Soil Retention Research Articles

Synthesis and application of a multifunctional poly (vinyl pyrrolidone)-based superabsorbent hydrogel for controlled fertilizer release and enhanced water retention in drought-stressed Pisum sativum plants.

Water scarcity poses a significant challenge to agricultural production, prompting the development of sustainable technologies to optimize water resource utilization. This study focuses on the synthesis and application of a multifunctional poly (vinylpyrrolidone); PVP-based superabsorbent hydrogel (SAH) for controlled release of essential fertilizers (nitrogen, phosphorus, and potassium) and enhanced water retention in soil. The hydrogel was prepared via a facile one-step approach and compared to a control soil without hydrogel amendment. The reaction was initiated in the presence of poly(vinylpyrrolidone) (PVP) to produce a PVP-based copolymer hydrogel. The hydrogel was then subjected to a basic treatment using either sodium hydroxide (hydrogel #1) or potassium hydroxide (hydrogel #2). The PVP-based SAH exhibited excellent swelling capacity, water retention, and fertilizer release properties. When applied to Pisum sativum plants under drought stress, the hydrogel significantly improved soil moisture levels, nutrient availability, and plant growth parameters compared to the control. The hydrogel #2-amended plants demonstrated enhanced biomass, chlorophyll content, and photosynthetic efficiency, highlighting the hydrogel's effectiveness in mitigating the adverse effects of drought stress. These findings demonstrate the potential of the PVP-based SAH as a promising strategy for sustainable agriculture, offering using readily available and inexpensive raw materials, suggesting a relatively low-cost and scalable production process. Furthermore, the hydrogel facilitates water conservation, controlled nutrient delivery, and improved plant performance under drought stress conditions.

Acidified biochar one-off application for saline-alkali soil improvement: A three-year field trial evaluating the persistence of effects

Salinization is a global soil degradation issue threatening agricultural productivity and environmental sustainability. Native biochar is a promising soil amendment, but its high alkalinity limits its use in saline-alkali lands. Acidified biochar, with a lower pH, is theoretically more suitable. This study aims to evaluate the persistence of effects of acidified biochar one-off application on soil particle size distribution, physicochemical properties, water retention, temperature regulation, and evaporation conditions of saline-alkali soil, thereby verifying its feasibility and exploring the optimal application range. We conducted a three-year cotton field experiment using palm fruit branch biochar as the raw material, acidified with ferrous sulfate, which involved four biochar applications (0, 10, 20, and 30 t ha−1) and four irrigation quotas (60 %, 80 %, 100 % and 120 % ETc). The results indicated that the initial acidified biochar application slightly increased surface soil (0–20 cm) pH by 0.1 %–3.9 %, this negative effect was nearly eliminated by the third year. Biochar application significantly altered surface soil particle size distribution, increasing sand content by 1.6 %–8.4 %, and persistently improved soil hydraulic properties, with water holding capacity still showing a 6.5 %–16.7 % increase in the third year. Biochar enhanced soil thermal insulation and suppressed soil evaporation, but these benefits gradually diminished with increasing cultivation years. Acidified biochar effectiveness was closely linked to irrigation quota. Significant differences in soil water and heat indicators were observed between the 20 and 30 t ha⁻¹ biochar treatments only under low irrigation quotas. Under sufficient irrigation (100 % and 120 % ETc), the optimal biochar application range was 15–20 t ha⁻¹, while under low irrigation (60 % and 80 % ETc), the optimal range was 20–25 t ha⁻¹. This study demonstrated that acidified biochar one-off application has significant multi-year benefits in improving soil structure and hydrothermal properties, providing a scientific basis for the improvement and sustainable utilization of saline-alkali soil.

Unveiling driving disparities between satisfaction and equity of ecosystem services in urbanized areas

