Soil Heat Research Articles

Small-scale genetic differentiation in mean flowering time, but not in plasticity, along a geothermal heating gradient.

Genetic differentiation in traits is assumed to frequently occur in response to divergent natural selection. For example, developmental traits might respond to differences in climate. However, little is known about when and at which spatial scales environmental differences lead to genetic differentiation, and to what extent there is genetic differentiation also in trait plasticity. Using a crossing design and a greenhouse heating experiment, we investigated genetic differentiation in thermal sensitivity of flowering time in a perennial herb along small-scale gradients in geothermal soil heating in Iceland. We found additive genetic variation in both flowering time and thermal plasticity of flowering time. Genetic differentiation in median flowering date of individuals showed a counter-gradient pattern; flowering being earlier at higher greenhouse temperatures, while at a given temperature individuals originating from warmer soils flowered later than individuals from colder soils. We found no corresponding pattern for plasticity, suggesting that genetic differentiation in phenology in response to soil heating has occurred through changes in trait means rather than in plasticity. Findings such as these, identifying genetic trait differentiation along an environmental gradient are key to understand how environmental variation can drive the process of local adaptation, and to predict responses to future environmental changes.

Drought in a warmer, CO2-rich climate restricts grassland water use and soil water mixing.

Soil water sustains terrestrial life, yet its fate is uncertain under a changing climate. We conducted a deuterium labeling experiment to determine whether elevated atmospheric carbon dioxide (CO2), warming, and drought impact soil water storage and transport in a temperate grassland. Elevated CO2 created a wetter rootzone compared with ambient conditions, whereas warming decreased soil moisture. Soil water remained well mixed in all global change treatments except for summer drought combined with warming and elevated CO2. These combined treatments caused the grassland to conserve water and restricted soil water flow to large, rapidly draining pores without mixing with small, slowly draining pores. Our results suggest that drought in a warmer, more CO2-rich climate can severely alter grassland ecohydrology by constraining postdrought soil water flow and grassland water use.

Phenotypic Profiling of Selected Cellulolytic Strains to Develop a Crop Residue-Decomposing Bacterial Consortium.

Slow decomposition rates of cereal crop residues can lead to agronomic challenges, such as nutrient immobilization, delayed soil warming, and increased pest pressures. In this regard, microbial inoculation with efficient strains offers a viable and eco-friendly solution to accelerating the decomposition process of crop residues. However, this solution often focuses mostly on selecting microorganisms based on the appropriate enzymic capabilities and neglects the metabolic versatility required to utilize both structural and non-structural components of residues. Therefore, this study aimed to address these limitations by assessing the metabolic profiles of five previously identified cellulolytic bacterial strains, including Bacillus pumilus 1G17, Micromonospora chalcea 1G49, Bacillus mobilis 5G17, Streptomyces canus 1TG5, and Streptomyces achromogenes 3TG21 using Biolog Phenotype Microarray analysis. Moreover, this study evaluated the impact of wheat straw inoculation with single strains and a bacterial consortium on soil organic carbon and nitrogen content in a pot experiment. Results revealed that, beyond the core subset of 12 carbon sources, the strains exhibited diverse metabolic capacities in utilizing 106 carbon sources. All strains demonstrated effective straw biomass degradation compared to the negative control, with significant differences detected only in oil seed rape straw biodegradation estimations. Furthermore, wheat straw inoculated with a bacterial consortium showed a significant increase in soil organic carbon content after 180 days in the pot experiment. Overall, these findings underscore the critical role of metabolic profiling in gaining a deeper understanding of microbial capabilities and addressing the complexities of residue composition and environmental variability.

Fuel accumulation shapes post-fire fuel decomposition through soil heating effects on plants, fungi, and soil chemistry.

