Changes In Soil Temperature Research Articles

Climate and vegetation collectively drive soil respiration in montane forest-grassland landscapes of the southern Western Ghats, India

Abstract CO2 release rates from soils via soil respiration play an important role in the carbon budget of terrestrial ecosystems. Though the roles of soil temperature and moisture on soil respiration are well recognised, less is known about how their effects vary across different land-cover types. This study looked at the interactive effects of land-cover change and microclimate on temporal patterns of soil respiration in a montane forest-grassland-plantation mosaic in a highly diverse but climatically sensitive ecosystem in the tropical Western Ghats of India. Across all vegetation types, soil respiration rates were highest during south-west monsoon (June–October), when root growth, litter decomposition and microbial activity are relatively high and were lowest during the summer. Among vegetation types, soil respiration rates were higher in grasslands compared to non-native pine plantations, whereas that of forest and invasive wattle (Acacia mearnsii) plantations were intermediate between grasslands and pine plantations. The decline in respiration rates following conversion from grasslands to pine plantations could be due to relatively lower microbial activity, soil temperatures and, subsequently, slower litter decomposition. In addition, the sensitivity of soil respiration to changes in temperature and moisture differed between different vegetation types. Across all vegetation types, respiration was largely insensitive to changes in soil temperature when moisture levels were low. However, when soil moisture levels were high, respiration increased with temperature in grassland and wattle patches, decreased in the case of pine plantations and remained largely unchanged in shola forests. Our results suggest that changes in aboveground vegetation type can significantly affect soil C cycling even in the absence of any underlying differences in soil type.

Природные особенности и ландшафты района дельты Селенги (Байкальская природная территория)

The article presents the data of landscape studies of the territory of the Ust-Selenginsk depression. It was formed at the beginning of the Paleogene period and became the historical core of the development of the Baikal rift zone. From the north and west, the research area is limited by large tectonically active faults, along which ascending geothermal flows seep. In the areas of their impact, changes in air and soil temperatures are recorded. The widespread development of mud volcanoes has also been noted here. The research area is characterized by peculiar and contrasting natural conditions, which determines the high degree of vulnerability of landscapes and the possibility of their irreversible transformations. It has been established that the modern tectonic lowering of the area contributes to its waterlogging. The drainage system in the area of the foothills of KhamarDaban and the left bank of the Selenga enhances the processes of soil salinization. Sands and loesslike deposits on ancient terraces and the right bank of the Selenga are influenced by Aeolian processes and turn into dunes when vegetation is destroyed. The high tectonic activity of the territory and the weak stability of the landscapes exclude the possibility of active economic activity within its borders.The problem associated with the implementation of environmental protection measures and human activities is characteristic. Its solution can be implemented based on knowledge about the features of landscape transformation.

Thermal recovery test for determining the thermal conductivity of the soil

This paper presents a new in-situ experimental procedure for determining a thermal conductivity of soil, as one of the thermophysical properties necessary for dimensioning vertical buried heat exchangers of geothermal heat pumps. The proposed method, called the thermal recovery test, is based on the assumption that there is a direct analogy between the hydrodynamic process of filling (recovery) the well with water from a porous aquifer after its partial or complete discharging and the process of establishment of thermal equilibrium in an infinite medium previously disturbed by a line heat sink (source). Apart from presentation the theoretical background of these two phenomena, the display of the identical theoretical logarithmic character of the change of hydrostatic pressure and soil temperature, description of the experimental procedure, the experimental results of three performed experiments are also presented. Additionally, results for the experimentally obtained values of the thermal conductivity of the soil are compared with those obtained from the thermal response test, and the advantages and drawbacks of the new thermal recovery test method are analyzed.

