Pub Date : 2024-12-17DOI: 10.1016/j.soilbio.2024.109697
Lin Xu, Yongping Kou, Qian Mao, Xiangzhen Li, Chaonan Li, Bo Tu, Jiabao Li, Lihua Tu, Lixia Wang, Hongwei Xu, Chengming You, Han Li, Sining Liu, Li Zhang, Bo Tan, Jiao Li, Yaling Yuan, Kai Wei, Zhenfeng Xu
Alkaline phosphatase (phoD) gene-encoding bacterial (phoD-harbouring) communities are crucial for organic phosphorus (P) mineralisation in agroecosystems. However, the relative contributions of natural factors (e.g., climate) and anthropogenic influences (e.g., fertilisation) to these communities remain unclear, particularly at large spatial scales. To address this, we analysed phoD amplicon sequence data from 290 samples across 15 independent cropland studies, spanning diverse climatic zones and soil types from central to eastern Asia. Our results reveal that climatic factors exert stronger effects than fertiliser regimes on soil phoD-harbouring communities. Specifically, the richness of soil phoD-harbouring communities decreased by approximately three times as mean annual precipitation increased from 160 mm to 1800 mm, and mean annual temperature rose from 9°C to 18°C. Compared to the control, chemical nitrogen (N) + P + organic fertiliser doubled richness, while the control’s richness was 10 times higher than that of chemical N + P + potassium fertiliser. Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the most dominant phoD-harbouring taxa, collectively accounting for 65.3% of the relative abundance. Precipitation explained up to 96.3% of the variance in community composition, while fertiliser regimes explained approximately 40%. Notably, excessive potassium fertilisation was linked to reduced richness and abundance of dominant phoD-harbouring taxa, potentially limiting the availability of plant-accessible P. This suggests that the amount of potassium fertiliser should be carefully considered in future agricultural practices, as it may reduce plant-available P by inhibiting soil phoD-harbouring communities.
{"title":"Climate outweighs fertiliser effects on soil phoD-harbouring communities in agroecosystems","authors":"Lin Xu, Yongping Kou, Qian Mao, Xiangzhen Li, Chaonan Li, Bo Tu, Jiabao Li, Lihua Tu, Lixia Wang, Hongwei Xu, Chengming You, Han Li, Sining Liu, Li Zhang, Bo Tan, Jiao Li, Yaling Yuan, Kai Wei, Zhenfeng Xu","doi":"10.1016/j.soilbio.2024.109697","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109697","url":null,"abstract":"Alkaline phosphatase (<em>phoD</em>) gene-encoding bacterial (<em>phoD</em>-harbouring) communities are crucial for organic phosphorus (P) mineralisation in agroecosystems. However, the relative contributions of natural factors (e.g., climate) and anthropogenic influences (e.g., fertilisation) to these communities remain unclear, particularly at large spatial scales. To address this, we analysed <em>phoD</em> amplicon sequence data from 290 samples across 15 independent cropland studies, spanning diverse climatic zones and soil types from central to eastern Asia. Our results reveal that climatic factors exert stronger effects than fertiliser regimes on soil <em>phoD</em>-harbouring communities. Specifically, the richness of soil <em>phoD</em>-harbouring communities decreased by approximately three times as mean annual precipitation increased from 160 mm to 1800 mm, and mean annual temperature rose from 9°C to 18°C. Compared to the control, chemical nitrogen (N) + P + organic fertiliser doubled richness, while the control’s richness was 10 times higher than that of chemical N + P + potassium fertiliser. Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the most dominant <em>phoD</em>-harbouring taxa, collectively accounting for 65.3% of the relative abundance. Precipitation explained up to 96.3% of the variance in community composition, while fertiliser regimes explained approximately 40%. Notably, excessive potassium fertilisation was linked to reduced richness and abundance of dominant <em>phoD</em>-harbouring taxa, potentially limiting the availability of plant-accessible P. This suggests that the amount of potassium fertiliser should be carefully considered in future agricultural practices, as it may reduce plant-available P by inhibiting soil <em>phoD</em>-harbouring communities.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"76 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841524","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 : 2024-12-15DOI: 10.1016/j.soilbio.2024.109692
Camilo Castillo-Avila, Dennis Castillo-Figueroa, Juan M. Posada
Soils harbor more than half of Earth's biodiversity, with soil fauna representing one of the most diverse groups. However, understanding the drivers influencing their biodiversity remains limited. Upper Andean tropical forests are among Earth's most biodiverse ecosystems, but have undergone large-scale historical transformations, resulting in landscapes with different forest successional stages. In this study, we aimed to analyze soil fauna communities along a successional gradient in Colombia's Eastern Andean forests and identify key microclimatic, soil, and forest structural drivers. We collected soil fauna from 168 samples (30x30x5 cm), in dry and wet seasons, in 14 permanent plots (20x20 m) located in four sites. Data on microclimate, nutrients, productivity, plant diversity, and litter functional richness were gathered from these permanent plots. We observed significant soil fauna biodiversity turnover among Andean montane forest sites, mirroring