Soil最新文献

{"title":"Two decades of conservation agriculture enhances soil structure, carbon sequestration, and water retention in Mediterranean soils","authors":"Jennifer Alvarez-Sagrero,Asmeret Asefaw Berhe,Stephany S. Chacon,Jeffrey P. Mitchell,Teamrat Afewerki Ghezzehei","doi":"10.5194/soil-12-979-2026","DOIUrl":"https://doi.org/10.5194/soil-12-979-2026","url":null,"abstract":"Conservation agriculture offers a pathway for enhancing soil health with climate co-benefits in Mediterranean agricultural systems. This study examined long-term impacts of combining reduced tillage with cover cropping over 20 years in California's Central Valley, providing insights into soil system response under sustained conservation management. We assessed soil physical, chemical, and structural properties comparing reduced tillage with cover crops (CTCC) to standard tillage without cover crops (STNC), employing density fractionation and spectroscopic analysis to understand carbon protection mechanisms. After two decades, conservation agriculture produced soil conditions consistent with the approach toward a management-induced steady state described for systems managed for 15–20 years (Caruso et al., 2018; West and Post, 2002), characterized by shifts in carbon stabilization pathways. Water-stable aggregate analysis revealed the most pronounced management effects, with CTCC exhibiting 136 % greater stability than STNC, indicating substantial improvements in soil structural integrity. These structural enhancements corresponded with a reorganization of carbon protection mechanisms: CTCC disproportionately enriched the occluded light fraction (44.1 % vs. 35.4 % of total recovered carbon in STNC), indicating that aggregate-mediated physical protection becomes a dominant carbon stabilization pathway under long-term conservation management. Mineral-associated organic carbon saturation analysis revealed that both management systems remained well below theoretical maximum capacity (11.5 % vs. 7.4 % saturation for CTCC and STNC, respectively), indicating that mineral surface availability is not the primary constraint on carbon storage in this Mediterranean system. Physical property improvements under CTCC included 15 % lower bulk density and 13 % greater water retention at field capacity, though benefits were concentrated in the surface horizon. Our findings demonstrate that two decades of conservation agriculture substantially altered soil functioning through aggregate-mediated physical protection, while creating measurable improvements in soil structural integrity and water retention capacity. These mechanism shifts are consistent with a soil system that maintains enhanced functionality and continued carbon sequestration potential in Mediterranean agricultural systems.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"12 1","pages":"979-998"},"PeriodicalIF":6.8,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biochar addition enhances soil aggregate stability by modulating soil internal forces: the critical role of readily oxidized organic carbon and particulate organic carbon","authors":"Xiaoshuai Song, Chenyang Xu, Huanhuan Zhao, Jiangwen Li, Wei Du, Wuquan Ding, Zhenghong Yu, Fengbao Zhang, Feinan Hu","doi":"10.5194/soil-12-963-2026","DOIUrl":"https://doi.org/10.5194/soil-12-963-2026","url":null,"abstract":"Abstract. Degradation of soil structure and function is a significant obstacle to sustainable agriculture, yet using biochar is known to be an effective way of increasing soil organic carbon and boosting structure. Aggregate stability is greatly influenced by soil internal forces (SIFs), such as van der Waals, hydration, and electrostatic forces. However, it is still not clear which specific organic carbon components play a significant role in the stability of aggregates and the action of soil internal forces. In this study, a field simulation experiment was conducted using maize straw and wheat straw biochars to investigate how biochar addition affects soil aggregate stability. The findings showed that as the rate of biochar application increased from 0 % to 10 % over 180 and 365 d, the contents of soil light fraction organic carbon (LFOC), particulate organic carbon (POC), dissolved organic carbon (DOC), readily oxidized organic carbon (ROC), as well as soil specific surface area and surface charge number, increased. The content of different carbon fractions decreased with prolonged incubation time, while soil electrochemical parameters continued to increase throughout the incubation period. Pearson correlation and redundancy analyses showed that soil active organic carbon fractions were strongly correlated with soil surface electrochemical properties, with ROC and POC being the primary factors. Soil aggregate stability increased with higher biochar application rates, and the beneficial effect of biochar on aggregate stability became increasingly pronounced over time. Based on the quantitative estimates of SIFs, the addition of biochar facilitated soil aggregate stability by increasing van der Waals attractive pressure and decreasing electrostatic repulsive pressure, and finally lowering net repulsive pressure between soil particles. The soil aggregate breaking strength increased rapidly initially and then leveled out as the electrolyte content decreased; 10−2 mol L−1 marked the tipping point. The study identified the active organic carbon (ROC and POC) fractions which could mediate the soil surface electrochemical properties and soil internal forces, thereby enhancing soil aggregate stability. Our research provides a theoretical basis for the targeted use and modification of biochar to efficiently improve soil structure.