Rapid urbanization intensifies the challenges of achieving satisfaction and equity in ecosystem services (ESs). Beginning with a theoretical overview, we identify five pivotal challenges in managing urban ESs, forming the basis for our integrative analysis. Employing a multi-level analytical perspective, our research quantifies ESs satisfaction through supply–demand ratios and evaluates ESs equity via supply–demand Gini coefficient. Simultaneously explored the driving force relationship between these two dimensions. This study uses Guangdong Province, a typical urbanized area in China, as a case study to assess the supply and demand relationships of four regulating ESs: water retention, soil retention, carbon storage, and water purification. Our results highlight the disparity in ES management effectiveness across different scales while the overall assessments might suggest adequate or equitable ESs, localized assessments within cities and regions often uncover specific ESs issues. A pivotal aspect is that single-factor critical to ESs satisfaction or equity dimension may have limited or opposing importance in another, but interactive effects of multiple factors can effectively mitigate these divergent impacts through non-linear synergies. These insights not only reveal the multiplex impacts of natural–social–economic drivers on urban expansion but also guide the targeted development in different management scale, multi-dimensional management strategies to address these disparities. This approach enriches the discourse on sustainable urban development and provides a robust framework for addressing the nuanced challenges of urban ESs management.

Unveiling the impact of low-molecular-weight organic acids on enrofloxacin sorption in North China agricultural soil: Insights and implications

Low-molecular-weight organic acids (LMWOAs) play a crucial role as components of dissolved organic matter in soil, influencing the sorption/desorption, degradation, and plant uptake of diverse pollutants within the agricultural soil ecosystem. This study delves into the sorption behavior and mechanism of the fluoroquinolone antibiotic enrofloxacin (ENR) on agricultural soil in North China, focusing on the impact of LMWOAs. Through batch equilibrium experiments, we explored the sorption/desorption kinetics of ENR under varying conditions such as temperature, pH, ion strength, and ion type, with the addition of acetic acid, oxalic acid, and citric acid individually. Our findings reveal that the sorption and desorption kinetics of ENR—whether with or without LMWOAs—conformed well to the pseudo-second-order kinetic model (R2 ≥ 0.997). The presence of LMWOAs notably enhanced ENR sorption while impeding desorption in soil, with oxalic acid demonstrating the highest promotion effect followed by acetic acid and citric acid. Moreover, the sorption capacity and affinity of ENR decreased with rising solution pH, dropping from 96.8%-98.5% to 30.9%–34.4%. Acidic conditions favored ENR retention in soil, with inhibition of sorption escalating alongside increasing ionic strength. LMWOAs, soil solution pH, and coexisting ions emerge as pivotal factors shaping ENR sorption behavior. Furthermore, LMWOA presence intensified desorption hysteresis of ENR on soil, with a desorption hysteresis coefficient (HI) ≤ 0.124. These results suggest that LMWOAs restrict ENR mobility in the local soil environment, heightening the risk of its accumulation in soil and crops. This study offers valuable insights into the intricate interplay among LMWOAs, ENR sorption dynamics, and environmental outcomes, underscoring the importance of understanding such complexities in agricultural soil management.

Drainage estimation across mountainous regions from large-scale soil moisture observations

Drainage is a crucial soil hydrological process that governs the partitioning of rainfall into runoff, groundwater recharge, soil water storage and evapotranspiration. Despite its significance, the drainage process is poorly understood due to the difficulty in direct measurements and insufficient understanding of its underlying physical mechanisms. To address these challenges, we present an innovative, physically-based, data-driven approach, SM2D (Soil Moisture to Drainage), to estimate drainage. SM2D was applied and examined using soil moisture data from a large-scale observation network over mountainous areas during 2014–2020. The soil moisture threshold governing drainage initiation proves to be significantly lower than the commonly employed field capacity metric in hydrological models. This threshold is influenced by factors such as mean soil moisture, bulk density, residual soil moisture, soil organic carbon, and parameters n and α of soil retention curve. Notably, field capacity has minimal impact on this threshold. Additionally, our analysis reveals that the drainage process is more influenced by the Soil Water Storage Increment (SWSI) than by mean soil moisture (MSM) that has traditionally been recognized as a key factor in drainage control. In comparison to commonly used exponential equations and those in models such as the Soil & Water Assessment Tool (SWAT), SM2D demonstrates superior performance in estimating drainage. The exponential equation derived from the SWSI outperforms those derived from other soil moisture metrics, including the commonly utilized MSM, challenging prevailing norms in drainage equations. SM2D holds the potential to generate extensive drainage datasets from satellite or large-scale soil moisture observations, advancing large-scale hydrological studies.

