Pub Date : 2024-11-09DOI: 10.1016/j.geoderma.2024.117092
Quan Li , Chao Zhang , Man Shi , Jianhua Lv , Changhui Peng , Junbo Zhang , Scott X. Chang , Tingting Cao , Tong Li , Xinzhang Song
Soil respiration (Rs), a critical component of the global carbon (C) cycle, is sensitive to changes in nitrogen (N) deposition. However, the temporal dynamics of the effects of long-term (≥ five years) N addition and its cessation on Rs in forests remain uncertain. We conducted a continuous field experiment, which included three years of N cessation after seven years of N addition at different rates (0, 30, 60, and 90 kg N∙ha−1∙yr−1), in a subtropical Moso bamboo forest to explore the response of Rs and its components, determine the influence of biotic and abiotic factors to long-term N addition, and identify any legacy effects. We found a two-phase pattern of Rs, with a significant increase in the first two years across three N addition rates and a constant significant increase in the last five years across low and medium N addition; however, Rs did not change under high N addition. The nitrogen addition legacy effects significantly increased Rs and autotrophic respiration but reduced heterotrophic respiration, which could persist for at least three years. The mechanism underlying the temporal variation in Rs and its components was related to the increase in fine root biomass and changes in soil microbial biomass and bacteria to fungi ratio. These findings have advanced our understanding of soil CO2 dynamics in subtropical forests under N deposition. Moreover, they reveal that the legacy effects of long-term N addition should be incorporated into global C cycle modeling to reflect the persistent effects of N deposition on forest ecosystem C budgets.
{"title":"Long-term nitrogen addition has a positive legacy effect on soil respiration in subtropical Moso bamboo forests","authors":"Quan Li , Chao Zhang , Man Shi , Jianhua Lv , Changhui Peng , Junbo Zhang , Scott X. Chang , Tingting Cao , Tong Li , Xinzhang Song","doi":"10.1016/j.geoderma.2024.117092","DOIUrl":"10.1016/j.geoderma.2024.117092","url":null,"abstract":"<div><div>Soil respiration (Rs), a critical component of the global carbon (C) cycle, is sensitive to changes in nitrogen (N) deposition. However, the temporal dynamics of the effects of long-term (≥ five years) N addition and its cessation on Rs in forests remain uncertain. We conducted a continuous field experiment, which included three years of N cessation after seven years of N addition at different rates (0, 30, 60, and 90 kg N∙ha<sup>−1</sup>∙yr<sup>−1</sup>), in a subtropical Moso bamboo forest to explore the response of Rs and its components, determine the influence of biotic and abiotic factors to long-term N addition, and identify any legacy effects. We found a two-phase pattern of Rs, with a significant increase in the first two years across three N addition rates and a constant significant increase in the last five years across low and medium N addition; however, Rs did not change under high N addition. The nitrogen addition legacy effects significantly increased Rs and autotrophic respiration but reduced heterotrophic respiration, which could persist for at least three years. The mechanism underlying the temporal variation in Rs and its components was related to the increase in fine root biomass and changes in soil microbial biomass and bacteria to fungi ratio. These findings have advanced our understanding of soil CO<sub>2</sub> dynamics in subtropical forests under N deposition. Moreover, they reveal that the legacy effects of long-term N addition should be incorporated into global C cycle modeling to reflect the persistent effects of N deposition on forest ecosystem C budgets.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"452 ","pages":"Article 117092"},"PeriodicalIF":5.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659646","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}
Pub Date : 2024-11-05DOI: 10.1016/j.geoderma.2024.117093
Haichao Li , Elias S. Azzi , Cecilia Sundberg , Erik Karltun , Harald Cederlund
The long-term persistence of biochar in soil is often predicted by extrapolating mineralization data from short-term laboratory incubations. Single first-order, double first-order, triple first-order and power models have been employed for this purpose, all of which have an inherent assumption that biochar is biodegradable. However, recent insights challenge this assumption by suggesting that a large fraction of biochar is inert. If so, it would make sense to reflect this in the models used, by incorporating an inert carbon (C) pool. We hypothesized that such inert pool models would fit better to incubation data than existing models and give more reliable long-term predictions. We evaluated this by fitting the models to data from a recently compiled extensive dataset of biochar incubations. The inclusion of an inert pool enhanced the model fits over first-order models in most cases. However, inert pool models overestimated biochar persistence compared to the measured outcomes. By contrast, the double first-order model, which has been the most widely used to date, underestimated biochar persistence even in the short term. The power model in general outperformed all other models and gave the most reliable predictions, although it was sensitive to increasing or fluctuating mineralization rates in the datasets.