Forty percent of terrestrial ecosystems require recurrent fires driven by feedbacks between fire and plant fuels. The accumulation of fine fuels in these ecosystems play a key role in fire intensity, which alters soil nutrients and shapes soil microbial and plant community responses to fire. Changes to post-fire plant fuel production are well known to feed back to future fires, but post-fire decomposition of new fuels is poorly understood. Our study sought to quantify how pre-fire fuel loading influenced post-fire fuel decomposition through soil abiotic properties, as well as plant and soil fungal communities. Prior to spring prescribed burns, we manipulated fine fuel loads in plots, both near (<10m) and away (>10m) from overstory pines, to modify soil heating in an old-growth longleaf pine savanna. We then assessed how fuel load and soil heating influenced post-fire plant fuel decomposition through changes to soil chemistry, vegetation, and fungi. Burning larger fuel loads made fires hotter, burn longer, and more completely combusted fuels. In these plots, decomposition of newly deposited fine fuels was slower in the eight months following fire. Decomposition changes from greater soil heating were mediated by greater shifts to postfire plant (2 and 4months postfire) and fungal communities (4 and 6months postfire). Soil properties (C: N ratios, soil pH, and P) controlled postfire decomposition throughout the year, but weakly responded to soil heating differences from fuels. Since the mechanisms for fuel effects on decomposition change over time, fire timing may be a future target for understanding fire feedbacks to fuel decomposition. Integrating these feedbacks with fuel production responses across fire-dependent ecosystems can help managers better set prescribed fire intervals and predict responses to reintroducing burning in fire-suppressed ecosystems.

A Fully Coupled Numerical Solution of Water, Vapor, Heat, and Water Stable Isotope Transport in Soil

A Fully Coupled Numerical Solution of Water, Vapor, Heat, and Water Stable Isotope Transport in Soil

Multi-scale temporal and spatial variations of soil heat flux under varying riparian forests: From a day to a year.

This study delves into the multi-scale temporal and spatial variations of soil heat flux (G) within riparian zones and its correlation with net radiation (Rn) across six riparian woodlands in Shanghai, each characterized by distinct vegetation types. The objective is to assess the complex interrelations between G and Rn, and how these relationships are influenced by varying vegetation and seasons. Over the course of a year, data on G and Rn is collected to investigate their dynamics. The multi-scale temporal patterns of G and its relationship with Rn are significantly influenced by both vegetation type and season, with the most pronounced variability observed seasonally, exhibiting distinct cycles for both broadleaf and conifer forests. The presence of shrubs is found to increase G, and the dominant temporal scales were found to vary within broadleaf forests. Additionally, G demonstrates a non-linear gradient with respect to the proximity to the river, with the river's influence on G diminishing at distances less than 11m in broadleaf and 6m in conifer woodlands. While the river enhances G and its hysteresis with Rn, vegetation characteristics dominate in dense canopies. This study underscores the importance of understanding the spatio-temporal variation patterns of soil heat flux and their response to different vegetation attributes. Such knowledge is vital for developing riparian soil heat flux models and informing riparian forest management strategies, especially in the context of climate change. The results provide insights into the complex interactions between soil heat flux, net radiation, and vegetation, offering a foundation for future research and management practices aimed at preserving and enhancing the ecological functions of riparian ecosystems.

Evaluating land use ımpact on evapotranspiration in Yellow River Basin China through a novel GSEBAL model: a remote sensing perspective

Evapotranspiration (ET) is critical to surface water dynamics. Effective water resource management necessitates an accurate ET estimation. In the Yellow River Basin China, a study area, cutting-edge technologies are needed to improve large-scale ET estimates. This study estimates ET using GSEBAL, an advanced ET estimation algorithm. Google Earth Engine integrates the surface energy balance model-based GSEBAL. The technique includes the collection, preparation, and calculation of ET using Landsat imagery and ERA5-Land meteorological data from 1990 to 2020. The study examined satellite LST, albedo, and NDVI data. The GSEBAL model calculates soil heat flow, net radiation, and sensible heat flux. The study tested the GSEBAL model utilizing essential ET datasets such as ECOSTRESS, MOD16, and SSEBop. The study showed that the model effectively predicted daily and seasonal ET variations in different climates. Root mean squared error, bias, and Pearson's correlation coefficient verified the model's reliability. The study also analyzed land use and land cover (LULC) over 30 years using Random Forest classifiers. In the 1990–2020 YRBC ET, land use changes affect ET rates annually and seasonally. The study area experiences changes in LST, NDVI, and LULC. Maximum ET values rose from 214.217 mm in 1990 to 234.891 mm in 2000. The pattern flipped in 2020, decreasing to 221.456 mm. In 2010, Summer had the highest ET, 484.455 mm. 2020 spring ET is 314.727 mm. Low ET decreased from 24.652 mm in 1990 to 18.2 mm in 2020, reducing water loss. Fall ET peaks at 24.9 mm in 2020; winter ET is 18.75 mm.