Physicochemical characteristics of andisols and their correlation to potato yield based on land mapping units

The high phosphate retention in andisol soil is often associated with a decrease in potato yield. Additionally, identification of the physical and chemical characteristics of andisols and their correlation to potato yield through soil mapping units (SMUs) is necessary to facilitate field surveys. Therefore, this study aimed to identify the physicochemical characteristics of andisols with a focus on available phosphorus (P) and the correlation to potato production based on SMUs. The experiment was conducted in Karo District, North Sumatra, Indonesia, from July 2022 to February 2023. A descriptive-analytical method was used by overlaying maps of slope, soil types, and altitude until 10 SMUs were selected that were planted with potatoes. Soil physicochemical properties were identified, while Pearson correlation analysis was performed on available-P and potato yield using IBM SPSS software. The results showed that the silt and clay fractions positively correlated with available-P in andisols. All soil physical characteristics were categorized as very weak to weak in supporting potato yield. A total of four SMUs including 1, 5, 8, and 10 were found to have lower available-P and very low to moderate correlations with soil pH, organic-C, C:N ratio, cation exchange capacity (CEC), as well as total-P. Based on the results, potato yield could increase by 1.765 and 0.380 tons ha-1 through the addition of organic-C and C:N ratio in Karo District. Therefore, soil amendment is required as an alternative to improve andisols soil.

Geotextile filtration characteristics in piping rescue under extreme soil-retained state

Geotextiles have significant potential in rescuing backward erosion piping (BEP) occurring in levees. To investigate the filtration characteristics of woven geotextile for BEP prevention under the extreme soil-retention state, laboratory experiments were conducted using woven geotextiles with different pore sizes. The extreme soil-retention characteristics of the geotextile were analyzed, and the optimal relationship between filter pore size and particle size of the protected soil was explored. Additionally, the impact of fine particle content of the protected soil on the filter’s filtration performance was studied. The results indicated that, for the medium sand and silty sand tested, the filter still met soil retention requirements when the ratio of the geotextile’s equivalent pore size (O95) to the protected soil’s characteristic particle size (d85) was 5.2 and 4.3, respectively. With the increase of filter pore size, the clogging degree of the filter showed a trend of rapid decrease followed by an increase, indicating that there was an optimal matching relationship between the filter aperture and the particle size of protected soil. When woven geotextiles are used for preventing BEP, to ensure optimal filtration performance of the filter, the recommended values for O95/d85 in medium sand and silty sand are 5.2 and 3.3, respectively.

Effects of Different Land Uses and Slope on Runoff and Soil Loss on the Loess Plateau of China

ABSTRACTThe Loess Plateau has one of the most serious areas of soil erosion in China; therefore, studying the effect of soil and water conservation measures on the erosion of loess soil slopes is important for land management and agricultural development. This study is based on 5 years of field runoff observations and rainfall data from 2015 to 2019. Correlation and regression analyses were used to study the runoff and sediment production of loess soil and its relationship with rainfall, slope and land use. The results show that > 80% of the erosive rainfall occurs mainly in July to August in the area. Runoff and soil loss from the plots differed substantially, depending on land use, soil conservation measures and slope degree. Bare plots experienced the highest soil loss rate of over 27 t/ha with higher runoff depth, followed by cultivated plots (4.55 t/ha), grass plots (0.43 t/ha), shrub plots (0.35 t/ha) and forest plots (0.13 t/ha). Among the four soil and water conservation measures, the runoff and sediment reduction benefits of forest and shrub plots were the highest. The runoff reduction benefit fluctuated at approximately 0.8, and the benefit of sediment reduction was ≈1. The overall performance was forest > shrubland > grassland > cultivated land > bare land, and the benefits of sediment reduction were greater than those of runoff reduction. Forests had the highest soil retention capacity on slopes from 5° to 25°, and forests on gentle slopes had the best water storage capacity. Shrub plots had the best water storage capacity when they were on steep slopes. Rainfall erosion forces were significantly and positively correlated (p < 0.01) with runoff depth and soil loss, making it the most significant rainfall indicator of sediment production. Under the same rainfall conditions, soil and water conservation measures are still required on bare slopes, land use is the main control factor for slope sediment production, and appropriate land use can greatly reduce the threat of slopes in terms of soil erosion. This study shows that soil and water conservation measures are imperative to prevent runoff and soil loss, especially for bare land without any measures; on steep slopes, a vegetation combination primarily featuring shrubs is expected to achieve greater benefits in reducing runoff and sediment. This study can provide a scientific basis for the management of vegetation measures and the implementation of soil and water conservation measures on loess soil slopes.

