Soil Temperature Research Articles

Experimental Study on Seasonal Ground-Coupled Heat Storage and Harvesting in Cold Regions

In recent years, global efforts toward sustainable energy have intensified, aiming to reduce carbon emissions and boost energy efficiency. Heating in winter and hot water for hygiene are essential, especially in cold climates where heating demands significantly impact household energy consumption. This study examines a city in western Inner Mongolia, characterized by a severe cold climate and unique geology. A test system with dual U-shaped buried pipes for ground source heat storage and extraction was constructed, utilizing two layout schemes. Drilling tests measured formation parameters, highlighting how pipe layout and soil characteristics influence heat storage. Short-term 5-day cycles and cross-seasonal 60-day cycles were tested. Results showed upper soil suited for frequent short-term storage, while lower soil favored long-term energy retention. Increasing buried pipes raised soil temperature and storage capacity, enhancing thermal stability in short-term cycles. However, while the long-term storage capacity improved, heat loss also rose. Effective ground source heat pump design in cold regions should consider environmental temperatures, pipe optimization, soil characteristics, and heat storage duration to achieve stable, efficient operation.

Influence of land-use type on earthworm diversity and distribution in Yunnan: Insights from soil properties

This study explores the soil biodiversity and distribution of earthworms in Yunnan Province. Employing a quadrat survey method, the province was divided into six climate types, among which four representative land-use types (arable land, wasteland, grassland, and garden) were selected for sampling of earthworms and soil. In total, 1984 earthworm individuals were gathered from 148 plots, representing 27 species occurrences across four families, with Moniligastridae being dominant. The present study emphasized that different land use modes can affect the distribution of earthworm communities; there are differences in soil physical and chemical properties under different land use types; therefore, various land use modes can further affect the density and biomass of earthworms by influencing soil physical and chemical properties. Soil properties such as SOM, TN, TK, and OP significantly affect earthworm communities. For example, SOM had a significant positive correlation with earthworm density in Wasteland and Arable land and a significant positive correlation with earthworm biomass in Grassland and Garden; in addition, soil temperature and TK content had a significant negative correlation with earthworm density in Garden. This study provides data support for understanding earthworm species diversity and its spatial distribution characteristics in Yunnan Province. It gives a scientific basis for further discussion of the influence of land use on soil fauna conservation and its ecological functions.

Observational evidence of impact of heavy rainfall events on surface energetics and soil variables over a tropical station Tirupati

Two back-to-back heavy rainfall events (HREs) produced enormous rainfall over a pilgrim city, Tirupati, located in the southern peninsular India, during 10–12 November 2021 (149.2 mm) and 17–19 November 2021 (234.2 mm). Surface measurements at Yerpedu, Tirupati (13.74°, 79.60°E) showed a drop of 2–3 °C in temperature and 8 hPa in pressure during HREs, indicating that these HREs were associated with two landfalling tropical depressions from the Bay of Bengal. The sporadic HREs in the past three decades caused floods over Tirupati and devastated landslides in the sacred Tirumala hills especially during the second HRE. Fundamental understanding of diurnal cycle of surface radiation is critical to model the climate. The effect of HREs on the surface essential climate variables at diurnal scale indicate a reduction in peak solar and net radiations by 500 W m−2 (> 62.5 %). Similar to observations, ERA5 reanalysis also indicates a significant reduction in net surface solar and thermal radiations, which are nearly equal in terms of % but vary in magnitude. Net solar and thermal radiations show dominant diurnal cycles with a reduced (66.7 % and 74.4 % respectively) diurnal amplitudes from no-rain to HREs. Soil moisture drydown curves at 5- and 10-cm depths shows 3 h long e-folding decay time for HREs, indicating an enhanced soil moisture memory after HREs. The soil drying process takes longer time at 10 cm than at 5 cm depth. Soil temperatures are significantly low at 5 cm to 30 cm depths and less than the 50 cm depth with weak diurnal variation during the events. The reflectivity (Z)-rain rate (R) and shape (μ)-slope (Λ) relations show variations from HREs to normal rain events. Knowing the importance of land-atmospheric processes feedbacks in model predictions at diurnal scale, this study quantified the HREs impact on surface essential climate variables, especially the energy balance and soil variables.

