ABSTRACT Maintaining soil health and crop productivity in the semi‐arid Vertisols of central India poses a significant challenge under intensive agricultural practices. This 6‐year field study assessed the combined impact of different tillage methods, maize‐based crop rotations, and nitrogen management on soil's physical, chemical, and biological characteristics, soil quality indices (SQI), and crop yields. The experiment used a split‐split‐plot design, featuring no‐till (NT) and conventional tillage (CT) as the main treatments, maize‐wheat and maize–chickpea rotations as sub‐treatments, and four nitrogen levels (0%, 50%, 100%, and 150% of the recommended dose) as sub‐sub treatments. Compared to CT, NT significantly increased soil organic carbon by 13%–21%, the mean weight diameter of aggregates by 29%–32%, available phosphorus by up to 110% in surface soils, and microbial activity, as evidenced by a 15% rise in dehydrogenase activity and a 5%–16% increase in β ‐glucosidase activity in the 0–5 cm layer. There were strong positive correlations between SOC and aggregate stability ( r = 0.78) and nutrient availability ( r = 0.70–0.78), underscoring the crucial role of organic matter in soil function. The maize‐wheat rotation consistently surpassed maize‐chickpea in soil quality metrics due to higher residue retention, while nitrogen fertilization showed a dose‐dependent enhancement in soil properties and crop yields. Grain yields of maize, wheat, and chickpea under NT were 21%, 15%, and 31% higher, respectively, than under CT. Although the highest yields were achieved at 150% N, the 100% N rate offered a favorable balance between improving soil health and sustaining yields. Overall, the study illustrates that long‐term use of no‐till, combined with a residue‐rich maize‐wheat rotation and optimized nitrogen management, significantly enhances soil quality, carbon sequestration, and crop productivity in semi‐arid Vertisols, providing a viable approach for sustainable intensification in similar agroecological areas.
ABSTRACT Land degradation threatens agricultural and forestry economies by lowering productivity, raising input costs, and increasing risk. This study examines whether Internet of Things applications moderate these losses in 1321 mainland Chinese counties from 2011 to 2024. Land degradation is measured separately through vegetation trends, modeled soil erosion, desertification, and salinity. IoT capacity is represented by policy pilots, base‐station density, and local innovation, which are treated as distinct proxies. Two‐way fixed effects estimates show weaker output, value added, employment, and investment in more degraded counties. Interaction estimates indicate that stronger IoT capacity is associated with smaller losses through productivity, input efficiency, risk stabilization, and market access. Staggered DID estimators, instrumental‐variable specifications, and spatial models produce comparable patterns, although interpretation remains conditional on their identifying assumptions. Effects are stronger in ecologically fragile counties and coordinated production systems. The findings position IoT as a resilience input that can complement land restoration and environmental governance.
ABSTRACT Optimized fertilization involving reduced mineral N input and organic substitution can alter resource stoichiometry, microbial carbon use efficiency (CUE) and nitrogen use efficiency (NUE). However, how fertilization‐induced resource imbalance reshapes microbial community to regulate CUE and NUE remains unclear. We conducted a field experiment in a Camellia oleifera plantation under conventional mineral nitrogen fertilizer (CK), organic manure (OM), and reduced mineral nitrogen combined with manure (RNM). Microbial CUE and NUE (via stoichiometric modeling), community structures and functions were determined at 30 and 120 days after fertilization. At 30 days, RNM and OM significantly increased NUE and alleviated resource limitations compared with CK. OM improved most microbial network properties relative to CK and RNM ( p < 0.05). At 120 days, C‐limitation disappeared while nutrient‐limitation persisted across all treatments. RNM and OM increased NUE by 1.13‐ and 4.26‐fold but decreased CUE by 7.5% and 61.3%, respectively. RNM showed the most balanced CUE‐NUE trade‐off. Notably, OM exhibited significantly lower microbial network metrics than CK and RNM except for the number of nodes ( p < 0.05), revealing a time‐dependent reversal effect. The laccase‐related microbial metabolic function was significantly associated with resource use efficiency ( p < 0.05), with a stronger association with NUE than CUE. Linear mixed‐effects models identified microbial network properties and resource limitation status were dominant predictors governing the CUE‐NUE balance ( > 0.3). Model explanatory power was substantially improved after fertilization type was included ( > 0.9). Our study provides novel evidence that fertilization‐induced stoichiometric imbalance reshapes microbial networks and further modulates microbial CUE and NUE. These findings highlight that microbial network attributes should be integrated into fertilization optimization strategies to balance soil carbon sequestration and nutrient retention.