{"title":"Can inert pool models improve predictions of biochar long-term persistence in soils?","authors":"Haichao Li , Elias S. Azzi , Cecilia Sundberg , Erik Karltun , Harald Cederlund","doi":"10.1016/j.geoderma.2024.117093","DOIUrl":"10.1016/j.geoderma.2024.117093","url":null,"abstract":"<div><div>The long-term persistence of biochar in soil is often predicted by extrapolating mineralization data from short-term laboratory incubations. Single first-order, double first-order, triple first-order and power models have been employed for this purpose, all of which have an inherent assumption that biochar is biodegradable. However, recent insights challenge this assumption by suggesting that a large fraction of biochar is inert. If so, it would make sense to reflect this in the models used, by incorporating an inert carbon (C) pool. We hypothesized that such inert pool models would fit better to incubation data than existing models and give more reliable long-term predictions. We evaluated this by fitting the models to data from a recently compiled extensive dataset of biochar incubations. The inclusion of an inert pool enhanced the model fits over first-order models in most cases. However, inert pool models overestimated biochar persistence compared to the measured outcomes. By contrast, the double first-order model, which has been the most widely used to date, underestimated biochar persistence even in the short term. The power model in general outperformed all other models and gave the most reliable predictions, although it was sensitive to increasing or fluctuating mineralization rates in the datasets.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"452 ","pages":"Article 117093"},"PeriodicalIF":5.6,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593054","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}
Pub Date : 2024-11-05DOI: 10.1016/j.geoderma.2024.117090
Jin-Jian Xu , Chao-Sheng Tang , Yaowen Yang , Zhao-Jun Zeng , Lin Li , Qing Cheng , Xi-Ying Zhang , Bin Shi
Soil cracking induced by extreme drought represents a widespread natural phenomenon occurring across the earth surface, capable of triggering multiple weakening mechanisms within surface soils, potentially leading to the instability and failure of slopes and agricultural infrastructures. This study proposes an innovative geophysical monitoring framework for detecting field soil cracking by combining the actively heated fiber-optic (AHFO) method and distributed fibre optical sensing (DFOS) based on optical frequency domain reflectometry (OFDR) technique, referred to as AH-OFDR framework. Laboratory calibration tests, field monitoring tests, numerical simulations, and sensitivity analyses were employed to comprehensively evaluate the feasibility, effectiveness, and limitations of the AH-OFDR framework for soil crack monitoring. Laboratory calibration confirmed that the DFOS-OFDR technique achieves a minimum spatial resolution and readout accuracy of 1 mm, along with a temperature measurement accuracy of ±0.1 °C. Field monitoring verified that the AH-OFDR framework can accurately detect soil cracks ranging in width from 0.01 m to 0.12 m. Additionally, numerical simulations not only validated the effectiveness of the AH-OFDR framework across a broader range of crack widths, from 0.01 m to 0.50 m, but also established a quantitative relationship between temperature changes and the spatial distribution of crack positions and widths. Notably, a critical crack width threshold of 0.30 m was identified within the AH-OFDR framework, significantly impacting the prediction of soil crack widths. Sensitivity analysis demonstrated the remarkable crack detection capabilities of the AH-OFDR framework, irrespective of the soil crack width and spacing. The AH-OFDR framework holds substantial potential as an innovative and high-resolution observational method for advancing our understanding of diverse geological and hydrogeological processes.
{"title":"Monitoring soil cracking using OFDR-based distributed temperature sensing framework","authors":"Jin-Jian Xu , Chao-Sheng Tang , Yaowen Yang , Zhao-Jun Zeng , Lin Li , Qing Cheng , Xi-Ying Zhang , Bin Shi","doi":"10.1016/j.geoderma.2024.117090","DOIUrl":"10.1016/j.geoderma.2024.117090","url":null,"abstract":"<div><div>Soil cracking induced by extreme drought represents a widespread natural phenomenon occurring across the earth surface, capable of triggering multiple weakening mechanisms within surface soils, potentially leading to the instability and failure of slopes and agricultural infrastructures. This study proposes an innovative geophysical monitoring framework for detecting field soil cracking by combining the actively heated fiber-optic (AHFO) method and distributed fibre optical sensing (DFOS) based on optical frequency domain reflectometry (OFDR) technique, referred to as AH-OFDR framework. Laboratory calibration tests, field monitoring tests, numerical simulations, and sensitivity analyses were employed to comprehensively evaluate the feasibility, effectiveness, and limitations of the AH-OFDR framework for soil crack monitoring. Laboratory calibration confirmed that the DFOS-OFDR technique achieves a minimum spatial resolution and readout accuracy of 1 mm, along with a temperature measurement accuracy of ±0.1 °C. Field monitoring verified that the AH-OFDR framework can accurately detect soil cracks ranging in width from 0.01 m to 0.12 m. Additionally, numerical simulations not only validated the effectiveness of the AH-OFDR framework across a broader range of crack widths, from 0.01 m to 0.50 m, but also established a quantitative relationship between temperature changes and the spatial distribution of crack positions and widths. Notably, a critical crack width threshold of 0.30 m was identified within the AH-OFDR framework, significantly impacting the prediction of soil crack widths. Sensitivity analysis demonstrated the remarkable crack detection capabilities of the AH-OFDR framework, irrespective of the soil crack width and spacing. The AH-OFDR framework holds substantial potential as an innovative and high-resolution observational method for advancing our understanding of diverse geological and hydrogeological processes.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"452 ","pages":"Article 117090"},"PeriodicalIF":5.6,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142585975","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}
