Pub Date : 2025-01-29DOI: 10.1016/j.geoderma.2025.117190
Yangyang Zhang, Xiao-yan Li, Fang Liu
Understanding the seasonal origins of mobile soil water (MSW) is critical for assessing the response of water movement to freeze–thaw, particularly in vulnerable alpine hillslope. However, the dominant factors determining the seasonal origins of MSW across different spatiotemporal scales remain poorly understood. To identify these origins under different freeze–thaw stages and topographic conditions, field samples were collected from the south, north, and valley regions of the northeastern Qinghai-Tibet Plateau from May to September 2022. We analyzed the dominant factors influencing the seasonal origins of MSW across topographies using a random forest regression model and explored causal relationships among factors through a structural equation model. Our results reveal dynamic changes in the seasonal origins of MSW and highlight key influencing factors under varying dry and wet conditions due to topographic heterogeneity. Specifically, (1) uneven seasonal precipitation, combined with substantial summer rainfall, results in summer precipitation accounting for 81 % of MSW replenishment. As melting progresses, the contribution from winter precipitation increases from 11 % in June to 23 % in September, indicating greater winter input at the watershed outlet in later seasons; (2) shallow MSW is replenished by both recent and antecedent summer precipitation, while deep MSW is primarily sustained by antecedent summer precipitation, emphasizing the significant role of summer precipitation in shallow MSW; and (3) under low soil water content (south slope), dynamic climate factors such as relative humidity and precipitation significantly influence precipitation infiltration, making them critical for determining the seasonal origins of MSW. In contrast, under high soil water content conditions (north slope and valley), static topographic heterogeneities influence water pathways, thus playing a dominant role in the seasonal sources of MSW.
{"title":"Seasonal soil water origins and determinants in an alpine hillslope on the northeastern Qinghai-Tibet Plateau","authors":"Yangyang Zhang, Xiao-yan Li, Fang Liu","doi":"10.1016/j.geoderma.2025.117190","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117190","url":null,"abstract":"Understanding the seasonal origins of mobile soil water (MSW) is critical for assessing the response of water movement to freeze–thaw, particularly in vulnerable alpine hillslope. However, the dominant factors determining the seasonal origins of MSW across different spatiotemporal scales remain poorly understood. To identify these origins under different freeze–thaw stages and topographic conditions, field samples were collected from the south, north, and valley regions of the northeastern Qinghai-Tibet Plateau from May to September 2022. We analyzed the dominant factors influencing the seasonal origins of MSW across topographies using a random forest regression model and explored causal relationships among factors through a structural equation model. Our results reveal dynamic changes in the seasonal origins of MSW and highlight key influencing factors under varying dry and wet conditions due to topographic heterogeneity. Specifically, (1) uneven seasonal precipitation, combined with substantial summer rainfall, results in summer precipitation accounting for 81 % of MSW replenishment. As melting progresses, the contribution from winter precipitation increases from 11 % in June to 23 % in September, indicating greater winter input at the watershed outlet in later seasons; (2) shallow MSW is replenished by both recent and antecedent summer precipitation, while deep MSW is primarily sustained by antecedent summer precipitation, emphasizing the significant role of summer precipitation in shallow MSW; and (3) under low soil water content (south slope), dynamic climate factors such as relative humidity and precipitation significantly influence precipitation infiltration, making them critical for determining the seasonal origins of MSW. In contrast, under high soil water content conditions (north slope and valley), static topographic heterogeneities influence water pathways, thus playing a dominant role in the seasonal sources of MSW.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"30 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.geoderma.2025.117189
Timothy J. Philpott, Gabriel Danyagri, Brian Wallace, Mae Frank
