of the core scientific issues in frozen soil studies. This study was based on in situ observation data of active layer soil volumetric water content (VWC), temperature, and bulk electrical conductivity (EC) obtained at an alpine meadow site from October 2016 to November 2019. The site is located in the headwater area of the Yellow River (HAYR). We analyzed the synergetic variations of active layer soil VWC, temperature, and bulk EC during the freeze and thaw processes and discussed the underlying mechanisms. When the thaw process occurred from 10 to 80 cm depths, the VWC and bulk EC at a 10 cm depth showed synchronous high-frequency fluctuations and both increased linearly. The linear decreasing rate of the VWC (bulk EC) at an 80 cm depth in the freeze depths between 0 and 40 cm was 2 (1.6–2.3) times that of the VWC (bulk EC) at an 80 cm depth in the freeze depths occurring 0–10 cm. As soil temperature decreased in the frozen layer, unfrozen water content (bulk EC) decreased nonlinearly along with the absolute value of soil temperature (|T|), following a power (logarithmic) function. This study provided data that partly elucidate the interactions among permafrost, meadow, and ecohydrological processes in the HAYR. Also, our results can be used as a scientific basis for decision making on the protection and restoration of alpine grasslands, as well as for soil salinization studies.

Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica

AbstractOutside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of &lt; 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.

Cool, CALM, collected: the Circumpolar Active Layer Monitoring program and network

ABSTRACT The Circumpolar Active Layer Monitoring (CALM) program is the primary global-change monitoring program concerned with the seasonally frozen active layer above permafrost. The active layer has been designated by the Global Climate Observing System and the Global Terrestrial Observing Network as an ‘Essential Climate Variable’. CALM was launched in 1991 on a volunteer basis in cooperation with the International Tundra Experiment. CALM observatories in Russia and Alaska have been supported since 1998 by the U.S. National Science Foundation through five consecutive five-year funding cycles. In its current configuration, the CALM network includes observation sites throughout the circum-Arctic region and a substantial number of sites in Antarctica. Open access to data and data harmonization are hallmarks of the program. In addition to its ongoing emphasis on field observations of active-layer thickness, temperature, soil moisture, and thaw subsidence are currently being monitored at many sites. Increased emphasis is being placed on observing the dynamics of other landscape and ecosystem parameters, including vegetation, landscape patterns, and soils. Other developing features of the program include expanded education and outreach activities, close cooperation with other international programs, and provision of quality-controlled, standardized data products that meet the needs of the wider scientific community.

Variations in active layer soil hydrothermal dynamics of typical wetlands in permafrost region in the Great Hing’an Mountains, northeast China

The freeze–thaw process of active layer can alter soil hydrothermal dynamics and plays an important role in the stability of permafrost ecosystem, particularly under the background of permafrost degradation resulting from climate warming. Wetlands in permafrost regions are considered to be symbiotic with permafrost. However, despite being the principal region of high-latitude permafrost in China, research on the freeze–thaw process in wetland in the Great Hing’an Mountains is limited. In this study, soil temperature and moisture data (from September 2018 to August 2020) collected from shrub and forest swamp observational sites in the Great Hing’an Mountains were used to analyze the freeze–thaw process and soil hydrothermal dynamics. The effect of wetland types on the freeze–thaw process and the coupling characteristics of soil temperature and moisture were discussed. The results demonstrated that the thawing process of active layer was unidirectional, while the freezing was bidirectional, and the thawing process took much longer than freezing process. The distribution of temperature and moisture of active layer varied in different stage of freeze–thaw process, yet similar trends were exhibited in different wetland types during the same freeze–thaw stage. The annual average temperature of forest swamp was higher than that of shrub swamp for all soil depths, while the annual average water content of forest swamp was lower than that of shrub swamp. A significant non-linear correlation was observed between moisture and temperature of each soil layer.