Pub Date : 2024-11-05DOI: 10.1016/j.geoderma.2024.117078
Sarah Fulton-Smith , Rebecca Even , M. Francesca Cotrufo
Agricultural practices that promote the formation of soil organic matter (SOM) are considered important climate change mitigation strategies by increasing resilience to climate shocks and promoting soil carbon sequestration. Efforts to increase root production and depth distribution through planting deep rooted crops and selective crop breeding have been identified as a promising strategy to achieve these goals. However, we lack a complete understanding of how the decomposition of roots in the deep soil (e.g., below 30 cm), contributes to SOM formation and stabilization. Here using unique soil-biomass microcosms in the field to trace 13C enriched root litter to a depth of 90 cm, we show that as decomposition dynamics change with depth, so do the SOM formation pathways. At our study site, root residues decomposed faster in the top 0–30 cm, achieving 97 % mass loss by 13 months of incubation compared to 77 % and 81 % in the 30–60 and 60–90 cm depths, respectively. Litter derived carbon (LDC) was preferentially recovered as stable mineral associated organic matter (MAOM), primarily within aggregates, with 67 % more in the 0–30 cm than in the 60–90 cm depth. At depth, root residues decomposed slower and accumulated as the less stable particulate organic matter (POM) within macroaggregates with 145 % more LDC recovered in light POM in the 60–90 cm depth than the 0–30 cm depth. We found that bulk SOM measurements were too coarse to elucidate the likely fate of newly incorporated litter in the soil, but our detailed fractionation demonstrated the relative contribution of new root inputs to functionally different SOM pools, MAOM and POM, and allowed us to interpret the role of microaggregates in these dynamics in new detail, particularly microaggregates within macroaggregates (i.e., occluded microaggregates). Our results highlight the importance of balancing the trade-off between MAOM and POM formation when considering strategies to enhance both carbon sequestration and soil health in agroecosystems. If POM is critical for aggregate formation and microaggregates play an important role in MAOM formation, efforts to increase soil carbon sequestration need to focus on both fractions and on supporting overall soil structure.
{"title":"Depth impacts on the aggregate-mediated mechanisms of root carbon stabilization in soil: Trade-off between MAOM and POM pathways","authors":"Sarah Fulton-Smith , Rebecca Even , M. Francesca Cotrufo","doi":"10.1016/j.geoderma.2024.117078","DOIUrl":"10.1016/j.geoderma.2024.117078","url":null,"abstract":"<div><div>Agricultural practices that promote the formation of soil organic matter (SOM) are considered important climate change mitigation strategies by increasing resilience to climate shocks and promoting soil carbon sequestration. Efforts to increase root production and depth distribution through planting deep rooted crops and selective crop breeding have been identified as a promising strategy to achieve these goals. However, we lack a complete understanding of how the decomposition of roots in the deep soil (e.g., below 30 cm), contributes to SOM formation and stabilization. Here using unique soil-biomass microcosms in the field to trace <sup>13</sup>C enriched root litter to a depth of 90 cm, we show that as decomposition dynamics change with depth, so do the SOM formation pathways. At our study site, root residues decomposed faster in the top 0–30 cm, achieving 97 % mass loss by 13 months of incubation compared to 77 % and 81 % in the 30–60 and 60–90 cm depths, respectively. Litter derived carbon (LDC) was preferentially recovered as stable mineral associated organic matter (MAOM), primarily within aggregates, with 67 % more in the 0–30 cm than in the 60–90 cm depth. At depth, root residues decomposed slower and accumulated as the less stable particulate organic matter (POM) within macroaggregates with 145 % more LDC recovered in light POM in the 60–90 cm depth than the 0–30 cm depth. We found that bulk SOM measurements were too coarse to elucidate the likely fate of newly incorporated litter in the soil, but our detailed fractionation demonstrated the relative contribution of new root inputs to functionally different SOM pools, MAOM and POM, and allowed us to interpret the role of microaggregates in these dynamics in new detail, particularly microaggregates within macroaggregates (i.e., occluded microaggregates). Our results highlight the importance of balancing the trade-off between MAOM and POM formation when considering strategies to enhance both carbon sequestration and soil health in agroecosystems. If POM is critical for aggregate formation and microaggregates play an important role in MAOM formation, efforts to increase soil carbon sequestration need to focus on both fractions and on supporting overall soil structure.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"452 ","pages":"Article 117078"},"PeriodicalIF":5.6,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586566","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}
Pub Date : 2024-11-01DOI: 10.1016/j.geoderma.2024.117086
Haifeng Yin , Yu Su , Jie Zeng , Xianwei Li , Chuan Fan , Jing-Zhong Lu , Zheng Zhou , Anwei Yu , Simin Wang , Stefan Scheu , Valentyna Krashevska
