Geoderma最新文献

{"title":"Interpreting and evaluating digital soil mapping prediction uncertainty: A case study using texture from SoilGrids","authors":"Linda Lilburne ,&nbsp;Anatol Helfenstein ,&nbsp;Gerard B.M. Heuvelink ,&nbsp;Andre Eger","doi":"10.1016/j.geoderma.2024.117052","DOIUrl":"10.1016/j.geoderma.2024.117052","url":null,"abstract":"<div><div>Soil information is critical for a wide range of land resource and environmental decisions. These decisions will be compromised when the soil information quality is unsatisfactory. Thus, users of soil information need to understand and consider the uncertainty of the available soil information and be able to judge whether it is fit for purpose. The uncertainty information provided with the SoilGrids<!--> <!-->2.0 product was examined in a case study. We hypothesised that the soil property predictions for the Netherlands (NL) might be less uncertain than those of New Zealand (NZ) because there were more relevant training data for NL than for NZ. The study objectives were to: 1)<!--> <!-->understand whether the provided uncertainty information is correct for both countries; 2)<!--> <!-->explore spatial patterns and relationships in the prediction error and uncertainty information using quantitative tools and new graphical analyses; 3)<!--> <!-->analyse whether these patterns and relations can be explained; and 4)<!--> <!-->explore how the uncertainty information and insights derived from graphical analyses might assist an end user to determine whether a map is suitable for their purpose. The study focused on soil texture.</div><div>Independent datasets showed that the SoilGrids 2.0 uncertainty information was too optimistic for sand and too pessimistic for clay for both countries. The graphical analyses confirmed the initial assumption that NL predictions were more accurate than those for NZ, but they also indicated that some locations in NL have high uncertainty. The graphical analyses allowed only a limited identification of the four sources of uncertainty in digital soil maps, but were quite insightful in helping us to better understand the reliability of the information. A set of recommendations was developed for both producers and consumers of digital soil mapping (DSM) products. This includes the provision of a summary map of accuracy classes. We suggest that more research and educational effort is needed to ensure that digital soil maps are used appropriately.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427703","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":"Comparison of cation exchange capacity extraction methods for soil data harmonization and soil classification in Central and East Europe","authors":"Cezary Kabala,&nbsp;Szymon Jedrzejewski","doi":"10.1016/j.geoderma.2024.117044","DOIUrl":"10.1016/j.geoderma.2024.117044","url":null,"abstract":"<div><div>Cation exchange capacity and base saturation are of crucial importance for soil characterisation and classification; however, the interchangeability of soil data for international assessment of soil productivity, soil classification, mapping, and modelling is limited due to the lacking comparisons between results obtained using different analytical methods in particular regions of the world. The aim of the present study was to analyse the relationships between cation exchange capacity and base saturation measured using the methods adopted in Central and East Europe, and ‘standard’ techniques required for soil classification suggested by World Reference Base (WRB). This study was carried out using 183 soil samples collected from Luvisols, Retisols, Planosols, Chernozems, Phaeozems, Cambisols, and Arenosols in Poland, representing a wide range of texture, pH, and organic carbon content. A close comparability was found in noncalcareous soils between the ‘total sorption capacity’ (T) measured in Central and East Europe as the sum of base cations and ‘total’ (‘hydrolytic’) acidity, with the ‘standard’ cation exchange capacity (CEC) measured using 1 M ammonium acetate buffered at pH 7. The close correlation between T and CEC values (in noncalcareous soils) facilitates reliable data recalculation and its application in global modelling, soil classification and mapping. For soils containing carbonates, CEC must be measured using reference methods, because no relationship exists between T and CEC. The ‘potential’ base saturation (V) derived on the basis of T may be reliably recalculated to ‘standard’ base saturation (BS), allowing a retrieval of archival data from Central and East European regional databases and published reports. Similarities between the values of cation exchange capacity and base saturation, whether measured or calculated using the local and standard methods, allow a positive verification of previously proposed correlations between the local soil taxa and the reference soil groups of the WRB classification and soil orders defined by USDA Soil Taxonomy. The pH values corresponding to 50 % of ‘standard’, ‘potential’, and ‘effective’ base saturation were estimated at 5.5, 5.2, and 4.8, respectively. Irrespective of the differences between current estimates and previously reported pH threshold values corresponding to 50 % base saturation, the obtained results confirm that field measurements of soil pH may be considered a substitute for laboratory-measured base saturation for some purposes, such as soil classification.