Tundra Underlain By Thawing Permafrost Persistently Emits Carbon to the Atmosphere Over 15 Years of Measurements

AbstractWarming of the Arctic can stimulate microbial decomposition and release of permafrost soil carbon (C) as greenhouse gases, and thus has the potential to influence climate change. At the same time, plant growth can be stimulated and offset C release. This study presents a 15‐year time series comprising chamber and eddy covariance measurements of net ecosystem C exchange in a tundra ecosystem in Alaska where permafrost has been degrading due to regional warming. The site was a carbon dioxide source to the atmosphere with a cumulative total loss of 781.6 g C m−2 over the study period. Both gross primary productivity (GPP) and ecosystem respiration (Reco) were already likely higher than historical levels such that increases in Reco losses overwhelmed GPP gains in most years. This shift to a net C source to the atmosphere likely started in the early 1990s when permafrost was observed to warm and thaw at the site. Shifts in the plant community occur more slowly and are likely to constrain future GPP increases as compared to more rapid shifts in the microbial community that contribute to increased Reco. Observed rates suggest that cumulative net soil C loss of 4.18–10.00 kg C m−2—8%–20% of the current active layer soil C pool—could occur from 2020 to the end of the century. This amount of permafrost C loss to the atmosphere represents a significant accelerating feedback to climate change if it were to occur at a similar magnitude across the permafrost region.

Derivation of Heat Conductivity from Temperature and Heat Flux Measurements in Soil

The general inverse problem formulation for a heat conductance equation is adopted for the types of measurement routinely carried out in the soil active layer. The problem solution delivers a constant thermal diffusivity coefficient a0 (in general, different from true value a) and respective heat conductivity λ0 for the layer, located between two temperature sensors and equipped with a temperature or heat flux sensor in the middle. We estimated the error of solution corresponding to systematic shifts in sensor readings and mislocation of sensors in the soil column. This estimation was carried out by a series of numerical experiments using boundary conditions from observations on Mukhrino wetland (Western Siberia, Russia), performed in summer, 2019. Numerical results were corroborated by analytical estimates of inverse problem solution sensitivity derived from classical Fourier law. The main finding states that heat conductivity error due to systematic shifts in temperature measurements become negligible when using long temperature series, whereas the relative error of a is approximately twice the relative error of sensor depth. The error a0−a induced by heat flux plate displacement from expected depth is 3–5 times less than the same displacement of thermometers, which makes the requirements for heat flux installation less rigid. However, the relative errors of heat flux observation typical for modern sensors (±15%) cause the uncertainty of a above 15% in absolute value. Comparison of the inverse problem solution to a estimated from in situ moss sampling on Mukhrino wetland proves the feasibility of the method and corroborates the conclusions of the error sensitivity study.

Metaplasmidome-encoded functions of Siberian low-centered polygonal tundra soils

Plasmids have the potential to transfer genetic traits within bacterial communities and thereby serve as a crucial tool for the rapid adaptation of bacteria in response to changing environmental conditions. Our knowledge of the environmental pool of plasmids (the metaplasmidome) and encoded functions is still limited due to a lack of sufficient extraction methods and tools for identifying and assembling plasmids from metagenomic datasets. Here, we present the first insights into the functional potential of the metaplasmidome of permafrost-affected active-layer soil—an environment with a relatively low biomass and seasonal freeze–thaw cycles that is strongly affected by global warming. The obtained results were compared with plasmid-derived sequences extracted from polar metagenomes. Metaplasmidomes from the Siberian active layer were enriched via cultivation, which resulted in a longer contig length as compared with plasmids that had been directly retrieved from the metagenomes of polar environments. The predicted hosts of plasmids belonged to Moraxellaceae, Pseudomonadaceae, Enterobacteriaceae, Pectobacteriaceae, Burkholderiaceae, and Firmicutes. Analysis of their genetic content revealed the presence of stress-response genes, including antibiotic and metal resistance determinants, as well as genes encoding protectants against the cold.

Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies

Enhanced warming of the Northern high latitudes has intensified thermokarst processes throughout the permafrost zone. Retrogressive thaw slumps (RTS), where thaw-driven erosion caused by ground ice melt creates terrain disturbances extending over tens of hectares, represent particularly dynamic thermokarst features. Biogeochemical transformation of the mobilized substrate may release CO2 to the atmosphere and impact downstream ecosystems, yet its fate remains unclear. The Peel Plateau in northwestern Canada hosts some of the largest RTS features in the Arctic. Here, thick deposits of Pleistocene-aged glacial tills are overlain by a thinner layer of relatively organic-rich Holocene-aged permafrost that aggraded upward following deeper thaw and soil development during the early Holocene warm period. In this study, we characterize exposed soil layers and the mobilized material by analysing sediment properties and organic matter composition in active layer, Holocene and Pleistocene permafrost, recently thawed debris deposits and fresh deposits of slump outflow from four separate RTS features. We found that organic matter content, radiocarbon age and biomarker concentrations in debris and outflow deposits from all four sites were most similar to permafrost soils, with a lesser influence of the organic-rich active layer. Lipid biomarkers suggested a significant contribution of petrogenic carbon especially in Pleistocene permafrost. Active layer samples contained abundant intrinsically labile macromolecular components (polysaccharides, lignin markers, phenolic and N-containing compounds). All other samples were dominated by degraded organic constituents. Active layer soils, although heterogeneous, also had the highest median grain sizes, whereas debris and runoff deposits consisted of finer mineral grains and were generally more homogeneous, similar to permafrost. We thus infer that both organic matter degradation and hydrodynamic sorting during transport affect the mobilized material. Determining the relative magnitude of these two processes will be crucial to better assess the role of intensifying RTS activity in CO2 release and ecosystem carbon fluxes.