Soil biodiversity and the structure of soil animal communities are important foundations for forest ecosystem functions. Forest gap formation is an important forest management practice used to transform monocultures into mixed forests. However, whether and how gap size and age affect soil biodiversity and modify nematode communities remains limited. We manipulated gap size (100, 200, and 400 m2) in Pinus massoniana plantations and studied the communities of soil nematodes, bacteria, fungi, and understory plants two and four years after gap formation. Compared to the no-gap treatment, soil nematode abundance across forest gaps increased by a factor of 1.40, which was largely attributed to the increase in herbivorous nematodes as the abundance and diversity of understory plants increased. The increased abundance of soil nematodes in forest gaps was also associated with increased soil pH presumably related to reduced input of pine needles. Furthermore, the abundance (−5.3 %) and diversity (−25.1 %) of soil nematodes decreased with gap age, presumably because of increased soil temperature and decreased soil moisture in the four- compared to the two-year-old gaps. In contrast to nematodes, the abundance and diversity of soil bacteria (21.8 % and 7.1 %) and fungi (10.5 % and 10.0 %) increased significantly with gap age. Overall, forest gaps increased the diversity of understory plants and soil biota, and changed the community and functional group structure of soil nematodes. These results provide guidelines for fostering soil biodiversity and maintaining soil functioning when transforming coniferous forests into mixed forests.
{"title":"Forest gap regulates soil nematode community through understory plant diversity and soil pH","authors":"Haifeng Yin , Yu Su , Jie Zeng , Xianwei Li , Chuan Fan , Jing-Zhong Lu , Zheng Zhou , Anwei Yu , Simin Wang , Stefan Scheu , Valentyna Krashevska","doi":"10.1016/j.geoderma.2024.117086","DOIUrl":"10.1016/j.geoderma.2024.117086","url":null,"abstract":"<div><div>Soil biodiversity and the structure of soil animal communities are important foundations for forest ecosystem functions. Forest gap formation is an important forest management practice used to transform monocultures into mixed forests. However, whether and how gap size and age affect soil biodiversity and modify nematode communities remains limited. We manipulated gap size (100, 200, and 400 m<sup>2</sup>) in <em>Pinus massoniana</em> plantations and studied the communities of soil nematodes, bacteria, fungi, and understory plants two and four years after gap formation. Compared to the no-gap treatment, soil nematode abundance across forest gaps increased by a factor of 1.40, which was largely attributed to the increase in herbivorous nematodes as the abundance and diversity of understory plants increased. The increased abundance of soil nematodes in forest gaps was also associated with increased soil pH presumably related to reduced input of pine needles. Furthermore, the abundance (−5.3 %) and diversity (−25.1 %) of soil nematodes decreased with gap age, presumably because of increased soil temperature and decreased soil moisture in the four- compared to the two-year-old gaps. In contrast to nematodes, the abundance and diversity of soil bacteria (21.8 % and 7.1 %) and fungi (10.5 % and 10.0 %) increased significantly with gap age. Overall, forest gaps increased the diversity of understory plants and soil biota, and changed the community and functional group structure of soil nematodes. These results provide guidelines for fostering soil biodiversity and maintaining soil functioning when transforming coniferous forests into mixed forests.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"451 ","pages":"Article 117086"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560785","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}
Pub Date : 2024-11-01DOI: 10.1016/j.geoderma.2024.117088
Xu Gai , Xiaogang Li , Wenli Xing , Xiaoping Zhang , Guangcai Chen
Soil amendments enhance phytoremediation utilizing trees, have attracted considerable attention because of their low cost, great benefits and huge potential. It’s demonstrated that amendments facilitate the metal immobilization via adjusting soil pH and metal availability, while the underlying mechanism on amendments improving phytoremediation efficiency remains unclear. In our previous studies, the phytoremediation efficiency of Quercus spp. for Cd and Zn was improved by application of soil amendments in a three-year field trial located in Hangzhou, China. Here, we collected the soil samples from the above mentioned experiment and further compared the characteristics of the rhizosphere bacterial community of Quercus texana and Quercus fabri amended with rice straw biochar, palygorskite, and a combination of rice straw biochar and palygorskite in Cd- and Zn-contaminated soils. There were no significant differences in bacterial diversity between the Q. texana and Q. fabri, which were characterized by a high and low accumulation of heavy metals. However, rhizosphere bacterial network of both species exhibited significant responses to the different soil amendments. Combined biochar increased the complexity and stability of bacterial networks, which was manifested mainly as an increase in network cohesion, negative:positive cohesion, and robustness. Partial least squares path modeling demonstrated that network stability was directly influenced by complexity (path coefficient = 0.551, p < 0.05) and keystone taxa (path coefficient = -0.29, p < 0.05), where keystone taxa can serve as a significant predictor variable for network stability. Furthermore, network complexity and stability were significantly correlated with heavy metal accumulation in Quercus spp., suggesting potential linkages between microbial network properties and phytoremediation efficiency. Together, the results emphasize that combined biochar enhances the complexity and stability of rhizosphere bacterial network, ultimately improving phytoremediation efficiency and biomass. Lower network stability in the rice straw biochar and palygorskite treatments may pose ecological risks. These novel findings provide important insights into optimizing amendments to improve phytoremediation efficiency by affecting rhizosphere microbial interactions.