Assessment of Chinese Medicinal Herbal Wastes Compost Inoculated with Antagonistic Fungi: Nitrogen Retention and Microbial Community in Phytopathogenic Soil

Assessment of Chinese Medicinal Herbal Wastes Compost Inoculated with Antagonistic Fungi: Nitrogen Retention and Microbial Community in Phytopathogenic Soil

The responses of ecosystem services in coastal cities to urbanization in 30 years: A case study of Qingdao City, China

Coastal urban areas play a pivotal role in regional economic growth, yet they are also sensitive regions where the natural environment interacts with human activities. Rapid urbanization has led to ecological issues, such as the degradation of key ecosystem services (ESs) in coastal cities. Understanding the impact of urbanization on the supply and demand of ESs in coastal cities is crucial for ensuring the healthy and sustainable development of the socio-economy in these areas. This study takes the coastal city of Qingdao as a case study, with a focus on the supply and demand relationships of seven key ESs—carbon sequestration, food production, habitat quality, recreational capacity, soil retention, water yield and marine aquaculture—as well as their responses to population growth, economic development, and spatial expansion, which are three distinct aspects of urbanization. The findings indicate that: (I) From 1992 to 2022, the evolution of different ESs exhibited variability, all displaying notable spatial imbalances. (II) During this period, the urbanization process in Qingdao had a pronounced negative effect on the supply and demand of ESs. Spatial urbanization had the most significant impact on carbon sequestration, food production, habitat quality, water yield, and marine aquaculture, while population urbanization most notably affected recreational capacity. (III) The sensitivity of different types of ESs to population, economic, and spatial urbanization varies. Carbon sequestration, food production, recreational capacity, soil retention, water yield, and marine aquaculture were most sensitive to economic urbanization, whereas habitat quality was most sensitive to spatial urbanization. This research provides a basis for decision-making in the sustainable development and comprehensive management of coastal cities and their ecosystems.

Fulvic Acid Enhances Nitrogen Fixation and Retention in Paddy Soils through Microbial-Coupled Carbon and Nitrogen Cycling.

Fulvic acid, the most soluble and active humic substance, is widely used as an agent to remediate contaminated soils and improve soil fertility. However, the influence of fulvic acid (FA), as a microbial carbon source, on carbon and nitrogen cycles in paddy soils remains elusive. Therefore, to investigate it, an incubation experiment was conducted. Gas analyses indicated that the carbon dioxide and methane emissions were enhanced in FA treatment, which increased up to 94.08-fold and 5.06-fold, respectively. 15N-labeling experiments revealed that nitrogen fixation capability was promoted (1.2-fold) to reduce the carbon and nitrogen imbalance due to fulvic acid amendment. Metagenomic analysis further revealed that gene abundances of degradation of lignin-like compounds, gallate degradation, methanogenesis, nitrogen fixation, and urea hydrolysis increased, while the bacterial ammonia oxidation and anaerobic ammonium oxidation decreased, caused by FA application. Metabolic reconstruction of metagenome-assembled genomes revealed that Azospirillaceae, Methanosarcinaceae, and Bathyarchaeota, with higher abundance in FA treatment, were the key microorganisms to maintain the carbon and nitrogen balance. The metabolic pathways of fulvic acid degradation and coupled nitrogen fixation and retention were constructed. Collectively, our results provided novel insights into the theoretical basis of the use of humic substances for reducing nitrogen fertilization and climate change.

Sodium alginate-g-polyacrylamide hydrogel for water retention and plant growth promotion in water-deficient soils

