Geoderma最新文献

Plateau zokor disturbances transform the stability and functional characteristics of soil fungal communities

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117232

Xiaojuan Zhang , Zhuangsheng Tang , Jie Yang , Saman Herath , Zhiwen Wang , Yiming Wang , Guangjun Chen , Lei Yue

As crucial regulators of the ecosystem functions, soil microbes are facing a range of challenges including ecological degradation caused by small mammal disturbances. These disturbances not only threaten biodiversity but also affect the healthy functioning of ecosystems. Effects of plateau zokor (Eospalax baileyi) disturbances on the complexity, stability and assembly processes of belowground microbial networks remain unclear. In this study, we employed ITS rRNA gene amplicon sequencing to systematically investigate fungal network properties, assembly mechanisms, functional potential, and the links to plant-soil functions in soil fungal communities through various stages of zokor mound succession: (i) new mounds (NM), (ii) semi-new mounds (SM), (iii) old mounds (OM) and (iv) pristine grassland (CK), as a control. The results demonstrated that zokor disturbances significantly altered plant species diversity and soil properties, simultaneously affecting the composition and structure of soil fungal communities. Disturbances increased the complexity of fungal community networks but decreased their stability. Moreover, dispersal limitation and homogeneous selection were identified as the primary mechanisms that shape fungal community structure. Functional potential analysis revealed that zokor disturbances led to a decline in the relative abundance of lichenized fungi and plant saprotrophs. Multiple environmental factors, including soil pH, soil organic carbon (SOC), and total phosphorus (TP) were identified as pivotal in driving changes in soil fungal communities. These results deepen our comprehension of the impacts of small mammal disturbances on fungal community characteristics in the Tibetan Plateau grassland ecosystem and provide valuable insights into the potential mechanisms sustaining fungal diversity in extreme environments.

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引用次数: 0

The role of pyrogenic carbon addition after wildfires in the boreal forest of China: Impact on plant–soil–microbial ecological stoichiometry

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117237

Xu Dou , Jianyu Wang , Kajar Köster , Cheng Yu , Yuexiao Ren , Long Sun , Tongxin Hu

Pyrogenic carbon (PyC) is a common byproduct of wildfires in terrestrial systems; however, its role in fire-prone forest ecosystems, particularly cold boreal forests, remains unclear. Ecological stoichiometry is a valuable tool for studying interactions within plant–soil–microbial continuum systems, which could help us understand post-fire changes in boreal forest ecosystems. In this study, we manipulated different additions of PyC in a forest of Dahurian larch (Larix gmelinii) after a wildfire to investigate the effects of PyC on plant–soil–microbial ecological stoichiometry. We engineered PyC under controlled conditions to simulate that produced by wildfires. The experimental design included no PyC addition (C0), 0.5 kg m⁻² PyC addition (C1), 1.0 kg m⁻² PyC addition (C2), and no fire as a control (CK). One year after PyC manipulation, understory vegetation and soil samples (0–10 cm depth) were collected to investigate how PyC addition affects plant–soil–microbial carbon (C), nitrogen (N), and phosphorus (P) stoichiometry. Our results showed that PyC addition (C1, and C2) increased plant biomass, particularly in the green tissues (35–53 % higher than that in the CK and 59–80 % higher than that in the C0 treatment). The C2 treatment also increased the plant C and N contents but did not significantly affect plant P content. PyC addition led to an increase in soil microbial biomass N (MBN) and P (MBP), altered the microbial biomass C:N:P ratio (to 27:1:1), and disrupted the microbial dynamic balance, indicating a possible shift towards a bacterial-dominated community. In boreal forest soils, post-fire PyC manipulation elevated soil organic C (SOC) and total P (STP). As there were no changes in soil total N (STN), the addition of PyC also increased the soil C:N and C:P ratios. Our findings highlight the potential of PyC as a soil conditioner that enhances plant biomass and alters nutrient cycling in boreal forests. However, PyC effects are modulated by soil resource availability and the nutrient environment. Further studies are required to elucidate the mechanisms underlying these differential nutrient responses.