{"title":"Mechanism insights into amendments enhanced dendroremediation for Cd and Zn-polluted soil: Bacterial co-occurrence networks’ complexity and stability","authors":"Xu Gai , Xiaogang Li , Wenli Xing , Xiaoping Zhang , Guangcai Chen","doi":"10.1016/j.geoderma.2024.117088","DOIUrl":"10.1016/j.geoderma.2024.117088","url":null,"abstract":"<div><div>Soil amendments enhance phytoremediation utilizing trees, have attracted considerable attention because of their low cost, great benefits and huge potential. It’s demonstrated that amendments facilitate the metal immobilization via adjusting soil pH and metal availability, while the underlying mechanism on amendments improving phytoremediation efficiency remains unclear. In our previous studies, the phytoremediation efficiency of <em>Quercus</em> spp. for Cd and Zn was improved by application of soil amendments in a three-year field trial located in Hangzhou, China. Here, we collected the soil samples from the above mentioned experiment and further compared the characteristics of the rhizosphere bacterial community of <em>Quercus texana</em> and <em>Quercus fabri</em> amended with rice straw biochar, palygorskite, and a combination of rice straw biochar and palygorskite in Cd- and Zn-contaminated soils. There were no significant differences in bacterial diversity between the <em>Q. texana</em> and <em>Q. fabri</em>, which were characterized by a high and low accumulation of heavy metals. However, rhizosphere bacterial network of both species exhibited significant responses to the different soil amendments. Combined biochar increased the complexity and stability of bacterial networks, which was manifested mainly as an increase in network cohesion, negative:positive cohesion, and robustness. Partial least squares path modeling demonstrated that network stability was directly influenced by complexity (path coefficient = 0.551, <em>p</em> < 0.05) and keystone taxa (path coefficient = -0.29, <em>p</em> < 0.05), where keystone taxa can serve as a significant predictor variable for network stability. Furthermore, network complexity and stability were significantly correlated with heavy metal accumulation in <em>Quercus</em> spp., suggesting potential linkages between microbial network properties and phytoremediation efficiency. Together, the results emphasize that combined biochar enhances the complexity and stability of rhizosphere bacterial network, ultimately improving phytoremediation efficiency and biomass. Lower network stability in the rice straw biochar and palygorskite treatments may pose ecological risks. These novel findings provide important insights into optimizing amendments to improve phytoremediation efficiency by affecting rhizosphere microbial interactions.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"451 ","pages":"Article 117088"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552320","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}
Pub Date : 2024-11-01DOI: 10.1016/j.geoderma.2024.117084
Antonio Satriani , Claudia Belviso , Stella Lovelli , Simone di Prima , Antonio Coppola , Shawkat B.M. Hassan , Anna Rita Rivelli , Alessandro Comegna
The addition of natural or synthetic zeolites induces changes in a soil’s chemical, physical, and biological characteristics. Zeolites possess intricate internal frameworks that allow them to modify soil structure and texture, thereby impacting soil hydrological properties. This potential offers opportunities to control soil and groundwater pollution as well as optimize irrigation management practices. In this study, three sandy-loam soils and a silty-loam soil were collected and mixed with different amounts of synthetic zeolite derived from coal fly ash. Repacked soil samples were combined with four levels of zeolite ranging from 1% to 10% by weight and were then hydraulically characterized. This included measuring soil water retention curves (SWRCs) of soil-zeolite mixtures. The data revealed, in accordance with recent research findings, that zeolite influences the hydraulic behavior of soils. In general, we observed that, as the percentage of zeolite increases in the soil, the SWRCs are shifted upwards. This effect is fundamental for explaining the observed changes in the whole set of investigated soil hydraulic properties. The observed changes are also fundamental to evaluate selected soil physical quality (SPQ) indices of agronomic interest, which are investigated in depth in the present research. A specific focus was on the impact of zeolite on modifying the soil’s capacity to retain water, hence on the energy required by plants to acquire a unit mass of soil water (referred to as integral energy, EI). Finally, the ANOVA test, linear regression, and multivariate analysis were performed on the entire dataset to support, from a statistical standpoint, the observed correlations between SPQ indices and zeolite amounts. These findings underscored the significance of soil texture in selecting the appropriate soil type for zeolite amendment, confirming that coarse-textured soils are more suitable for zeolite treatment compared to fine-textured soils.