Mathematical Modeling of Temperature Fields in Cultivation Structures

Purpose. The main purpose of the article is to develop a method for calculating thermal fields in greenhouse soil in the case of its artificial heating. Since the temperature regime in greenhouse soil has a significant impact on plant yields, it is very important, on the one hand, to ensure the required temperature in the soil, and on the other hand, to determine the energy-saving heating regime. Methodology. The method is based on the numerical integration of the heat transfer equation. A two-dimensional heat transfer equation was used to analyze and predict the unsteady process of soil heating in a greenhouse under artificial heating, and two finite-difference schemes were used to solve it. On the basis of the constructed numerical models, a computer program was developed to conduct a computational experiment. Findings. Effective computer models have been created to predict the unsteady formation of thermal zones in the greenhouse soil during its artificial heating. The results of numerical modeling are presented. Originality. Prognostic numerical models have been developed to analyze the dynamics of thermal fields formation in greenhouse soil during its artificial heating. On the basis of the developed numerical models, a set of application programs was created to conduct a computational experiment to determine the unsteady temperature field in greenhouse soil. The constructed numerical models belong to the class of «operational models», i.e., they are designed for the operational analysis of thermal fields in the soil. For the practical use of the developed numerical models, standard input information is required. Practical value. The constructed numerical models are a tool for analyzing the dynamics of soil heating and can be used in the development of energy-saving heating technology. These models can be used to determine the time of optimal soil heating in different zones (root system, soil surface) and to determine the rational location of heating elements, the time when the heating elements should be turned off, and the time when they should be turned on again. These models allow us to develop an energy-saving technology for heating the soil in a greenhouse.

Microclimate Comparison Between Different Growth Forms at the Treeline Ecotone of Jiaozi Mountain, China

Climatic conditions strongly control the geographic distribution of treelines; long-term in situ climatic measurements at the treeline are still rare. While microclimatic differences between trees and shrubs at treeline ecotones are already well established and explained, supporting empirical data remain limited. In this study, we compared in situ microclimate measurements in the canopy, stem, and root zones of tree and shrub plots of Juniperus squamata Buch.-Ham. ex D.Don at the treeline ecotone of Jiaozi Mountain, Yunnan, China, in 2022. Although the shrubs experienced higher wind speeds compared to the trees at the treeline ecotone, the short stature of shrubs created warm stem and soil temperatures that are more suitable for plant growth and survival. Shrub distribution at higher elevations may be due to higher soil temperatures. The inability of shrubs to grow upright may be attributed to the fact that their canopy is limited by lower temperatures above the canopy during the frost season. This can provide new insights into the mechanisms of treeline formation.

Local and Downstream Effects of Vertical Soil Water Flow on Summer Persistent Extreme Precipitation Events in Southeast China

AbstractPersistent extreme precipitation events (PEPEs) in Southeast China cause casualties and economic losses, and accurate simulations of these events continue to face significant challenges. This study identifies critical features associated with PEPEs during boreal summer in this region, such as both cool land surface and air at 850 hPa, indicating strong land‐atmosphere interactions. Vertical soil water flow (VSWF) significantly affects near‐surface soil hydro‐thermodynamics and can potentially enhance the PEPEs' simulation. However, VSWF is often ignored in land surface models. To improve the simulation of PEPEs, the VSWF term is incorporated into the soil heat transfer equation within the Noah‐MP model coupled with the Weather Research and Forecasting model, improving the simulation of PEPEs. Further analysis reveals that incorporating VSWF strengthens the cold features of PEPEs and improves precipitation simulation. Detailed examination shows that incorporating VSWF induces a secondary circulation anomaly and a positive geopotential height anomaly in Southeast China compared to simulations without VSWF. The southeast flank of the anticyclone anomaly reduces water vapor transport, while the northwest flank enhances it. Additionally, the geopotential height anomaly triggers adjustments in downstream regions of Southeast China, depending on changes in downstream circulation patterns of PEPEs. This research contributes to a better understanding of land‐atmosphere interactions, particularly the effects of VSWF on PEPEs in Southeast China.

Steaming soil is effective in eliminating invasive alien plants (IAPs) - part I: effect of exposure method.