Biobased hydrophobic liquid mulch film from soybean oil and starch for enhanced terraced field cultivation.

Terraced agriculture faces soil loss during rainstorms leading to natural disasters and crop growth impediments. This study describes a novel biobased hydrophobic liquid mulch film comprised of waste soybean oil, starch, and acrylate monomers that can be used to enhance terraced field cultivation. The novel film, optimized at a 3:7 soybean oil to acrylate monomers ratio, exhibited superior spray ability, reduced wicking, and excellent film formation, which are crucial for its effectiveness as a water erosion barrier. The wet state of the SOSA film demonstrated optimal impact resistance, with increased elongation at break and reduced breaking strength compared to its dry state, facilitating seedling emergence. It significantly improved soil moisture retention (4.8-5.7 %) and temperature (0.9-5.6 °C) and boosted maize seed germination by 28 %. Under extreme conditions of a 24° slope and 90 mm/h rainfall, the SOSA film achieved an 80.6 % reduction in soil loss and a 57.4 % increase in pakchoi yield over bare soil. This study's comprehensive analyses confirmed the film's formation mechanism and provided a scientific basis for its practical application performance, highlighting the film's unprecedented success in using waste materials for sustainable terrace farming and its potential as a transformative approach to soil conservation and crop productivity.

Aqua-stream: an IoT based smart water management system for sustainable living

<p class="03IJISAEAbstract">Aqua-stream, an innovative internet of things (IoT) enabled water management system, utilizes the power of long short-term memory (LSTM) networks, a sophisticated time-series forecasting machine learning technique with Kafka. Aqua-stream seamlessly integrates LSTM within the Kafka streaming architecture for efficient real-time data processing, ensuring quick responses to emerging water management needs. LSTM is employed for real-time anomaly detection, dynamically analyzing streaming data to prevent leaks through automated shut-off valves. The system’s comprehensive dashboard utilizes LSTM insights for live water quality analysis; adaptive scheduling based on individual preferences and personalized recommendations, enhancing cost-effective water management. This streamlined approach extends to the smart gardening system, where LSTM guides automation for optimal plant care incorporating sensors to monitor soil moisture, temperature, and sunlight levels. This system automatically adjusts watering and lighting to ensure optimal conditions for plant growth. Users can control and monitor their garden remotely via a smartphone, facilitating plant care while saving water and energy. Aqua-stream redefines home water management, offering a holistic solution that combines intelligent water conservation with smart gardening for a sustainable and connected living experience. Aqua-stream represents a seamless integration of LSTM-based machine learning and IoT technologies, offering an intelligent, yet simplified, solution for sustainable and connected living.</p>

Construction and verification of distributed hydrothermal coupling model in the source area of the Yangtze River

Study regionThe source area of the Yangtze River, a typical catchment in the cryosphere on the Tibet Plateau, was used to develop and validate a distributed hydrothermal coupling model. Study focusClimate change has caused significant changes in hydrological processes in the cryosphere, and related research has become hot topic. The source area of the Yangtze River (SAYR) is a key catchment for studies of hydrological processes in the cryosphere, which contains widespread glacier, snow, and permafrost. However, the current hydrological modeling of the SAYR rarely depicts the process of glacier/snow and permafrost runoff from the perspective of coupled water and heat transfer, resulting in distortion of simulations of hydrological processes. Therefore, we developed a distributed hydrothermal coupling model, namely WEP-SAYR, based on the WEP-L (Water and energy transfer process in large river basins) model by introducing modules for glacier and snow melt and permafrost freezing and thawing. New hydrological insights for the regionIn the WEP-SAYR model, the soil hydrothermal transfer equations were improved, and a freezing point equation for permafrost was introduced. In addition, the glacier and snow meltwater processes were described using the temperature index model. Compared to previously applied models, the WEP-SAYR portrays in more detail glacier/snow melting, dynamic changes in permafrost water and heat coupling, and runoff dynamics, with physically meaningful and easily accessible model parameters. The model can describe the soil temperature and moisture changes in soil layers at different depths from 0 to 140cm. Moreover, the model has a good accuracy in simulating the daily/monthly runoff and evaporation. The Nash-Sutcliffe efficiency exceeded 0.75, and the relative error was controlled within ±20%. The results showed that the WEP-SAYR model balances the efficiency of hydrological simulation in large scale catchments and the accurate portrayal of the cryosphere elements, which provides a reference for hydrological analysis of other catchments in the cryosphere.