Evaluating Soil Carbon Efflux Responses to Soil Moisture and Temperature Variations in Brazilian Biomes

Changes in soil moisture and temperature can directly influence soil carbon emissions, which can add carbon to the atmosphere and make the greenhouse effect more intense. In this sense, research is needed that contributes to this knowledge and that simulates future scenarios, allowing actions to be taken in advance. Thus, an experiment was set up in which carbon dioxide efflux was collected over a period of one year in three Brazilian biomes, Cerrado, Pantanal, and Cerrado-Amazonian Ecotone, and to verify the influence of soil moisture, leaf area index and litter, multiple regression models were carried out. Correlation analyses were performed, and subsequently, sensitivity analyses were conducted for possible efflux increase sowing to 2ºC and 10% decreases or increases in soil temperature and moisture, respectively, simulating possible climate change scenarios. The results showed that of the three study areas, the Cerrado forest was most resistant to changes in these variables, and the correlation between the carbon efflux and the variables, soil temperature and moisture, were positive and significant for Cerrado and Pantanal.

Development of a robust daily soil temperature estimation in semi-arid continental climate using meteorological predictors based on computational intelligent paradigms.

Changes in soil temperature (ST) play an important role in the main mechanisms within the soil, including biological and chemical activities. For instance, they affect the microbial community composition, the speed at which soil organic matter breaks down and becomes minerals. Moreover, the growth and physiological activity of plants are directly influenced by the ST. Additionally, ST indirectly affects plant growth by influencing the accessibility of nutrients in the soil. Therefore, designing an efficient tool for ST estimating at different depths is useful for soil studies by considering meteorological parameters as input parameters, maximal air temperature, minimal air temperature, maximal air relative humidity, minimal air relative humidity, precipitation, and wind speed. This investigation employed various statistical metrics to evaluate the efficacy of the implemented models. These metrics encompassed the correlation coefficient (r), root mean square error (RMSE), Nash-Sutcliffe (NS) efficiency, and mean absolute error (MAE). Hence, this study presented several artificial intelligence-based models, MLPANN, SVR, RFR, and GPR for building robust predictive tools for daily scale ST estimation at 05, 10, 20, 30, 50, and 100cm soil depths. The suggested models are evaluated at two meteorological stations (i.e., Sulaimani and Dukan) located in Kurdistan region, Iraq. Based on assessment of outcomes of this study, the suggested models exhibited exceptional predictive capabilities and comparison of the results showed that among the proposed frameworks, GPR yielded the best results for 05, 10, 20, and 100cm soil depths, with RMSE values of 1.814°C, 1.652°C, 1.773°C, and 2.891°C, respectively. Also, for 50cm soil depth, MLPANN performed the best with an RMSE of 2.289°C at Sulaimani station using the RMSE during the validation phase. Furthermore, GPR produced the most superior outcomes for 10cm, 30cm, and 50cm soil depths, with RMSE values of 1.753°C, 2.270°C, and 2.631°C, respectively. In addition, for 05cm soil depth, SVR achieved the highest level of performance with an RMSE of 1.950°C at Dukan station. The results obtained in this research confirmed that the suggested models have the potential to be effectively used as daily predictive tools at different stations and various depths.

Root and rhizosphere contribution to the net soil COS exchange

Background and aimsPartitioning the measured net ecosystem carbon dioxide (CO2) exchange into gross primary productivity (GPP) and ecosystem respiration remains a challenge, which scientists try to tackle by using the properties of the trace gas carbonyl sulfide (COS). Its similar pathway into and within the leaf makes it a potential photosynthesis proxy. The application of COS as an effective proxy depends, among other things, on a robust inventory of potential COS sinks and sources within ecosystems. While the soil received some attention during the last couple of years, the role of plant roots is mostly unknown. In our study, we investigated the effects of live roots on the soil COS exchange.MethodsAn experimental setup was devised to measure the soil and the belowground plant parts of young beech trees observed over the course of 9 months.ResultsDuring the growing season, COS emissions were significantly lower when roots were present compared to chambers only containing soil, while prior to the growing season, with photosynthetically inactive trees, the presence of roots increased COS emissions. The difference in the COS flux between root-influenced and uninfluenced soil was fairly constant within each month, with diurnal variations in the COS flux driven primarily by soil temperature changes rather than the presence or absence of roots.ConclusionWhile the mechanisms by which roots influence the COS exchange are largely unknown, their contribution to the overall ground surface COS exchange should not be neglected when quantifying the soil COS exchange.

