Geoderma最新文献

{"title":"Empirical estimation of saturated soil-paste electrical conductivity in the EU using pedotransfer functions and Quantile Regression Forests: A mapping approach based on LUCAS topsoil data","authors":"Calogero Schillaci ,&nbsp;Simone Scarpa ,&nbsp;Felipe Yunta ,&nbsp;Aldo Lipani ,&nbsp;Fernando Visconti ,&nbsp;Gábor Szatmári ,&nbsp;Kitti Balog ,&nbsp;Triven Koganti ,&nbsp;Mogens Greve ,&nbsp;Giulia Bondi ,&nbsp;Georgios Kargas ,&nbsp;Paraskevi Londra ,&nbsp;Fuat Kaya ,&nbsp;Giuseppe Lo Papa ,&nbsp;Panos Panagos ,&nbsp;Luca Montanarella ,&nbsp;Arwyn Jones","doi":"10.1016/j.geoderma.2025.117199","DOIUrl":"10.1016/j.geoderma.2025.117199","url":null,"abstract":"<div><div>Soil Electrical conductivity (EC) is a measure of the ability of soil to conduct an electric current, which is primarily influenced by the concentration of soluble salts in the soil solution that takes place principally through water-filled pores. Ions (Ca²⁺, Mg ²⁺, K ⁺, Na ⁺, and NH ⁴⁺, SO₄^2-, Cl^-, NO₃^–, and HCO₃^–) from soluble salts dissolved in soil water carry electrical charges and conduct the electrical current. EC is considered a proxy of soil salinity and other soil characteristics, whose monitoring is much needed in the context of climate change, increasing irrigation in agricultural areas and sea level rise. The pan-European LUCAS soil monitoring scheme, established in 2009, provided EC_1:5 in the topsoil (0–20 cm) in the surveys of the years 2015 and 2018 for almost 20,000 samples. In this work, using the LUCAS 2018 dataset, we provide an empirically-derivedpedotransfer function to convert diluted EC_1:5 to saturated EC_e using the LUCAS soil texture and soil organic carbon, and a framework for EC_e mapping with a machine-learning algorithm named Quantile Regression Forest. The final model resulted in an R² of 0.302 with an RMSE of 0.265 dS m⁻¹ for soil samples not used for model calibration. The results are presented as predicted EC_e in the topsoil, and they reveal that in Atlantic and Northern Europe, salts may accumulate in soils through several natural processes, i.e., primary salinization, but in Mediterranean and Southern Europe, they accumulate because of human interventions on the soil water and solute regimes. Among these interventions, seawater intrusion into coastal aquifers, irrigation with waters containing soluble salts, poor drainage of irrigated lands and of naturally saline soils, stand out. Hotspot analysis per country or Nomenclature of Territorial Units for Statistics (NUTS 0) revealed high topsoil EC_e levels occurred in Spain 0.11 %. Increasing EC_e can led to constrained crop productivity in irrigated farming. With this assessment, we try to determine the hotspots for future monitoring and understanding the main drivers for sustainable soil management. Future challenges for EC_e mapping that need to be address are sample numerosity and depth and availability of a consistent set of EC_e data measured to provide a regression based PTF for the use of diluted EC_1:5.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117199"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating mineral-associated organic carbon saturation and sequestration potential using MIR spectral based local quantile regression","authors":"Longnan Shi ,&nbsp;Karen Daly ,&nbsp;Sharon O’Rourke","doi":"10.1016/j.geoderma.2025.117181","DOIUrl":"10.1016/j.geoderma.2025.117181","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Associating with mineral surfaces, mineral-associated organic carbon (MAOC) is able to persist against fast decomposition via chemical bonding or physical occlusion, considered as key to soil organic carbon (SOC) stabilisation. In this study, the feasibility and capability of using mid-infrared (MIR) spectral models to predict MAOC and optimising the estimation of theoretical MAOC saturation limits was tested. Based on measured MAOC from physical carbon fractionation, the spectral MAOC model (R&lt;sup&gt;2&lt;/sup&gt; = 0.86, RMSE = 4.41 g C kg&lt;sup&gt;−1&lt;/sup&gt;) predicted MAOC values from a large regional scale spectral library. Based on measured MAOC from physical carbon fractionation, the