Plant litter crust enhances nitrogen accumulation by regulating microbial diversity and urease activity in semi-arid sandy soils

Plant litter plays a crucial role in regulating soil nitrogen (N) cycling in dryland ecosystems. However, the mechanisms by which plant litter crust drives microbial community composition to influence N levels in sandy soils remain unclear. In this study, we examined the effects of litter crust on sandy soil microhabitat characteristics (temperature, moisture, and porosity), microbial diversity and composition, urease activity, and soil N variables (total-N, nitrate-N, and ammonium-N) across different stages of litter crust development (including early-, mid-, and post-term) in a field setting. We found that litter crust promotes bacterial and fungal alpha diversity in sandy soils, leading to a shift in bacterial community composition from oligotrophs (i.e., Actinobacteria) to copiotrophs (i.e., Proteobacteria and Bacteroidetes), and a shift in fungal community composition dominance from Ascomycota to Basidiomycota. Litter crust enhances the complexity and stability of bacterial and fungal co-occurrence networks in sandy soils, especially in early- and mid-term stages of crust development. Additionally, litter crust increases nitrification (aerobic ammonia oxidation) and decreases denitrification (nitrate reduction) in these soils. Notably, the increase in soil moisture and urease activity, along with the decrease in soil temperature due to litter crust, effectively promotes N accumulation in sandy soils. Our results demonstrate that N levels during the litter crust period are mainly influenced by a combination of bacterial beta diversity and fungal alpha diversity at the 0–5 cm depth, and bacterial alpha diversity along with soil properties (i.e., soil variables and urease activity) at the 5–10 cm depth. Overall, our results reveal that litter crust contributes to N accumulation in sandy soils by regulating bacterial and fungal community composition and diversity, as well as by buffering soil temperature and soil moisture, and enhancing urease activity. These findings provide new insights into the critical role of soil microbes in maintaining N functions during litter crust development in semi-arid sandy ecosystems.

Smart Planter: Simplifying Plant Care with AI Sensors

Abstract: This paper presents a smart plant care system developed to address the challenges of indoor plant maintenance for busy or novice plant owners. Leveraging AI sensors and IoT technology, the system continuously monitors crucial environmental parameters—soil moisture, temperature, and light exposure—to optimize plant health. Real-time data analytics and machine learning algorithms analyze this data, predicting care needs and automating responses like watering adjustments, with minimal user input. The user-friendly mobile app interface provides actionable insights, enabling remote monitoring and proactive care. This report covers the system’s layered architecture, practical benefits, implementation challenges, and potential for integration with smart home systems. It also explores future advancements in AI-driven plant care, emphasizing the potential of this technology to transform indoor gardening by making it more accessible, efficient, and precise.

Survey Paper on IoT-Enabled Seed Dispensing Robot

As a result, the IoT-Enabled Seed Dispensing Robot is used to automate the seed planting process with precision technologies. Based on real time environmental conditions such as soil moisture and temperature it optimizes seed placement through GPS tracking and IoT sensor data. Remote monitoring and control of the robot is via a cloud-based platform resulting in significant reduction in labour cost and superior farming efficiency. Having the ability to handle terrain and obstacle mapping, it is well suited for any agricultural application and is a reliable, scalable way to meet the challenges of modern farming.

