Rubber-based intercropping is a recommended practice due to its ecological and economic benefits. Understanding the implications of ecophysiological changes in intercropping farms on the production and technological properties of Hevea rubber is still necessary. This study investigated the effects of seasonal changes in the leaf area index (LAI) and soil moisture content (SMC) of rubber-based intercropping farms (RBIFs) on the latex biochemical composition, yield, and technological properties of Hevea rubber. Three RBIFs: rubber-bamboo (RB); rubber-melinjo (RM); rubber-coffee (RC), and one rubber monocropping farm (RR) were selected in a village in southern Thailand. Data were collected from September to December 2020 (S1), January to April 2021 (S2), and May to August 2021 (S3). Over the study period, RB, RM, and RC exhibited significantly high LAI values of 1.2, 1.05, and 0.99, respectively, whereas RR had a low LAI of 0.79. The increasing SMC with soil depths was pronounced in all RBIFs. RB and RM expressed less physiological stress and delivered latex yield, which was on average 40% higher than that of RR. With higher molecular weight distributions, their rheological properties were comparable to those of RR. However, the latex Mg content of RB and RM significantly increased to 660 and 742 mg/kg, respectively, in S2. Their dry rubbers had an ash content of more than 0.6% in S3.

In the Ulan Buh Desert, which is located in a seasonally frozen region, a frozen soil layer can appear in the winter after the wind erosion of dry sand from the surface of a mobile sand dune, thus altering the wind-sand transport process. To clarify the wind-sand transport pattern after the emergence of a frozen soil layer, this study used wind tunnel experiments to study the variations in the wind erosion rate and sediment transport pattern of frozen and nonfrozen desert soil with different soil moisture contents (1-5%). The results revealed that the relationships of the wind speed, soil moisture content and wind erosion rate are in line with an exponential function, and the wind erosion rate decreases by 6-52% after the desert soil is frozen. When the soil moisture content of the nonfrozen desert and frozen desert soil is 4% and 3%, respectively, the wind erosion rate of the soil can be reduced by more than 65% compared with that of natural dry sand (soil moisture content of 0.28%), i.e., the wind erosion rate can be effectively reduced. The sediment transport rate of nonfrozen desert soil decreases with increasing height, with an average ratio of approximately 65% for saltation. The sediment transport rate of frozen desert soil first increases but then decreases with increasing height, with an average ratio of approximately 80% for saltation. When sand particles hit the source of frozen desert soil, the interaction between particles and bed surface is dominated by the process of impact and rebound, so that more particles move higher, and some sand particles move from creep to saltation. In summary, freezing has an inhibitory effect on the wind-sand activity of desert soil, and freezing makes it easier for sand to move upwards.

Monitoring groundwater levels and soil moisture content (SMC) is crucial for managing water resources and assessing risks, but can be challenging, especially over large acreages. Recent advances in geophysical methods provide new opportunities for accurate groundwater assessment. Seismic wave speed data, sensitive to changes in pore water pressure, can be used in a passive monitoring approach, while electrical conductivity data can be used for monitoring SMC. Combining seismic and electromagnetic induction (EMI)-based monitoring techniques enhances our understanding of groundwater dynamics. Seismic methods enable wide spatial coverage with moderate depth resolution, whereas EMI offers high-resolution, rapid data acquisition, particularly effective for shallow subsurface monitoring. Integrating these approaches can leverage the strengths of each, yielding comprehensive, high-resolution insights into dynamic subsurface hydrological processes. Integrating these approaches allows for improved groundwater monitoring, aiding in better understanding and managing droughts in regions like the Netherlands.

This study conducted an in-depth analysis of the landslide problem in the loess hill and gully area in northern Shaanxi Province, selecting the loess landslide site in Quchaigou, Ganquan County, Yan'an City, as the object to assess the stability of loess slopes under the conditions of different plant root densities and soil moisture contents through field investigation, physical mechanics experiments and numerical simulation of the GeoStudio model. Periploca sepium, a dominant species in the plant community, was selected to simulate the stability of loess slope soils under different root densities and soil water contents. The analysis showed that the stability coefficient of Periploca sepium natural soil root density was 1.263, which was a stable condition, but the stability of the stabilized slopes decreased with the increase in soil root density. Under the condition of 10% soil moisture content, the stability coefficient of the slope body is 1.136, which is a basic stable state, but with the increase in soil moisture content, the stability of the stable slope body decreases clearly. The results show that rainfall and human activities are the main triggering factors for loess landslides, and the vegetation root system has a dual role in landslide stability: on the one hand, it increases the soil shear strength, and on the other hand, it may promote water infiltration and reduce the shear strength. In addition, the high water-holding capacity and permeability anisotropy of loess may lead to a rapid increase in soil deadweight under rainfall conditions, increasing the risk of landslides. The results of this study are of great significance for disaster prevention and mitigation and regional planning and construction, and they also provide a reference for landslide studies in similar geological environments.