Lagged effects of snow on extreme precipitation in the arid area of Northwest China and the associated mechanisms

Study regionThe arid area of Northwest China. Study focusThis study aims to explore the lagged effects of snow on extreme precipitation and the associated mechanisms by using composite analysis and extracting significant areas. Due to the complex terrain of the study area, we have explored the response of soil temperature, soil moisture, and various energy changes in different sub-regions, these explorations are conducted in conjunction with the study of lagged effects of snow on extreme precipitation and provide a reference for future climate prediction. New hydrological insights for the regionThe response pathways of soil and energy are explored during the impact of snow on extreme precipitation in different significant areas. Latent heat flux is the main energy source, but sensible heat flux and effective radiation can also become the local dominant energy sources due to the influence of many environmental factors. Differences in the paths of influence in different regions will result in different atmospheric circulation anomalies. When the low-value system appears, it is more likely to cause extreme precipitation.

Rice Straw Mulch Installation in a Vineyard Improves Weed Control and Modifies Soil Characteristics

After harvesting rice paddy fields, rice straw is a significant problem due to uncontrolled CO2 emissions when the straw is burned. One solution to this problem is to use this rice by-product for mulching planting lines of fruit trees or vineyards with the purpose of controlling weeds and improving soil characteristics. A 3-year experiment was conducted at the Polytechnic University of Valencia (Spain) demonstration vineyard, where rice-straw mulch was installed at three rates in 2021, 24.0, 43.1, and 63.1 t ha−1, and in 2022, 25.0, 37.5, and 50.0 t ha−1. Weeds were mainly controlled with the highest treatment rate (50.0–63.1 t ha−1), as the time of the year for mulch installation is decisive for achieving different weed control rates. On average, mulch decreased soil bulk density (5.4%), and increased the soil organic carbon (24.3%) and water-soluble organic carbon (24.3%) compared to bare soil. Soil temperature changes were observed due to the mulch treatment, with soil temperature lower in bare soil than in mulched soil during the cold season, and higher during the warm season. This effect was highly dependent on the mulch application rate. Soil moisture content was also higher under the mulch treatment, showing a mulch-rate response during the four seasons of the year. The changes in the physical and biological soil properties induced a higher soil respiration rate when mulched soil was compared to bare soil. This study concludes that the use of rice straw as a mulch had positive effects on weed control and soil properties, although three factors concerning mulch management were paramount: rate, the timing of installation, and replacement rate.

Climatic shifts threaten alpine mycorrhizal communities above the treeline

The European Alps are experiencing more than twice the increase in air temperature observed in the rest of the world. Thus, the treeline ecotone, and the unique habitats above it, offer a preview of drastic changes in plant and animal communities. However, our knowledge about climate change impacts on microbial diversity belowground is scarce. Here we investigate how upslope shift of the treeline ecotone, associated with changes in soil nutrient content, temperature and precipitation, will influence alpine ectomycorrhizal (EM) communities of Dryas octopetala, Bistorta vivipara and Salix herbacea across different habitat types in the Alps. We also assessed the degree of EM community taxonomic composition turnover in these habitats across three different climatic projections for 2040 and 2070. Our results indicate that the specialized EM fungal communities from snowbed habitats will be mostly negatively influenced under the current trajectory of environmental shifting predicted for the region. In contrast, fungi from the treeline ecotone, having wider niches, will be positively influenced by future climate and extend upwards. In addition, our predictions of EM community turnover for putative future climatic scenarios revealed high rates of turnover across the entire alpine region. This, together with glacier retreats, will aid colonization of alpine snowbed habitats by new EM plants and associated fungi, bringing additional pressures on local mycorrhizas and likely leading to fungal species extinctions.