Grassland irrigation and grazing prohibition have significantly affected vegetation and microbial diversity by changing soil temperature and moisture, evidences from a 6 years experiment of typical temperate grassland

Grasslands are characterized by high primary productivity and offer a diverse array of ecosystem services that contribute to human well-being. The dynamic balance between vegetation-soil in grassland ecosystems is being affected by anthropogenic activities and climate change, in which soil microbial communities play a critical regulating role. However, how microbial biodiversity interacts with vegetation-soil and responds to environmental change remains unclear. We conducted a six-year field experiment in the grasslands of Inner Mongolia to study the effects of grazing and altered precipitation on major vegetation types (or species), soil properties, and microbial community composition. The results showed that increased precipitation influenced positive associations within microbial communities, which helped to increase vegetation diversity. The biomass of Stipa.sareptana increased by 0.054 % under reduced precipitation, while it significantly increased by 2.07 % under the combination of grazing ban and reduced precipitation. Grazing prohibition had a significant negative effect on bacterial diversity and Shannon's index, but a significant positive effect on fungal diversity and abundance. Increasing precipitation had no significant effect on bacterial diversity under grazing conditions, while decreasing precipitation significantly reduced the Shannon index of bacteria. Fungal communities were very sensitive to changes in precipitation, and both increasing and decreasing precipitation significantly affected the structure of fungal communities. In summary, our results highlight how grassland irrigation and moderate grazing can be employed as a management strategy to promote plant diversity and thereby improve ecosystem functioning and resilience.

Effects of Prescribed Burns on Soil Respiration in Semi-Arid Grasslands

Carbon fluxes are valuable indicators of soil and ecosystem health, particularly in the context of climate change, where reducing carbon emissions from anthropogenic activities, such as forest fires, is a global priority. This study aimed to evaluate the impact of prescribed burns on soil respiration in semi-arid grasslands. Two treatments were applied: a prescribed burn on a 12.29 ha paddock of an introduced grass (Eragostis curvula) with 11.6 t ha−1 of available fuel, and a simulation of three fire intensities, over 28 circular plots (80 cm in diameter) of natural grasslands (Bouteloua gracilis). Fire intensities were simulated by burning with butane gas inside an iron barrel, which represented three amounts of fuel biomass and an unburned treatment. Soil respiration was measured with a soil respiration chamber over two months, with readings collected in the morning and afternoon. Moreover, CO2 emissions by combustion and productivity after fire treatment were quantified. The prescribed burns significantly reduced soil respiration: all fire intensities resulted in a decrease in soil respiration when compared with the unburned area. Changes in albedo increased the soil temperature; however, there was no relationship between changes in temperature and soil respiration; in contrast, precipitation highly stimulated it. These findings suggest that fire, under certain conditions, may not lead to more CO2 being emitted into the atmosphere by stimulating soil respiration, whereas aboveground biomass was reduced by 60%. However, considering the effects of fire in the long-term on changes in nutrient deposition, aboveground and belowground biomass, and soil properties is crucial to effectively quantify its impact on the global carbon cycle.

The Dynamic Characteristics and Influencing Factors of Soil Respiration in Different Types of Grasslands in the Barkol Lake Basin

Determining regional and global carbon cycles hinges on investigating the dynamic characteristics and influencing factors of soil respiration in various types of natural grasslands located in arid regions, and these characteristics are important indicators for assessing the structural and functional health of grassland ecosystems. Such investigations also provide theoretical support for carbon sink monitoring, energy conservation, emission reduction and low-carbon development in the western arid zone and are important for obtaining an in-depth understanding of the carbon cycle, as well as for ecosystem management, restoration and the reconstruction of arid areas. In this study, during the growing season (from May to October) of 2022, the LI-8100A automated soil CO2 flux system was used to measure the soil respiration rate (Rs), temperature from 1.5 m above the surface to depths of 5–25 cm (T, T5, T10, T15, T20 and T25) and the soil moisture content (SM) at a depth of 20 cm in four types of grasslands: lowland meadow, alpine meadow, temperate desert steppe and temperate steppe desert. Five replicates were established for each plot, and the responses of Rs to T and SM were fitted to construct the optimal regression model. The results revealed that (1) the daily average soil respiration was highest in the lowland meadow (0.07 to 5.76 μmol·m−2·s−1), followed by the alpine meadow (−0.57 to 0.95 μmol·m−2·s−1), the temperate desert steppe (−0.45 to 3.0 μmol·m−2·s−1) and the temperate steppe desert (−1.29 to 1.61 μmol·m−2·s−1); (2) the soil respiration rates of the four grassland types were significantly correlated with the temperature in the 5–15 cm soil layer, and the best model was an exponential function; the peak values generally appeared between 13:00 and 17:00 (h), with the minimum values at 2:00 or 8:00 (h); the maximum value was observed in July–August, and the minimum value was observed in October; and the soil respiration in the lowland meadow was higher than that in the other three types of grassland during the same period. The average variation intensities of the soil respiration from May to October were as follows: temperate steppe desert (91.78%) > temperate desert steppe (76%) > alpine meadow (58.77%) > lowland meadow (43.93%). (3) The partial correlation analysis revealed that when soil temperature was used as a control, the correlation between SM and soil respiration in the four types of grasslands changed, and the coefficient of determination (R2) increased to varying degrees, explaining up to 80% of the variation in the soil respiration in the lowland meadows. The correlation between soil respiration and the SM normalized to 10 °C explained up to 93.8% of the variation in soil respiration; the two-factor fitting equations revealed that the model with soil temperature and SM was superior to the single-factor model with either soil temperature or SM.