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142321971","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":"Groundwater level effects on greenhouse gas emissions from undisturbed peat cores","authors":"Erne Blondeau ,&nbsp;Gerard L. Velthof ,&nbsp;Marius Heinen ,&nbsp;Rob F.A. Hendriks ,&nbsp;Anneke Stam ,&nbsp;Jan J.H. van den Akker ,&nbsp;Monne Weghorst ,&nbsp;Jan Willem van Groenigen","doi":"10.1016/j.geoderma.2024.117043","DOIUrl":"10.1016/j.geoderma.2024.117043","url":null,"abstract":"<div><div>Peat soils store a large part of the global soil carbon stock, which can potentially be lost when they are drained and taken into cultivation, resulting in CO₂ emission and land subsidence. Groundwater level (GWL) management has been proposed to mitigate peat oxidation, but may lead to increased emissions of nitrous oxide (N₂O) and methane (CH₄).</div><div>The aim of this experiment was to study trade-offs between greenhouse gas emissions from peat soils as a function of GWL. We incubated 1 m deep, 24 cm diameter undisturbed bare soil cores, after removal of the grass layer, from three contrasting Dutch grassland peat sites for 370 days at 16 °C. The cores were subjected to drying-wetting cycles, with the GWL varying between near the soil surface to 160 cm below the surface. We measured gas fluxes of CO₂, N₂O and CH₄ from the soil surface, extracted pore water for DOC and mineral nitrogen analysis, and measured soil hydraulic and shrinkage characteristics.</div><div>Emissions of CO₂ increased after lowering the GWL, but showed different GWL-response curves during rewetting of the soil. On average, highest CO₂ emissions of 1.5 g C·m⁻² day⁻¹ were found at a GWL of 80 cm below the surface. However, the 0 cm GWL was the only treatment with significantly lower CO₂ emissions than other GWLs. Cumulative CO₂ emissions differed significantly between sampling sites. Emissions of N₂O showed a different response, peaking at GWL heights above −20 cm, particularly after a recent GWL rise. Though not significantly different, the highest N₂O emissions were measured at the 0 cm GWL treatment. We confirmed this pattern for N₂O in un-replicated soil cores with grass sward, although emission values were lower in these cores due to the root uptake of mineral nitrogen. CH₄ emissions or −uptake remained low under any GWL. We conclude that raising the GWL is a successful strategy to reduce CO₂ emissions from peat oxidation. However, raising the GWL close to the soil surface could lead to N₂O emissions that negate any gains in terms of global warming potential. Our results suggest that raising the GWL in peat grasslands to −20 cm creates such a risk. A constant GWL at the surface (0 cm) would be preferential for mitigating both CO₂ and N₂O emissions, although such conditions don’t allow for agricultural grass production (mowing or grazing).</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142321973","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":"Global meta-analysis reveals differential effects of climate and litter quality on soil fauna-mediated litter decomposition across size classes","authors":"Kaiyu Li ,&nbsp;Lihong Song ,&nbsp;Qinyao Ran ,&nbsp;Fang Yuan ,&nbsp;Chengjia Deng ,&nbsp;Hongyan Liu","doi":"10.1016/j.geoderma.2024.117042","DOIUrl":"10.1016/j.geoderma.2024.117042","url":null,"abstract":"<div><div>Litter decomposition is significantly influenced by soil fauna, litter quality, and climate. Effects of soil fauna on litter decomposition are largely dependent on the size classes of the fauna. However, the understanding of how different soil fauna groups affect litter decomposition remains elusive. In this study, we conducted a global <em>meta</em>-analysis of experiments using litterbags with varying mesh sizes to quantify the contributions of mesofauna and macrofauna to litter decomposition by calculating log response ratios. Additionally, we quantitatively assessed how climatic conditions and litter quality influence the effect of these two faunal size classes on litter decomposition. Our findings demonstrated that mesofauna and macrofauna increased litter decomposition by an average of 12.25% and 22.14%, respectively. Furthermore, the relative increase in litter decomposition induced by mesofauna and macrofauna exhibited a significant statistical difference on a global scale. Specifically, in dry and temperate climatics, the effect of soil macrofauna on litter decomposition was significantly greater than that of mesofauna. Climatic conditions, particularly temperature and precipitation, were the primary factors influencing litter decomposition by both mesofauna and macrofauna. In contrast, litter quality significantly influenced decomposition only by macrofauna in dry and tropical climatic conditions. Our findings underscore that the relative increase in litter decomposition rates to mesofauna and macrofauna differed significantly on a global scale and that the climate and litter quality differentially regulate litter decomposition across faunal size classes.