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"16 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-tree soil footprints show higher organic carbon and lower bulk density with no detectable end-of-summer moisture penalty","authors":"Ana Paula Ferreira de Brito, Mark Farrell, Luke Mosley","doi":"10.5194/egusphere-2026-5762","DOIUrl":"https://doi.org/10.5194/egusphere-2026-5762","url":null,"abstract":"<strong>Abstract.</strong> Scattered trees can create fine-scale surface soil enrichment, but it is unclear how far these patterns extend through the mineral soil profile, translate into carbon stocks, and influence moisture content. We quantified the soil functional footprint of 14 established trees from four contrasting cohorts in an arboretum–grassland system under a Mediterranean climate in South Australia. Soil was sampled at 1, 2, 4 and 8 m from each stem at depth intervals to 30 cm. Directly measured surface bulk density was lower at 1, 2 and 4 m than at 8 m, while soil organic carbon (SOC) concentration was 30% higher at 1 m and declined by 8% with each doubling of distance. Total nitrogen, nitrate-N and Colwell-extractable P also varied with distance, whereas gravimetric moisture did not decline towards the trees under the end-of-summer conditions sampled. Distance × tree cohort interactions were not significant for these principal responses. After accounting for depth and tree identity, distance explained 3% of joint soil property variation whereas depth explained 39%. On an equivalent-soil-mass basis, SOC stock at 1 m distance from the tree exceeded that at 8 m by 16.5 Mg C ha⁻¹, although the categorical fixed-depth 0–30 cm SOC-stock test was not significant. Within the radially-weighted 0-8 m footprint, we combined two carbon pools, model-assisted mineral-soil SOC and current projected whole-tree carbon. Together these amounted to 67.4–123.2 Mg C ha⁻¹, with mineral-soil SOC accounting for 59–89% of this combined soil tree total. These results identify a shared, property-specific radial soil footprint characterised by lower bulk density and higher carbon and nutrient concentrations without a detectable dry-season moisture penalty. They also demonstrate why depth resolution, soil mass correction and radial area weighting are essential when converting near-tree enrichment into spatially explicit carbon accounting and monitoring.<strong> </strong>Because the near-tree zone retained higher carbon and nutrients without an end-of-summer moisture penalty, established trees may support understorey forage production and its resilience under increasing aridity rather than imposing a dry-season water cost.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"32 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149130436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the plant growth promotion potential of Pseudomonas species isolated from the rhizosphere of Lotus creticus grown in the Mediterranean coastal regions of Morocco","authors":"Imane Achkouk, Anass El Yemlahi, Ouiam El Galiou, Amin Laglaoui, Mounir Hassani Zerrouk, Mohammed Bakkali, Abdelhay Arakrak","doi":"10.5194/soil-12-947-2026","DOIUrl":"https://doi.org/10.5194/soil-12-947-2026","url":null,"abstract":"Abstract. Rhizosphere-associated bacteria play a key role in enhancing plant performance under saline and nutrient-limited soil conditions, where plant establishment is strongly constrained. In this study, we evaluated the plant growth-promoting potential of rhizobacteria isolated from the rhizosphere of wild-growing Lotus creticus along the Mediterranean coast of Morocco. Of the 30 isolates, five bacterial strains (R125, P79, R8, R150, and R15) were selected based on their plant growth-promoting traits. These strains were identified through 16S rRNA gene sequencing as Pseudomonas protegens, Pseudomonas sesami, Pseudomonas versuta, Pseudomonas helleri, and Pseudomonas trivialis. Phenotypic characteristics, including IAA production, phosphate solubilization capacity, cellulase and protease activities, and tolerance to salinity and temperature, were evaluated. Additionally, a pot experiment was conducted to assess the impact of inoculation on L. creticus growth. Pseudomonas protegens P79 was characterized by strong IAA production, high phosphate solubilization capacity (150.5 mg L−1), and notable cellulase and protease activities. It also demonstrated high tolerance to salinity (up to 13 % NaCl) and temperature (up to 45 °C). Comparatively, Pseudomonas sesami R8 exhibited broad-spectrum antifungal activity, including strong inhibition of the growth of Aspergillus ochraceus. The pot experiment revealed that inoculation with Pseudomonas helleri R125 and Pseudomonas trivialis R150 significantly (P < 0.05) enhanced the aerial dry biomass of L. creticus by 300 %. In contrast, Pseudomonas protegens P79 was more effective in promoting root elongation by 8 % under growth chamber conditions. This study highlights the potential of Pseudomonas strains as promising biostimulants for sustainable agriculture and rehabilitation of coastal marginal soils under combined salinity and nutrient stresses.