Soil Microorganisms: Their Role in Enhancing Crop Nutrition and Health

Maintaining soil health is fundamental to sustaining agricultural productivity, however, the intricate role of soil microbial diversity in this process is not fully understood. Current research acknowledges that soil microorganisms including bacteria, fungi, and archaea are pivotal in driving essential soil functions such as nutrient cycling, organic matter decomposition, and disease suppression. However, the impacts of global environmental changes and intensive agricultural practices on the diversity of these microorganisms remain a critical gap in the literature. This gap is significant because a decline in microbial diversity could severely compromise soil health, and consequently crop productivity. Here, we provide a comprehensive review of the factors influencing soil microbial diversity and examine their implications for crop performance. We assess both natural factors such as soil pH, moisture, temperature, and vegetation type as well as human-induced factors including tillage systems and fertilizer application. The review synthesizes recent findings on how these factors shape microbial communities and their functional roles in nutrient cycling, soil structure formation, and disease suppression. Our analysis highlights the mechanisms by which microbial diversity enhances plant growth and yield, addressing the gap in understanding the direct links between microbial diversity and agricultural outcomes. Our findings underscore the urgent need for sustainable agricultural practices that protect and enhance microbial diversity to safeguard long-term soil fertility and crop productivity. By addressing the challenges in manipulating soil microbial communities and integrating microbial ecology with crop management practices, this research advances our ability to sustain agricultural systems in the face of global environmental changes.

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.

Seasonal patterns of CO2 exchange in a tropical intensively managed pasture in Southeastern Brazil

Tropical pastures are one of the main land uses in Brazil, forming the backbone of the country's beef and milk production chain. Adopting sustainable management practices that increase the productivity of pastoral livestock systems is essential to mitigate environmental impacts and ensure food security. However, eddy covariance studies that contribute to understanding the influence of grazing management strategies on the ability of intensively grazed tropical pastures to absorb carbon remain scarce. Therefore, our main objective was to investigate the dynamics of CO2 and water vapor exchange and biomass production in a tropical C4 grass (Pennisetum purpureum Schum. cv. Cameroon) pasture under intermittent stocking management strategies from March 2021 to June 2023. We found that the pasture acted as a net source of CO2 to the atmosphere in both years studied. The annual NEE was 34 ± 14 g CO2-C m−2 yr−1 in 2021–2022 and 21 ± 12 g CO2-C m−2 yr−1 in 2022–2023. Reco, influenced by rising air and soil temperatures, increased rainfall, and higher incoming solar radiation levels, especially during spring and summer, played a crucial role in this result. The pasture absorbed more CO2, showed higher evapotranspiration, and produced more leaves in the rainy periods when the pasture structure was kept close to the previously established management targets. CO2 losses to the atmosphere prevailed in the dry periods and in wet periods where the pasture structure was far from the optimal limits for elephant grass.