Natural polymer-based hydrogels are preferred as soil water retention agents due to their inherent biocompatibility and biodegradability. Generally, these natural polymers are chemically modified by graft polymerization of vinyl monomers to improve their water absorption and retention properties. Among the polysaccharides used to prepare natural hydrogels, those based on sodium alginate (Alg) stand out for their high-water absorption and retention capacity, as well as for their ability to promote plant growth. The main objective of this study was to develop a biodegradable alginate-based hydrogel as a water retainer to promote plant growth under water deficit conditions. The synthesis was achieved by grafting poly(acrylamide) (PAM) onto Alg backbone, using bisacrylamide as chemical crosslinker and different ratios of alginate:acrylamide (Ac). In addition, Eucalyptus nitens seedlings were used as a model plant to evaluate the effect of alginate-g-polyacrylamide (Alg:PAM) hydrogel application to the growing medium on plant survival, growth, and physiological responses under both well-watered and water-deficient soil conditions. The maximum degree of swelling (65 g/g) was obtained for the hydrogel prepared. The pseudo-second order model described the water uptake kinetics of the hydrogel. The degradability of Alg:PAM hydrogel reached up to 85 % in 5 weeks in soil and occurs by breaking the glycosidic bonds of the alginate. The E. nitens seedlings cultivated with different doses of Alg:PAM hydrogel (4:1 Alg:Ac) showed higher values of height and root diameter relative growth, survival and photosynthetic responses in comparison to non-treated plants. The results indicate that Alg:PAM hydrogel (4:1 Alg:Ac) has promising applications in forestry as a water retention and seedling growth promoter under water deficient conditions.

Urban growth simulation guided by ecosystem service trade-offs in Wuhan metropolitan area: Methods and implications for spatial planning

The effective integration of ecosystem services (ESs) and urban growth simulation is crucial for spatial planning decisions that support sustainable and high-quality development. Interactions (i.e., trade-offs, synergies, and irrelevance) generally exist among ESs, however, few studies have been done on the methodology for simulating urban growth that optimizes the synergistic effect of ESs. In this study, the Wuhan metropolitan area was taken as the research area. Four key ESs in 2000, 2010, and 2020: water yield (WY), carbon storage (CS), habitat quality (HQ), and soil retention (SR) were evaluated by using the InVEST model. Then the ordered weighted averaging (OWA) method was applied to optimally allocate ESs trade-offs and identify ecological priority protection areas (EPPAs). Finally, the PLUS model was used to simulate urban growth scenarios under different levels of ESs protection constraints and propose spatial planning strategies. The results revealed the following. (1) From 2000 to 2020, the three ESs (i.e., WY, CS, and HQ) exhibited the spatial distribution pattern with high in the east and low in the west, and higher in the woodland than in built-up areas, except SR, which remained at a weak level throughout the region. (2) During the 20 years, SR and the other three ESs, HQ and CS showed a synergistic relationship; WY exhibited a very weak trade-off with HQ; and WY and CS changed from a very weak trade-off to a weak synergy. (3) Seven ecosystem service patterns (ESPs) were generated, and ESP 5 was compared as the ideal option. The weights of SR, WY, CS, and HQ in this pattern were 0.063, 0.187, 0.313, and 0.437, respectively. (4) By 2030, the built-up areas will exhibit edge expansion and interconnection development trends, with the high-constraint ecological protection scenario as the most compact mode, and the spatial structure of “two districts, one axis, four cities as one” is consistent with the development tendency. Our findings can help to enrich the method of urban growth management oriented by ecological protection, and provide a scientific basis for ecological environment restoration and land use spatial planning practices.

Ecosystem services in the Yangtze River Basin and their trade-offs/synergies relationships in response to climate change

Abstract The Yangtze River Basin is an important ecological security barrier with significant economic status, but it is greatly affected by climate change. Therefore, we investigated the spatio-temporal evolution characteristics of annual ecosystem service (net primary production (NPP), water conservation and soil retention), their interrelationships and responses to climate change in the Yangtze River Basin from 2001 to 2020. The annual NPP, soil retention and water conservation were 511 gC m−2, 632 t and 272 mm, respectively and they all increased over 2001–2020 though this varied in both time and space. The capacities of soil retention and water conservation did not increase, and even gradually decreased for first 10 years (2001–2010), most likely due to the subsequent effects of the catastrophic flood of Yangtze River occurred in 1998. There are tradeoffs between NPP and soil retention/water conservation in the west Sichaun Province, which is different from the rest of the Yangtze River Basin where synergistic relationships dominate. Precipitation is the dominate climatic influencing factor on the ecosystem service trends found in the Yangtze River Basin. The concept of ecosystem services is being incorporated into decision-making and management, this study is critical to guide regional effective resource utilization, ecosystem management decisions and feasible policies.