The growing frequency, extent and severity of wildfire is destabilizing carbon sinks in western North America, underscoring an urgent need to better understand fire impacts on soil carbon stocks, carbon stability, and fungi that regulate soil carbon cycling. Here, we examined the effects of wildfire two years post-burn on soil carbon and fungal communities across a fire severity gradient in Douglas-fir forests in central British Columbia, Canada. We observed no significant differences in soil carbon or fungal community composition between low-severity and unburned stands. In contrast, high-severity wildfire resulted in a 49 % reduction in belowground carbon stocks (20.7 Mg C·ha−1), a 91 % decline in ectomycorrhizal fungi, 5- to 27-fold increases in pathogenic fungi, and a proliferation of pyrophilous taxa compared to unburned stands. Carbon was lost primarily as light particulate organic matter, whereas impacts to mineral-associated carbon were muted. Pyrogenic carbon preferentially associated with the mineral fraction, modestly increasing (∼0.15 Mg C·ha−1) the proportion of carbon resistant to decay in this stable fraction. Select helotialean (e.g. Phialocephala fortinii) and other pyrophilous taxa were well-correlated with pyrogenic carbon, suggesting this consortium is well-adapted to decompose persistent carbon and will likely continue to mineralize soil carbon even after high severity wildfire. The markedly higher abundance of pathogenic fungi and reduced ectomycorrhizal abundance in stands affected by high-severity fires pose risks to post-fire recovery, particularly if pathogen proliferation reduces conifer fitness. These results highlight that low-severity wildfires have comparatively muted impacts on soil carbon and fungal communities relative to high-severity wildfires, underscoring the importance of management strategies such as thinning and prescribed burns to mitigate the catastrophic effects of high-severity wildfires.
{"title":"Low-severity wildfire prevents catastrophic impacts on fungal communities and soil carbon stability in a fire-affected Douglas-fir ecosystem","authors":"Timothy J. Philpott, Gabriel Danyagri, Brian Wallace, Mae Frank","doi":"10.1016/j.geoderma.2025.117189","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117189","url":null,"abstract":"The growing frequency, extent and severity of wildfire is destabilizing carbon sinks in western North America, underscoring an urgent need to better understand fire impacts on soil carbon stocks, carbon stability, and fungi that regulate soil carbon cycling. Here, we examined the effects of wildfire two years post-burn on soil carbon and fungal communities across a fire severity gradient in Douglas-fir forests in central British Columbia, Canada. We observed no significant differences in soil carbon or fungal community composition between low-severity and unburned stands. In contrast, high-severity wildfire resulted in a 49 % reduction in belowground carbon stocks (20.7 Mg C·ha<ce:sup loc=\"post\">−1</ce:sup>), a 91 % decline in ectomycorrhizal fungi, 5- to 27-fold increases in pathogenic fungi, and a proliferation of pyrophilous taxa compared to unburned stands. Carbon was lost primarily as light particulate organic matter, whereas impacts to mineral-associated carbon were muted. Pyrogenic carbon preferentially associated with the mineral fraction, modestly increasing (∼0.15 Mg C·ha<ce:sup loc=\"post\">−1</ce:sup>) the proportion of carbon resistant to decay in this stable fraction. Select helotialean (e.g. <ce:italic>Phialocephala fortinii</ce:italic>) and other pyrophilous taxa were well-correlated with pyrogenic carbon, suggesting this consortium is well-adapted to decompose persistent carbon and will likely continue to mineralize soil carbon even after high severity wildfire. The markedly higher abundance of pathogenic fungi and reduced ectomycorrhizal abundance in stands affected by high-severity fires pose risks to post-fire recovery, particularly if pathogen proliferation reduces conifer fitness. These results highlight that low-severity wildfires have comparatively muted impacts on soil carbon and fungal communities relative to high-severity wildfires, underscoring the importance of management strategies such as thinning and prescribed burns to mitigate the catastrophic effects of high-severity wildfires.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"14 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.geoderma.2025.117166
Ivan Šimkovic, Andrej Hrabovský, Adela Joanna Hamerníková, Silvia Ihnačáková, Pavel Dlapa