To reduce the amount of pesticides in the environment, it is necessary to consider the wettability properties of pesticide droplets on the leaf surface to improve the spraying effect. The wettability properties of the droplet on the leaf surface are related not only to the properties of the liquid itself but also to the properties of the leaf surface. It is typically believed that leaf surface properties are difficult to control, and thus research has generally ignored this aspect of pesticide use. However, in the field environment, the structure and properties of the leaf surface can be altered by changing the moisture content of the soil where plants are grown. In this study, the roughness, contact angle, and surface free energy of the leaf surface were measured and calculated under different soil moisture contents to study the changes in the leaf surface wettability properties, with the aim of achieving efficient pesticide spraying by adjusting the soil water content. The results showed that the surface composition and microstructure of leaves were altered by the change in the soil moisture content, and the wettability properties of leaves decreased initially and then increased with a decrease in the soil moisture content. When the amount of soil water was sufficient or seriously insufficient, the wettability properties of the leaves were increased, but a lack of soil water may lead to irreversible damage to the plants. Therefore, before spraying pesticides on the leaf surfaces, the plants should be fully watered to improve the wettability properties of the leaf surface, which is conducive to the deposition and adhesion of pesticide droplets on the leaf surface and improved application effectiveness. The results of this study can provide a useful reference for the theoretical research and practices of precision spraying.

Introduction: Permafrost and seasonally frozen soil are widely distributed on the Qinghai-Tibetan Plateau, and the freezing-thawing cycle can lead to frequent phase changes in soil water, which can have important impacts on ecosystems.Methods: To understand the process of soil freezing-thawing and to lay the foundation for grassland ecosystems to cope with complex climate change, this study analyzed and investigated the hydrothermal data of Xainza Station on the Northern Tibet from November 2019 to October 2021.Results and Discussion: The results showed that the fluctuation of soil temperature showed a cyclical variation similar to a sine (cosine) curve; the deep soil temperature change was not as drastic as that of the shallow soil, and the shallow soil had the largest monthly mean temperature in September and the smallest monthly mean temperature in January. The soil water content curve was U-shaped; with increased soil depth, the maximum and minimum values of soil water content had a certain lag compared to that of the shallow soil. The daily freezing-thawing of the soil lasted 179 and 198 days and the freezing-thawing process can be roughly divided into the initial freezing period (November), the stable freezing period (December-early February), the early ablation period (mid-February to March), and the later ablation period (March-end of April), except for the latter period when the average temperature of the soil increased with the increase in depth. The trend of water content change with depth at all stages of freezing-thawing was consistent, and negative soil temperature was one of the key factors affecting soil moisture. This study is important for further understanding of hydrothermal coupling and the mechanism of the soil freezing-thawing process.

This study adopted the method of exchanging space for time and set up three experimental groups based on the shape, degree of damage, and degree of humification of the litter, namely the undecomposed layer, the semi-decomposed layer, and the decomposed layer. Using typical slopes of arbor and bamboo forests in the Pi River Basin as the research object, from October 2021 to December 2022, the soil carbon release flux was measured by using a closed static chamber gas chromatography method to reveal the carbon release law at the soil-air interface during the decomposition process of litter and quantitatively characterize the dynamic impact of the litter decomposition process on soil carbon release flux. Results showed that soil methane flux remained negative (sink) while soil carbon dioxide flux was positive (source) in both litter-covered and bare soil conditions. The methane and carbon dioxide release from soil was positively correlated with and significantly influenced by environmental factors such as soil moisture content and temperature. The methane release flux from soil showed a linear fitting relationship with soil moisture content and temperature, while the carbon dioxide release flux from soil was more in line with the exponential fitting relationship with soil moisture content and temperature. However, there were significant differences in the roles of various factors under different types of litter.