Effects of habitat fragmentation on ecosystem services and their trade-offs in Southwest China: A multi-perspective analysis

Exploring the relationships between habitat fragmentation on ecosystem services (ESs) is important for ecological conservation and spatial pattern optimisation. However, analyzing the influence of different habitat fragmentation processes on ESs and their trade-offs from a multiple perspective is still relatively lacking. Therefore, taking Southwest (SW) China as an example, this paper evaluated the dynamics and trade-off relationship of four main types of ESs (i.e., carbon storage (CS), grain production (GP), water retention (WR), soil retention (SR)) during 2000–2020, and analyzed the effects of four habitat fragmentation processes (i.e., decreasing habitat area, increasing habitat density, increasing habitat shape complexity and decreasing habitat cohesion) on ESs and their trade-offs by using geographically and temporally weighted regression model. The results showed that ESs showed a deterioration trend during 2000–2020, with GP, WR, CS, SR, and total ecosystem services (TES) declined by 66.45 %, 54.33 %, 41.68 %, 76.25 % and 65.83 %, respectively. The GP-SR, GP-CS and GP-WR pairs exhibited trade-offs, while other ES types pairs exhibited synergies with each other. Increasing habitat density and increasing in habitat shape complexity were the two strongest fragmentation processes influencing ESs and their trade-offs. The effects of various habitat fragmentation processes on ESs and their trade-offs have obvious spatial heterogeneity. With changes in terrain relief, proportion of karst area, habitat quality, and urbanization level, the association of habitat fragmentation-ESs and habitat fragmentation-ESs trade-offs existed different sensitivities. The results can provide effective guidance for landscape planning and ecosystem management in the SW.

Filtration compatibility of clay-nonwoven geotextiles under normal stress

Nonwoven geotextiles are commonly utilized as filter materials in drainage and filtration engineering. This study focuses on the clogging phenomenon of the nonwoven geotextile filter wrapping the blind drain in the active anti-floating technology of underground structures. In this paper, the filtration compatibility of clay-nonwoven geotextiles was evaluated using a newly developed gradient ratio test device that can apply normal stress. Two fabrication technics and four specifications of nonwoven geotextiles were used to filter clay, and the geotextiles’ clogging degree was assessed after the test. The influences of normal stresses, hydraulic gradients, and fabrication technics on nonwoven geotextile filtration performance were discussed based on results from a series of gradient ratio tests. Relevant assessment parameters (clogging coefficient, soil retention, and equivalent porosity) were also presented to quantify the clogging degree of nonwoven geotextiles after the test. Furthermore, the clogging process of nonwoven geotextiles filtering clay was initially explored, and the filtration effect of the needle-punched and heat-bonded nonwoven geotextiles was evaluated. The results showed that normal stress had a significant effect on nonwoven geotextile filtration, with needle-punched nonwoven geotextiles having better soil filtration and water permeability. Discussions on nonwoven geotextile applications in specific environments or conditions are also presented.

A new quantitative method for determining patient risk for reusable medical device categorization based on using and interpreting Kremer’s cleaning classification system

The cleaning of reusable medical devices involves inherent challenges that can impact on the effectiveness of the cleaning process; consequently, the subsequent safety of patients. Fluid dynamics play a critical role in determining the flow and distribution of cleaning agents where the design of the device can either facilitate or hinder this important process. Complex geometries, narrow channels, or irregular surfaces can impede effective flushing of contaminants leading to incomplete cleaning that creates a greater likelihood for patient contamination risks. Device features (n =23) were exposed to the most challenging cleaning conditions to find the point of failure in both fluid dynamics and soil retention. Experimental results obtained from the aforementioned along with associated compound risks were used to assign a risk value. Using the "hardest to clean" device feature approach as the base risk value, the total quantitative risk score was calculated for different reusable medical devices from numerical values obtained from addressing 14 questions focusing on variability in geometry, material use, types of cleaning, and intended patient use. Patient risk values for devices with different features were calculated from using Kremer's cleaning categories based on position within value ranges. Occurrences less than 18 correspond to minimal risk devices while a total risk score between the values of 18-39 are moderate and equal to or above 40 scores corresponds to the maximal category. Application of this quantitative assessment approach will facilitate appropriate mitigation of risk for cleaning reusable medical devices by informing use of targeted effective interventions. Future use of this Kremer cleaning classification will complement and augment disinfection and sterilization modalities.