Seasonal variation of surface energy balance over Mubi northeastern Nigeria during 2000-2020

Several studies have been undertaken on surface energy balance (SEB) at various places in the world, but none have been undertaken for Mubi, Northeastern Nigeria. In the effort of consideration, this study aims to evaluate the seasonal variation of SEB in Mubi, with emphasis on the observational data from 2000 to 2020. Evaluation of seasonal variations was executed using time series analysis to find out the impact of precipitation, evapotranspiration, soil, and air temperature changes on SEB components. It was found that the SEB components variations of sensible heat (H) had a maximum value of 1035.13 Wm−2 in the dry season, in the month of December, while a minimum value of -104.13 Wm−2 during the rainy season, in the month of July; latent heat (LH), had a peak value of 5243.46 Wm-2 in the dry season in the month of April, while in the rainy season, the lower value was found to be 2460.6 Wm-2, in the month of August; soil heat (G) had minimum and maximum values of 886.43 Wm-2 in March and 275.25 Wm-2 in August respectively; and net radiative (Rn) varies roughly between the highest month in March with 2809.35 Wm−2 (rainy season months) and lowest month in August with 6879.69 Wm−2 (dry season months). It was also found that precipitation, evapotranspiration, soil, and air temperature follow the same trend with some SEB results, affirming their dependency on each other. Therefore, it is expected that this study will help to understand the amount of energy received or emitted in the Mubi region. Along with the main work, some recommendations were made by researchers on some applications of SEB to the community.

Subsurface temperature change attributed to climate change at the northern latitude site of Kapuskasing, Canada

Subsurface temperatures have been measured in different regions of the world, usually near the surface up to a depth of about a hundred meters. In this work a forward model calculation for a Northern Hemisphere soil temperature site at Kapuskasing, Canada, is presented, employing the solution of the differential equation of heat conduction through a semi-infinite homogeneous solid, subject to surface boundary conditions determined by surface air temperature. In this way, a detailed analysis is made of the subsurface temperature as a function of ground depth and for the time interval ranging from 1970 to the future (including the next century), for different scenarios of climate change. From these results, it was possible to determine the following characteristic quantities: (a) the depth where the surface perturbation (practically) finishes (in the range of about 180-200 m); (b) the depth where the subsurface temperature changes its slope from negative to positive; (c) the temperature change at the surface for the years where data exist; (d) the thermal gradient at steady state in the starting year (1880); (e) the temperature differences extrapolated at surface and at a 20 m depth, this last value corresponding to the depth at which seasonal and diurnal temperature variations are negligible; (f) the heat flow at surface to the inner part of the soil attributed to climate change, and (g) the temperature changes at surface for the 100 years interval (1980-2080) and mainly for the next century (2080-2180), for each site and for each IPCC Representative Concentration Pathway (RCP) scenario. As an example, the impact of the change in mean annual soil temperature due to global warming in near-surface geothermal energy is described.

Differences in soil microbial community structure and assembly processes under warming and cooling conditions in an alpine forest ecosystem

Global climate change affects the soil microbial community assemblages of many ecosystems. However, little is known about the effects of climate warming on the structure of soil microbial communities or the underlying mechanisms that influence microbial community composition in alpine forest ecosystems. Thus, our ability to predict the future consequences of climate change is limited. In this study, with the use of PVC pipes, the in situ soils of the rush-tip long-bud Abies georgei var. smithii forest at 3500 and 4300 m above sea level (MASL) of the Sygera Mountains were incubated in pairs for 1 year to simulate climate cooling and warming. This shift corresponds to a change in soil temperature of ±4.7 °C. Findings showed that climate warming increased the complexity of bacterial networks but decreased the complexity of fungal networks. Climate cooling also increased the complexity of bacterial networks. However, in fungal communities, climate cooling increased the number of nodes but decreased the total number of edges. Stochastic processes acted as the drivers of bacterial community composition, with climate warming leading the shift from deterministic to stochastic drivers. Fungal communities were more sensitive to climate change than bacterial communities, with soil temperature (ST) and soil water content (SWC) acting as the main drivers of change. By contrast, soil bacterial communities were more closely related to soil conditions than fungal communities and remained stable after a year of soil transplantation. In conclusion, fungi and bacteria had different response patterns, and their responses to climate cooling and warming were asymmetric. This work is expected to contribute to our understanding of the response to climate change of soil microbial communities in alpine forests and our prediction of the functions of soil microbial ecosystems in alpine forests.