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引用次数: 0

A meta-analysis reveals earthworms as mutualists rather than predators of soil microorganisms 荟萃分析显示蚯蚓是土壤微生物的互助者而非捕食者

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117238

Manuel Blouin , Aïssa Robin , Lysandre Amans , Frédérique Reverchon , Isabelle Barois , Patrick Lavelle

Microorganisms constitute the largest biomass on Earth after plants, and earthworms are one of the main components of animal biomass. Both are critical drivers of soil functions and ecosystem services. Studies report either positive or negative effects of earthworms on soil microbial communities, leading to contrasting views on whether microorganisms serve as prey or mutualists for earthworms. This meta-analysis aimed to settle this debate, and examines how biotic and abiotic factors affect earthworm impacts on microbial abundance and diversity. Based on a selective search retaining only genuinely quantitative approaches, we kept 169 observations, showing that, on average, earthworms increased bacterial abundance by 16.5 % and fungal abundance by 31.4 %. Bacterial species richness rose by 8.5 % in the presence of earthworms, but fungal richness was not significantly affected. Epigeic and anecic earthworms had more notable effects than endogeics. Plant presence in experimental designs strongly amplified earthworms’ effects on bacterial (+30 %) and fungal (+97 %) abundances. The largest earthworm-induced effects were observed in carbon- and nitrogen-rich soils and at low pH, while the addition of organic matter reduced these effects. Comparing microbial abundance in earthworm casts to control units without earthworms revealed effect sizes two- to three-fold greater (for bacteria and fungi, respectively) than when using the soil surrounding earthworm casts as a control. Our meta-analysis demonstrates that, despite ingesting some microorganisms, earthworms have a net positive effect on their abundance, positioning them as mutualists rather than predators of bacteria and fungi.

微生物是地球上仅次于植物的最大生物量，而蚯蚓则是动物生物量的主要组成部分之一。两者都是土壤功能和生态系统服务的重要驱动力。有研究报告称，蚯蚓对土壤微生物群落有积极或消极的影响，这导致人们对微生物是蚯蚓的猎物还是互助者产生了截然不同的看法。本荟萃分析旨在解决这一争论，研究生物和非生物因素如何影响蚯蚓对微生物丰度和多样性的影响。根据只保留真正定量方法的选择性搜索，我们保留了 169 项观察结果，结果显示，蚯蚓平均使细菌丰度增加了 16.5%，真菌丰度增加了 31.4%。有蚯蚓存在时，细菌物种丰富度提高了 8.5%，但真菌丰富度并未受到显著影响。与内生蚯蚓相比，外生蚯蚓和内生蚯蚓的影响更为明显。实验设计中植物的存在极大地增强了蚯蚓对细菌（+30 %）和真菌（+97 %）丰富度的影响。在富含碳和氮的土壤中以及在低 pH 值条件下观察到的蚯蚓诱导效应最大，而添加有机物则会降低这些效应。将蚯蚓粪中的微生物丰度与没有蚯蚓的对照组进行比较，发现其效应大小（细菌和真菌）分别是以蚯蚓粪周围土壤为对照组的两到三倍。我们的荟萃分析表明，尽管蚯蚓会摄入一些微生物，但它们对微生物的丰度有净积极影响，使它们成为细菌和真菌的互助者而不是捕食者。

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引用次数: 0

Soil quality improvement on Qinghai-Tibet Plateau induced by soil hydrothermal changes from 1980s to 2020s 20 世纪 80 年代至 2020 年代土壤水热变化对青藏高原土壤质量的影响

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117235

Kuan Chen , Jingyao Suo , Xiaodong Song , Yiyao Liu , Xiang Xiang , Yingping Pan , Jiarui Wang , Liang Ren , Xiaodong Ge , Xia Xu , Xiuchen Wu , Lei Duan , Yongmei Huang