{"title":"Impact of a synthetic zeolite mixed with soils of different pedological characteristics on soil physical quality indices","authors":"Antonio Satriani , Claudia Belviso , Stella Lovelli , Simone di Prima , Antonio Coppola , Shawkat B.M. Hassan , Anna Rita Rivelli , Alessandro Comegna","doi":"10.1016/j.geoderma.2024.117084","DOIUrl":"10.1016/j.geoderma.2024.117084","url":null,"abstract":"<div><div>The addition of natural or synthetic zeolites induces changes in a soil’s chemical, physical, and biological characteristics. Zeolites possess intricate internal frameworks that allow them to modify soil structure and texture, thereby impacting soil hydrological properties. This potential offers opportunities to control soil and groundwater pollution as well as optimize irrigation management practices. In this study, three sandy-loam soils and a silty-loam soil were collected and mixed with different amounts of synthetic zeolite derived from coal fly ash. Repacked soil samples were combined with four levels of zeolite ranging from 1% to 10% by weight and were then hydraulically characterized. This included measuring soil water retention curves (SWRCs) of soil-zeolite mixtures. The data revealed, in accordance with recent research findings, that zeolite influences the hydraulic behavior of soils. In general, we observed that, as the percentage of zeolite increases in the soil, the SWRCs are shifted upwards. This effect is fundamental for explaining the observed changes in the whole set of investigated soil hydraulic properties. The observed changes are also fundamental to evaluate selected soil physical quality (SPQ) indices of agronomic interest, which are investigated in depth in the present research. A specific focus was on the impact of zeolite on modifying the soil’s capacity to retain water, hence on the energy required by plants to acquire a unit mass of soil water (referred to as integral energy, E<sub>I</sub>). Finally, the ANOVA test, linear regression, and multivariate analysis were performed on the entire dataset to support, from a statistical standpoint, the observed correlations between SPQ indices and zeolite amounts. These findings underscored the significance of soil texture in selecting the appropriate soil type for zeolite amendment, confirming that coarse-textured soils are more suitable for zeolite treatment compared to fine-textured soils.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"451 ","pages":"Article 117084"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552316","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}
Pub Date : 2024-11-01DOI: 10.1016/j.geoderma.2024.117085
K.A. Congreves, Q. Wu
The concept of soil health recognizes soil as a living and dynamic natural system, a notion that aptly fits in the realm of biology. However, soil health tests and scoring tools are often dominated by indicators other than soil biology, such as soil fertility and chemistry. Biological indicators of soil health remain understudied and underrepresented in soil health assessments. To address this gap, here we evaluate soil attributes that reflect biological functions and vitality (including organic and total C, total N, mineralized C, extracellular enzyme activity, and phospholipid fatty acid (PLFA) analysis for microbial biomass and adaptation response ratio (ARR)). We assess if these biological indicators can be contextualized by soil classification and measure their responsiveness to agricultural management practices in Prairie region of Saskatchewan Canada. Despite the dynamic nature of biological indicators of soil health, we find that soil classification by great group constrains measurements and serves as a useful contextualizing factor to adjust scoring functions. Further, we find biological indicators of soil health (namely soil organic C, total N, and P and S enzyme activity) generally improve with more regenerative crop production practices such as cover cropping or organic management. Although other indicators such as CO2 mineralization, N and C cycling enzymes, PLFA and ARR showed fewer differences among crop production practices, all were greater under prairie grassland than cropland. In contextualizing soil health scores by soil classification and including biological indicators of soil health that embody soil pools, processes, and life, soil health assessments will not only better represent soil biology and appropriately contextualize soil health scores, but also move towards better targeting soil functioning and vitality.