ABSTRACT Understanding the relationships among land degradation, ecosystem functioning and human well‐being is essential for conserving tropical high‐mountain ecosystems. This study examined the relationships among land degradation, Cultural Ecosystem Services (CES), ecosystem disservices (EDS) and visitor perceptions at Laguna Colorados in the Sumapaz Páramo, Colombia, by integrating visitor‐perception data with complementary ecological evidence derived from multitemporal remote sensing. Perceptions were assessed through structured questionnaires administered to 92 adult visitors selected using simple random sampling. Responses were analysed in relation to sociodemographic characteristics using Spearman's rank correlations, hierarchical cluster analysis and principal component analysis. Knowledge of Nature and Landscape Appreciation were the most highly valued CES, whereas Religion and Spirituality received comparatively lower ratings and emerged as a distinct perceptual dimension. Tourism, Knowledge of Nature, Recreation and Sports, and Landscape Appreciation were positively associated and were perceived as an interconnected CES bundle. Soil contamination and insufficient surveillance and control were the most frequently reported EDS, each identified by 32% of respondents. These perceptions were broadly consistent with multitemporal remote‐sensing evidence, suggesting increasing vegetation heterogeneity, localised declines in vegetation vigour, moisture loss and greater soil exposure between 2003 and 2025. Integrating social‐perception data with complementary ecological evidence provides a more comprehensive understanding of land degradation as a socioecological process and can inform ecological restoration, adaptive visitor management and evidence‐based conservation planning in tropical high‐mountain ecosystems.
ABSTRACT Aeolian desertification poses a critical threat to ecosystem stability in arid regions worldwide. Although the combination of sand barriers and vegetation has been widely applied for sand fixation, its long‐term effectiveness is constrained by barrier degradation, slow natural development of biological soil crusts (BSCs), and the resulting spatial–temporal heterogeneity in surface erodibility. This study addresses the knowledge gap regarding how artificial BSC inoculation interacts with different sand barrier types and vegetation species to regulate soil properties and wind erosion resistance. established a three‐factor completely randomized block design involving five sand barrier types (6‐year, 4‐year, and 2‐year brush‐net rope checkerboard barriers; HDPE barriers; and no barriers as shifting sand control), five vegetation conditions ( Pinus sylvestris var. mongolica , Caragana korshinskii , Hedysarum scoparium , Artemisia ordosica , and non‐vegetated), and artificial BSC inoculation. Soil samples were collected at 0–10 cm and 10–20 cm depths, and wind erosion depth was monitored using the erosion pin method at 30, 60, and 90 days post‐inoculation. Three‐way ANOVA revealed that sand barrier type was the dominant factor influencing BSC development, with the 6‐year barrier producing the greatest crust thickness (5.63 mm at 60 days, F = 9.15, p < 0.001) and the most stable crust area (CV ≤ 15%). Wind erosion depth was significantly reduced under the 6‐year barrier compared to shifting sand (from 51.0 mm to 3.32 mm, a 93.5% reduction at 60 days). Soil organic carbon (SOC) in the surface layer was significantly affected by vegetation type ( F = 3.43, p = 0.015), with the C. korshinskii treatment under the 4‐year barrier achieving the highest SOC content (2.28 g/kg). Pearson correlation analysis demonstrated that wind erosion depth was significantly negatively correlated with crust thickness ( r = −0.542 to −0.951, p < 0.05) but not with crust area, indicating that crust thickness is the primary driver of wind erosion resistance. The optimal restoration model identified was “artificial BSCs + 6‐year brush‐net barrier + H. scoparium / A. ordosica ”, which enhances system stability through the chain mechanism of “barrier stabilization → BSC‐mediated soil improvement → plant consolidation”. For large‐scale restoration in arid sandy lands, we recommend integrating long‐lasting brush‐net barriers with artificial BSC inoculation and well‐adapted shrub species to maximize synergistic effects.