the distinctive floristic composition between them. We also found that soil fauna richness and abundance increased with succession, attributed to higher productivity and more suitable microclimatic conditions in old-growth forests. Our findings suggest that the primary driver of soil fauna richness in tropical mountain Andean forests is the amount of energy (i.e, forest productivity), while soil fauna abundance is mainly influenced by thermal conditions. Additionally, factors framed within the physiological tolerance hypothesis (i.e., calcium, aluminum) and within the habitat heterogeneity hypothesis (i.e., litter functional richness, plant diversity) also play a role, albeit to a lesser extent. This study emphasizes the importance of examining forest recovery including soil fauna groups to understand successional patterns in tropical mountain forests.
{"title":"Drivers of soil fauna communities along a successional gradient in upper Andean tropical forests","authors":"Camilo Castillo-Avila, Dennis Castillo-Figueroa, Juan M. Posada","doi":"10.1016/j.soilbio.2024.109692","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109692","url":null,"abstract":"Soils harbor more than half of Earth's biodiversity, with soil fauna representing one of the most diverse groups. However, understanding the drivers influencing their biodiversity remains limited. Upper Andean tropical forests are among Earth's most biodiverse ecosystems, but have undergone large-scale historical transformations, resulting in landscapes with different forest successional stages. In this study, we aimed to analyze soil fauna communities along a successional gradient in Colombia's Eastern Andean forests and identify key microclimatic, soil, and forest structural drivers. We collected soil fauna from 168 samples (30x30x5 cm), in dry and wet seasons, in 14 permanent plots (20x20 m) located in four sites. Data on microclimate, nutrients, productivity, plant diversity, and litter functional richness were gathered from these permanent plots. We observed significant soil fauna biodiversity turnover among Andean montane forest sites, mirroring the distinctive floristic composition between them. We also found that soil fauna richness and abundance increased with succession, attributed to higher productivity and more suitable microclimatic conditions in old-growth forests. Our findings suggest that the primary driver of soil fauna richness in tropical mountain Andean forests is the amount of energy (i.e, forest productivity), while soil fauna abundance is mainly influenced by thermal conditions. Additionally, factors framed within the physiological tolerance hypothesis (i.e., calcium, aluminum) and within the habitat heterogeneity hypothesis (i.e., litter functional richness, plant diversity) also play a role, albeit to a lesser extent. This study emphasizes the importance of examining forest recovery including soil fauna groups to understand successional patterns in tropical mountain forests.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"12 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823367","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 : 2024-12-15DOI: 10.1016/j.soilbio.2024.109693
Sara G. Cazzaniga, Philippe Belliard, Joris van Steenbrugge, Sven van den Elsen, Carin Lombaers, Johnny Visser, Leendert Molendijk, Jose G. Macia-Vicente, Joeke Postma, Liesje Mommer, Johannes Helder
Plant-parasitic nematodes are harmful pathogens for many agricultural crops. Within this category, root-knot nematodes (RKN, Meloidogyne spp.) are worldwide regarded as the most impactful because of their wide geographical distribution and their polyphagous nature. Host plant resistances against RKN have been successfully introduced in a few crops only. As the use of nematicides is becoming increasingly restricted because of environmental and human health concerns, there is a need for alternative strategies to control RKN. One such approach is the stimulation of local nematode antagonists. We investigated this in an experimental field setting with two main variables: density of the Columbia root-knot nematode Meloidogyne chitwoodi, and the type of cover crop. For each of the three M. chitwoodi densities, the effects of ten cover crop treatments were tested on both the resident (DNA) and the active (RNA) fractions of the bacterial and fungal communities. In our analyses, we focused on changes in the abundance of plant-parasitic nematode antagonists. From the eight bacterial and 26 fungal genera known from global literature to harbour potential antagonists of plant-parasitic nematodes, we detected respectively five and 14 genera in our agricultural field. Among the bacterial genera, four genera were shown to comprise bacterial species for which nematode antagonism has been documented. The fungal genera included facultative nematode parasites (e.g., Arthrobotrys spp.), endophytes strengthening host defences (e.g., Acremonium spp.), as well as multiple obligatory nematophagous species. This study revealed that conventionally managed arable fields may harbour an unexpectedly high diversity of nematode antagonists. Multiple antagonists were stimulated by cover crops in a cover crop-specific manner, and, to a lesser extent, by increased RKN densities. The richness in putative nematode antagonists did not translate into M. chitwoodi suppression, and we currently investigating whether this relates to the facultative nematophagous lifestyle of most of these antagonists.