Novel fabrication of polyethylene glycol/ceramic composite pellets with an excellent phase change shape stable trait and their potential applications for greenhouse insulation

Organic solid–liquid phase change materials (PCMs) face challenges in practical applications due to their susceptibility to leakage during phase transitions. To address this issue, we constructed the polyethylene glycol (PEG)/ceramic pellets (CPs) composite phase change shape stable materials (PCSHs) with thermal energy storage capability, thermal stability, and a firm texture using the melting impregnation method. The PCSHs exhibit remarkable shape stability in the leakage test due to the capillary action and surface tension generated by the micropore structure on their surface. They also can convert light energy into heat and store it as latent heat, achieving an optimal photothermal conversion efficiency of 45.21 % and a maximum melting enthalpy of 13.33 kJ/kg at a PEG loading of ∼ 12 %. An outdoor greenhouse insulation simulation experiment confirmed that the PCSHs can maintain soil temperatures above 30 °C for over 30 min after illumination ceases. This work presents a facile synthesis strategy for shape-stable PCMs with potential applications in greenhouse insulation.

Effects of different tillage methods on soil properties and maize seedling growth in alternating wide and narrow rows rotation mode in the Songliao Plain of China

The Songliao Plain is the main maize (Zea mays L.) producing region in Northeast China. The no-tillage22NT: no-tillage. (NT) method in alternating wide and narrow rows rotation mode is widely used for maize planting in this region. However, in spring, the NT method in this mode suffer from low soil temperature and high soil water content33SWC: soil water content. (SWC), which severely restrict maize seed germination and seedling growth. We pioneered the research and practice of the ridge tillage44RT: ridge tillage. (RT) method and strip tillage55ST: strip tillage. (ST) method in this mode. We developed a new tillage machine to enable the implementation of RT and ST methods in alternating wide and narrow rows rotation mode, which has not been previously reported in this region. In this mode, the relative research of the RT method and ST method has not been conducted, and the effects of the RT method and ST method on the soil properties and maize seedling growth have not been clarified. Therefore, a 3-year field experiment was conducted at 7 randomly selected experimental sites in this region to research the effects of RT, ST, and NT methods on soil properties and maize seedling growth. During the spring sowing period, for soil pH, organic matter66OM: organic matter. (OM), available nitrogen, available phosphorus, and available potassium, both the RT method and ST method resulted in greater values than the NT method, and there was no significant difference between the RT method and ST method. This indicated that prolonged NT was not conducive to even distribution of OM, resulting in slightly lower available nitrogen, phosphorus, and potassium compared to the RT and ST methods. Within 30 days after spring sowing, for soil temperature, RT method value > ST method value > NT method value; for SWC, NT method value > RT method value > ST method value. For mean seedling emergence time77MET: mean seedling emergence time. (MET), RT method value < ST method value < NT method value; for seedling emergence rate88ER: seedling emergence rate. (ER), plant height, stem thickness, and plant dry weight, RT method value > ST method value > NT method value. Higher soil temperature, more suitable SWC, and better nutrient availability were beneficial in shortening MET, promoting dry matter accumulation, which ultimately increased plant height, stem thickness, and plant dry weight of maize seedlings. In RT, ST, and NT methods, soil temperature and plant dry weight were positively and linearly correlated in the 10–22 °C soil temperature interval. In the RT method and ST method, SWC and plant dry weight were positively and linearly correlated in the 15–24 % SWC interval. In the NT method, SWC and plant dry weight were negatively and linearly correlated in the 27–35 % SWC interval. Moreover, maize yield responses were positive for the RT method and ST method compared with the NT method. The RT method and ST method well solved the problems of low soil temperature and high SWC that existed in NT fields, which affected the early growth of maize seedlings, and ensured the stability and improvement of maize yields. The results suggest that both the RT method and ST method may provide significant improvements over the existing NT method.

Effects of PBAT/PLA biodegradable film mulching on greenhouse gas emissions in rain-fed maize farmland of Northeast China