Compressibility behavior of colemanite added bentonite under short and long-term high temperature

Introduction
 The increasing energy demand and the limited fossil fuel resources make searching for new sustainable clean energy sources. In this regard, it is vital to use energy geo-structures as a renewable and clean energy source. The geo-structures are in direct contact with the soil and cause temperature changes throughout the soil mass.
 Bentonite is considered suitable as an engineering barrier in deep geological disposal repositories for spent nuclear fuel, mainly because of its favorable swelling properties and extremely low permeability [1]. It was reported by many researchers that the engineering properties of clayey soils change at high temperatures [2,3]. Therefore, there is a need for soil materials that can maintain their long-term engineering properties under high temperatures. Borates are naturally occurring minerals. They can be found mainly in sediments and sedimentary rocks. The most commercially important boron minerals are tincalconite, colemanite, and ulexite [4].
 In the present study, it was tried to improve the compressibility behavior of bentonite by adding colemanite under high temperature. The oedometer tests were performed under a constant temperature (80 ºC) on the bentonite-colemanite mixtures. In this context, samples exposed to short and long-term high temperature (80 ºC) were used and the results were compared with the room temperature results.
 Material Characterization and Methods
 The Ca-bentonite sample used which is activated with sodium bicarbonate. Colemanite was added to bentonite at a rate of 10% of the bentonite by dry weight. In this context, B10C sample represents a 10% colemanite added bentonite mixture. The liquid limits of bentonite and colemanite are 270% and 37%, respectively. The samples (smaller than 75 μm) were obtained by mixing the mixture powder with tap water at a water content of 1.5 times the pre-determined liquid limit value of the mixtures. The slurries were consolidated under a vertical pressure of 12.5 kPa for 14 days. Samples 70 mm in diameter and 19 mm in height were obtained by trimming. The samples were placed in oedometers for tests at room and high temperature (80 ºC). The experimental system was modified for high-temperature tests. The modified system consists of a conventional apparatus, a heat ring, a thermostat, and a water tank. Thus, by heating the cell water, the temperature of the sample was indirectly increased to 80 °C. For long-term experiments, samples were placed in thermal pools in clamped molds (constant volume). These molds were kept in the thermal pools under a constant temperature of 80 °C for 6 months. Then, the consolidation tests of these samples were performed at 80 °C.
 Results and Discussions
 The result of the consolidation tests of bentonite mixtures at 80 °C after being kept in the thermal pool for 6 months is given in Figure 1. For comparison, the test results at room temperature and 80 °C are also shown. The compression amount of bentonite increased with the increase in temperature, while the swelling amount decreased. The total compression deformation of the bentonite sample, which showed 53% compression at room temperature, reached 65% when the temperature was increased to 80 °C. However, swelling deformation decreased from 7% to 3% when the temperature was increased. When the volumetric deformation behavior of bentonite (NC) is examined, thermal contraction behavior at high temperature (90 °C) was reported [2]. In other words, the vertical compression amount of NC bentonite increases at elevated temperatures. In addition, since the structure of the clay deteriorated at high temperature and the deformations were permanent, it was an expected result that the rebound (swelling) behavior would decrease at high temperature.
 There was a decrease in the amount of compression in the sample cured for 6 months, compared to 80 °C. However, although the compression amount of the 6-month cured sample decreased, the amount of compression still slightly increased compared to the room temperature. Compression-swelling deformation amounts of the samples cured for 6 months and tested at 80 °C are presented in Table 1 in detail. When the swelling behavior of additive-free bentonite was examined, increasing temperature decreased the rebound behavior of bentonite. In addition, the swelling amount of the sample cured for 6 months was determined to be almost the same as the sample at 80 °C. The reason for this was that the deformations that occurred at high temperatures were permanent. 
 When the temperature of the colemanite-added bentonite mixtures was increased, the amount of deformation increased. However, the amount of deformation of additive-free bentonite decreased with the colemanite addition at 80 °C, and returned to its room temperature value (approximately 53%). In other words, the addition of colemanite had a positive effect by reducing the deformation amount of bentonite at both short and long term high temperatures. The short and long term effects of 80 °C temperature on colemanite added samples were almost the same.