{"title":"On the diversity of nematode antagonists in an agricultural soil, and their steerability by root-knot nematode density and cover crops","authors":"Sara G. Cazzaniga, Philippe Belliard, Joris van Steenbrugge, Sven van den Elsen, Carin Lombaers, Johnny Visser, Leendert Molendijk, Jose G. Macia-Vicente, Joeke Postma, Liesje Mommer, Johannes Helder","doi":"10.1016/j.soilbio.2024.109693","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109693","url":null,"abstract":"Plant-parasitic nematodes are harmful pathogens for many agricultural crops. Within this category, root-knot nematodes (RKN, <em>Meloidogyne</em> spp.) are worldwide regarded as the most impactful because of their wide geographical distribution and their polyphagous nature. Host plant resistances against RKN have been successfully introduced in a few crops only. As the use of nematicides is becoming increasingly restricted because of environmental and human health concerns, there is a need for alternative strategies to control RKN. One such approach is the stimulation of local nematode antagonists. We investigated this in an experimental field setting with two main variables: density of the Columbia root-knot nematode <em>Meloidogyne chitwoodi</em>, and the type of cover crop. For each of the three <em>M. chitwoodi</em> densities, the effects of ten cover crop treatments were tested on both the resident (DNA) and the active (RNA) fractions of the bacterial and fungal communities. In our analyses, we focused on changes in the abundance of plant-parasitic nematode antagonists. From the eight bacterial and 26 fungal genera known from global literature to harbour potential antagonists of plant-parasitic nematodes, we detected respectively five and 14 genera in our agricultural field. Among the bacterial genera, four genera were shown to comprise bacterial species for which nematode antagonism has been documented. The fungal genera included facultative nematode parasites (<em>e.g</em>., <em>Arthrobotrys</em> spp.), endophytes strengthening host defences (<em>e.g</em>., <em>Acremonium</em> spp.), as well as multiple obligatory nematophagous species. This study revealed that conventionally managed arable fields may harbour an unexpectedly high diversity of nematode antagonists. Multiple antagonists were stimulated by cover crops in a cover crop-specific manner, and, to a lesser extent, by increased RKN densities. The richness in putative nematode antagonists did not translate into <em>M. chitwoodi</em> suppression, and we currently investigating whether this relates to the facultative nematophagous lifestyle of most of these antagonists.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"85 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823366","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}
Global change may change plant carbon input, which may in turn accelerate or retard the mineralization of soil organic matter (SOM), a phenomenon known as priming effect. However, deep soil priming effect on large geographic scale is poorly understood, hindering a complete understanding of the response of whole-soil carbon dynamics to plant carbon input. Across a 2000 km grassland transect in Inner Mongolia, China, this study showed that soil priming effects at 0-200 cm depth varied systematically with climate and soil properties. The intensity of priming effect varied with depth. Averaged across 10 sites along the transect, glucose addition increased native SOM decomposition by 5.1% in surface soil (0-10 cm), while decreased it by 12.9% and 25.7% in middle (30-50 cm) and deep (150-200 cm) soils, respectively. Interestingly, the regulating factors of priming at different depths were significantly different. The priming effect in surface soil was primarily regulated by SOM stability represented by content of soil minerals and (clay+silt) %, whereas that in middle soil was mainly regulated by soil substrates, SOM stability and soil pH, and that in deep soil was mainly controlled by soil substrates. This study demonstrates distinct controls of the priming effect across soil depths at the regional scale, and contributes to improving our understanding of how whole-soil carbon dynamics respond to global change.