As regulations on pesticides become more stringent, it is likely that there will be interest in steam as an alternative approach for soil disinfestation. This study investigates the feasibility of utilizing a soil steaming device for thermal control of invasive plants. Seeds of Echinochloa crus-galli, Impatiens glandulifera, Solidago canadensis, and rhizome fragments of Reynoutria × bohemica were examined for thermal sensitivity through two exposure methods: (1) steam treatment of propagative material in soil; (2) exposure of propagative material to warm soil just after heated by steam. Soil temperatures in the range of 60-99 °C and dwelling period of 3 min were tested. Increased soil temperature decreased seed germination/rhizome sprouting. The exposure method had a significant effect where higher temperatures were needed to reduce the seed germination/rhizome sprouting in method 2 explained by the effect of extra heat given in method 1. Using method 1, for E. crus-galli and S. canadensis, the maximum mean temperature of approximately 80 °C was enough to achieve the effective weed control level (90%). This was lower for I. glandulifera and higher for R. × bohemica. Using method 2, 90% control was achieved at 95 °C for S. canadensis; more than 115 °C for I. glandulifera; and more than 130 °C for E. crus-galli and R. × bohemica. Our findings showed a promising mortality rate for weeds propagative materials through soil steaming. However, the species showed varying responses to heat and therefore steam regulation should be based on the differences in weeds' susceptibility to heat. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of Warming on Soil Fungal Community Along Altitude Gradients in a Subalpine Meadow.

The subalpine grassland ecosystem is sensitive to climatic changes. Previous studies investigated the effects of warming on grassland ecosystems at a single altitude, with little information about the response of subalpine meadows to warming along altitude gradients. This study aimed to evaluate the effects of warming on aboveground grass, belowground soil properties, and fungal community along altitude gradients in the subalpine meadow of Mount Wutai using the high-throughput sequencing method. Warming reduced the restriction of low temperatures on the growth of subalpine grass, resulting in increasing grass biomass, community height, and coverage. More grass biomass led to higher soil organic carbon resources, which primarily affected fungal community composition following warming. Warming might induce more stochastic processes of fungal community assembly, increasing fungal diversity at low altitudes. In contrast, warming triggered more deterministic processes to decrease fungal diversity at medium and high altitudes. Warming might improve the efficiency of soil nutrient cycling and organic matter turnover by increasing the relative abundance of soil saprotrophs and improving fungal network connectivity. The relative abundance of certain grass pathogens significantly increased following warming, thereby posing potential risks to the sustainability and stability of subalpine meadow ecosystems. Overall, this study comprehensively evaluated the response of the subalpine meadow ecosystems to warming along altitude gradients, clarifying that warming changes soil fungal community composition at different altitudes. The long-term monitoring of pathogen-related shifts should be conducted in subalpine meadow ecosystem following warming. This study provided significant scientific insights into the impact of future climatic changes on subalpine ecosystems.

Thermal Adaptation of Enzyme‐Mediated Processes Reduces Simulated Soil CO2 Fluxes Upon Soil Warming

AbstractUnderstanding factors influencing carbon effluxes from soils to the atmosphere is important in a world experiencing climatic change. Two important uncertainties related to soil organic carbon (SOC) stock responses to a changing climate are (a) whether soil microbial communities acclimate or adapt to changes in soil temperature and (b) how to represent this process in SOC models. To further explore these issues, we included thermal adaptation of enzyme‐mediated processes in a mechanistic SOC model (ReSOM) using the macromolecular rate theory. Thermal adaptation is defined here to encompass all potential responses of soil microbes and microbial communities following a change in temperature. To assess the effects of thermal adaptation of enzyme‐mediated processes on simulated SOC losses, ReSOM was applied to data collected from a 13‐year soil warming experiment. Results show that a model omitting thermal adaptation of enzyme‐mediated processes substantially overestimates observed CO2 effluxes during the initial years of soil warming. The bias against observed CO2 effluxes was lower for models including thermal adaptation of enzyme‐mediated processes. In addition, for a simulated linear 3°C soil warming over 100 years, models including thermal adaptation of enzyme‐mediated processes simulated SOC losses of a factor of three smaller than models omitting this process. As thermal adaptation of microbial community characteristics is generally not included in models simulating feedback between the soil, biosphere and atmosphere, we encourage future studies to assess the potential impact that microbial adaptation has on soil carbon – climate feedback representations in models.

Decline in diversity of tropical soil fauna under experimental warming.