Although it has been recognized that soil structure formation affects soil organic carbon (SOC) sequestration, experimental data elucidating the relation between mechanical properties of soil structure and soil organic matter (SOM) stability are lacking. This study assesses the link between aggregate stability and SOM stability in lowland and hilly land soils of Central Europe. Overall, 39 topsoil samples were taken. Besides determining basic properties and nutrient availability, stability of soil aggregates was quantified using wet sieving (WS) and rainfall simulation (RS) procedures. The samples were analyzed by thermogravimetry and differential scanning calorimetry (TG-DSC). Besides significant correlations with basic soil properties and contents of selected nutrients, the aggregate stability data were linked to thermal processes, such as water desorption and SOM degradation. The RS values were significantly correlated (r > 0.7, p < 0.001) with the rate of water desorption (T < 200 °C) and SOM degradation (200 – 570 °C). Observed correlation pattern, with multiple maxima, suggests that aggregate stability is supported by clay and several SOM fractions, each showing different thermal stability. Significant correlations observed bellow 200 °C indicate that properties controlling soil specific surface area (SOM and clay) are important also for the aggregate stability. The 78 % of the variance observed in aggregate stability testing was explained by multilinear regression using weight loss rates recorded at selected temperatures (80, 130, 248, 401 and 455 °C) as predictors. We observed different relations between exothermic energy values, soil aggregate stability and thermal stability of SOM (SOC). Exothermic heat flux normalized with respect to SOC mass (energy density) indicates presence of stable organic fraction, as it showed correlation also with clay, which has positive effect on SOC stabilization. This is in line with the positive correlation between SOC energy density and aggregate stability. On contrary, normalizing the heat with respect to SOM mass indicates the content of labile organic components, as the correlations with clay or aggregate stability were insignificant. The TG-DSC data revealed that hilly land soils are depleted in fresh organic material, which is due to their genesis and the erosion intensified by tillage.
{"title":"Thermogravimetric data suggest synergy between different organic fractions and clay in soil structure formation","authors":"Ivan Šimkovic, Andrej Hrabovský, Adela Joanna Hamerníková, Silvia Ihnačáková, Pavel Dlapa","doi":"10.1016/j.geoderma.2025.117166","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117166","url":null,"abstract":"Although it has been recognized that soil structure formation affects soil organic carbon (SOC) sequestration, experimental data elucidating the relation between mechanical properties of soil structure and soil organic matter (SOM) stability are lacking. This study assesses the link between aggregate stability and SOM stability in lowland and hilly land soils of Central Europe. Overall, 39 topsoil samples were taken. Besides determining basic properties and nutrient availability, stability of soil aggregates was quantified using wet sieving (WS) and rainfall simulation (RS) procedures. The samples were analyzed by thermogravimetry and differential scanning calorimetry (TG-DSC). Besides significant correlations with basic soil properties and contents of selected nutrients, the aggregate stability data were linked to thermal processes, such as water desorption and SOM degradation. The RS values were significantly correlated (r > 0.7, p < 0.001) with the rate of water desorption (T < 200 °C) and SOM degradation (200 – 570 °C). Observed correlation pattern, with multiple maxima, suggests that aggregate stability is supported by clay and several SOM fractions, each showing different thermal stability. Significant correlations observed bellow 200 °C indicate that properties controlling soil specific surface area (SOM and clay) are important also for the aggregate stability. The 78 % of the variance observed in aggregate stability testing was explained by multilinear regression using weight loss rates recorded at selected temperatures (80, 130, 248, 401 and 455 °C) as predictors. We observed different relations between exothermic energy values, soil aggregate stability and thermal stability of SOM (SOC). Exothermic heat flux normalized with respect to SOC mass (energy density) indicates presence of stable organic fraction, as it showed correlation also with clay, which has positive effect on SOC stabilization. This is in line with the positive correlation between SOC energy density and aggregate stability. On contrary, normalizing the heat with respect to SOM mass indicates the content of labile organic components, as the correlations with clay or aggregate stability were insignificant. The TG-DSC data revealed that hilly land soils are depleted in fresh organic material, which is due to their genesis and the erosion intensified by tillage.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"12 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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 (Lolium perenne) 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.