全球变化可能会改变植物的碳输入，进而加速或延缓土壤有机质（SOM）的矿化，这种现象被称为引物效应。然而，人们对大地理尺度上的深层土壤引诱效应知之甚少，这阻碍了人们全面了解全土碳动态对植物碳输入的响应。这项研究在中国内蒙古2000公里的草原横断面上发现，0-200厘米深度的土壤引诱效应随气候和土壤特性的变化而系统地变化。引诱效应的强度随深度而变化。对横断面上的 10 个地点进行平均，添加葡萄糖可使表层土壤（0-10 厘米）中的原生 SOM 分解增加 5.1%，而中层土壤（30-50 厘米）和深层土壤（150-200 厘米）中的原生 SOM 分解分别减少 12.9% 和 25.7%。有趣的是，不同深度的打底调节因子存在显著差异。表层土壤的引诱效果主要受以土壤矿物质含量和（粘土+淤泥）%为代表的 SOM 稳定性的调控，而中层土壤的引诱效果主要受土壤基质、SOM 稳定性和土壤 pH 的调控，深层土壤的引诱效果主要受土壤基质的调控。这项研究表明，在区域尺度上，不同土壤深度的启动效应受不同的控制，有助于加深我们对整个土壤碳动态如何响应全球变化的理解。
{"title":"Depth-dependent regulations of soil priming effects along a 2000 km grassland transect","authors":"Yunlong Hu, Jiguang Feng, Shuai Zhang, Zhongkui Luo, Biao Zhu","doi":"10.1016/j.soilbio.2024.109696","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109696","url":null,"abstract":"Global change may change plant carbon input, which may in turn accelerate or retard the mineralization of soil organic matter (SOM), a phenomenon known as priming effect. However, deep soil priming effect on large geographic scale is poorly understood, hindering a complete understanding of the response of whole-soil carbon dynamics to plant carbon input. Across a 2000 km grassland transect in Inner Mongolia, China, this study showed that soil priming effects at 0-200 cm depth varied systematically with climate and soil properties. The intensity of priming effect varied with depth. Averaged across 10 sites along the transect, glucose addition increased native SOM decomposition by 5.1% in surface soil (0-10 cm), while decreased it by 12.9% and 25.7% in middle (30-50 cm) and deep (150-200 cm) soils, respectively. Interestingly, the regulating factors of priming at different depths were significantly different. The priming effect in surface soil was primarily regulated by SOM stability represented by content of soil minerals and (clay+silt) %, whereas that in middle soil was mainly regulated by soil substrates, SOM stability and soil pH, and that in deep soil was mainly controlled by soil substrates. This study demonstrates distinct controls of the priming effect across soil depths at the regional scale, and contributes to improving our understanding of how whole-soil carbon dynamics respond to global change.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"10 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823364","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 : 2024-12-15DOI: 10.1016/j.soilbio.2024.109694
Akeem T. Shorunke, Bobbi L. Helgason, Richard E. Farrell
Crop residues are an important source of N for subsequent crops and contribute to cropping system nitrous oxide (N2O) emissions. Oilseed residues, particularly canola (Brassica napus L.), can instigate higher N2O emissions compared to pulse and wheat crop residues but the reason for this disproportionate emission response is unknown. To determine the quantity and source of N2O emissions, we conducted an incubation experiment (84 d) using 15N and 13C labelled residues of canola, wheat ,flax, pea and investigated key N-cycling gene abundances, microbial abundance and community structure using PLFA and soil C and N dynamics. Residue addition of all types significantly increased microbial abundance and abundances of denitrification and nitrification genes. Canola residue resulted in significantly greater nosZI abundance. Lower incorporation of canola residue 13C into PLFA and higher 13CO2 emissions suggests that canola residue C was used less efficiently (i.e., less for growth and more for respiration), depleting O2 and stimulating denitrification. The magnitude of N2O emission from residue-amended soils was significantly higher (p < 0.05) than the unamended control soil and differed with residue type: canola > pea = wheat > flax > control. The canola residue emission factor was 1.56% of residue N – significantly higher than that of wheat (0.99%), pea (0.95%) and flax (0.18%). This higher canola emission factor resulted from greater residue-derived (1.47%) N2O as well as residue-induced (0.65%) soil emissions. The combined use of stable isotope tracing of 15N2O and 13CO2 and microbial characterization quantified differences in residue-derived N2O emissions from common crops that were linked to differences in microbial abundance, community structure and activity.