The Qinghai-Tibet Plateau (QTP), as the world’s Third Pole, has experienced a sharp trend of warming and humidifying in recent decades within the context of global climate change. Under these circumstances, the soil nutrient cycling has been significantly modified. However, whether the soil quality had changed over recent decades on QTP remains unclear. In this study, we calculated, and drew high-resolution maps of the soil quality index (SQI) on QTP using soil property data in 1980s and 2020s. Results showed significantly an increasing trend of soil quality over the past four decades. The variation in trends of four typical ecosystems, more specifically, alpine cushion vegetation showing the most notable increase, followed by alpine meadow and alpine steppe, while forest & shrub exhibiting the smallest increase in soil quality. This implied that regions with more significant SQI changes correspond to stronger climate change. Through attribution analysis of 10 factors affecting the variation in SQI, including climate, soil hydrothermal, vegetation, and human activities, we found that the improvement in soil quality were predominantly driven by soil hydrothermal conditions. Additionally, we observed a pronounced increase in nitrogen limitation, with the factors contributing to this trend varying across different ecosystems. Our study emphasizes the warning of intensified nitrogen limitation, and, under the context of climate change, this phenomenon is likely to become increasingly severe in the future.

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引用次数: 0

Long-term regulation of maize crop residue carbon accumulation in soil and aggregates by epigeic and endogeic earthworms is tillage regime-specific

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117231

Xinyu Zhu , Yunchuan Hu , Zhen He , Donghui Wu , Andrey S. Zaitsev

Earthworms influence soil carbon (C) sequestration by modulating the balance between plant residue C incorporation and soil C mineralization below ground. The knowledge of the prolonged effects and backstaging mechanisms of C sequestration by earthworms belonging to different ecological groups in no-tillage (NT) and conventional tillage (CT) agroecosystems is still surprisingly sketchy. Therefore, we analyzed the contribution of the epigeic species Eisenia nordenskioldi (Eisen) and the endogeic species Metaphire tschiliensis (Michaelsen) to the distribution of C in soil and soil aggregates of different sizes from the ¹³C-labeled maize residue. For this, we ran a 337-day-long mesocosm experiment with simulated NT and CT systems. At the end of the experiment, epigeic and endogeic earthworm treatments in NT soil significantly increased SOC concentration by 16.61% and 17.31%, respectively if compared with the situation on day 40. However, no significant effects were observed in CT soil. In NT soil, the presence of M. tschiliensis significantly increased residue-derived C in SOC, whereas this effect was not significant in CT soil. The presence of M. tschiliensis increased the ¹³C content in all soil aggregate size classes in both NT and CT soils at the end of the experiment. The interaction between the two earthworm species treatments significantly positively affected the ¹³C content across all soil aggregate size classes in NT soil. This means that in NT soil, earthworms can aid the accumulation of larger amounts of ¹³C via enriching soil aggregates with C derived from crop residues. Our study further demonstrated that compared to epigeic earthworms, endogeics are more likely to promote the retention of maize residue-derived C in soil. Such differential contribution of the two ecological groups of earthworms explored to the stabilization of C in aggregates highlights the need for functionally diverse soil macrofauna in agroecosystems to achieve synergies in the delivery of essential ecological services in low input agriculture.

蚯蚓通过调节植物残留物碳吸收与地下土壤碳矿化之间的平衡来影响土壤碳固存。对于免耕（NT）和传统耕作（CT）农业生态系统中不同生态群落的蚯蚓固碳的长期影响和反向作用机制，我们的了解仍然少得令人吃惊。因此，我们分析了表生蚯蚓 Eisenia nordenskioldi (Eisen) 和内生蚯蚓 Metaphire tschiliensis (Michaelsen) 对 13C 标记玉米残留物中不同大小的土壤和土壤团聚体中 C 的分布所起的作用。为此，我们进行了一次长达 337 天的中观实验，模拟 NT 和 CT 系统。实验结束时，与第 40 天的情况相比，NT 土壤中的表生蚯蚓和内生蚯蚓处理的 SOC 浓度分别显著增加了 16.61% 和 17.31%。但是，在 CT 土壤中没有观察到明显的影响。在新界土壤中，稻蓟马的存在明显增加了 SOC 中残留物衍生的 C，而在 CT 土壤中这一影响并不明显。在实验结束时，M. tschiliensis 的存在增加了 NT 和 CT 土壤中所有粒径级别的 13C 含量。两种蚯蚓物种处理之间的交互作用显著正向影响了新界土壤中所有土壤骨料大小等级中的 13C 含量。这意味着，在新界土壤中，蚯蚓可以通过富集土壤团聚体中来自作物残留物的 C 来帮助积累更多的 13C。我们的研究进一步证明，与表生蚯蚓相比，内生蚯蚓更有可能促进玉米残留物衍生的碳在土壤中的保留。所探讨的两种蚯蚓生态群对稳定团聚体中碳的贡献存在差异，这突出表明农业生态系统中需要功能多样的土壤大型动物，以在低投入农业中实现提供基本生态服务的协同效应。