ABSTRACT Understanding the spatiotemporal dynamics of land use change (LUC), land surface temperature (LST), and vegetation indices is critical for assessing ecological changes and informing sustainable land management. This study investigates the long‐term interrelationships between LUC, LST, and vegetation indices in China's Caohai National Nature Reserve (CNNR) from 2000 to 2024. A comparative analysis was conducted by dividing the reserve into an Ecological Landscape Protection Zone (ELPZ) and a Land Use Development Zone (LUDZ). Utilizing multi‐temporal Landsat imagery, we quantified trends in land use types, LST, and vegetation indices, assessing their correlations through Pearson correlation and linear regression analysis. The results indicate that: (1) Cultivated land and construction land underwent the most substantial transitions, with net increases of 25.17% and 362.68%, respectively; (2) The mean LST followed a non‐linear trend, rising from 19.56°C (2000) to a peak of 21.68°C (2013) before fluctuating to 21.36°C in 2024; (3) Vegetation indices increased significantly ( p < 0.05), indicating improved vegetation cover, particularly in the LUDZ; (4) LST exhibited a significant negative correlation with the spatial extent of forest and water bodies ( R 2 > 0.7) and a positive correlation with cultivated and construction land ( R 2 > 0.5); (5) A strengthening positive correlation between NDVI and LST was observed in the ELPZ ( R 2 : 0.69–0.80), contrasting with a weak‐to‐negative correlation in the urbanized LUDZ ( R 2 : 0.10–0.03). These findings underscore the necessity of land management policies that control urban expansion and promote vegetation restoration to mitigate regional warming and enhance ecological resilience.
ABSTRACT Mining activities are prevalent worldwide and pose significant threats to the supply of ecosystem services (ESs) for humanity. Many mining areas face challenges related to recovery and reclamation following resource depletion. A key challenge for the sustainable development of these areas is how to achieve collaborative optimization of land pattern and enhancing ESs during the restoration process. To address the above challenges, we have innovatively analyzed land suitability through machine learning, and combined with ESs assessment (InVEST) and driving factor analysis (Geographic detector, Structural equation model) to explore the optimal land pattern for future Fushun mining area restoration. The findings are as follows: (1) From 1990 to 2020, water yield (WY), soil conservation (SC), and food production (FP) exhibited an increasing trend (8%, 3%, 22%), while habitat quality (HQ) and carbon sequestration (CS) showed a decreasing trend (12%, 4%). Plus model predicts that ESs will decrease 4%–60% in the future from 2030 to 2050. (2) Surface mining significantly impacts SC by indirectly altering terrain, which subsequently affects ESs that are coordinated with SC; normalized difference vegetation index (NDVI) is the main factor to improve ESs (0.2–0.6). (3) Machine learning analysis revealed that high forestland reclamation suitability is primarily concentrated in the open‐pit mine and factory boundaries, whereas mine pits are more suitable for water reclamation. The peripheral areas of the mining site are more suited for farmland and construction land reclamation. (4) Based on the results of land suitability and ecosystem services, the optimal land pattern under ESs enhancement scenarios was proposed. In the future, the land pattern of “pit water storage—in field farming—peripheral afforestation” should be formed to rationally restore land and comprehensively enhance ESs. This study proposes a new method for optimizing the land pattern of mining areas for the improvement of ecosystem services, which provides an important reference for the sustainable development of other mining areas in the world.