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0016706124002714/pdfft?md5=37cd64a6b7f71dd660246977814b5dc3&pid=1-s2.0-S0016706124002714-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316036","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":"Mesoscale soil moisture measurements along the rover route using the mobile cosmic-ray neutron sensing in the eastern Tibetan Plateau","authors":"Yongyong Zhang ,&nbsp;Shaoxiong Wu ,&nbsp;Wenzhi Zhao ,&nbsp;Jianhua Xiao","doi":"10.1016/j.geoderma.2024.117046","DOIUrl":"10.1016/j.geoderma.2024.117046","url":null,"abstract":"<div><div>Water resources in the soil play an essential role in hydrological processes and ecosystem functions on the Tibetan Plateau. However, accurately measuring soil moisture distribution in this region presents challenges due to the diverse ecosystem types, complex terrain, and harsh environmental conditions. In this study, we introduce an approach for estimating mesoscale soil moisture in the Qilian Mountains (QLM) region of the eastern Tibetan Plateau using a cosmic-ray neutron rover. Soil moisture estimates derived from neutron count rates, newly adjusted by vegetation effects, demonstrated good agreement with soil moisture measurements obtained through soil sampling at 26 calibration sites across the region (RMSE = 0.025 g g⁻¹). The calibration parameter N₀_NDVI was 443 cpm in the QLM. Utilizing NDVI as vegetation correction method showed potential improvements in the accuracy of converting neutron counts to soil moisture across the diverse mountainous ecosystem types. The newly developed calibration equation provided a high-precision, high spatial resolution soil moisture transect across various landscapes measured by the rover. The average mesoscale soil moisture along the rover route varied by ecosystem types, with values of 0.10 g/g in deserts, 0.17 g/g in grasslands, 0.13 g/g in forests, 0.18 g/g in subalpine shrublands, and 0.20 g/g in croplands. Land cover types emerged as crucial determinants of mesoscale soil moisture variability in the QLM region. These findings offer valuable mesoscale soil moisture data and new insights into soil water information at the transect scale across diverse ecosystem types in the Tibetan Plateau.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320108","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":"Changes in plant resource inputs lead to rapid alterations in soil dissolved organic matter composition in an old-growth tropical forest","authors":"Guoxiang Niu ,&nbsp;Gege Yin ,&nbsp;Junjian Wang ,&nbsp;Peng Zhang ,&nbsp;Yingxue Xuan ,&nbsp;Qinggong Mao ,&nbsp;Weibin Chen ,&nbsp;Xiankai Lu","doi":"10.1016/j.geoderma.2024.117047","DOIUrl":"10.1016/j.geoderma.2024.117047","url":null,"abstract":"<div><div>Alterations in plant resource inputs to soil affect soil organic matter (OM) dynamics. However, it remains unclear how to alter soil dissolved OM (DOM) composition. Here, we used UV/fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry to analyze soil DOM’s optical and molecular characteristics after eight months of detritus input and removal in an old-growth tropical forest. Changes in plant inputs significantly altered soil DOM’s optical properties, and the most pronounced changes were observed in the humification index and fluorescent components. In litterfall removal and no-input plots, molecular characteristic values increased greatly, such as O/C, double-bond equivalent, aromaticity index, and proportion of carboxyl-rich alicyclic molecules, while biolabile compounds decreased. The abundance of lignin-like and tannin-like compounds was more than 20 % higher in litter removal plots than in no-input plots. Our findings indicate that changes in plant resource inputs can lead to rapid alterations in soil DOM composition.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320109","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":"Forest catchment structure mediates shallow subsurface flow and soil base cation fluxes","authors":"Amanda Pennino ,&nbsp;Brian D. Strahm ,&nbsp;Kevin J. McGuire ,&nbsp;Jennifer A. Bower ,&nbsp;Scott W. Bailey ,&nbsp;Madeline E. Schreiber ,&nbsp;Donald S. Ross ,&nbsp;Stephanie A. Duston ,&nbsp;Joshua R. Benton","doi":"10.1016/j.geoderma.2024.117045","DOIUrl":"10.1016/j.geoderma.2024.117045","url":null,"abstract":"<div><div>Hydrologic behavior and soil properties across forested landscapes with complex topography exhibit high variability. The interaction of groundwater with spatially distinct soils produces and transports solutes across catchments, however, the spatiotemporal relationships between groundwater dynamics and soil solute fluxes are difficult to directly evaluate. While whole-catchment export of solutes by shallow