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引用次数: 0

Nitrogen addition promotes the coupling of deep soil carbon and nitrogen under different vegetation restoration types in the Chinese Loess Plateau

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117236

Shihao Gong , Xiaoxia Zhang , Hengshuo Zhang , Lianwei Gao , Tonggang Zha

Carbon-nitrogen coupling is important to maintain various functions in forest ecosystems and is thus, an important indicator of forest ecosystem health. However, the magnitude of this indicator’s importance to environmental changes remains virtually unknown, especially for deep soils across vegetation types. In this study, four representative sites, namely Pinus tabulaeformis forest, Robinia pseudoacacia forest, Pinus tabulaeformis x Robinia pseudoacacia mixed forest, and Populus davidiana x Quercus wutaishanica natural secondary forest, were selected as representatives of typical artificial and natural forests. A one-year N addition experiment was conducted to analyze C-N coupling conditions of different vegetation restoration types, and soil properties in the 0 – 100 cm layer, litter traits, and rainfall distribution characteristics were measured and compared during the growing season. (1) Soil C and N in artificial forests decoupled with increasing soil depth, while soil C and N were highly coupled among all soil depths in natural forest. (2) N addition had a greater effect on deep soil nutrient accumulation compared to topsoil. (3) N addition decreases the rates of change of deep soil N, which, in turn, enhanced the C and N coupling. (4) Moreover, further analyses with a structural equation model showed that summer precipitation is the key regulator of soil C:N ratio in topsoil. Soil pH, litter C:N ratio, and N deposition were primarily responsible for controlling deep soil C and N coupling. These results indicate that N addition and vegetation restoration types affect soil C and N coupling and should be taken into consideration when assessing deep soil C and N biogeochemical cycles. The importance of deep soil should be considered as much as possible during afforestation on the Loess Plateau. Afforestation should be conducted in a way of natural restoration. This study provides novel insights into the regulatory mechanisms of C and N biogeochemistry and the afforestation patterns of vegetation restoration in arid and semi-arid regions.

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引用次数: 0

The problematic case of data leakage: A case for leave-profile-out cross-validation in 3-dimensional digital soil mapping

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117223

Kingsley John , Daniel D. Saurette , Brandon Heung

Data leakage occurs when there is an overlap between the data used for model fitting and hyperparameter tuning, and those used for testing. This overlap biases the model performance, making it uninformative regarding the model’s ability to generalize. This is a significant issue in machine learning and predictive soil mapping, compromising model reliability. To demonstrate this issue, the 3-dimensional (3D) digital soil mapping (DSM) approach, whereby depth is used as a predictor of soil properties, was investigated. We compare two common approaches from the literature: leave-sample-out cross-validation (LSOCV) versus leave-profile-out cross-validation (LPOCV). Here, we argue that LSOCV results in contamination of the test dataset due to the potential vertical autocorrelation of soil properties from different samples within the same profile, and a more appropriate approach for testing 3D DSM models should be to fully partition all soil samples from the same profile to either the training or test dataset (i.e., LPOCV). Using the Ottawa region of Ontario, Canada, as a case study, cation exchange capacity (CEC), clay content, pH, and total organic carbon (TOC) were predicted using machine learning, and the discrepancy in accuracy metrics was reported. Furthermore, we evaluated the effects of data augmentation (i.e., the creation of additional synthetic data points from the original data) on accuracy metrics, a common practice in 3D DSM. Here, it was shown that with the augmented dataset, LSOCV generated overly optimistic accuracy metrics (e.g., CCC) that were 29–62% higher than LPOCV, while for the non-augmented data, the accuracy metrics were 8–18% higher, suggesting that vertical autocorrelation had a strong influence on inflating model accuracy through data leakage. As such, we strongly urge DSM practitioners to provide greater clarity when describing how model accuracy metrics were ascertained and to consider the use of LPOCV when applied to 3D DSM. This brings about broader concerns that policymakers and stakeholders may use map products with the false impression that the maps are more accurate than they are. Future research should focus on refining DSM methods and considering data structure to prevent data leakage in modelling soil properties.