{"title":"Rhizodeposition stimulates soil carbon decomposition and promotes formation of mineral-associated carbon with increased clay content","authors":"Md. Rumainul Islam, Bahareh Bicharanloo, Xing Yu, Balwant Singh, Feike A. Dijkstra","doi":"10.1016/j.geoderma.2025.117180","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117180","url":null,"abstract":"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 (<ce:italic>Lolium perenne</ce:italic>) in these soils in a glasshouse. After 76 days, plants were pulse-labelled with <ce:sup loc=\"post\">13</ce:sup>C-enriched CO<ce:inf loc=\"post\">2</ce:inf> 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.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"59 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-27","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.geoderma.2025.117188
Jie Chen, Xin Tang, Han Xu, Yanpeng Li, Adriana Corrales, Yide Li, Yakov Kuzyakov, Zhanfeng Liu, Shirong Liu
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.
{"title":"Mycorrhizal and nutrient controls of carbon sequestration in tropical rainforest soil","authors":"Jie Chen, Xin Tang, Han Xu, Yanpeng Li, Adriana Corrales, Yide Li, Yakov Kuzyakov, Zhanfeng Liu, Shirong Liu","doi":"10.1016/j.geoderma.2025.117188","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117188","url":null,"abstract":"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 NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup> 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 NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>) 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.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"32 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-27","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-26DOI: 10.1016/j.geoderma.2025.117179
Péter Sipos, Ivett Kovács, Adrienn Tóth, Péter Németh, Attila Demény
Although both ferromanganese and calcareous nodules are common in hydromorphic soils, their joint presence has rarely been evaluated. Studying their occurrence in soils forming toposequences may significantly contribute to a better understanding of their formation. We investigated the relationship between their formations in four soil profiles from a salt affected toposequence through mineralogical, micro-fabric, micro-chemical, morphological, and stable isotope analyses.
{"title":"Paragenetic relationship between ferromanganese and calcareous nodules in a hydromorphic toposequence","authors":"Péter Sipos, Ivett Kovács, Adrienn Tóth, Péter Németh, Attila Demény","doi":"10.1016/j.geoderma.2025.117179","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117179","url":null,"abstract":"Although both ferromanganese and calcareous nodules are common in hydromorphic soils, their joint presence has rarely been evaluated. Studying their occurrence in soils forming toposequences may significantly contribute to a better understanding of their formation. We investigated the relationship between their formations in four soil profiles from a salt affected toposequence through mineralogical, micro-fabric, micro-chemical, morphological, and stable isotope analyses.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"37 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Improvements in stocks and stability of forest soil organic carbon can be achieved through the management of tree species. Given the long lifespan of trees and their role as the keystone species in forested ecosystems, decisions regarding tree species management can have a significant impact on soil carbon balance, with effects that may persist for decades. Here, a common garden experiment involving five temperate tree species in northeast China was conducted to quantify the influence of tree species on soil carbon dynamics, including its fractions (mineral-associated organic carbon, particulate organic carbon, and microbial necromass carbon), microbial properties (biomass and activities), and the temperature sensitivity of soil carbon decomposition (Q10). We observed that the decomposition of high-quality litter by soil microbes resulted in increased microbial biomass but decreased microbial biomass-specific enzyme activities and respiration. Although there was no significant difference in soil carbon among tree species, the sources of soil carbon varied among species. Specifically, tree species producing high-quality litter contributed to elevated microbial and fungal necromass carbon. Microbial necromass carbon was positively correlated with soil mineral-associated organic carbon, although tree species had no significant effect on mineral-associated organic carbon. The Q10 increased with longer litter turnover time, as well as with higher microbial biomass-specific oxidase activity and respiration, but decreased with greater litterfall production, microbial biomass, and microbial necromass carbon. Overall, our findings indicate that fast-decaying tree litter increases soil microbial necromass carbon and decreases Q10. This is the first study to establish a connection between Q10 with microbial necromass carbon using experimental data. Moreover, the tree species-specific origins of soil carbon and their influence on Q10 should be considered when managing forests as carbon sinks in the context of future global warming.