INFLUENCE OF AGRICULTURAL PRACTICES ON THE PROCESS OF SOIL FREEZING

Only the change in soil temperature with time has been systematically studied on different types of soils. At the same time, many agricultural practices aim to regulate the soil’s temperature regime. Thus, snow retention and mulching with plant residues are effective measures aimed at increasing the temperature of the surface layers of the earth. In the article, the authors investigated the process of world freezing with a mulched surface under a layer of snow covered with an ice crust. Methods of theoretical analysis (structuralfunctional, systemic approach) and mathematical statistics are used. The authors conducted field studies in two versions at LLC “Plemsovkhoz” Kenzhe “of the Kabardino-Balkarian Republic. The first option is bare soil, and the second option is mulched soil with the creation of an ice crust on the snow surface in winter. Studies were carried out on the influence of the mulching layer of vegetation and the ice crust on the snow surface on the annual variation in soil surface temperature and soil temperature. These study results indicate that mulching the soil surface with plant residues and creating an ice crust on the snow surface contributes to the “smoothing” of the soil temperature. So, when using the proposed technological methods, the temperature of the soil with a change in depth from 0 to 100 cm changes from 0°С to +2.5 °С, while without their use - from -3 °С to +2 °С. The authors proved that the temperature of the soil at a depth of 30 cm, when using the proposed technological methods, reaches above 0 °C. This confirms the effectiveness of these techniques in preventing dirt freezing.

Heat transfer performance of large energy pile group in a hybrid system subjected to imbalanced thermal load - A numerical investigation

Introduction
 When a energy pile system is coupled with other heating or/and cooling systems, determining the share of thermal demand that energy piles can meet is crucial in designing the size of each system. In the long term, imbalance in thermal load can affect the heat transfer performance of energy piles, and may also lead to annual accumulation of ground temperature over the years, ultimately causing system failure. Furthermore, the mechanical responses of energy piles are also affected by the temperature changes in the pile body and surrounding soil during operation. While Current researches have predominantly focused on mechanical response under temperature load, understanding the heat transfer performance of energy pile groups is equally necessary. Existing studies on heat transfer largely draw from ground source heat pump (GSHP) systems, despite differences in depth and diameter between energy piles and borehole heat exchangers (BHEs), particularly for closely spaced piles. To address this gap, we conducted a series of numerical experiments based on the Tsinghua Science Museum project to investigate the thermal behavior of energy pile group under annual, imbalanced load and the influence of pile spacing. Based on simulation results, we provide design recommendations on how to determine the proportion of heat load that can be carried by energy piles in hybrid systems.
 Method
 We utilized COMSOL software to conduct three-dimensional modeling of a single pile, and developed a two-dimensional model of a pile group using a self-programmed Matlab program. The accuracy of the model was evaluated by comparing it with the results obtained from energy pile field tests (thermal response tests and thermal performance tests) conducted in Shunyi, Beijing. Subsequently, we established two-dimensional and three-dimensional numerical models for the Tsinghua Science Museum project in Beijing. We performed a series of numerical experiments to investigate the behavior of energy piles under balanced and imbalanced temperature loads for one year. Furthermore, we simulated the thermal responses of energy pile groups with different pile spacings of 2m, 2.85m, and 4m.
 Results
 The cooling load surpasses the heating load causing an imbalanced load. The soil temperature rises noticeably by 2.6 °C compared to the initial state after an operation period of 1 year, indicating an undesirable phenomenon of soil heat accumulation. With continuous running over years, the system will fail due to the excessive soil temperature. Moreover, the heat exchange liquid temperature ranges from -4.35 ℃ to +39.65 ℃, which exceeds the acceptable range of 2 ℃ to 33 ℃. To address this concern, a hybrid system can be utilized where the energy pile system bears a balanced portion of the thermal load, and the auxiliary system bears the remaining load. Simulation under various thermal load proportions reveals a linear relationship between the maximum/minimum outlet temperature and the total heat exchange volume. An energy pile system undertaking 60% heating load and 40% cooling load can run stably for long periods. The soil temperature varies in a range of 8.5 ℃ to 17.9 ℃, while the pile body temperature has a variation range of 4.0 ℃ to 22.8 ℃ (Figure 1).
 The study results for various pile spacings are presented in Table 1. Pile spacing plays a significant role in soil heat accumulation and heat exchange fluid temperature. Despite an invariable pattern in the inflow and outflow temperature curves for varied pile
 spacing, the flow temperature range is significantly influenced. The smaller the spacing, the more prominent is the thermal accumulation in the soil, leading to larger changes in soil temperature and the flow temperature. During design simulation, if the range of flow temperature exceeds the limits of the energy pile system, it may present a safety risk during system operation. In such cases, increasing the pile spacing can render the system more reliable and safe.
 Conclusions
 (1) Whether the system can operate normally can be judged by whether the simulation result of the heat exchange liquid temperature exceeds the limit value. There is a linear relationship between the flow temperature and the total heat exchange. Therefore, the proportion of the load that the energy pile system can bear in the hybrid system can be determined. For the Tsinghua project, the energy pile system can bear 60% of the heating load and 40% of the cooling load.
 (2) The pile spacing affects the magnitude of variation in heat exchange fluid temperature by influencing the degree of heat accumulation in soil. If the range of flow temperature exceeds acceptable limits, it is advised to increase the pile spacing during the design phase to ensure the energy pile system can operate effectively.