model with a medium RMSE (R&lt;sup&gt;2&lt;/sup&gt; = 0.86, RMSE = 4.41 g C kg&lt;sup&gt;−1&lt;/sup&gt;) among 41 randomizations was identified as the most generalized and was selected to predict MAOC values from a large regional-scale spectral library. As SOC increased, the rate of MAOC accumulation diminished, indicating the presence of a theoretical saturation limit. Hence, quantile regression at 95th was performed on the whole dataset based on the relationship between MAOC and silt + clay to estimate theoretical MAOC saturation limits. Using this approach, estimated theoretical MAOC saturation limits was 67.5 ± 2 g C kg&lt;sup&gt;−1&lt;/sup&gt; with a 95 % confidence interval ranging from 64.0 to 71.4 g C kg&lt;sup&gt;−1&lt;/sup&gt;. To advance this, a new data-driven approach combining quantile regression and MIR spectral library was proposed using a spectral neighbourhood framework, called ‘local quantile regression’, to improve the estimation of theoretical MAOC saturation limits in quantile regression. By defining neighbourhoods around each soil sample based on spectral dissimilarity, quantile regression was conducted within these neighbourhoods, and inverse distance weight averaging was applied to improve the robustness of the estimates. MAOC theoretical saturation limits estimated in local quantile regression varied from 44 g C kg&lt;sup&gt;−1&lt;/sup&gt; to 82 g C kg&lt;sup&gt;−1&lt;/sup&gt;. In contrast to the constant theoretical upper limit in global quantile regression, local quantile regression using MIR data captures chemical information, specifically, clay minerals related to carbon storage that offers potentially more realistic assessment of MAOC saturation. Moreover, based on correlation analysis and variable importance used in random forest model, soil mineralogy related properties, such as CEC and different cations, followed by land management related covariates, like available phosphorus and climatology, were identified as primary and secondary driving factors behind this variation of MAOC saturation limit. Hence, local quantile regression provided a conservative but more feasible MAOC sequestration target, overcoming limitations in global quantile regression and offering a better framework for regional-scale carbon sequestration estimation. Based on local quantile regression estimated MAOC saturation, the MAOC se","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117181"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of soil detachment capacity to different rock dip angles in karst trough valley","authors":"Lisha Jiang ,&nbsp;Fengling Gan ,&nbsp;Xiaohong Tan ,&nbsp;Hailong Shi ,&nbsp;Youjin Yan ,&nbsp;Qiuhao Liao ,&nbsp;Junbing Pu","doi":"10.1016/j.geoderma.2025.117174","DOIUrl":"10.1016/j.geoderma.2025.117174","url":null,"abstract":"<div><div>The karst region is distinguished by pronounced and complex soil erosion, while the bedrock strata dip and root traits significantly influence the erosion slope, thereby altering the hydrodynamic characteristics and impacting Dc. Thus, it is imperative to comprehensively understand the influence mechanism of these factors on Dc in karst trough valley. The samples were collected from two types of natural grassland, <em>Erigeron canadensis</em> (EC; fibrous root system) and <em>Neyraudia reynaudiana</em> (NR; tap root system), as well as bare land (BL) without roots serving as the control. Subsequently, the samples underwent flow scouring in an indoor hydraulic flume at three rock dip angles (15°, 45°, and 65°) and three flow rates (60, 80, and 100 L·min⁻¹) on dip/anti-dip slope. The results indicated that i) the soil organic matter (SOM), water-stable aggregates (WSA), root length density (RLD), root surface area density (RSAD), and root volume density (RVD) on the anti-dip slope were higher compared to those on the dip slope. Additionally, the EC demonstrated the highest abundance in karst trough valley. ii) The Dc of different rock dip angles both dip and anti-dip slopes followed the order of 45° &gt; 65° &gt; 15°. The Dc of two grassland and bare land can be ranked as follows: EC &lt; NR &lt; BL. iii) The Dc of the dip/anti-dip