{"title":"Fast-decaying tree litter reduces the temperature sensitivity of soil carbon decomposition by increasing microbial necromass carbon","authors":"Ruihan Li, Chuankuan Wang, Chunhua Lv, Tao Zhou, Shuang Yin, Zhenghu Zhou","doi":"10.1016/j.geoderma.2025.117185","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117185","url":null,"abstract":"Improvements in stocks and stability of forest soil organic carbon can be achieved through the management of tree species. Given the long lifespan of trees and their role as the keystone species in forested ecosystems, decisions regarding tree species management can have a significant impact on soil carbon balance, with effects that may persist for decades. Here, a common garden experiment involving five temperate tree species in northeast China was conducted to quantify the influence of tree species on soil carbon dynamics, including its fractions (mineral-associated organic carbon, particulate organic carbon, and microbial necromass carbon), microbial properties (biomass and activities), and the temperature sensitivity of soil carbon decomposition (<ce:italic>Q</ce:italic><ce:inf loc=\"post\">10</ce:inf>). We observed that the decomposition of high-quality litter by soil microbes resulted in increased microbial biomass but decreased microbial biomass-specific enzyme activities and respiration. Although there was no significant difference in soil carbon among tree species, the sources of soil carbon varied among species. Specifically, tree species producing high-quality litter contributed to elevated microbial and fungal necromass carbon. Microbial necromass carbon was positively correlated with soil mineral-associated organic carbon, although tree species had no significant effect on mineral-associated organic carbon. The <ce:italic>Q</ce:italic><ce:inf loc=\"post\">10</ce:inf> increased with longer litter turnover time, as well as with higher microbial biomass-specific oxidase activity and respiration, but decreased with greater litterfall production, microbial biomass, and microbial necromass carbon. Overall, our findings indicate that fast-decaying tree litter increases soil microbial necromass carbon and decreases <ce:italic>Q</ce:italic><ce:inf loc=\"post\">10</ce:inf>. This is the first study to establish a connection between <ce:italic>Q</ce:italic><ce:inf loc=\"post\">10</ce:inf> with microbial necromass carbon using experimental data. Moreover, the tree species-specific origins of soil carbon and their influence on <ce:italic>Q</ce:italic><ce:inf loc=\"post\">10</ce:inf> should be considered when managing forests as carbon sinks in the context of future global warming.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"121 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding phosphorus (P) mobilization in “legacy P”-rich croplands is critical for sustainable agricultural P management. However, the role of soil organic carbon (SOC) quality (i.e., biochemical recalcitrance) in regulating the enzyme activity associated with microbial mineralization of organic P in such environments has not been extensively investigated. Therefore, in this study, upland Ultisols subjected to seven different fertilization regimens (i.e. no fertilizer, chemical N, P, NP, and NPK fertilizer, swine manure, and NPK plus swine manure) for 35 years were collected to clarify and quantify the effect of SOC quality on acid (ACP) and alkaline phosphatase (ALP) activities. The ratio between labile and recalcitrant C, an index of SOC quality, increased by 15.5 %– 22.9 % with manure application compared with the non-fertilized control, whereas it decreased by 1.94 %–18.5 % under chemical fertilizations. ACP activity was determined to be 3–6-fold greater than ALP activity in the same soil, and both were significantly greater under manure fertilization than the other regimens. A significant positive correlation was observed among SOC quality, phosphatase activities, the abundances of their encoding genes, and the compositional dissimilarities of corresponding functional bacterial communities. Soil nutrient content, SOC quality, and functional gene abundance were the predominant influencing factors regulating ACP activity rather than soil pH, nutrient stoichiometry, and the composition of functional bacterial community. This finding suggests that the increased ACP activity was strongly associated with the proliferation of functional taxa dominated by copiotrophs. In contrast, soil pH and the composition of functional bacterial community were the primary regulators of ALP activity, suggesting a mitigation of acidity-induced inhibition that promoted its enhancement. The findings of this study provide an empirical basis for manipulating microbial mineralization of organic P through the application of labile organic materials to maintain P bioavailability in fertilized croplands.