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"272 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149083849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil moisture as the dominant driver of CO\u0000 2\u0000 efflux in Mediterranean urban green spaces: evidence for a Gaussian temperature response and mechanistic modelling of moisture and temperature interactions","authors":"Teresa Alía, Sergio González-Ubierna, Abel Sánchez-Jiménez, Rubén Abad-Calderón, Miguel Ángel Casermeiro","doi":"10.5194/soil-12-915-2026","DOIUrl":"https://doi.org/10.5194/soil-12-915-2026","url":null,"abstract":"Abstract. Soil respiration is a key component of the global carbon cycle, yet its dynamics in urban Mediterranean environments remain poorly understood. This study investigated the effects of soil temperature, soil moisture, and plant community on soil CO2 efflux in urban green spaces of Madrid (Spain), characterized by a Mediterranean pluvioseasonal-oceanic bioclimate with pronounced summer drought. Four dominant ruderal plant communities (Diplotaxis virgata, Hordeum leporinum, Malva spp., and Dactylis glomerata) were monitored across three urban green spaces. Soil CO2 efflux, temperature, and moisture were measured biweekly over one year using an infrared gas analyzer. Contrary to the Q10 exponential assumption, soil respiration showed a Gaussian relationship with temperature, with a positive correlation below a breakpoint of 18.4 °C and a negative effect above this threshold, consistent across plant communities. Soil respiration exhibited a positive exponential relationship with soil moisture and a logarithmic relationship with a rewetting index for values below 20. A mechanistic model described soil respiration as the joint outcome of temperature-driven moisture loss and moisture-stimulated CO2 emissions. Plant community identity had a limited effect, with the exception of Malva spp., which consistently produced higher emissions. These findings challenge the universal applicability of temperature-based respiration models and highlight soil moisture as the dominant driver of CO2 efflux in water-limited urban ecosystems. As climate change is expected to intensify both the urban heat island effect and summer drought in Mediterranean cities, soil moisture emerges as a critical variable for projecting urban soil CO2 fluxes and for designing evidence-based management strategies for Mediterranean urban green spaces, including improved soil infiltration capacity, moisture-sensitive irrigation planning, and the incorporation of moisture-temperature coupling into urban carbon monitoring protocols.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"16 1","pages":"915-935"},"PeriodicalIF":6.8,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term storage of air-dried samples compromises water-extractable organic carbon as a soil health indicator","authors":"Swarnali Mahmood, Franky Celestin, Diego Arruda Huggins de Sá Leitão, Ryan E. Champiny, Xinlin Wang, JoAnn B. Donald, Audrey Plauche, S. Carolina Córdova, Christine D. Sprunger, Gabriel Maltais-Landry, Yang Lin","doi":"10.5194/soil-12-937-2026","DOIUrl":"https://doi.org/10.5194/soil-12-937-2026","url":null,"abstract":"Abstract. The assessment of soil health relies on sensitive indicators to detect management-induced changes, yet the analytical reliability of these indicators following long-term storage is rarely assessed. We investigated how multi-year storage of air-dried samples influenced the concentrations of several common soil health indicators, including water-extractable organic carbon and nitrogen (WEOC, WEN), mineralizable carbon (Cmin), and permanganate-oxidizable carbon (POX-C), using archived samples from a cover crop experiment. Concentrations of WEOC nearly doubled after three years of storage, while WEN decreased by 19 %. A small but significant 6 % increase in Cmin concentration was also observed. In contrast, POX-C concentrations remained stable, indicating robustness to storage effects. These storage effects were consistent among three treatments with different cover crop species. In addition, WEOC concentrations consistently declined over time in this experiment along with four long-term agricultural sites in the USA, but their bulk soil organic carbon (SOC) or soil organic matter (SOM) did not. These results suggest that multi-year storage of air-dried samples inflates the WEOC pool. Therefore, we caution the use of WEOC as a soil health indicator in archived samples, as the observed variations might reflect storage artifacts rather than genuine management impacts.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"2 3-4 1","pages":"937-945"},"PeriodicalIF":6.8,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cropping-system diversification drives long-term soil carbon gains more strongly than reduced tillage","authors":"Saurav Das, Hallie Spell, Andrew Smith, Carolyn Garrity","doi":"10.5194/egusphere-2026-4553","DOIUrl":"https://doi.org/10.5194/egusphere-2026-4553","url":null,"abstract":"<strong>Abstract.