ABSTRACT Waste generation and subsequent disposal in adequate sites still have limitations in some Brazilian municipalities. Therefore, environmental monitoring of these areas is extremely important, as it helps to preserve the environment. The purpose of this study is to analyze the chemical and physical parameters of soil in a landfill area. For this, soil samples were collected at 10 sampling points, where the concentrations of seven chemical elements (Cadmium, Lead, Cobalt, Copper, Chromium, Nickel, and Zinc) were analyzed, at three depths (0, 50, and 120 cm). Furthermore, granulometry, permeability, and optimum moisture content were determined. The results indicated the presence of a Dystrophic Red Latosol (Oxisol). With 51.00% clay, 28.00% silt, and 21.00% sand, it is classified as a clayey soil, with 32.70% optimum moisture and a 2.11 × 10 −7 cm.s −1 permeability, thus within the values stipulated by current regulations. The chemical elements indicated changes in elements Copper and Nickel, mainly, and Copper may be of natural origin, due to the source material and its weathering products. As for Nickel, the values were similar to those found in research carried out in the same geological formation. Statistical analysis indicated that there was no difference between depths. Therefore, we conclude that the waste disposal activity did not alter the soil natural quality, possibly due to the natural protection system, through the low permeability clayey soil.
ABSTRACT Establishing scientifically grounded soil erosion control targets and feasible vegetation restoration strategies is crucial for high quality development of the Chinese Loess Plateau which is severely affected by soil erosion. Currently, the commonly used tolerable soil loss (TSL) is inadequate for addressing the spatial heterogeneity in topography and temporal variability in climatic conditions attributed to its static characteristics. This study developed a dynamic assessment framework using the Revised Universal Soil Loss Equation (RUSLE) model to construct a monthly soil erosion rate raster dataset at a 500 m resolution for 2001–2024. Model validation was conducted through comparison with sediment yield data from 25 tributary hydrological stations. By analyzing the soil erosion rate and the prevailing climatic and land management factors, we established monthly erosion control targets (ECT) and the corresponding vegetation cover targets (VCT). Results showed that (1) the average erosion rate declined from 15.5 to 10.17 t ha −1 year −1 , with a mean of 10.53 t ha −1 year −1 , and peaks occurred in summer, especially July; (2) the estimated ECT values ranged from 13.4 to 8.9 t ha −1 year −1 , with a mean of 7.2 t ha −1 year −1 , peaking at 1.6 t ha −1 month −1 in July; (3) the estimated VCT ranged from 43.4% to 66.6%, averaging 59.8%. Overall, 51.6% of the Loess Plateau has already met the VCT requirements necessary to sustain the ECT. These findings provide scientific guidance for soil and water conservation and vegetation restoration tailored to local conditions, with potential applicability to other erosion‐prone regions.
ABSTRACT Soil erosion remains a major environmental challenge in Nigeria, driven by the combined effects of climate variability and land use/land cover (LULC) changes. Understanding future dynamics is essential for effective soil conservation planning. This study assessed future soil erosion in the Kampe Omi Dam Basin using the Revised Universal Soil Loss Equation (RUSLE) integrated with Coupled Model Intercomparison Phase six (CMIP6) climate projections and simulated LULC scenarios for intermediate‐emission SSP2‐4.5 and high‐emission SSP5‐8.5 pathways for 2021–2040 and 2041–2060, relative to a 1995–2014 baseline. The results showed no statistically significant trend in annual precipitation, although rainfall erosivity exhibited spatial variability with a general declining tendency across scenarios. Cropland expansion and vegetation loss increased the cover‐management (C) factor, whereas improved conservation practices reduced the support practice (P) factor. The soil loss ranged from 0.00 to 7776.90 t/ha/yr. Despite increasing land‐use pressure, mean soil loss is projected to decline by over 50% in 2021–2040 and by more than 40% by 2041–2060 relative to the baseline (33.71 t/ha/yr), suggesting that reduced rainfall erosivity and improved management may offset erosion risks. Low erosion risk (0–10 t/ha/yr) dominated the basin (88.16%), although localised high‐risk hotspots persisted. Sensitivity analysis showed that while soil loss was most responsive to changes in the C‐factor under perturbed conditions, erosion outcomes were influenced by rainfall erosivity, LULC dynamics, and conservation practices, with the P‐factor exerting an important moderating effect. These findings support targeted watershed management to mitigate future erosion risks and soil conservation planning.