{"title":"Predominant effects of soil organic carbon quality on phosphatase activity in upland Ultisols under long-term fertilizations","authors":"Yunbin Jiang, Dexu Kuang, Wei Li, Cheng Han, Huan Deng, Kailou Liu, Shangshu Huang, Wenhui Zhong","doi":"10.1016/j.geoderma.2025.117186","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117186","url":null,"abstract":"Understanding phosphorus (P) mobilization in “legacy P”-rich croplands is critical for sustainable agricultural P management. However, the role of soil organic carbon (SOC) quality (i.e., biochemical recalcitrance) in regulating the enzyme activity associated with microbial mineralization of organic P in such environments has not been extensively investigated. Therefore, in this study, upland Ultisols subjected to seven different fertilization regimens (i.e. no fertilizer, chemical N, P, NP, and NPK fertilizer, swine manure, and NPK plus swine manure) for 35 years were collected to clarify and quantify the effect of SOC quality on acid (ACP) and alkaline phosphatase (ALP) activities. The ratio between labile and recalcitrant C, an index of SOC quality, increased by 15.5 %– 22.9 % with manure application compared with the non-fertilized control, whereas it decreased by 1.94 %–18.5 % under chemical fertilizations. ACP activity was determined to be 3–6-fold greater than ALP activity in the same soil, and both were significantly greater under manure fertilization than the other regimens. A significant positive correlation was observed among SOC quality, phosphatase activities, the abundances of their encoding genes, and the compositional dissimilarities of corresponding functional bacterial communities. Soil nutrient content, SOC quality, and functional gene abundance were the predominant influencing factors regulating ACP activity rather than soil pH, nutrient stoichiometry, and the composition of functional bacterial community. This finding suggests that the increased ACP activity was strongly associated with the proliferation of functional taxa dominated by copiotrophs. In contrast, soil pH and the composition of functional bacterial community were the primary regulators of ALP activity, suggesting a mitigation of acidity-induced inhibition that promoted its enhancement. The findings of this study provide an empirical basis for manipulating microbial mineralization of organic P through the application of labile organic materials to maintain P bioavailability in fertilized croplands.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-23DOI: 10.1016/j.geoderma.2025.117184
Li-Xue Qiu, Dong-Xing Guan, Yi-Wen Liu, Yu Luo, H. Henry Teng, Yakov Kuzyakov, Lena Q. Ma
Silicon (Si) and arbuscular mycorrhizal fungi (AMF) improve phosphorus (P) nutrition in crops, but the mechanisms underlying their interactive effects on P uptake by roots remain elusive. This study investigated the impact of Si and AMF (Rhizophagus irregularis DAOM) on P uptake at rice (Oryza sativa L.) late jointing stage grown in soils with low and high P availability (18.2 vs 62.1 mg P kg−1) under greenhouse conditions. Under low P availability, AMF increased P content in rice leaves and stems by 16.1 % and 11.8 %, respectively. However, simultaneous Si application with AMF inoculation counteracted this positive effect, reducing the P content in leaves and stems by 15.9 % and 8.28 %, respectively, compared to AMF alone, due to a 20.8 % decrease in AMF colonization rate. This reduction may be associated with Si deposition on root cell walls and increased competition between AMF and P-solubilizing bacteria (PSB). In contrast, under high P availability, the combination of Si and AMF increased stem P content by 8.42 % compared to AMF alone, linked to Si-induced raise in PSB abundance. This could strengthen cooperation between AMF and PSB, as AMF mycelial secretions provideeasily available carbon sources for PSB, and PSB dissolvedinsoluble P forms for AMF uptake. These findings highlight the crucial role of soil P availability in modulating the efficacy of Si and AMF co-application to increase P uptake during rice vegetative growth. Under low P availability, Si reduces AMF functioning by decreasing colonization rates, while under high P availability, Si reinforces the P-promoting effects of AMF by stimulating PSB abundance. This study emphasizes the importance of considering soil P status when developing strategies that employ Si and AMF to optimize P utilization in agroecosystems.