当用于模型拟合和超参数调整的数据与用于测试的数据发生重叠时，就会出现数据泄漏。这种重叠会使模型的性能产生偏差，从而使模型的泛化能力失去参考价值。这是机器学习和预测性土壤制图中的一个重要问题，会影响模型的可靠性。为了证明这个问题，我们研究了三维（3D）数字土壤制图（DSM）方法，即使用深度作为土壤特性的预测指标。我们比较了文献中的两种常见方法：留样交叉验证（LSOCV）和留样剖面交叉验证（LPOCV）。在此，我们认为 LSOCV 会导致测试数据集受到污染，因为同一剖面中不同样本的土壤特性可能存在垂直自相关性，而测试三维 DSM 模型的更合适方法应该是将同一剖面中的所有土壤样本完全划分到训练或测试数据集中（即 LPOCV）。以加拿大安大略省渥太华地区为例，我们使用机器学习预测了阳离子交换容量（CEC）、粘土含量、pH 值和总有机碳（TOC），并报告了准确度指标的差异。此外，我们还评估了数据增强（即从原始数据中创建额外的合成数据点）对准确度指标的影响，这是三维 DSM 中的一种常见做法。结果表明，使用增强数据集时，LSOCV 生成的准确度指标（如 CCC）过于乐观，比 LPOCV 高出 29-62%，而对于非增强数据，准确度指标则高出 8-18%，这表明垂直自相关对通过数据泄漏夸大模型准确度有很大影响。因此，我们强烈敦促 DSM 实践者在描述如何确定模型精度指标时提供更清晰的信息，并考虑在三维 DSM 中使用 LPOCV。这将带来更广泛的担忧，即政策制定者和利益相关者在使用地图产品时，可能会产生地图比实际更准确的错误印象。未来的研究应侧重于完善 DSM 方法，并考虑数据结构，以防止土壤特性建模过程中的数据泄漏。

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引用次数: 0

More persistent precipitation regimes induce soil degradation 更持久的降水机制导致土壤退化

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117230

Olga Vindušková , Gaby Deckmyn , Simon Reynaert , Karen Vancampenhout , Steffen Schlüter , Jan Frouz , Hans De Boeck , Miguel Portillo-Estrada , Erik Verbruggen , Han Asard , Gerrit T.S. Beemster , Ivan Nijs

In the mid-latitudes, precipitation regimes are becoming more persistent, with longer consistently dry and rainy periods. Such a rise in precipitation regime persistence (PRP) – defined as the length of consecutive dry or wet periods – could significantly affect soil properties and their role in soil–plant-water relationships. To investigate these effects, we conducted a 16-month outdoor grassland mesocosm experiment. We simulated four levels of PRP by varying the duration of alternating dry and rainy periods: 1, 6, 15, or 60 days. The regimes started with either a dry or a wet period, resulting in two levels of timing and eight different treatments altogether, all of which received the same total amount of water across the entire experiment.