{"title":"Using soil classification to improve interpretation of biological soil health indicators","authors":"K.A. Congreves, Q. Wu","doi":"10.1016/j.geoderma.2024.117085","DOIUrl":"10.1016/j.geoderma.2024.117085","url":null,"abstract":"<div><div>The concept of soil health recognizes soil as a living and dynamic natural system, a notion that aptly fits in the realm of biology. However, soil health tests and scoring tools are often dominated by indicators other than soil biology, such as soil fertility and chemistry. Biological indicators of soil health remain understudied and underrepresented in soil health assessments. To address this gap, here we evaluate soil attributes that reflect biological functions and vitality (including organic and total C, total N, mineralized C, extracellular enzyme activity, and phospholipid fatty acid (PLFA) analysis for microbial biomass and adaptation response ratio (ARR)). We assess if these biological indicators can be contextualized by soil classification and measure their responsiveness to agricultural management practices in Prairie region of Saskatchewan Canada. Despite the dynamic nature of biological indicators of soil health, we find that soil classification by great group constrains measurements and serves as a useful contextualizing factor to adjust scoring functions. Further, we find biological indicators of soil health (namely soil organic C, total N, and P and S enzyme activity) generally improve with more regenerative crop production practices such as cover cropping or organic management. Although other indicators such as CO<sub>2</sub> mineralization, N and C cycling enzymes, PLFA and ARR showed fewer differences among crop production practices, all were greater under prairie grassland than cropland. In contextualizing soil health scores by soil classification and including biological indicators of soil health that embody soil pools, processes, and life, soil health assessments will not only better represent soil biology and appropriately contextualize soil health scores, but also move towards better targeting soil functioning and vitality.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"451 ","pages":"Article 117085"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552318","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}
Pub Date : 2024-11-01DOI: 10.1016/j.geoderma.2024.117087
Xiaomei Zhang , Xiaolong Zhang , Bin Liang , Xinqi Li , Haofeng Lv , Weiwei Zhou , Xiuyun Wu , Lushan Wang
Long-term excessive fertilization and irrigation under greenhouse cultivation systems cause nitrogen leaching, while the residual content varies at different soil depths with cultivation durations. However, it remains unclear whether it changes the composition and assemblage of the soil bacterial community, especially at deeper layers (as deep as 4 m), after long-term intensified cultivation. This study selected soils from three sites in Shouguang (a typical representative intensive planting area), i.e., greenhouse monoculturing for 20 years (G20), greenhouse monoculturing for 10 years (G10), and an adjacent rotation field (F) for physicochemical property determination and high-throughput pyrosequencing. The results showed that, contrary to the vertical characterization of soil bacterial community composition, the 2-m soil was dominated by Methylomirabilota, a nitrate/nitrite-dependent anaerobic methane oxidizer, uncovered for the first time in the soil habitat. This was attributed to the high levels of dissolved organic carbon (DOC, 201.2–255.7 mg kg−1), proving that applying C-rich organic fertilizers, e.g. plant residues, is effective in preventing accumulated nitrate from moving downward and threatening groundwater in greenhouse soils. Besides, greenhouse cultivation increased the inter-layer composition differences of the bacterial community, and compared with the abundant, the rare subcommunity showed higher sensitivity to environmental changes. The total nitrogen most significantly affected the bacterial community composition and assemblage. Therefore, 20 years of consecutive monocropping significantly decreased the microbial co-occurrence network complexity and species dispersal rate, yielding a low-fitted neutral community model (NCM) and more specialized ecological niches, especially for the rare subcommunity. As far as is known, this is the first study that explores the likely changes in the bacterial community composition and quantifies the responses of the rare subcommunity to long-term greenhouse cultivation at this soil depth. Discovery of Methylomirabilota broadens our understanding of micro-biodiversity in deep-soil ecosystem, and hints its application potential in soil remediation.
{"title":"Digging deeper to find the effect of long-term greenhouse cultivation with excessive fertilization and irrigation on the structure and assemblage of soil bacterial community","authors":"Xiaomei Zhang , Xiaolong Zhang , Bin Liang , Xinqi Li , Haofeng Lv , Weiwei Zhou , Xiuyun Wu , Lushan Wang","doi":"10.1016/j.geoderma.2024.117087","DOIUrl":"10.1016/j.geoderma.2024.117087","url":null,"abstract":"<div><div>Long-term excessive fertilization and irrigation under greenhouse cultivation systems cause nitrogen leaching, while the residual content varies at different soil depths with cultivation durations. However, it remains unclear whether it changes the composition and assemblage of the soil bacterial community, especially at deeper layers (as deep as 4 m), after long-term intensified cultivation. This study selected soils from three sites in Shouguang (a typical representative intensive planting area), i.e., greenhouse monoculturing for 20 years (G20), greenhouse monoculturing for 10 years (G10), and an adjacent rotation field (F) for physicochemical property determination and high-throughput pyrosequencing. The results showed that, contrary to the vertical characterization of soil bacterial community composition, the 2-m soil was dominated by Methylomirabilota, a nitrate/nitrite-dependent anaerobic methane oxidizer, uncovered for the first time in the soil habitat. This was attributed to the high levels of dissolved organic carbon (DOC, 201.2–255.7 mg kg<sup>−1</sup>), proving that