{"title":"Interactions of silicon and arbuscular mycorrhizal fungi on phosphorus uptake during rice vegetative growth","authors":"Li-Xue Qiu, Dong-Xing Guan, Yi-Wen Liu, Yu Luo, H. Henry Teng, Yakov Kuzyakov, Lena Q. Ma","doi":"10.1016/j.geoderma.2025.117184","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117184","url":null,"abstract":"Silicon (Si) and arbuscular mycorrhizal fungi (AMF) improve phosphorus (P) nutrition in crops, but the mechanisms underlying their interactive effects on P uptake by roots remain elusive. This study investigated the impact of Si and AMF (<ce:italic>Rhizophagus irregularis</ce:italic> DAOM) on P uptake at rice (<ce:italic>Oryza sativa</ce:italic> L.) late jointing stage grown in soils with low and high P availability (18.2 vs 62.1 mg P kg<ce:sup loc=\"post\">−1</ce:sup>) under greenhouse conditions. Under low P availability, AMF increased P content in rice leaves and stems by 16.1 % and 11.8 %, respectively. However, simultaneous Si application with AMF inoculation counteracted this positive effect, reducing the P content in leaves and stems by 15.9 % and 8.28 %, respectively, compared to AMF alone, due to a 20.8 % decrease in AMF colonization rate. This reduction may be associated with Si deposition on root cell walls and increased competition between AMF and P-solubilizing bacteria (PSB). In contrast, under high P availability, the combination of Si and AMF increased stem P content by 8.42 % compared to AMF alone, linked to Si-induced raise in PSB abundance. This could strengthen cooperation between AMF and PSB, as AMF mycelial secretions provide<ce:hsp sp=\"0.25\"></ce:hsp>easily available carbon sources for PSB, and PSB dissolved<ce:hsp sp=\"0.25\"></ce:hsp>insoluble P forms for AMF uptake. These findings highlight the crucial role of soil P availability in modulating the efficacy of Si and AMF co-application to increase P uptake during rice vegetative growth. Under low P availability, Si reduces AMF functioning by decreasing colonization rates, while under high P availability, Si reinforces the P-promoting effects of AMF by stimulating PSB abundance. This study emphasizes the importance of considering soil P status when developing strategies that employ Si and AMF to optimize P utilization in agroecosystems.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"158 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-22DOI: 10.1016/j.geoderma.2025.117172
Ryan D. Hangs, Jeff J. Schoenau, J.Diane Knight, Richard E. Farrell
Solid cattle manure amendments provide a low-cost alternative nutrient source to inorganic fertilizers, while providing a carbon input to the soil. The augmented soil organic carbon levels, however, may be largely offset by manure-related greenhouse gas (GHG) emissions. Soil nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions were measured at the landscape-scale in a Canadian prairie agricultural field supporting silage barley (Hordeum vulgare L.) production. Manure was applied to meet barley P requirements, while total N rate was supplemented using anhydrous ammonia. A non-manured control (NMC) also was included, to calculate N2O emission factors. The NMC zone consisted of an annual application of anhydrous ammonia at 80 kg N ha−1. In addition to solid cattle manure at a constant (CRM; 45 Mg ha−1) or variable (VRM; 0–72 Mg ha−1) rate, the manured treatment zones also received 80 kg N ha−1 of anhydrous ammonia. The VRM treatment included set-backs from the watershed basin centers in ephemeral wetlands that did not receive solid cattle manure. Gas samples were collected using chamber-based methodology, with chambers installed at 130 locations across six watershed basins (n = 2 per zone) during 2019–2021. Cumulative N2O emissions were 76 % (CRM) and 62 % (VRM) higher following manure addition. The normalized N2O emissions for CRM were 24 % greater than VRM and NMC, with CRM having 31 % larger manure-induced N2O emissions than VRM. Though all soils were net CH4 sinks, manure application reduced CH4 consumption by 33 % (CRM) and 25 % (VRM) compared with the NMC. Manure addition did not impact cumulative CO2 emissions. Although VRM application mitigated manure-related GHG emissions, enhanced GHG intensity following manure addition highlights the importance of ensuring balanced soil fertility, to support optimal crop growth and maximize yield-scaled GHG performance metrics in manured landscapes.