Active layer thickness as a function of soil water content

Active layer thickness (ALT) is a critical metric for monitoring permafrost. How soil moisture influences ALT depends on two competing hypotheses: (a) increased soil moisture increases the latent heat of fusion for thaw, resulting in shallower active layers, and (b) increased soil moisture increases soil thermal conductivity, resulting in deeper active layers. To investigate their relative influence on thaw depth, we analyzed the Field Measurements of Soil Moisture and Active Layer Thickness (SMALT) in Alaska and Canada dataset, consisting of thousands of measurements of thaw depth and soil moisture collected at dozens of sites across Alaska and Canada as part of NASA’s Arctic Boreal Vulnerability Experiment (ABoVE). As bulk volumetric water content (VWC) integrated over the entire active layer increases, ALT decreases, supporting the latent heat hypothesis. However, as VWC in the top 12 cm of soil increases, ALT increases, supporting the thermal conductivity hypothesis. Regional temperature variations determine the baseline thaw depth while precipitation may influence the sensitivity of ALT to changes in VWC. Soil latent heat dominates over thermal conductivity in determining ALT, and the effect of bulk VWC on ALT appears consistent across sites.

Promising Screw Piles Designs for Construction on Permafrost Soils

Promising designs of screw piles with improved technical characteristics have been developed, which reduce risk of buckling from soil as a result of influence of tangential forces of frost heave, reduce energy consumption when screwing piles into the soil, and also simplify designs and manufacturing techniques of blades. Usage of cryophobic coatings applied to trunk part placed in the active soil layer is proposed to reduce bulging of piles. Applying anti-friction coatings to the blades, as well as usage of greases filling slots at their edges is proposed to reduce friction when tightening. Strengthening adhesive interaction between pile and soil below active layer can be achieved by applying cryophilic coatings and freezing water in gap between pile shaft and soil. Simplification of pile design is assumed by replacing screw blades with segmented or cable blades.

Soil Disturbance Affects Plant Productivity via Soil Microbial Community Shifts.

Recent advances in climate research have discovered that permafrost is particularly vulnerable to the changes occurring in the atmosphere and climate, especially in Alaska where 85% of the land is underlain by mostly discontinuous permafrost. As permafrost thaws, research has shown that natural and anthropogenic soil disturbance causes microbial communities to undergo shifts in membership composition and biomass, as well as in functional diversity. Boreal forests are home to many plants that are integral to the subsistence diets of many Alaska Native communities. Yet, it is unclear how the observed shifts in soil microbes can affect above ground plant communities that are relied on as a major source of food. In this study, we tested the hypothesis that microbial communities associated with permafrost thaw affect plant productivity by growing five plant species found in Boreal forests and Tundra ecosystems, including low-bush cranberry and bog blueberry, with microbial communities from the active layer soils of a permafrost thaw gradient. We found that plant productivity was significantly affected by the microbial soil inoculants. Plants inoculated with communities from above thawing permafrost showed decreased productivity compared to plants inoculated with microbes from undisturbed soils. We used metagenomic sequencing to determine that microbial communities from disturbed soils above thawing permafrost differ in taxonomy from microbial communities in undisturbed soils above intact permafrost. The combination of these results indicates that a decrease in plant productivity can be linked to soil disturbance driven changes in microbial community membership and abundance. These data contribute to an understanding of how microbial communities can be affected by soil disturbance and climate change, and how those community shifts can further influence plant productivity in Boreal forests and more broadly, ecosystem health.

Spectral analysis of soil temperature and their coincidence with air temperature in Iran.