ABSTRACT Previous studies often overlooked the dynamic effects of karst vegetation restoration on soil multi‐trophic biodiversity and the underlying community‐assembly mechanisms. To fill this gap, we performed a seasonal comparative analysis of soil biodiversity, co‐occurrence network architecture, and assembly processes across three representative karst restoration patterns (grass, forest‐grass, and forest). During the wet season, the grass pattern exhibited significantly lower biodiversity than both the forest‐grass and forest patterns by 17%–49%. In the dry season, the forest pattern achieved the highest biodiversity indices and displayed minimal seasonal fluctuation. Vegetation type and season jointly shaped soil biotic co‐occurrence networks: the forest–grass pattern generated the greatest network complexity and connectivity, whereas the dry season fostered tighter network structures. The bacterial community was predominantly driven by heterogeneous selection with a relatively high contribution in the wet season, whereas it was dominated by dispersal limitation in the dry season. In contrast, the fungal community was largely influenced by dispersal limitation across seasons. As for the protist and nematode communities, undominated accounted for a relatively high contribution in the wet season, while dispersal limitation became the dominant driver in the dry season. Moreover, soil moisture, nutrient status, biodiversity, and network properties emerged as the principal drivers of assembly, with their pathways varying by taxon and season. Collectively, our reveal integrated regulation of soil biotic communities by restoration pattern and seasonal dynamics in karst ecosystems, offering a robust theoretical basis for soil‐biota recovery.
ABSTRACT Soil nutrient depletion severely constrains crop productivity in degraded and saline environments. Strategies such as biochar–compost integration could be useful for sustainable agriculture and land restoration on a global scale. This study evaluated the effects of biochar (1% Bc), compost (1% Co), and their blends (0.5% Bc + 0.5% Co and 1% Bc + 1% Co) on soil properties, growth, physiology and nutrient balance of the halophytic fodder crop P. antidotale under controlled greenhouse conditions. The 0.5% Bc + 0.5% Co treatment increased total plant biomass by 68%, net photosynthesis by 68% and stomatal conductance by 90% compared to the control while soil water holding capacity and CO 2 flux were also significantly enhanced. Sole biochar improved leaf water‐use efficiency (18%) and maximized K + /Na + ratios across plant organs, indicating improved ionic balance under nutrient‐poor soil conditions. Biochar–compost blends significantly increased leaf nitrogen (25%) and carbon (4%) concentrations relative to untreated plants with the lower mixture ratio consistently outperforming higher amendment levels. These responses are likely mediated through improved soil water retention, nutrient availability and rhizosphere functioning. Overall, integrating moderate biochar–compost amendments offers an effective and scalable strategy for enhancing halophyte productivity and soil quality in degraded agroecosystems.
ABSTRACT Ditch‐buried straw return (DB) is an innovative practice combining deep tillage and straw incorporation. This study aimed to evaluate its effects on soil physical quality compared to rotary tillage (RT) and identified key constraints to crop in sandy‐loam and clay‐loam paddy soils within rice–wheat systems. Two field experiments were conducted in two paddy soils. Soil physical properties and a comprehensive indicator—least limiting water range (LLWR)—were employed to evaluate soil physical quality. Compared with RT, DB decreased soil bulk density ( ρ b ), penetration resistance, and increased SOC, infiltration rate ( K v ), and available water content (AWC). Combined with the coupled changes in soil water retention, soil aeration, and mechanical impedance, DB has a larger LLWR than RT in both two paddy soils. The sandy‐loam soil exhibited a better physical quality with macroporosity > 5%, air capacity > 10%, and AWC > 15%, whereas the clay‐loam soil showed much higher ρ b and poorer AWC. The wheat in the clay‐loam soil was promoted by the improved soil aeration and water permeability. While in sandy‐loam soil, wheat and rice benefited from the slight increase in ρ b and decreased SOC in the topsoil layer, which may be attributed to the burial of excess straw from the topsoil into subsoil. These findings demonstrated that DB is an effective practice facilitating crop growth in rice–wheat rotation systems. Alleviating soil compaction and decreasing residue accumulation on the soil surface may serve as potential strategies promoting crop growth in clay‐loam and sandy‐loam soil, respectively.