</strong> Long-term measurements across the soil profile are essential for understanding how agricultural management affects soil organic carbon (SOC) storage, accumulation, and vertical distribution. We analyzed a 40-year record (1984–2023) from the Farming Systems Trial in Pennsylvania, USA, comparing conventional (CNV), legume-based organic (LEG), and manure-based organic (MNR) cropping systems. Seven sampling events were used to evaluate long-term surface SOC trajectories, three campaigns included the complete 0–100 cm soil profile, and full- and reduced-tillage treatments were compared from 2008 onward. Surface SOC increasingly diverged among cropping systems over time (system × year: χ² = 35.0, P &lt; 0.001). By 2023, SOC concentrations in the 0–20 cm layer were 2.46% in MNR, 2.30% in LEG, and 1.92% in CNV. Equivalent-soil-mass-corrected SOC stocks were 70.3, 65.7, and 54.7 Mg C ha⁻¹, respectively, corresponding to gains of 15.6 Mg C ha⁻¹ in MNR and 11.0 Mg C ha⁻¹ in LEG relative to CNV. Across the full 1 m profile, MNR and LEG stored 119.0 and 108.9 Mg C ha⁻¹, respectively, compared with 92.9 Mg C ha⁻¹ under CNV. The effect of cropping system varied strongly with soil depth (system × depth: χ² = 77.9, P &lt; 0.001). In both 2021 and 2023, 91–94% of the additional SOC stored under the organic systems occurred within the upper 30 cm. Permanganate-oxidizable carbon followed the same vertical pattern, indicating that both total SOC and management-responsive carbon increased primarily within the surface and transition layers. Cropping-system diversification and organic inputs had a substantially greater influence on SOC than tillage intensity, which had no significant overall or system-dependent effect. These findings show that diversified organic cropping systems can produce substantial and persistent SOC gains over four decades. Full-profile sampling combined with equivalent-soil-mass accounting also clarifies where those gains occur, providing a stronger basis for evaluating agricultural soil-carbon storage.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"16 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149020026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-disturbance soil monitoring in forests using remote sensing: an evidence map","authors":"Maisy Roach-Krajewski, Xavier Giroux-Bougard, David Paré, Catlan Dallaire, Luc Guindon, Florian Jordan, Charlotte Norris, Kara Webster, Jérôme Laganière","doi":"10.5194/soil-12-885-2026","DOIUrl":"https://doi.org/10.5194/soil-12-885-2026","url":null,"abstract":"Abstract. Forest soils underpin ecosystem resilience and productivity but are increasingly threatened by natural and anthropogenic disturbances. Monitoring post-disturbance soil degradation at operational scales remains challenging in forests, where ground-signal obstruction and reliance on proxy indicators constrain remote sensing (RS) applications. To identify where RS can benefit soil monitoring and inform emerging reporting needs, we developed a structured evidence map of studies assessing post-disturbance forest soil degradation using RS methods. From 4338 records, 72 primary studies were synthesized across disturbance types, biomes, platforms, scales, and indicators. The evidence base is dominated by wildfire and harvesting, reflecting disturbance pathways that produce observable surface impacts. Multispectral satellite data remain the primary tool for mapping post-fire severity and erosion-related indicators, while LiDAR and stereo-photogrammetry are most often used to quantify surface deformation after harvest operations. Indicators tied to subsurface physical, chemical, or biological change remain sparsely represented due to observability limits. Overall, RS is most effective for mapping disturbance footprints, detecting surface-expressed indicators, and stratifying landscapes for targeted field assessment, rather than directly measuring soil properties. This evidence map clarifies the benefits and limits of RS, identifies persistent gaps, and highlights priorities for developing disturbance-aware soil-monitoring frameworks. It also clarifies which soil indicators are most consistently observable with RS and which require complementary approaches. By linking disturbance processes to observable indicators, this synthesis helps identify realistic RS-supported objectives that may inform future reporting frameworks within national forest monitoring and assessment programs.