Physical evaluation of active soil layer can be a suitable indicator for detecting climate change trends, especially the temporal study of soil and air temperatures. Using the singular spectrum analysis (SSA), trends, oscillatory components, and the degree of the coincidence of the soil temperature (ST) versus air temperature (AT) and precipitation (Prc) time series were investigated in Iran for three thermal regime classes (mesic, thermic, and hyperthermic) during 1993-2017. The results showed that the highest and lowest increases in ST trend occurred in the mesic and thermic thermal regimes, respectively. The return period of approximately 2.1 to 2.6 years was detected in all three studied thermal classes likely as a result of quasi-biennial oscillation (QBO) variation. In the mesic regime, the annual ST was affected to an equal extent by almost every season. For the thermic regime, the annual ST was most influenced by the ST oscillations in autumn and spring and regarding the hyperthermic regime in winter and summer. Result demonstrated by the implementation of the coincidence which exists between the short- and long-term oscillations of ST and AT time series, one can generate and reconstruct ST data gaps based on AT.

Root exudates increase soil respiration and alter microbial community structure in alpine permafrost and active layer soils

Due to climate warming, alpine ecosystems are changing rapidly. Ongoing upward migrations of plants and thus an increase of easily decomposable substrates will strongly affect the soil microbiome. To understand how belowground communities will respond to such changes, we set up an incubation experiment with permafrost and active soil layers from northern (NW) and southern (SE) slopes of a mountain ridge on Muot da Barba Peider in the Swiss Alps and incubated them with or without artificial root exudates (AREs) at two temperatures, 4°C or 15°C. The addition of AREs resulted in elevated respiration across all soil types. Bacterial and fungal alpha diversity decreased significantly, coinciding with strong shifts in microbial community structure in ARE-treated soils. These shifts in bacterial community structure were driven by an increased abundance of fast-growing copiotrophic taxa. Fungal communities were predominantly affected by AREs in SE active layer soils and shifted towards fast-growing opportunistic yeast. In contrast, in the colder NW facing active layer and permafrost soils fungal communities were more influenced by temperature changes. These findings demonstrate the sensitivity of soil microbial communities in high alpine ecosystems to climate change and how shifts in these communities may lead to functional changes impacting biogeochemical processes.

Temporal, Spatial, and Temperature Controls on Organic Carbon Mineralization and Methanogenesis in Arctic High-Centered Polygon Soils.

Warming temperatures in continuous permafrost zones of the Arctic will alter both hydrological and geochemical soil conditions, which are strongly linked with heterotrophic microbial carbon (C) cycling. Heterogeneous permafrost landscapes are often dominated by polygonal features formed by expanding ice wedges: water accumulates in low centered polygons (LCPs), and water drains outward to surrounding troughs in high centered polygons (HCPs). These geospatial differences in hydrology cause gradients in biogeochemistry, soil C storage potential, and thermal properties. Presently, data quantifying carbon dioxide (CO2) and methane (CH4) release from HCP soils are needed to support modeling and evaluation of warming-induced CO2 and CH4 fluxes from tundra soils. This study quantifies the distribution of microbial CO2 and CH4 release in HCPs over a range of temperatures and draws comparisons to previous LCP studies. Arctic tundra soils were initially characterized for geochemical and hydraulic properties. Laboratory incubations at −2, +4, and +8°C were used to quantify temporal trends in CO2 and CH4 production from homogenized active layer organic and mineral soils in HCP centers and troughs, and methanogen abundance was estimated from mcrA gene measurements. Results showed that soil water availability, organic C, and redox conditions influence temporal dynamics and magnitude of gas production from HCP active layer soils during warming. At early incubation times (2–9 days), higher CO2 emissions were observed from HCP trough soils than from HCP center soils, but increased CO2 production occurred in center soils at later times (>20 days). HCP center soils did not support methanogenesis, but CH4-producing trough soils did indicate methanogen presence. Consistent with previous LCP studies, HCP organic soils showed increased CO2 and CH4 production with elevated water content, but HCP trough mineral soils produced more CH4 than LCP mineral soils. HCP mineral soils also released substantial CO2 but did not show a strong trend in CO2 and CH4 release with water content. Knowledge of temporal and spatial variability in microbial C mineralization rates of Arctic soils in response to warming are key to constraining uncertainties in predictive climate models.

Unearthing Antibiotic Resistance Associated with Disturbance-Induced Permafrost Thaw in Interior Alaska.