slope showed a significant negative correlation with WSA, root diameter (RD), RLD, RSAD, and RVD (<em>P</em> &lt; 0.05). iv) The results of the multivariate analysis of variance showed that the root traits had the highest contribution rate to Dc, followed by rock dip angles, and bedrock strata dip was the lowest. The resistance of EC to Dc is better under different rock dip angles of the dip/anti-dip slope. Therefore, expanding the coverage of EC across both dip and anti-dip slopes will contribute to mitigating soil erosion and facilitating ecosystem restoration. The research findings enhance the comprehension of soil erosion mechanisms in karst trough valley and facilitate the formulation of effective ecological restoration strategies.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117174"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rhizodeposition stimulates soil carbon decomposition and promotes formation of mineral-associated carbon with increased clay content","authors":"Md. Rumainul Islam ,&nbsp;Bahareh Bicharanloo ,&nbsp;Xing Yu ,&nbsp;Balwant Singh ,&nbsp;Feike A. Dijkstra","doi":"10.1016/j.geoderma.2025.117180","DOIUrl":"10.1016/j.geoderma.2025.117180","url":null,"abstract":"<div><div>Rhizodeposition plays a key role in the formation and decomposition of soil organic carbon (SOC), but interactions with clay remain unclear. In this study, we examined how rhizodeposition contributes to SOC decomposition and the formation of particulate and mineral-associated organic C (POC and MAOC, respectively) in different soils with varying clay content. We collected soils from a grassland site covering three soil types and two depths, ranging in clay content from 15.6 to 66.4 %. We then grew ryegrass (<em>Lolium perenne</em>) in these soils in a glasshouse. After 76 days, plants were pulse-labelled with ¹³C-enriched CO₂ to assess rhizodeposit C and SOC decomposition rates and the recovery of rhizodeposition in microbial biomass, POC and MAOC. The SOC decomposition showed no relationship with clay content, but a strong positive relationship with rhizodeposit C decomposition, indicating a positive rhizosphere priming effect. The rhizodeposition recovered in the MAOC was positively related to clay content and rhizodeposition recovered in microbial biomass. Our results suggest that microbial products from rhizodeposition are increasingly incorporated into MAOC with increased clay content. Our results further highlight the role of rhizodeposition for soil C decomposition and stabilisation and how both processes interact with clay content.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117180"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil phoD-harboring bacteria mediate the responses of phosphorus availability to N addition and mowing among soil aggregates","authors":"Haiying Cui ,&nbsp;Shanling Wang ,&nbsp;Tianyan Wei ,&nbsp;Xuechen Yang ,&nbsp;Xiuping Li ,&nbsp;Mingcai Fan ,&nbsp;Xiaochong Zhang ,&nbsp;Wenzheng Song ,&nbsp;Jian-Ying Ma ,&nbsp;Wei Sun","doi":"10.1016/j.geoderma.2025.117170","DOIUrl":"10.1016/j.geoderma.2025.117170","url":null,"abstract":"<div><div>Phosphorus (P), like nitrogen (N), is a major limiting nutrient for ecosystem structures and functions. Soils in grasslands commonly have limited P availability for organisms, especially under global change (i.e., N deposition) and land-use intensification (i.e., mowing or hay harvest). Soil <em>phoD</em>-harboring bacteria regulate P cycling and maintain P supply in soils. However, it remains unclear how P availability responds to N addition and mowing. The potential microbial mechanisms also require clarification among soil aggregates. We conducted a seven-year field experiment to investigate how N addition at different levels (0, 5, 10, and 20 g N/m⁻² y⁻¹) and mowing (unmown and mown) affects soil available P in macro- and micro- aggregates in a temperate grassland in Northeast China. We found that N addition markedly decreased available P in macroaggregates, regardless of mowing. In contrast, available P in microaggregates decreased following N addition under mown but increased at addition levels of 10 and 20 g N/m⁻² yr⁻¹ under unmown. Our results also showed that soil available P was positively related to the diversity of <em>phoD</em>-harboring bacteria and <em>phoD</em> gene abundance in macroaggregates, and to alkaline phosphatase activity and <em>phoD</em> gene abundance in microaggregates. These findings suggests that microbial characteristics mediating the response of available P to N addition and mowing vary with soil aggregates. Our study highlights that soil aggregates should be carefully protected if we wish to promote the sustainable development of grassland ecosystems and P supply under a scenario of future global change and land-use intensification.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117170"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Creating soil districts for Australia based on pedogenon mapping","authors":"Quentin Styc,&nbsp;Julio Pachon,&nbsp;Wartini Ng,&nbsp;José Padarian,&nbsp;Alex McBratney","doi":"10.1016/j.geoderma.2025.117164","DOIUrl":"10.1016/j.geoderma.2025.117164","url":null,"abstract":"<div><div>Soil is a highly diverse natural resource crucial for the functioning of ecosystems and essential for ensuring food security, biodiversity, water quality, and climate regulation. Despite its significance, soil faces increasing degradation pressures from agriculture, urbanisation, and climate change. Previous work has classified soil into pedogenons—homogeneous groups based on soil-forming factors similarity. These maps are valuable for evaluating soil condition and anthropogenic impacts, distinguishing less affected areas (genosoils) from more impacted areas (phenosoils). However, the large number of pedogenons in a region can complicate management, monitoring, and legislation. To address these challenges, we propose a methodology for designing soil districts that: i) utilises pedogenon spatial information to create compact and contiguous soil districts, ii) groups pedogenons based on soil-forming factor similarities and geographic location, and iii) provides a set of descriptors to explain the composition and characteristics of each soil district.</div><div>Applying this methodology, we created 236 soil districts from the pedogenon map of Australia, forming units that can be used for legislative and monitoring purposes depending on stakeholders’ needs. The median size of these districts is 22,000 km².</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117164"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mycorrhizal and nutrient controls of carbon sequestration in tropical rainforest soil","authors":"Jie Chen ,&nbsp;Xin Tang ,&nbsp;Han Xu ,&nbsp;Yanpeng Li ,&nbsp;Adriana Corrales ,&nbsp;Yide Li ,&nbsp;Yakov Kuzyakov ,&nbsp;Zhanfeng Liu ,&nbsp;Shirong Liu","doi":"10.1016/j.geoderma.2025.117188","DOIUrl":"10.1016/j.geoderma.2025.117188","url":null,"abstract":"<div><div>Tree mycorrhizal associations have substantial consequences for soil organic carbon (SOC), but it remains unclear how nutrient availability will regulate the performance of arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) trees, and then consequently affect SOC sequestration in tropical forest soils. This study characterized the performances of AM and ECM trees, SOC content, and soil microbial functions under variable soil nitrogen (N) and phosphorus (P) content across an intact tropical rainforest based on the spatial dataset from a 60-ha dynamic plot and fitted statistical models to examine the mycorrhizal and nutrient controls on SOC stocks. ECM trees showed a better performance in soils containing higher N in total or in NH₄⁺ forms and enhanced SOC content via increases in both species richness and basal area, which led to an increase in SOC as soil N content evaluated. AM trees had a greater basal area at N-richer (i.e., available N and NH₄⁺) niches while a higher species richness under higher soil P levels (i.e., total and available P). The AM tree community patterns had inconsistent regulations on SOC, with basal area showing a positive while species richness exerting a negative effect on SOC content. Such counteracting effects from AM trees might attenuate SOC accumulation along the P