Reducing drought vulnerability of forest soils using Xanthan gum-based soil conditioners

Climate change increases the frequency and severity of droughts in many parts of Europe, thereby affecting the availability of water resources. Therefore, preserving the soil water content is essential for maintaining forest diversity and plant vitality. To improve soil hydraulic properties and reduce drought vulnerability, three xanthan-gum-based soil conditioners (SC_R, SC_CG, and SC_ZZC) were developed under the European ONEforest project. These soil conditioners (SCs), including oxide ash and cellulose fibres of different lengths, differ in their filler properties. This study evaluated the performance of these soil conditioners in forest soils in Slovenia (S1), Spain (S2), and Germany (S3). Water absorption, water retention, hydraulic conductivity, seed germination, and plant growth in the untreated soils and mixtures were analysed.The results showed a 53% to 100% increase in water absorption with high dosage of SCs (1.7% of dry SC per dry soil mass). The addition of SCs also significantly improved the water retention capacity of the treated soils within a suction range of 0-100 kPa, which is advantageous for maintaining adequate water availability for plant growth. The effect of SCs on unsaturated hydraulic conductivity varies depending on the soil type. For example, at a similar suction, the unsaturated hydraulic conductivity of mixtures with soils S2 and S3 can be more than an order of magnitude lower than that of untreated soils S2 and S3. In contrast, mixtures with soil S1 showed unsaturated hydraulic conductivity similar to that of the untreated soil. In the seeding experiment, plants in treated soils survived for up to 8 d without watering compared to those in untreated soils, with survival linked to the initial water content of the mixtures. These findings suggest that soil conditioners reduce drought vulnerability by improving water retention and regulating water loss. However, the optimal dosage should be adjusted according to different soil types and local environmental conditions.

Coupled Hydrogeophysical Modeling to Constrain Unsaturated Soil Parameters for a Slow‐Moving Landslide

AbstractGeophysical methods have proven to be useful for investigating unstable slopes as they are both non‐invasive and sensitive to the spatial distribution of physical properties in the subsurface. Of particular interest are the links between electrical resistivity and near‐surface moisture content; recent work has demonstrated that it is possible to calibrate hydrological models using geophysical measurements. In this study we explore the use of in‐field electrical resistivity data for calibrating unsaturated soil retention parameters and saturated hydraulic conductivity used for modeling unsaturated fluid flow. We study a synthetic case study, and a well‐characterized site in the northeast of England and develop an approach to calibrate retention parameters for a mudstone and a sandstone formation, the former being an actively failing unit. Petrophysical relationships between electrical resistivity and moisture content (or saturation) are established for both formations. 2D hydrological models are driven by effective rainfall estimations; subsequently these models are coupled with a geophysical forward model via a Markov chain Monte Carlo approach. For the synthetic case, we show that our modeling approach is sensitive to the moisture retention parameters, while less so to saturated hydraulic conductivity. We observe the same characteristics and sensitivities for the field case, albeit with a greater data misfit. Further hydrological simulations suggest that the slope retained high moisture contents in the months preceding a rotational failure. Therefore, we propose that coupled hydrological and geophysical modeling approaches could aid in enhancing landslide monitoring, modeling, and early warning efforts.

Impacts of landscape configurations on ecosystem services and their trade-offs across different landscape compositions

Landscape sustainability depends on the design of landscape patterns that can be guided by ecosystem services (ESs). Clarifying the impacts of landscape configurations on ESs and their trade-offs will facilitate landscape planning and management to achieve the best design without changing most landscape compositions. However, limited work has focused on these impacts, and whether these impacts are the same on different compositions remains unexplored. Thus, this study analyzes the impacts of landscape configurations on ESs and their trade-offs for different compositions. In this analysis, Gaussian mixture model was used to cluster the landscape by compositions, five important ESs (crop production, water yield, carbon storage, soil retention, and outdoor recreation) were quantified, and the constraint line was used to analyze the impact, taking the Xiangjiang River Basin as an example. Results showed that three clusters of landscape compositions, which are similar to the urban–rural–natural gradient, were identified. Furthermore, the impacts of landscape configurations on ESs and their trade-offs had largely the same direction in different compositions. However, change in landscape composition makes the high correlations among them weaker or shift to constraint impacts. Based on the results of the study, we can not only contribute to local landscape development but also argue three general approaches for landscape planning and management. First, considering the trade-offs and making a choice adapted to local conditions. Second, adjusting landscape configurations with virtually no changes of compositions. Third, external intervention based on rational landscape configurations.