Monitoring antibiotic resistance genes (ARGs) across ecological niches is critical for assessing the impacts distinct microbial communities have on the global spread of resistance. In permafrost-associated soils, climate and human driven disturbances augment near-surface thaw shifting the predominant bacteria that shape the resistome in overlying active layer soils. This thaw is of concern in Alaska, because 85% of land is underlain by permafrost, making soils especially vulnerable to disturbances. The goal of this study is to assess how soil disturbance, and the subsequent shift in community composition, will affect the types, abundance, and mobility of ARGs that compose the active layer resistome. We address this goal through the following aims: (1) assess resistance phenotypes through antibiotic susceptibility testing, and (2) analyze types, abundance, and mobility of ARGs through whole genome analyses of bacteria isolated from a disturbance-induced thaw gradient in Interior Alaska. We found a high proportion of isolates resistant to at least one of the antibiotics tested with the highest prevalence of resistance to ampicillin. The abundance of ARGs and proportion of resistant isolates increased with disturbance; however, the number of ARGs per isolate was explained more by phylogeny than isolation site. When compared to a global database of soil bacteria, RefSoil+, our isolates from the same genera had distinct ARGs with a higher proportion on plasmids. These results emphasize the hypothesis that both phylogeny and ecology shape the resistome and suggest that a shift in community composition as a result of disturbance-induced thaw will be reflected in the predominant ARGs comprising the active layer resistome.

Experimental studies of the parameters of a positional sprinkler system

The most important factor affecting the yield of agricultural crops is the formation of an optimal water regime in the active soil layer. One of the main methods of carrying out such works is sprinkling, since it is closest to the process of natural precipitation. At the same time, existing water sprinklers do not provide watering agricultural lands that meets agro-technological requirements due to the design features and the specifics of the landscape on which they are used, forming in the process of watering zones with excessive and insufficient moisture. In this regard, a positional water sprinkler has been developed, which has the ability to water along a path close to rectangular. Obtaining this trajectory is achieved due to the design features obtained as a result of mathematical modeling. The article presents the structural diagram of the developed water sprinkler, considers the principle of its operation, presents the results of mathematical analysis and modeling of kinematic processes occurring during its operation. The above research results show that the use of the proposed water sprinkler will improve the quality of watering due to the watering trajectory closest to rectangular.

The Change Mechanism of Soil Hydrological Properties in the Permafrost Active Layer of the Qinghai–Tibet Plateau

The hydrological properties of the active soil layer are the key parameters that regulate soil water–heat–solute migration and alter hydrologic cycles in a permafrost region. To date, much remains unknown about the interaction mechanism between permafrost degradation and eco-hydrological processes in the permafrost regions of the Qinghai–Tibet Plateau (QTP). In this study, the soil texture, soil hydrological properties, and the soil moisture status of meadow soils with different degrees of degradation were analyzed in the laboratory, and hydrothermal process monitoring was conducted on the QTP. The results showed a close relationship between soil hydrological properties and soil physicochemical properties. Freeze–thaw cycles changed the physicochemical and hydrological properties, resulting in the degradation of frozen soil. In addition, vegetation on the ground delayed the degradation of frozen soil. The actual available soil water content (SWC) in the root layer was a key factor in the ecohydrological process. The actual effective SWC in the root layers of different alpine meadows was ranked as follows: non-degraded meadow (NDM) > moderately-degraded meadow (MDM) > seriously degraded meadow (SDM) (1.8–5.0% at NDM and −2.0–4.2% at SDM). In addition, the weak soil permeability in an SDM intensified the deficiency of the available SWC, thereby increasing the difficulty of ecological restoration. This study provides a basis for ecological environmental protection in permafrost regions and provides a hydrological process model for cold regions under future climate change scenarios.

The influence of soil treatment and irrigation methods on tomato yield and quality in the lowlands of Dagestan

A positive effect of irrigation of meadow-chestnut soil on soil fertility was described for the dry-steppe zone of Dagestan. The object of research was tomatoes (Gift variety) planted on irrigated lands of Dagestan. The subject of research is tillage and irrigation methods. The influence of agrotechnical methods on agrophysical soil properties, level and quality of tomatoes was determined. Maintaining the moisture of the active soil layer within 80…100 % NV can optimize agrophysical fertility indicators of the meadow-chestnut soil. In combination with tillage at a depth of 0.23…0.25 m, it ensures the tomato yield of 80…86 t/ha.