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"47 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148964294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of enhancing soil fertility without obviously elevating global warming potential under an optimal rice straw incorporation rate in a paddy soil","authors":"Mengxue Zhang, Rujia Liao, Wenzhao Zhang, Cheng Fang, Simon Guerrero-Cruz, András Táncsics, Baoli Zhu, Wenxue Wei, Rong Sheng","doi":"10.5194/soil-12-871-2026","DOIUrl":"https://doi.org/10.5194/soil-12-871-2026","url":null,"abstract":"Abstract. The utility of rice straw as an organic fertilizer has been widely recognized as a promising approach to enhancing soil fertility. However, straw return is currently in a dilemma, as it may also provoke greenhouse gas (GHG) emissions, leading to serious environmental consequences. It is urgent to reveal the feasibility of straw incorporation regarding soil fertility improvement without notable increases in GHG emissions. Here, a soil microcosm experiment was conducted using paddy soils collected from a long-term rice straw incorporation field experiment. The treatments of the field experiment, namely CK, ST1, ST2, and ST3 corresponding to the straw application rates of 0 %, 50 %, 100 %, and 150 % of the local rice straw yield, respectively, were continued in the microcosm experiment. The dynamics of GHG fluxes and concentrations in soils, and the variations in the abundances of soil microbial communities were systematically determined. The results indicated that ST1 treatment obviously improved soil fertility but did not induce significant elevation of global warming potential (GWP) with only 3 % increase compared to CK. Although ST2 and ST3 treatments showed greater improvements in soil fertility, they significantly increased GWP by up to 151 %. The minimal GWP increase under ST1 was mainly attributed to the significant reduction in N2O emission and the slight rise in CH4 emission compared to CK. The further investigations revealed that ST1 possessed the highest nosZII abundance and the lowest nirS/nosZII ratio, indicating its highest N2O consumption ability. Meanwhile, its CH4 production ability fluctuated around the soil CH4 holding capacity (190 mmol mol−1), and most of the produced CH4 was consumed by methanotrophs in soil. In conclusion, rice straw can be incorporated into paddy soils at a suitable application rate, which can effectively enhance soil fertility without inducing an additional warming effect.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"3 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visual Evaluation of Soil Structure (VESS) in temperate forest soils: pH mediates the effects of texture and organic carbon on soil structure and hydraulic functioning","authors":"Niklas Schmücker, Madlene Nussbaum, Alice Johannes, Claudia Guidi, Peter Lehmann","doi":"10.5194/egusphere-2026-4629","DOIUrl":"https://doi.org/10.5194/egusphere-2026-4629","url":null,"abstract":"<strong>Abstract.</strong> Soil structure is an important determinant of ecosystem functioning in forest soils, because it influences water flow, aeration, root growth, and biological activity. The Visual Evaluation of Soil Structure (VESS) is a rapid field method to assess soil structural quality in agricultural systems, but its applicability to temperate forest soils remains largely unknown. We evaluated the applicability and interpretation of VESS across 27 temperate forest sites in Switzerland that span a wide range of soil textures, pH values, and soil organic carbon (SOC) contents. At each site, VESS assessments were combined with measurements of saturated hydraulic conductivity (K_sat), bulk density, soil texture, SOC content, pH and the SOC:clay ratio. A single property alone was not sufficient to explain the variation in VESS scores. However, strong relationships emerged when soils were grouped into three aggregation regimes defined by pH, clay and sand content (<em>R</em>² = 0.65). In acidic coarse-textured soils, VESS scores improved with increasing pH and silt content, controlled by aggregate stabilization by Fe/Al-oxyhydroxides. In acidic soils with more clay (19–43 %), better VESS scores were associated with increasing SOC content but decreasing SOC:clay ratios, indicating the limiting effect of clay surfaces saturated with organic matter. In contrast, in near-neutral soils VESS scores improved as SOC:clay ratios increased. This trend is in agreement with findings from non-forested lands where the pH is typically in the neutral range as well. The relationship between VESS and K_sat was likewise dependent on aggregation regimes defined by pH and texture. Since saturated conductivity is very sensitive to the formation of large pore networks and not only aggregate formation, cluster-specific analyses identified four hydraulic regimes. In three of the four identified clusters, better VESS scores were associated with higher K_sat. Only under strongly acidic conditions did this relationship reverse. This indicates a decoupling between aggregate-scale structural quality and the preferential flow pathways governing saturated water flow. The classification of four regimes allowed to express K_sat as function of VESS score and one basic soil property with coefficient of determination <em>R</em>² = 0.89. We conclude that VESS is a useful tool for assessing soil structural quality in temperate forest soils across a broad range of textural conditions. However, its interpretation depends strongly on the aggregation regimes that are controlled by pH, governing both the visual expression of soil structure and its relationship to hydraulic functioning.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"144 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}