ABSTRACT Subalpine meadows play important roles in biodiversity conservation and soil carbon sequestration, but gully erosion poses a serious threat to their ecological stability. Soil shear strength ( τ ) is a key mechanical parameter for evaluating gully stability and soil resistance to failure. However, the spatial variation in soil shear strength and its controlling factors in subalpine meadow gullies remain insufficiently understood. In this study, three typical subalpine meadow gullies in Gaobenshan, Yunnan Province, China, were selected and divided into head, middle, and outlet segments. Soil samples were collected from the gully edge, wall, and floor of each segment. Soil shear strength and physicochemical and mineralogical properties were measured. Their relationships were then analyzed. The results showed that soil shear strength was lowest in the gully head segment of this subalpine meadow gully system. Compared with the gully head segment, soil shear strength in the gully wall and floor of the middle segment increased significantly by 10%–50% and 4%–47%, respectively. In the outlet segment, soil shear strength reached its maximum at the gully edge and floor, whereas soil shear strength in the gully wall decreased by 4%–37% compared with that in the middle segment. Correlation analysis indicated that soil physicochemical properties and mineral composition were significantly correlated with soil shear strength ( p < 0.05). Structural equation modeling (SEM) further showed that, at the investigated sites, increased soil water content reduced cohesion, whereas improved aggregate stability, increased soil organic matter, and decreased soil bulk density enhanced the internal friction angle, suggesting potential pathways by which soil physicochemical properties affect soil shear strength. This may indicate that soil‐structure improvement driven by the combined effects of soil physicochemical properties enhances soil shear strength. This study preliminarily revealed the linkage between gully development and soil mechanical properties in the investigated subalpine meadow gullies and identified the main factors associated with soil shear strength in gully soils. Monitoring changes in these factors may help evaluate gully stability and provide a scientific basis for gully‐erosion control in subalpine meadow ecosystems.
ABSTRACT Chemical compliance remains the usual endpoint for closing contaminated‐soil remediation projects, although it does not establish recovery of soil function or the durability of the post‐treatment state. This critical review examines when microbiological evidence can contribute to ecological closure decisions. It proposes a five‐tier sequence covering chemical and exposure adequacy, residual matrix harm, land‐use‐critical soil function, reference‐based ecological trajectory, and advanced resolution of decision‐relevant ambiguity. Microbiome metrics are not treated as independent exit criteria. Their main decision value lies in detecting incomplete recovery, distinguishing stable from transient biological change, and resolving uncertainty after lower‐tier endpoints have been assessed. The framework separates hard blocking failures from soft contradictions and restricts high‐resolution molecular methods to predeclared escalation triggers. Two retrospective worked applications to published field studies illustrate that available site‐level datasets may satisfy only part of the required evidence package and do not validate the framework as a closure standard. Implementation requires site‐specific sampling design, informative reference states, cost‐proportionate escalation, regulatory agreement, and standardized reporting. The immediate proposal is an auditable decision process, not a universal microbiome threshold.