Impact of abiotic factors on the litter and soil mesofauna abundance in the Leucaena leucocephala (Lam) de Wit plantations

An experiment was conducted in an undisturbed Leucaena leucocephala (Lam)de Wit (subabul) plantation ecosystem to study the impact of abiotic factors on the distribution of litter and soil mesofauna. The findings revealed a significant correlation between the abundance of soil and litter mesofauna and abiotic factors. In the natural subabul plantation, the soil mesofauna population ranged from 38.00 (1st fortnight) to 307.00 /400g (11th fortnight), with a mean population of 123.48 /400g. Similarly, the litter mesofauna population ranged from 19.67 (12th fortnight) to 1013.33 /100g (9th fortnight), with a mean population of 211.52/100g. Soil temperature at 7 and 14 hours significantly negatively correlated with soil mesofauna. The distribution of soil mesofauna was impacted by abiotic factors up to 97 per cent, with in-situ soil temperature showing an impact of up to 74.1 per cent. A unit change in soil temperature would lead to a decrease of 18.23 units of soil mesofauna. Additionally, atmospheric maximum relative humidity and this abiotic factor impacted 83 per cent of soil mesofauna, while soil moisture and these two abiotic factors impacted 92.6 per cent of soil mesofauna abundance. All three factors exhibited a negative impact on soil mesofauna. On the other hand, rainfall showed a significant positive relationship with litter mesofauna, whereas in-situ soil temperature showed a significant negative relationship. Furthermore, abiotic factors contributed to 69.6 per cent of the abundance of litter mesofauna, with rainfall showing an influence of up to 40 per cent. A unit change in rainfall would increase 3.122 units in litter mesofauna abundance.

Effects of phase change material inclusion on reducing greenhouse gas emissions from soil in cold region.

Increased gas emissions from soil into the atmosphere are one form of ecosystem feedback in response to climate change. Soil temperature plays a critical role in the soil emission of carbon dioxide (CO2) and nitrous oxide (N2O) suggesting that the release of gases can be reduced by regulating soil temperature. This study proposes a green microencapsulated phase-change material (mPCM) as a soil temperature regulator due to its ability to absorb and release heat during temperature phase transition. The objective is to test how mPCM in soil mixtures influences CO2 and N2O fluxes under laboratory-controlled conditions. For this purpose, a series of soil incubations were carried out with different temperature regimes and soil moisture. The test results revealed that at 20% soil moisture mPCM reduced cumulative CO2 emissions from the soil by 16.4% during the thawing stage and by 20.5% during the freezing stage. At 25% soil moisture, mPCM showed a greater effect reducing cumulative CO2 emissions by 23.9% during the thawing stage and by 24.2% during the freezing stage. At below-zero temperatures, mPCM reduced the total N2O flux by 11.6% at 20% soil moisture and by 26.0% at 25% soil moisture, compared to soil without mPCM. As soil moisture increased, the effects of mPCM on CO2 and N2O fluxes became more pronounced. Cyclic freezing and thawing of soil led to an increase in gas flux. This variation was reduced by the mPCM due to its ability to mitigate the change of soil temperature. Inhibition of the rise in soil temperature due to the inclusion of mPCM reduced the rate of activation of soil mineralization, which reduced gas fluxes. This study demonstrates the potential of mPCM application to reduce greenhouse gas emissions from soil through thermoregulation.