Climate change is exacerbating a global decline in biodiversity. Numerous observational studies link rising temperatures to declining biological abundance, richness and diversity in terrestrial ecosystems, yet few studies have considered the highly diverse and functionally significant communities of tropical forest soil and leaf litter fauna. Here, we report major declines in the order-level richness and diversity of soil and leaf litter fauna following three years of experimental whole-profile soil warming in a tropical forest. These declines were greatest during the dry season, suggesting that warming effects could be exacerbated by drought. Contrary to findings from higher latitudes, total faunal abundance increased under warming, and these effects were paralleled by major shifts in community composition. These responses were driven by increased dominance of a relatively small number of thermophilic taxa, and of oribatid mites in particular. Our study provides direct experimental evidence that warming causes diversity declines and compositional shifts for tropical forest soil and leaf litter fauna, a result with potential consequences for soil functions and biogeochemical cycles, and that highlights the vulnerability of tropical biodiversity to climate change.

Spatiotemporal Distribution of Soil Thermal Conductivity in Chinese Loess Plateau

The Chinese Loess Plateau (CLP) is ecologically fragile, and water resources are extremely scarce. Soil thermal conductivity (λ) is a vital parameter for controlling surface heat transfer and is the key to studying the energy exchange and water balance of the soil surface. The objective of this study is to investigate the spatial distribution characteristics of soil thermal conductivity on the Loess Plateau. The research primarily employed soil heat transfer models and the Google Earth Engine (GEE) platform for remote sensing cloud computing, compares and analyzed the suitability of six models (Cambell model, Lu Yili model, Nikoosokhan model, LT model, LP1 model, and LP2 model), and utilized the selected improved model (LT model) to analyze the spatiotemporal characteristics of thermal conductivity on the CLP, examining the impacts of soil particle composition, bulk density, elevation, moisture content, and land use on thermal conductivity. The results show that the LT model is the best in the relevant evaluation indices, with a determination coefficient (R2) of 0.84, root mean square error (RMSE) of 0.18, and relative error (RE) of 0.16. Furthermore, the λ on the CLP shows an overall trend of increasing from northwest to southeast, with a lower λ between May and August and a higher one between September and October. The λ of different land use types is as follows: built-up land &gt; cropland &gt; grassland &gt; forest land &gt; barren. The bulk density (ρb) and altitude mainly influence λ in the CLP. The results of this study can provide a theoretical basis for studying hydrothermal variation in the CLP, model application, energy development, and land resource use.

Soil Heating Significantly Increases Leaf Magnesium Concentration and Fruit Yield in Tomatoes Produced in a Plastic Greenhouse During Winter

Magnesium (Mg) deficiency frequently occurs in tomato leaves grown in plastic greenhouses during winter in northern China. In this study, field experiments were conducted to test the effects of soil temperature and the potassium (K) fertilizer application rate on tomato K and Mg absorption and fruit yield. The treatments were soil non-heating (control) and soil heating with electric hotlines, with three K2O application rates (180 kg ha−1, 580 kg ha−1, and 980 kg ha−1). The soil heating treatments increased the average soil temperature by 2.1 °C during the day, significantly increasing leaf Mg and chlorophyll concentrations by 21.3% (from 6.86 to 8.32 g·kg−1) and 12% (from 1.25 to 1.40 mg·g−1), respectively, and fruit yield by 5.5% (from 150 to 158.2 t·ha−1) and significantly decreasing the leaf K concentration by 10.5% (from 29.4 to 26.3 g·kg−1). However, the K fertilizer application rate had no significant effect on fruit yield and leaf K and chlorophyll concentrations. Moreover, the soil non-heating treatments showed a significant negative correlation between leaf K and Mg concentrations. Low soil temperature exacerbates K–Mg ion antagonism, which is the main driving factor for Mg deficiency in winter greenhouse tomatoes. Soil heating can significantly promote Mg absorption and improve fruit yield in tomatoes produced in plastic greenhouses during winter. The results of this study provide theoretical and technical support for regulating Mg nutrition in tomatoes grown in plastic greenhouses in northern China.