{"title":"Evidence of the need for crop-specific N2O emission factors","authors":"Akeem T. Shorunke, Bobbi L. Helgason, Richard E. Farrell","doi":"10.1016/j.soilbio.2024.109694","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109694","url":null,"abstract":"Crop residues are an important source of N for subsequent crops and contribute to cropping system nitrous oxide (N<sub>2</sub>O) emissions. Oilseed residues, particularly canola (<em>Brassica napus</em> L.), can instigate higher N<sub>2</sub>O emissions compared to pulse and wheat crop residues but the reason for this disproportionate emission response is unknown. To determine the quantity and source of N<sub>2</sub>O emissions, we conducted an incubation experiment (84 d) using <sup>15</sup>N and <sup>13</sup>C labelled residues of canola, wheat ,flax, pea and investigated key N-cycling gene abundances, microbial abundance and community structure using PLFA and soil C and N dynamics. Residue addition of all types significantly increased microbial abundance and abundances of denitrification and nitrification genes. Canola residue resulted in significantly greater <em>nosZI</em> abundance. Lower incorporation of canola residue <sup>13</sup>C into PLFA and higher <sup>13</sup>CO<sub>2</sub> emissions suggests that canola residue C was used less efficiently (i.e., less for growth and more for respiration), depleting O<sub>2</sub> and stimulating denitrification. The magnitude of N<sub>2</sub>O emission from residue-amended soils was significantly higher (<em>p <</em> 0.05) than the unamended control soil and differed with residue type: canola > pea = wheat > flax > control. The canola residue emission factor was 1.56% of residue N – significantly higher than that of wheat (0.99%), pea (0.95%) and flax (0.18%). This higher canola emission factor resulted from greater residue-derived (1.47%) N<sub>2</sub>O as well as residue-induced (0.65%) soil emissions. The combined use of stable isotope tracing of <sup>15</sup>N<sub>2</sub>O and <sup>13</sup>CO<sub>2</sub> and microbial characterization quantified differences in residue-derived N<sub>2</sub>O emissions from common crops that were linked to differences in microbial abundance, community structure and activity.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"14 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823365","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}
Nitrogen (N) deposition significantly impacts ecosystem carbon (C) cycling. However, most experimental N deposition studies applied N fertilizers in low-frequency, typically once or twice per year during the growing season. Few studies have been conducted to investigate the effects of high-frequency N deposition at varying rates on the formation and stability of soil organic carbon (SOC). Additionally, the effects of N addition on the two SOC fractions — particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) — and the underlying mechanisms are not well understood. To address these gaps, we conducted a long-term N addition experiment in a typical steppe ecosystem in Inner Mongolia, China, beginning in 2008. The N addition rates ranged from 0 to 50 g N m-2 yr-1, with a high frequency of N additions (once a month, 12 additions per year). After a decade of N addition, we observed a consistent decrease in SOC (by 3.9 ± 0.51 %) and POC (by 17.5 ± 2.31 %) and an increase in MAOC (by 5.8 ± 1.68 %) compared to the control treatment (i.e., the treatment without N addition). The decline in POC was attributed to stimulated microbial decomposition due to improved quality of particulate organic matter and increased priming effect from SOC. The increase in MAOC was associated with enhanced mineral protection, resulting from increased solubility of iron/aluminum (Fe/Al) that are reactive in directly adsorbing SOC molecules to form stable metal-SOC complexes. However, this increase in MAOC does not offset the decrease in POC, leading to an overall decrease in SOC under N enrichment. This study reveals the crucial roles of microbial decomposition and mineral protection in determining SOC fractions in N-enriched steppe ecosystems.