gradient, resulting in a positive trend in SOC with soil total N:P ratios. As soil available P increased, species richness of AM trees increased, which was accompanied by a higher abundance of pathogens while a lower abundance of AM fungi. This indicated a decreased dependence of AM trees on mycorrhizal P acquisition, accompanied by the high susceptibility of roots to pathogen attacks, which may promote AM tree diversity. The performances of ECM trees were positively related to ECM fungi abundance, offering ECM trees a competitive P strategy and pathogen resistance. Summarily, our results suggest that both the basal area and species richness of mycorrhizal trees act as significant regulators for SOC sequestration along soil N or P gradient in tropical forests. Such findings provide a mechanistic understanding of soil C dynamics during vegetation changes under the rising global stoichiometric imbalance between N and P.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117188"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Macrofaunal biopores: Diversity and regeneration rates across diverse pedoclimatic conditions studied with repacked soil cores","authors":"Charlotte Védère ,&nbsp;Hanane Aroui Boukbida ,&nbsp;Yvan Capowiez ,&nbsp;Sougueh Cheik ,&nbsp;Guillaume Coulouma ,&nbsp;Rinh Pham Dinh ,&nbsp;Séraphine Grellier ,&nbsp;Claude Hammecker ,&nbsp;Thierry Henry Des Tureaux ,&nbsp;Ajay Harit ,&nbsp;Jean Louis Janeau ,&nbsp;Pascal Jouquet ,&nbsp;Jean Luc Maeght ,&nbsp;Pascal Podwojewski ,&nbsp;Cornelia Rumpel ,&nbsp;Stéphane Sammartino ,&nbsp;Norbert Silvera ,&nbsp;Siwaporn Siltecho ,&nbsp;Lotfi Smaili ,&nbsp;Bounsamay Soulileuth ,&nbsp;Nicolas Bottinelli","doi":"10.1016/j.geoderma.2025.117177","DOIUrl":"10.1016/j.geoderma.2025.117177","url":null,"abstract":"<div><div>It is well known that biopores are crucial for soil functioning. However, their dynamics is rarely studied and their origin with regards to the soil organisms involved is still hard to determine. In this study we investigated the diversity of biopores and their regeneration rates <em>in situ</em> in various pedoclimatic conditions. Our approach involved field incubation of repacked soil cores with lateral openings across nine study sites in five countries (France, Vietnam, India, Laos and Thailand). After 12 months, biopores were characterized by X-ray computed tomography and grouped according to their diameter, length and sphericity index using principal component analysis followed by K-means clustering. The regeneration dynamics of biopores was assessed by comparing those created after one year of incubation to the biopores determined in soil cores taken from the surrounding soils (assuming the latter are in a steady-state). Additionally, we examined the relationships between newly formed biopores and soil macrofauna taxa. Our results evidenced significant variability in biopore diameter (0.90 to 15.84 mm), length (1 to 1600 mm) and sphericity index (0.03 to 0.93). We propose 10 biopore groups allowing to distinguish most of the study sites. Complete regeneration of biopores after 12 months was achieved in seven out of nine sites. Three groups of biopores showed a positive relation with earthworm abundance (r values ranged from 0.69 to 0.90), whereas the other groups of biopores showed no association with any macrofauna taxa. We conclude that biopore formation can be assessed under field conditions with repacked soil cores, regardless the pedoclimatic conditions. However, the involvement of macrofauna other than earthworms in biopore formation still remains to be unraveled. To capture their contribution to biopore formation, improvements of the repacked soil core approach and complementary laboratory experiments were suggested.