applying C-rich organic fertilizers, e.g. plant residues, is effective in preventing accumulated nitrate from moving downward and threatening groundwater in greenhouse soils. Besides, greenhouse cultivation increased the inter-layer composition differences of the bacterial community, and compared with the abundant, the rare subcommunity showed higher sensitivity to environmental changes. The total nitrogen most significantly affected the bacterial community composition and assemblage. Therefore, 20 years of consecutive monocropping significantly decreased the microbial co-occurrence network complexity and species dispersal rate, yielding a low-fitted neutral community model (NCM) and more specialized ecological niches, especially for the rare subcommunity. As far as is known, this is the first study that explores the likely changes in the bacterial community composition and quantifies the responses of the rare subcommunity to long-term greenhouse cultivation at this soil depth. Discovery of Methylomirabilota broadens our understanding of micro-biodiversity in deep-soil ecosystem, and hints its application potential in soil remediation.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"451 ","pages":"Article 117087"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572578","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}
Pub Date : 2024-11-01DOI: 10.1016/j.geoderma.2024.117083
Xun Xiao , Yuekai Wang , Wentai Dai , Kailou Liu , Fahui Jiang , Zubin Xie , Ren Fang Shen , Xue Qiang Zhao
Maize (Zea mays L.) fertilizer nitrogen (N) recovery efficiency (FNRE) shows regional differences in China, and is more strongly affected by soil properties than by climate. However, how soil factors regulate maize FNRE is poorly understood. Herein, 15N tracer pot experiments combined with absolute microbial quantification sequencing were conducted using eight soils covering the main maize cropping systems from northern to southern China. The aim was to elucidate which soil factors affect maize FNRE and identify their optimal range for maximizing FNRE while minimizing N loss. Our results show that soil pH, soil organic matter (SOM), and clay and sand contents were the key factors affecting maize biomass and FNRE across the eight tested soils. Maize biomass and FNRE had parabolic relationships with soil pH, SOM, clay, and sand contents, whereas N loss displayed the opposite trend. The highest maize biomass and FNRE and lowest fertilizer N loss were in the soils with pH of 6.50–6.62, SOM level of 35.25–46.90 g kg−1, clay content of 41.12 %–44.42 %, and sand content of 17.71 %–23.41 %. Under these soil conditions, maize growth and soil N retention capabilities exhibited a high degree of coordination. Bacterial communities differed significantly among the soils, sharing the same soil drivers as maize biomass and FNRE. The abundance of N cycling genes (nasA, narI, narJ, nrfA, and nrfB) involved in dissimilatory nitrate reduction to ammonium (DNRA) was positively correlated with FNRE and negatively correlated with fertilizer N loss, suggesting that DNRA may contribute to soil N retention and enhance FNRE by affecting substrates for nitrification and denitrification. Our study demonstrates that soil pH, SOM, and texture are three key factors driving FNRE variation in maize cropping systems across China, and high microbial-driven DNRA may account for maximum maize FNRE. These findings highlight the importance of tailored FNRE enhancement strategies based on soil characteristics.
{"title":"Driving factors of variation in fertilizer nitrogen recovery efficiency in maize cropping systems across China and its microbial mechanism","authors":"Xun Xiao , Yuekai Wang , Wentai Dai , Kailou Liu , Fahui Jiang , Zubin Xie , Ren Fang Shen , Xue Qiang Zhao","doi":"10.1016/j.geoderma.2024.117083","DOIUrl":"10.1016/j.geoderma.2024.117083","url":null,"abstract":"<div><div>Maize (<em>Zea mays</em> L.) fertilizer nitrogen (N) recovery efficiency (FNRE) shows regional differences in China, and is more strongly affected by soil properties than by climate. However, how soil factors regulate maize FNRE is poorly understood. Herein, <sup>15</sup>N tracer pot experiments combined with absolute microbial quantification sequencing were conducted using eight soils covering the main maize cropping systems from northern to southern China. The aim was to elucidate which soil factors affect maize FNRE and identify their optimal range for maximizing FNRE while minimizing N loss. Our results show that soil pH, soil organic matter (SOM), and clay and sand contents were the key factors affecting maize biomass and FNRE across the eight tested soils. Maize biomass and FNRE had parabolic relationships with soil pH, SOM, clay, and sand contents, whereas N loss displayed the opposite trend. The highest maize biomass and FNRE and lowest fertilizer N loss were in the soils with pH of 6.50–6.62, SOM level of 35.25–46.90 g kg<sup>−1</sup>, clay content of 41.12 %–44.42 %, and sand content of 17.71 %–23.41 %. Under these soil conditions, maize growth and soil N retention capabilities exhibited a high degree of coordination. Bacterial communities differed significantly among the soils, sharing the same soil drivers as maize biomass and FNRE. The abundance of N cycling genes (<em>nasA</em>, <em>narI</em>, <em>narJ</em>, <em>nrfA,</em> and <em>nrfB</em>) involved in dissimilatory nitrate reduction to ammonium (DNRA) was positively correlated with FNRE and negatively correlated with fertilizer N loss, suggesting that DNRA may contribute to soil N retention and enhance FNRE by affecting substrates for nitrification and denitrification. Our study demonstrates that soil pH, SOM, and texture are three key factors driving FNRE variation in maize cropping systems across China, and high microbial-driven DNRA may account for maximum maize FNRE. These findings highlight the importance of tailored FNRE enhancement strategies based on soil characteristics.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"451 ","pages":"Article 117083"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552317","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}
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