Higher PRP (longer alternation periods) decreased soil aggregate stability, without a similar trend in total soil carbon. PRP also affected potential soil water repellency (SWR) in interaction with timing. Higher PRP decreased potential SWR when the timing of the dry periods coincided with summer heatwaves and plant productivity was overall hindered. However, when the dry periods coincided with less warm months and the overall plant productivity was maintained, PRP increased potential SWR. PRP enhanced actual soil water repellency measured in the field which reduced infiltration rates. Water retention was also affected, with lower field capacity and available water capacity in the more persistent treatments, and wilting point following a convex relationship across the PRP range. Furthermore, bulk density increased with PRP. Structural equation modeling revealed that these soil degradation patterns often but not always correspond with plant productivity, which in general declined with PRP. However, some soil properties proved to be more sensitive to PRP than plant productivity. Overall, more persistent precipitation regimes induced soil degradation especially by reducing aggregate stability, water retention, and infiltration, and this soil legacy may exacerbate the effects of future climate change on temperate grasslands.

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引用次数: 0

Update and expansion of the soil and landscape grid of Australia

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-03-01 DOI: 10.1016/j.geoderma.2025.117226

Brendan P. Malone , Ross Searle , Matthew Stenson , David McJannet , Peter Zund , Mercedes Román Dobarco , Alexandre M.J.-C. Wadoux , Budiman Minasny , Alex McBratney , Mike Grundy

The Soil and Landscape Grid of Australia (SLGA) has been significantly updated and expanded. The initial version, released in 2015, provided the first continental-scale characterization of soil resources adhering to GlobalSoilMap specifications. It featured digital maps for 11 key soil attributes (including bulk density, organic carbon, soil texture, pH, available water capacity, total nitrogen, total phosphorus, effective cation exchange capacity, and soil thickness) at a 90 m × 90 m spatial resolution and served as a widely accessed national resource with substantial global influence.

The updated version, developed between 2018 and 2023, includes enhancements to the original 11 soil attributes and introduces 13 additional products. These additions improve the representation of key soil characteristics, such as soil carbon composition, soil microbial distribution, and soil moisture fluxes, contributing to a more comprehensive understanding of Australia’s soil and landscape resources.

The updated data and methodologies offer a robust foundation for developing a national soil monitoring program and other applications. The advancements in the SLGA and its associated data systems are detailed, and all products are freely available for public use.

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引用次数: 0

Soil water, salt, and microplastics interact during migration: Performance and mechanism

IF 5.6 1区农林科学 Q1 SOIL SCIENCE

Geoderma

Pub Date : 2025-02-24 DOI: 10.1016/j.geoderma.2025.117229

Xuguang Xing , Haoxuan Feng , Sihan Jiao , Tianjiao Xia , Dongwei Li , Fengyue Zhao , Weihua Wang

Farmland salinization and microplastics (MPs) pollution are important environmental issues that threaten soil ecosystems. However, the interactions among soil water, salt, and MPs during migration in MPs-contaminated saline soils remain unexplored. To address this, we conducted an infiltration test using loam soils with four different salinity levels and polyethylene MPs concentrations. Experimental results showed that both MPs and salts inhibited water infiltration and that the inhibitory effect of MPs weakened with increasing soil salinity. After infiltration, MPs increased the water content in the shallow soil layer (0–15 cm) and decreased that in the deep layer (15–30 cm). Furthermore, total salt content of MPs-containing soils was higher than that of MP-free soils in the deep layer. Notably, MPs hindered the leaching of Na⁺ and SO₄^2-, and a larger obstruction was observed for Na⁺ compared to SO₄^2- leaching. In addition, MPs migrated more easily in non-saline soils, and higher salinity had a stronger inhibitory effect on MPs migration than lower salinity. Mechanism analysis indicated that MPs influence water movement through their water-repellent properties, changing the soil pore size distribution, and degradation of soil structure. Moreover, salts affect water movement by reducing the mobility of soil water and blocking soil macropores. Additionally, the surface of MPs is negatively charged and can adsorb Na⁺ in soil through electrostatic forces, further influencing salt migration. Furthermore, the presence of salt ions affects the migration ability of MPs by reducing their electrostatic repulsion and increasing the mean hydrodynamic diameter of MPs particles. These findings provide valuable insights for developing healthy soil–crop systems for croplands rich in MPs and salts.

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引用次数: 0