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117177"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143125296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil carbon concentration drives anoxic microsites across horizons, textures, and aggregate position in a California grassland","authors":"Emily M. Lacroix ,&nbsp;Anna Gomes ,&nbsp;Alexander S. Honeyman ,&nbsp;Katie R. Huy ,&nbsp;Scott Fendorf ,&nbsp;Vincent Noël ,&nbsp;Meret Aeppli","doi":"10.1016/j.geoderma.2025.117165","DOIUrl":"10.1016/j.geoderma.2025.117165","url":null,"abstract":"<div><div>Anoxic microsites, zones of oxygen depletion in otherwise well-aerated soils, serve as prominent controls on several biogeochemical cycles (e.g., carbon, nitrogen, iron). However, relatively little is known about the spatiotemporal distribution of anoxic microsites and thus little is known about their biogeochemical influence. Here, we use time-integrative measures of past anoxia (i.e., electrochemical measurements and quantification of anaerobic functional genes) to determine how the spatial distribution of anoxic microsites varies between aggregate interiors and bulk soils in soils of two distinct textures across multiple depths in a California grassland. We found greater evidence of anoxia in topsoils vs. subsoils and finer vs. coarse-textured soils. Counter to many traditional depictions of soil aggregates, we observed that aggregate interiors showed equal or less evidence of anoxic microsites than bulk soils. Across the entire dataset, our combined proxies for anoxic microsite prevalence were strongly and positively correlated with organic C concentration (R² = 0.80), highlighting the importance of soil organic C availability and microbial oxygen demand in creating anoxic microsites. Our results contribute to a growing body of evidence that soil oxygen demand (i.e., microbial respiration) can play a more prominent role in anoxic microsite formation than soil oxygen supply, provoking questions about the suitability of using aggregate size and moisture as lone proxies for soil oxygen availability.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117165"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Balancing legume-cereal proportions in cover crop mixtures to minimize N2O emissions","authors":"Guillermo Guardia ,&nbsp;Diego Abalos ,&nbsp;Emanuele Ribatti ,&nbsp;Federico Ardenti ,&nbsp;Federico Capra ,&nbsp;Giacomo Mortella ,&nbsp;Vincenzo Tabaglio ,&nbsp;Miguel Ángel Ibáñez ,&nbsp;Ji Chen ,&nbsp;Andrea Fiorini","doi":"10.1016/j.geoderma.2025.117195","DOIUrl":"10.1016/j.geoderma.2025.117195","url":null,"abstract":"<div><div>Legume-cereal cover crop mixtures offer a promising approach to reduce nitrate leaching and enhancing soil fertility. However, the impacts of these mixtures on N₂O emissions during both the cover cropping and post-incorporation phases, as well as the relative contribution of roots and shoots to N₂O emission, remain uncertain. To address these knowledge gaps, we conducted a two-phase greenhouse experiment. In the first phase, cover crops were grown encompassing six treatments: control (no cover crop), pure vetch (<em>Vicia villosa</em> Roth), pure rye (<em>Secale cereale</em> L.), and mixtures with 33 %, 50 % and 66 % of the pure rye sowing rate paired with 66 %, 50 % and 33 % of the pure vetch sowing rate, respectively. In the second phase, focusing on the post-incorporation effects, the same treatments were arranged in mesocosms with both roots and shoots, and in mesocosms with roots only. During the first phase, the proportion of fine/very fine roots and root length density were negatively correlated with mineral N content and N₂O emissions. Mixing rye with vetch increased total dry biomass and N yield for all mixtures compared to rye alone. In mixtures, the proportion of fine roots, root length density, and the root C:N ratio decreased compared to rye. Most of the N₂O emissions occurred after cover crop incorporation, with roots contributing more (average 57 %) than shoots (average 31 %). Total N₂O emissions increased with increasing proportion of vetch, but the mixture with 33 % vetch and 66 % rye maintained N₂O emissions as low as rye monoculture. Our study indicates that adjusting the seed proportion in legume-cereal mixtures serves as an effective tool to balance the benefits of pure legume (increased total biomass, and C and N yields) and pure cereal (decreased N₂O emissions and soil mineral N pool) cover cropping.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117195"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}