Maize yield reduction is more strongly related to soil moisture fluctuation than soil temperature change under biodegradable film vs plastic film mulching in a semi-arid region of northern China

Maize yield reduction is more strongly related to soil moisture fluctuation than soil temperature change under biodegradable film vs plastic film mulching in a semi-arid region of northern China

Simulation of Soil Temperature under Plateau Zokor's (Eospalax baileyi) Disturbance in the Qinghai Lake Watershed, Northeast Qinghai-Tibet Plateau.

The soil temperature is a key factor affecting the fragile terrestrial ecosystems on the Qinghai-Tibet Plateau, and has been remarkably altered by the soil mammal's disturbance. This study first analyzed the soil temperature variation in grassland, mound, and bald patch under the disturbance of plateau zokor (Eospalax baileyi) from October 2018 to July 2020 in the Qinghai Lake watershed. Then, the SHAW (simultaneous heat and water) model was used to simulate the soil temperature change of three land surface types, and the sensitivity of soil temperature to environmental parameters before and after the disturbance was explored. The results showed the following: (1) The daily range of soil temperature was mound > bald patch > grassland, which became smaller as the depth increased, due to the co-influence of vegetation coverage and soil bulk density. There was an obvious hysteresis of soil heat transfer for grassland, as compared with mound and bald patch, especially at 5 and 15 cm depths. (2) The SHAW model was applicable for the simulation of soil temperature under the plateau zokor's disturbance, especially during the growing season, and had better simulation accuracy for deep soil. (3) Air-entry potential and pore-size distribution index obviously affected soil temperature change, because of the change in root system and soil pores under the plateau zokor's disturbance. With the evolution of disturbance process, the response of soil temperature to the leaf area index weakened gradually, owing to the different duration of disturbance and restoration. In general, the plateau zokor's disturbance alters the soil properties and vegetation characteristics, and further, distinctly affects heat transfer and soil temperature.

Grazing regulates soil N cycling of annual pastures by enhancing soil N turnover in arid climate condition

AbstractNitrogen is the second limited factor in arid regions. Little information is available on soil N cycling and availability under grazing in arid regions, which is required to evaluate land‐use management with respect to soil N availability and dynamics. In 2011, we established a rotational grazing field experiment in arid grassland. We conducted experiments to explore the effects of herbivores grazing on soil net N mineralization and N processes via changes in soil temperature, moisture, pH, and microbial biomass nitrogen (MBN) in 2016 and 2017. Our results showed that grazing did not alter soil N mineralization because higher soil moisture and soil MBN under grazing had positive and negative effects on soil N mineralization, thereby balancing soil N mineralization. Plant N uptake at the grazing plots was, nevertheless, 23% higher than that at the non‐grazing plots. These demonstrated that grazing potentially improved soil inorganic N availability and alleviated soil N limitation in arid regions. Soil nitrification was main pathway of N transformation in arid regions. Grazing improved soil accumulation of NO3− content, resulting in environmental problems (such as N2O emission and N leaching); however, grazing had a little effect (~15% increase) on soil N leaching and (~7% decrease) on N2O emission. These N processes reflect important mechanisms of resilience and ecosystem stability under grazing in an N‐limited environment. Our results provide an important perspective for grassland management, aiming to maintain soil N supplying capacity in annual pasture sustainably. Overall, our study suggests that grazing is an effective management practice for the sustainable usage of local grasslands, as it improves soil physicochemical and biological properties, which, in turn, increases N supply.