Analysis of the effect of the heat stabilizer outer surface finning on soil cooling efficiency

Relevance. The construction of buildings and structures in permafrost conditions is associated with the problem of soil thawing. To prevent this phenomenon, heat stabilizer have proven themselves good in practice. Their successful use is difficult without preliminary modeling of heat flows in the soil–heat stabilizer system. The most effective design of a passive heat stabilizer is an installation with two-phase of refrigerant. An additional increase in the efficiency of using a two-phase heat stabilizer is possible due to the finning of the outer surface of the outer pipe of it. Aim. To calculate the efficiency of using a heat stabilizer with and without finning of the outer surface. Objects. Heat stabilizer, refrigerant, heat transfer, frozen soil. Methods. The mathematical model for describing the processes of heat and mass transfer in the heat stabilizer–frozen soil system is considered in an axisymmetric formulation. There are three subtasks: the movement of liquid refrigerant in the inner tube of the heat stabilizer, the two-phase convective flow of refrigerant in the gap between the inner and outer tubes and conductive heat exchange in the system of the heat stabilizer–frozen soil. The influence of the finning of the outer surface of the heat stabilizer is considered within the framework of the modified concept of the skin factor. Results and conclusions. The authors have obtained the pressure and temperature distributions along the length of the heat stabilizer. It was found that the presence of fins on the outer surface of the external pipe of the heat stabilizer increases the heat flow from the soil by 10%. It is determined that the soil is effectively cooled within 1 m from the heat stabilizer; this distance is recommended as optimal for the placement of an adjacent heat stabilizer.

Soil respiration related to the molecular composition of soil organic matter in subtropical and temperate forests under soil warming

The chemical composition and degradability of soil organic matter (SOM) are among the most important factors influencing the feedback between soil CO2 emissions and climate warming. We hypothesized that the response of soil respiration to long-term warming in various forest ecosystems depends on how soil warming alters the chemical composition of SOM. Therefore, we compared the effects of long-term soil warming on soil respiration, SOM molecular structure, and bacterial and fungal diversity in two forest ecosystems in the southern subtropical and warm temperate zones of China. In the subtropical forest, soil warming did not affect soil respiration in the short term (2–3 years) but decreased it in the longer term (10 years, −10%). The decline in soil respiration was associated with an increased aliphaticity of SOM and lower O-alkyl C content, along with an increased abundance of microbial K-strategists over time. In the warm temperate forest, soil warming significantly stimulated soil respiration by 35% in the short term and 30% in the long term. The sustained positive response to warming was likely related to the increased decomposability of SOM owing to increased root C input. Our results suggest that the molecular composition of SOM is affected by warming and in turn feeds back to longer-term soil respiration responses. The different responses at the two study sites suggest considerable variation in the feedback within different forest ecosystems.

Tree demographic drivers across temperate rain forests, after accounting for site-, species-, and stem-level attributes.

Diverse drivers such as climate, soil fertility, neighborhood competition, and functional traits all contribute to variation in tree stem demographic rates. However, these demographic drivers operate at different scales, making it difficult to compare the relative importance of each driver on tree demography. Using c. 20,000 stem records from New Zealand's temperate rain forests, we analyzed the growth, recruitment, and mortality rates of 48 tree species and determined the relative importance of demographic drivers in a multilevel modeling approach. Tree species' maximum height emerged as the one most strongly associated with all demographic rates, with a positive association with growth rate and negative associations with recruitment and mortality rates. Climate, soil properties, neighborhood competition, stem size, and other functional traits also played significant roles in shaping demographic rates. Forest structure and functional composition were linked to climate and soil, with warm, dry climates and fertile soil associated with higher growth and recruitment rates. Neighborhood competition affected demographic rates depending on stem size, with smaller stems experiencing stronger negative effects, suggesting asymmetric competition where larger trees exert greater competitive effects on smaller trees. Our study emphasizes the importance of considering multiple drivers of demographic rates to better understand forest tree dynamics.

Estimation method of soil thermal conductivity distribution of coaxial vertical borehole heat exchanger based on distributed thermal response test

Soil thermal conductivity (λs) is a vital parameter for sizing vertical borehole heat exchanger (VBHE) of ground-source heat pump, which may vary dramatically with the depth. To measure the λs distribution of coaxial VBHE, this study proposes an estimation method based on distributed thermal response test (DTRT). Firstly, a 3D numerical model is built and validated, which is utilized to simulate some DTRTs under various conditions. A 1D model is then developed for any layer of coaxial VBHE, which is discovered to agree better with the 3D model than the traditional infinite line source model. The proposed estimation method utilizes the 1D model to match DTRT data to identify the λs distribution, and then it is compared with the traditional direct method based on the simulated DTRT data. The results show that the traditional method probably has great errors, and that the proposed method could accurately estimate the λs of nearly all the soil layers, the errors of which are basically smaller than 4 %. The precision of the proposed method is slightly affected by the DTRT duration, number of split layers and errors of soil heat capacities. The proposed method is simple and concise, which is convenient for practical application.