subsurface flow represents an integration of soil environments and conditions but many studies compartmentalize soil solute fluxes as hillslope vs. riparian, deep vs. shallow, or as individual soil horizon contributions. This potentially obscures and underestimates the hillslope variation and magnitude of solute fluxes and soil development across the landscape. This study determined the spatial variation and of shallow soil base cation fluxes associated with weathering reactions (Ca, Mg, and Na), soil elemental depletion, and soil saturation dynamics in upland soils within a small, forested watershed at the Hubbard Brook Experimental Forest, NH. Base cation fluxes were calculated using a combination of ion-exchange resins placed in shallow groundwater wells (0.3 – 1 m depth) located across hillslope transects (ridges to lower backslopes) and measurements of groundwater levels. Groundwater levels were also used to create metrics of annual soil saturation. Base cation fluxes were positively correlated with soil saturation frequency and were greatest in soil profiles where primary minerals were most depleted of base cations (i.e., highly weathered). Spatial differences in soil saturation across the catchment were strongly related to topographic properties of the upslope drainage area and are interpreted to result from spatial variations in transient groundwater dynamics. Results from this work suggest that the structure of a catchment defines the spatial architecture of base cation fluxes, likely reflecting the mediation of subsurface stormflow dynamics on soil development. Furthermore, this work highlights the importance of further compartmentalizing solute fluxes along hillslopes, where certain areas may disproportionately contribute solutes to the whole catchment. Refining catchment controls on base cation generation and transport could be an important tool for opening the black box of catchment elemental cycling.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320107","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 Soil Organic Carbon using multitemporal PRISMA imaging spectroscopy data","authors":"Kathrin J. Ward ,&nbsp;Saskia Foerster ,&nbsp;Sabine Chabrillat","doi":"10.1016/j.geoderma.2024.117025","DOIUrl":"10.1016/j.geoderma.2024.117025","url":null,"abstract":"<div><div>Soils are the largest terrestrial carbon pool and a valuable good that provides important ecosystem services. Since soils are threatened by degradation and in order to fight climate change the knowledge of the status quo especially of its soil organic carbon (SOC) content is required. A promising tool to map and monitor our soils are spaceborne imaging spectrometers which are able to produce up-to-date, inexpensive and spatially explicit maps. Especially the recent launch of new imaging spectroscopy sensors with a high signal-to-noise ratio opens up new possibilities. One of those is the combination of multitemporal spaceborne imaging spectroscopy data into SOC composite maps with a higher spatial coverage. This study explores different multitemporal combination workflows in order to support finding a best practice. To our knowledge for the first time, a spatially more complete SOC composite map was generated using four PRISMA images recorded over the same study site in northern Germany. Two different workflows of computation were compared: workflow one, creates a synthetical bare soil composite using averaged spectra as a basis for model development. Workflow two uses compositing after individual SOC modeling for each image. Within these workflows, different approaches were tested to estimate the SOC content, amongst them are a range of SOC spectral features and a two-step local PLSR which replaces the wet-chemistry SOC analyses for model calibration and validation by laboratory spectra and a large scale soil spectral library. Results show that the best method to produce a multitemporal composite SOC map based on imaging spectroscopy data was workflow two: the SOC maps composite, using the SOC spectral feature approach (R<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> = 0.83, RPD = 2.42). While workflow two and the traditional PLSR approach was more robust for all input dates (R<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> = 0.79, RPD = 2.21). Best results of the single images reached R<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> values of 0.76-0.91 and RPD values ranging between 2.06-3.42. Three of the tested SOC spectral features provided accuracies comparable to the modeling approaches. These results are promising regarding the improvement of the spatial coverage and the refinement of the mapping and monitoring of SOC and other soil parameters. Further investigations in this direction are needed as they are precursors of what will be feasible by upcoming operational imaging spectroscopy missions with increased availability.