固体牛粪改良剂为无机肥料提供了一种低成本的替代营养源，同时为土壤提供了碳输入。然而，增加的土壤有机碳水平可能在很大程度上被与肥料有关的温室气体（GHG）排放所抵消。在景观尺度上测量了加拿大草原种植青贮大麦（Hordeum vulgare L.）农田土壤氧化亚氮（N2O）、甲烷（CH4）和二氧化碳（CO2）的排放。施粪肥满足大麦对磷的需求，施无水氨补充全氮。另设非施肥对照（NMC），计算N2O排放因子。NMC区每年施用80 kg N ha - 1的无水氨。除了恒定的固体牛粪(CRM；45 Mg ha−1)或可变(VRM；0 ~ 72 Mg ha−1)施氮量时，施氮处理区同时施80 kg N ha−1的无水氨。VRM处理包括来自短暂湿地的分水岭盆地中心的挫折，这些湿地没有接收固体牛粪。在2019-2021年期间，使用基于腔室的方法收集气体样本，在六个流域的130个地点安装了腔室（每个区域n = 2）。添加有机肥后，累积N2O排放量分别增加76% （CRM）和62% （VRM）。CRM的标准化N2O排放量比VRM和NMC高24%，其中CRM的粪便引起的N2O排放量比VRM高31%。虽然所有土壤都是CH4的净汇，但与NMC相比，施用有机肥减少了33% （CRM）和25% （VRM）的CH4消耗。添加粪肥对累积二氧化碳排放量没有影响。虽然施用VRM减轻了与肥料相关的温室气体排放，但增加肥料后的温室气体强度强调了确保土壤肥力平衡的重要性，以支持最佳作物生长和最大化肥料景观中按产量比例衡量的温室气体绩效指标。
{"title":"Variable rate precision application of feedlot cattle manure mitigates soil greenhouse gas emissions","authors":"Ryan D. Hangs, Jeff J. Schoenau, J.Diane Knight, Richard E. Farrell","doi":"10.1016/j.geoderma.2025.117172","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117172","url":null,"abstract":"Solid cattle manure amendments provide a low-cost alternative nutrient source to inorganic fertilizers, while providing a carbon input to the soil. The augmented soil organic carbon levels, however, may be largely offset by manure-related greenhouse gas (GHG) emissions. Soil nitrous oxide (N<ce:inf loc=\"post\">2</ce:inf>O), methane (CH<ce:inf loc=\"post\">4</ce:inf>), and carbon dioxide (CO<ce:inf loc=\"post\">2</ce:inf>) emissions were measured at the landscape-scale in a Canadian prairie agricultural field supporting silage barley (<ce:italic>Hordeum vulgare</ce:italic> L.) production. Manure was applied to meet barley P requirements, while total N rate was supplemented using anhydrous ammonia. A non-manured control (NMC) also was included, to calculate N<ce:inf loc=\"post\">2</ce:inf>O emission factors. The NMC zone consisted of an annual application of anhydrous ammonia at 80 kg N ha<ce:sup loc=\"post\">−1</ce:sup>. In addition to solid cattle manure at a constant (CRM; 45 Mg ha<ce:sup loc=\"post\">−1</ce:sup>) or variable (VRM; 0–72 Mg ha<ce:sup loc=\"post\">−1</ce:sup>) rate, the manured treatment zones also received 80 kg N ha<ce:sup loc=\"post\">−1</ce:sup> of anhydrous ammonia. The VRM treatment included set-backs from the watershed basin centers in ephemeral wetlands that did not receive solid cattle manure. Gas samples were collected using chamber-based methodology, with chambers installed at 130 locations across six watershed basins (n = 2 per zone) during 2019–2021. Cumulative N<ce:inf loc=\"post\">2</ce:inf>O emissions were 76 % (CRM) and 62 % (VRM) higher following manure addition. The normalized N<ce:inf loc=\"post\">2</ce:inf>O emissions for CRM were 24 % greater than VRM and NMC, with CRM having 31 % larger manure-induced N<ce:inf loc=\"post\">2</ce:inf>O emissions than VRM. Though all soils were net CH<ce:inf loc=\"post\">4</ce:inf> sinks, manure application reduced CH<ce:inf loc=\"post\">4</ce:inf> consumption by 33 % (CRM) and 25 % (VRM) compared with the NMC. Manure addition did not impact cumulative CO<ce:inf loc=\"post\">2</ce:inf> emissions. Although VRM application mitigated manure-related GHG emissions, enhanced GHG intensity following manure addition highlights the importance of ensuring balanced soil fertility, to support optimal crop growth and maximize yield-scaled GHG performance metrics in manured landscapes.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"12 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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