Plastic film mulching can effectively increase soil temperature, retain moisture, and enhance crop yield and quality. However, long-term application might pose risks of increased greenhouse gas (GHG) emissions and residual film pollution. Biodegradable film provides a crucial solution to alleviate farmland plastic pollution, but it remains unclear whether biodegradable film can simultaneously enhance crop yields and reduce GHG emissions. Thus, a two-year field experiment was conducted in rain-fed maize farmland of Northeast China. This field experiment included four treatments: BM1 (0.006 mm-thick biodegradable film), BM2 (0.010 mm-thick biodegradable film), PM (0.010 mm-thick traditional plastic film), and CK (non-mulching control). Results indicated that film mulching increased cumulative CO2 emissions by improving soil temperature and moisture. BM1 and BM2 achieved lower cumulative CO2 emissions than PM. N2O emissions were mainly concentrated in the emergence and jointing stages, whose peaks and cumulative values were reduced by film mulching. BM1 and BM2, however, had higher cumulative N2O emissions than PM. All treatments were CH4 sinks, and mulching treatments showed low soil CH4 absorption compared to CK. Additionally, mulching treatments increased maize yield, GWP and GHGI by 4.19 % to 15.89 %, 8.52 % to 52.20 % and − 0.06 % to 45.93 %, respectively, compared to CK. PM showed the highest GWP and GHGI. All mulching treatments improved the net ecosystem economic budget, with increases of 3.03–3.08 thousand CNY ha−1 and 0.35–1.39 thousand CNY ha−1 in 2022 and 2023, respectively, compared to CK. Biodegradable film treatments had higher net ecosystem economic budgets than traditional plastic film treatment. Overall, the biodegradable film can be used to replace traditional plastic film to enhance maize yield while minimizing residual film pollution and GHG emissions in the experimental region.

Effects of stand age and soil microbial communities on soil respiration throughout the growth cycle of poplar plantations in northeastern China

IntroductionMany studies have identified stand age and soil microbial communities as key factors influencing soil respiration (Rs). However, the effects of stand age on Rs and soil microbial communities throughout the growth cycle of poplar (Populus euramevicana cv.‘I-214’) plantations remain unclear.MethodsIn this study, we adopted a spatial approach instead of a temporal one to investigate Rs and soil microbial communities in poplar plantations of 15 different ages (1–15 years old).ResultsThe results showed that Rs exhibited clear seasonal dynamics, with the highest rates observed in the first year of stand age (1-year-old). As stand age increased, Rs showed a significant decreasing trend. We further identified r-selected microbial communities (copiotrophic species) as key biological factors influencing the decline in Rs with increasing stand age. Other abiotic factors, such as soil temperature (ST), pH, soil organic carbon (SOC), nitrate nitrogen (NO3−-N), and the C/N ratio of plant litter (Litter C/N), were also significantly correlated with Rs. Increased stand age promoted fungal community diversity but suppressed bacterial community diversity. Bacterial and fungal communities differed significantly in abundance, composition, and function, with the Litter C/N ratio being a key variable affected by microbial community changes.ConclusionThis study provides crucial empirical evidence on how stand age affects Rs, highlighting the connection between microbial community assemblages, their trophic strategies, and Rs over the growth cycle of poplar plantations.

Climate and Ecosystem Factors Mediate Soil Freeze-Thaw Cycles at the Continental Scale.

Freeze-thaw cycles (FTC) alter soil function through changes to physical organization of the soil matrix and biogeochemical processes. Understanding how dynamic climate and soil properties influence FTC may enable better prediction of ecosystem response to changing climate patterns. In this study, we quantified FTC occurrence and frequency across 40 National Ecological Observatory Network (NEON) sites. We used site mean annual precipitation (MAP) and mean annual temperature (MAT) to define warm and wet, warm and dry, and cold and dry climate groupings. Site and soil properties, including MAT, MAP, maximum-minimum temperature difference, aridity index, precipitation as snow (PAS), and organic mat thickness, were used to characterize climate groups and investigate relationships between site properties and FTC occurrence and frequency. Ecosystem-specific drivers of FTC provided insight into potential changes to FTC dynamics with climate warming. Warm and dry sites had the most FTC, driven by rapid diurnal FTC close to the soil surface in winter. Cold and dry sites were characterized by fewer, but longer-duration FTC, which mainly occurred in spring and increased in number with higher organic mat thickness (Spearman's ⍴=0.97, p<0.01). The influence of PAS and MAT on the occurrence of FTC depended on climate group (binomial model interaction p (χ2)<0.05), highlighting the role of a persistent snowpack in buffering soil temperature fluctuations. Integrating ecosystem type and season-specific FTC patterns identified here into predictive models may increase predictive accuracy for dynamic system response to climate change.