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0016706124002544/pdfft?md5=78bfac29bb6aca950664fba31be8a851&pid=1-s2.0-S0016706124002544-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316028","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":"Monitoring long-term peat subsidence with subsidence platens in Zegveld, The Netherlands","authors":"Harry T.L. Massop ,&nbsp;Rudi Hessel ,&nbsp;Jan J.H. van den Akker ,&nbsp;Sanneke van Asselen ,&nbsp;Gilles Erkens ,&nbsp;Paul A. Gerritsen ,&nbsp;Frank H.G.A. Gerritsen","doi":"10.1016/j.geoderma.2024.117039","DOIUrl":"10.1016/j.geoderma.2024.117039","url":null,"abstract":"<div><div>Peat oxidation in peat meadow areas is causing greenhouse gas emissions as well as land subsidence. Due to yearly fluctuations in soil surface level, long-term monitoring is needed to determine long-term net subsidence rates. In the experimental peat-meadow farm at Zegveld (NL) subsidence platens were installed in 1970 in a field with low ditchwater level, and in 1973 in a field with high ditchwater level. Platens were installed at 7 different depths, allowing to investigate where in the peat profile subsidence occurs. Elevation of platens as well as soil surface has been measured with surveyor’s levelling each year at the end of winter, so that a long timeseries up to 2023 is available. Analysis showed that surface level in the field with high ditchwater level subsided by 24 cm in 50 years (4.8 mm/yr), while in the field with low ditchwater level this was 31 cm in 53 years (5.8 mm/yr). Results also indicated that in the field with low ditchwater level, most subsidence due to permanent shrinkage and peat oxidation occurred between 40 and 100 cm depth, while for the other field this was between 0 and 20 and between 40 and 60 cm depth. Finally, in 2023 subsidence was still observed under continuously saturated conditions at 140 cm depth. Presumably, in the aerated part of the profile peat oxidation and the associated earthification process is the main cause of subsidence, while the observed subsidence in the saturated soil at 140 cm depth must be due to other processes, such as consolidation and creep.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0016706124002684/pdfft?md5=7e668e4d4993534c965d518e26fc42fa&pid=1-s2.0-S0016706124002684-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316027","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":"Unraveling the threshold and interaction effects of environmental variables on soil organic carbon mapping in plateau watershed","authors":"Chi Zhang ,&nbsp;Yiyun Chen ,&nbsp;Yujiao Wei ,&nbsp;Peiheng Yu ,&nbsp;Yongsheng Hong ,&nbsp;Yazhen Hu ,&nbsp;Jiaxue Wang ,&nbsp;Zhou Shi","doi":"10.1016/j.geoderma.2024.117032","DOIUrl":"10.1016/j.geoderma.2024.117032","url":null,"abstract":"<div><div>Understanding the spatial distribution and mechanisms driving soil organic carbon (SOC) is crucial for assessing soil carbon stocks and implementing effective carbon sequestration strategies in agricultural landscapes. The linear and nonlinear relationships between environmental variables and SOC have been extensively documented, but the threshold and interaction effects among multiple covariates on SOC remain underexplored. This study focused on farmland within the Qilu Lake watershed in Yunnan Province, China, which is characterized by complex surface conditions shaped by both climate change and anthropogenic activities. Utilizing 216 soil samples from the watershed, this research aimed to investigate the threshold and interaction effects of environmental variables on SOC. To achieve this, gradient boosted decision tree (GBDT) combined with partial dependence analysis were employed to elucidate the spatial distribution of SOC and the intricate relationships between environmental factors and SOC. In order to enhance the accuracy of SOC prediction, we employed the landscape metrics as environmental variables, thereby facilitating a more comprehensive description of the landscape. The results indicated that GBDT (R² = 0.47) outperformed random forest (R² = 0.38), achieving higher accuracy and lower uncertainty, indicated by a narrower 90% prediction interval. The SOC distribution was predominantly influenced by soil moisture, elevation, and the contagion index (CONTAG), with threshold effects observed at relatively high soil moisture levels (&gt;50%), CONTAG levels (&gt;85%), and relatively low elevations (&lt;1812 m). Moreover, the nonlinear relationship between one environmental variable and SOC could be influenced by another, suggesting interaction effects rather than a simple additive effect. Our findings suggest that combining GBDT modeling with partial dependence analysis provides an efficient and interpretable approach for SOC mapping. Knowledge of the threshold and interaction effects is critical for understanding the complex relationships between environmental variables and SOC, which has important implications for soil carbon management.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0016706124002611/pdfft?md5=649aa0496d11084d6f9b7432da293470&pid=1-s2.0-S0016706124002611-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142275681","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}