Soil detachment capacity (Dc) is an important parameter used to determine erosion intensity in physical-processbased erosion models. Freeze-thaw affects soil detachment processes by altering the mechanical properties of soil; however, due to the compound action of freeze-thaw and runoff on D-c, quantifying the impact of seasonal freeze-thaw on D-c remains challenging. A series of experiments with six freeze-thaw cycles (FTC), six initial soil moisture contents (SMC), three slope gradients, and five flow discharges were conducted to investigate the effect of freeze-thaw and hydrodynamic characteristics on D-c. The results showed that soil shear strength (tau(m)), cohesion (Coh), and internal friction angle (phi) gradually tended to become stable with increasing FTC, indicating that repeated FTC had a cumulative impact on soil mechanical properties, and there was a critical FTC between 5 and 7. When FTC rose from 1 to 15, the reduction in tau m, Coh, and phi was 0.03-23.96%, 2.63-75.21%, and - 5.70-19.24%, respectively, which increased with an increasing SMC, suggesting that the deterioration effect of FTC on soil mechanical properties was promoted by increasing SMC. During alternating FTC, the relative range and variation coefficient of D-c were 2.21-2.43 and 67.87-75.72%, respectively, indicating that D-c was highly sensitive to FTC. Furthermore, D-c increased by 2.37-71.22% after 15 FTC. Alternating freeze-thaw weakened the soil resistance to detachment. Moreover, the promoting effect of FTC on D-c intensified with an increasing SMC, indicating that the variation in D-c was strongly affected by SMC during FTC. A prediction model (R-2=0.955, RRMSE=14.99%) was established to quantify the influence of freeze-thaw and hydrodynamic characteristics on D-c. The explanation rate of variables in the D-c prediction equation was quantitated: the explanation rate of stream power (64.3%) was higher than that of FTC (10.02%) and SMC (3.92%), suggesting that the impact of freeze-thaw on D-c was covered by hydrodynamic characteristics. Further validation is required for the prediction equations when applied beyond the range of construction conditions.

This study, focusing on porous sheet mulching cultivation for high -quality and annual steady production of Satsuma mandarin, investigated trees photosynthetic oxidation stress according to the soil moisture in the porous mulching cultivation. Leaf, vesicle tissue water status, chlorophyll fluorescence, plant hormone abscisic acid (ABA) and jasmonic acid (JA) activity were measured using a phychrometer sample chamber, potable fluorescene meter and UHPLC and MS/MS were measured. Leaf water potential fluctuated according to the change in soil moisture content between the non -sheet mulching (control) and restoring the porous sheet (mulching) groups throughout this experiment period, and about 2 weeks intervals drip irrigation after the mulching (Mul. + Drip). In September, the leaf water potential of the control (-0.9 similar to -1.3 MPa) was higher than that of the mulching (-2.5 similar to -2.7 MPa), and Mul. + Drip (-2.2 similar to -2.3 MPa) groups. In October, due to continuous dry weather, the results of control and mulching were -3.0 MPa and -4.0 MPa or below respectively, which were lower than Mul. + Drip (-2.64 MPa). The water potential of vesicle tissue also fluctuated similarly to that of the leaf water potential. The osmotic potential was tendentially higher in the control than that in mulching and Mul. + Drip group. The turgor pressure remained constant at 0.5 MPa in October and November except for the time in September. The soluble solids content (SSC) of fruit at harvest was higher at 14.55 degrees Brix in the mulching and 13.96 degrees Brix in the Mul. + Drip, which were both higher than 11.05 degrees Brix in the control, showing a significant difference and confirming a rise in the SCC caused by osmotic control. The degree of oxidative damage according to water stress level caused by drought stress was investigated by the comparison of the maximum quantum efficiency value of (Fv/Fm), the initial fluorescence value (Fo) value, and the change in photosynthetic rate. The concentration of ABA in the leaf, fruit peel, and flesh was relevant to the leaf moisture stress and fruit sugar content. The concentration of JA varied as the concentration of ABA changed. In conclusion, Fv/Fm and Fo of chlorophyll PSII and ABA regarding photosynthetic oxidative damage were found to be indicators of the degree of damage according to tree water stress levels.

Forest fires have significantly impacted the permafrost environment, and many research programs looking at this have been undertaken at higher latitudes. However, their impacts have not yet been systematically studied and evaluated in the northern part of northeast China at mid-latitudes. This study simultaneously measured ecological and geocryological changes at various sites in the boreal forest at different stages after forest fires (chronosequence approach) in the northern Da Xing'anling (Hinggan) Mountains, Northeast China. We obtained results through field investigations, monitoring and observations, remote sensing interpretations, and laboratory tests. The results show that forest fires have resulted in a decreased Normalized Difference Vegetation Index (NDVI) and soil moisture contents in the active layer, increased active layer thickness (ALT) and ground temperatures, and the release of a large amount of C and N from the soils in the active layer and at shallow depths of permafrost. NDVI and species biodiversity have gradually increased in the years since forest fires. However, the vegetation has not fully recovered to the climax community structures and functions of the boreal forest ecosystems. For example, ground temperatures, ALT, and soil C and N contents have been slowly recovering in the 30years after the forest fires, but they have not yet been restored to pre-fire levels. This study provides important scientific bases for assessment of the impacts of forest fires on the boreal forest ecosystems in permafrost regions, environmental restoration and management, and changes in the carbon stock of soils at shallow (<3m) depths in the Da Xingan'ling Mountains in northeast China.