ABSTRACT Tea plantations represent significant carbon (C) sinks in agricultural landscapes, yet how variety‐specific organic inputs are associated with the molecular composition and stability of soil organic carbon (SOC) within aggregate hierarchies remains unclear. Here, we examined soils from 15‐year‐old plantations of four tea varieties, including Chuancha No. 3 (CC3), Chuanmu No. 217 (CM217), Chuannong Huangyazao (CN), and Camellia sinensis “ Fuding Dabaicha ” (FD), in subtropical China. Soil samples were collected from topsoil (0–20 cm) and subsoil (20–40 cm) layers and fractionated into macro‐ (> 2 mm), large meso‐ (2–1 mm), meso‐ (1–0.25 mm), and microaggregates (< 0.25 mm). Solid‐state 13 C cross‐polarization magic‐angle spinning nuclear magnetic resonance spectroscopy was used to characterize aggregate‐associated SOC molecular composition. Aggregate‐associated SOC composition and carbon sequestration capacity differed significantly among tea varieties and soil layers. Across both topsoil (0–20 cm) and subsoil (20–40 cm), FD soils exhibited the highest SOC stocks, followed by CN, CM217, and CC3, indicating enhanced carbon sequestration potential under FD cultivation. The greater SOC accumulation in FD soils was accompanied by distinct molecular signatures, characterized by higher proportions of alkyl C and aromatic C and lower proportions of O‐alkyl C within aggregate fractions. FD soils also exhibited greater hydrophobicity, aromaticity, and humification indices, particularly in macroaggregates and microaggregates. Stability indices were positively correlated with alkyl C, aromatic C, and humification indices, suggesting that the enrichment of chemically resistant carbon components coupled with aggregate‐scale physical protection contributed to enhanced SOC stabilization. Our findings indicate that tea variety selection and management practices favoring stable aggregate formation may help enhance long‐term soil C sequestration.
ABSTRACT Although improvements in soil quality under straw incorporation have been well documented, responses across soil profiles under different tillage depths remain unclear. To address this issue, a field experiment was established in 2011 in Mollisols with conventional tillage (20 cm depth) without straw (CT) and with straw (SCT), no tillage with straw mulching (SNT), inversion tillage (35 cm depth) with straw (SIT), and subsoil tillage (20–35 cm depth) with straw (SST). Compared with CT, nutrient contents, microbial biomass, enzyme activities, and phospholipid fatty acids (PLFAs) increased significantly in 0–60 cm soil layers in each of SCT, SIT, and SST treatments; microbial phosphorus limitation in 20–60 cm layers decreased; and a soil quality index (SQI) increased by 7.35%–45.45% in 0–60 cm layers. Yield of maize in SCT, SIT, and SST increased significantly by 8.62%–30.01%. Dominant factors affecting SQI varied by soil depth. Of soil chemical properties, these included available potassium and nitrogen (0–20 cm), NO 3 − –N and dissolved organic carbon (DOC) (20–40 cm), microbial carbon and DOC (40–60 cm), and bacteria and G + , total PLFAs and G + , and G + and G − among PLFAs, respectively. Partial least‐squares path modeling suggested that straw incorporation directly affected soil chemical properties, reduced microbial phosphorus limitation, and increased the SQI from 0 to 20 cm. Straw incorporation with tillage jointly increased the SQI from 20 to 60 cm. This study provides feasible strategies for improving the quality of soil profiles and provides valuable insights for the sustainable agricultural management of Mollisols.
ABSTRACT As a vital water conservation region in China, the Three River Source Region (TRSR) plays a critical role in safeguarding regional ecological security and ensuring the sustainable utilization of water resources. In this study, the Revised Universal Soil Loss Equation (RUSLE) was employed to quantify soil erosion in the study area across three periods (2014–2016, 2017–2019, and 2020–2022). The Self‐Organizing Map (SOM) was applied to classify spatial erosion patterns within road network areas, and Partial Least Squares Structural Equation Modeling (SEM) was used to quantify the direct and indirect effects among topography, ecology, soil, road networks, grazing, and erosion, thereby elucidating the spatiotemporal evolution and driving mechanisms of soil erosion under road network expansion. The results show that (1) the RUSLE‐estimated soil loss rates for the three periods were 4114, 4278, and 4012 t/(km 2 a), respectively, exhibiting an overall initial increasing trend followed by a decline. SOM identified five erosion clusters within road network areas, forming a gradient from valley to mountain to plateau. Cluster I primarily represents areas of slight to mild erosion, which are distributed across the western region and tend to expand southward into valley zones. Clusters II, III, and V correspond to moderate erosion areas, which are located mainly in the eastern and south‐central regions, with Cluster III showing a temporal pattern of northward expansion along transportation corridors. Cluster IV represents severe erosion zones concentrated in the south‐central region. Overall, all clusters maintained relatively high spatial connectivity across the study periods. (2) SEM analysis revealed that road network expansion and grazing activities jointly amplified erosion in the early stage, whereas engineering measures and institutional interventions, such as slope protection, drainage facilities, fencing, and rotational grazing, significantly mitigated their positive effects in the middle‐to‐late stages. (3) On the basis of the response characteristics of the five cluster types, we propose differential, zone‐specific management measures that integrate roads, grazing, forestry and water for coordinated prevention and control, thereby providing scientific support for precision zonal governance. The SOM–SEM coupled framework developed in this study elucidates the mechanisms by which road network expansion and the intensification of human activities drive soil erosion through mediating pathways such as ecology, soil and topography and offers decision‐making guidance for integrated human–road–land–water management.
ABSTRACT Deep‐rooted plantations are central to dryland ecological restoration, yet their long‐term cultivation drives widespread deep soil desiccation, threatening ecosystem sustainability. While artificial water replenishment is a key deep soil desiccation mitigation strategy, the depth‐dependent positional effect of stored water on eco‐hydrological processes remains poorly quantified, with no consensus on the optimal replenishment threshold. Here, we used a calibrated and validated HYDRUS‐1D model to simulate soil water dynamics, evapotranspiration partitioning, and deep percolation across eight storage depths in mature apple orchards (a typical deep‐rooted system) on the Chinese Loess Plateau, under extreme dry, normal, and extreme wet precipitation levels. Results revealed consistent depth‐dependent patterns across all scenarios, defining critical thresholds: soil water storage increased with depth, while depths above 5 m were insufficient for sustained water retention. Cumulative transpiration ( T ) exhibited three stages (slow decrease at < 3 m, sharp decline at 3–5 m, plateau at > 5 m), matching root water uptake effectiveness. Cumulative evaporation ( E ) dropped sharply at < 3 m then stabilized, indicating evaporation's maximum influence depth. Evapotranspiration ( ET ) initially declined steeply with depth before leveling off, whereas the T / ET ratio increased above 3 m and decreased at greater depths. Deep percolation remained negligible (< 1 mm year −1 ) at all depths. A multi‐criteria evaluation identified 5 m as the optimal eco‐hydrological threshold. This study refines soil water reservoir theory and provides transferable guidance for deep soil desiccation restoration in global drylands.
ABSTRACT Root exudates serve as a key driver for the restoration of soil organic carbon (SOC), particularly in aeolian desertification ecosystems where aboveground litter retention is limited. While Salix cupularis is widely planted as an effective pioneer shrub for ecological rehabilitation on the Qinghai‐Tibet Plateau, how the quantity of its root exudates regulates the dynamics of microbial‐derived SOC in sandy soils remains unclear. Using 13 C isotope labeling and DNA‐SIP, we simulated the root carbon exudation of S. cupularis with a glucose gradient: ambient rate (V), half the ambient rate (1/2 V), and twice the ambient rate (2 V) to investigate carbon decomposition pathways in sandy soil. We found that different glucose input levels significantly altered soil carbon components and enriched distinct microbial communities. Under V treatment, a higher proportion of glucose was efficiently incorporated into particulate organic carbon (POC). Conversely, both the 1/2 V and 2 V treatments diverted more glucose toward microbial respiration. While 1/2 V treatment increased microbial biomass, it simultaneously induced a positive priming effect, thereby exacerbating native soil carbon loss. Meanwhile, 2 V treatment significantly reduced microbial diversity and further elevated respiration, resulting in the lowest carbon sequestration efficiency. This study elucidates the mechanisms underlying microbial adaptation to varying nutrient inputs and reveals the dosage‐dependent advantage of S. cupularis root exudation in maintaining soil carbon balance. These findings offer novel perspectives on optimizing carbon sequestration strategies and understanding the ecological restoration capacity of pioneer plants in desertified ecosystems.