{"title":"Increase in mineral-associated organic carbon does not offset the decrease in particulate organic carbon under long-term nitrogen enrichment in a steppe ecosystem","authors":"Li Liu, Junjie Yang, Jing Wang, Qiang Yu, Cunzheng Wei, Liangchao Jiang, Jianhui Huang, Yunhai Zhang, Yong Jiang, Haiyang Zhang, Xingguo Han","doi":"10.1016/j.soilbio.2024.109695","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109695","url":null,"abstract":"Nitrogen (N) deposition significantly impacts ecosystem carbon (C) cycling. However, most experimental N deposition studies applied N fertilizers in low-frequency, typically once or twice per year during the growing season. Few studies have been conducted to investigate the effects of high-frequency N deposition at varying rates on the formation and stability of soil organic carbon (SOC). Additionally, the effects of N addition on the two SOC fractions — particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) — and the underlying mechanisms are not well understood. To address these gaps, we conducted a long-term N addition experiment in a typical steppe ecosystem in Inner Mongolia, China, beginning in 2008. The N addition rates ranged from 0 to 50 g N m<sup>-2</sup> yr<sup>-1</sup>, with a high frequency of N additions (once a month, 12 additions per year). After a decade of N addition, we observed a consistent decrease in SOC (by 3.9 ± 0.51 %) and POC (by 17.5 ± 2.31 %) and an increase in MAOC (by 5.8 ± 1.68 %) compared to the control treatment (i.e., the treatment without N addition). The decline in POC was attributed to stimulated microbial decomposition due to improved quality of particulate organic matter and increased priming effect from SOC. The increase in MAOC was associated with enhanced mineral protection, resulting from increased solubility of iron/aluminum (Fe/Al) that are reactive in directly adsorbing SOC molecules to form stable metal-SOC complexes. However, this increase in MAOC does not offset the decrease in POC, leading to an overall decrease in SOC under N enrichment. This study reveals the crucial roles of microbial decomposition and mineral protection in determining SOC fractions in N-enriched steppe ecosystems.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"35 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823362","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 : 2024-12-12DOI: 10.1016/j.soilbio.2024.109684
S. Mitsunobu, R. Wagai, H. Shimada, H. Kato, K. Ito, S. Sato, M. Hayatsu, K. Minamisawa
A major greenhouse gas, nitrous oxide (N2O) significantly emitted from agricultural soils, is reduced to innocuous N2 gas by the activity of two groups of N2O-reducing microbes (typical clade I and more recently discovered atypical clade II) having different enzymatic efficiency. Yet, basic information such as the locations of N₂O reduction hotspots and soil factors regulating their formations is still lacking. In addition, oxygen availability, which is strongly constrained by soil pore property, likely dictates their ecology in soil as N2O reductase enzyme (coded by nosZ genes) is inhibited by O2. Accordingly, the aim of this study was to assess the mechanistic linkage among soil pore networks, chemical microenvironments (pH, Eh, and O2 and N2O abundances), ecology of N₂O-reducing microbes, and the occurrence of N₂O reduction hotspots in single soil aggregates. Using water-stable macroaggregates from two contrasting soil types (highly porous Andosol and less porous clay-rich Acrisol), we determined microscale depth profiles of N2O and O2 dynamics, three-dimensional pore properties, and the two N2O reducer populations in the single aggregates after 48-hour lab incubation under a water-saturated condition. The N2O and O2 depth profiles showed the increase in N2O production with O2 depletion towards deeper part of the incubated aggregates, indicating denitrification N2O production especially in Andosol aggregate where O2 availability was higher. The gene distribution with depth clearly showed higher abundance of nosZ harboring microbes (including both clades I and II) in the Acrisol aggregate than Andosol aggregate especially towards the aggregate interior. In the Acrisol aggregate, the abundance of nosZ clade I harboring microbes was maximum at the middle depth corresponding to N2O maxima, whereas the nosZ clade II harboring microbes had slightly different niche as their population monotonically increased towards the aggregate core, which were consistent with theoretical O2 availability and pore connectivity. The current findings underscore the intimate connection between soil physical complexity and microbial ecology, which merits further investigation.
{"title":"First microscale data on depth profiles of microbial N₂O reduction, O2 availability, and pore networks inside contrasting single soil aggregates","authors":"S. Mitsunobu, R. Wagai, H. Shimada, H. Kato, K. Ito, S. Sato, M. Hayatsu, K. Minamisawa","doi":"10.1016/j.soilbio.2024.109684","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109684","url":null,"abstract":"A major greenhouse gas, nitrous oxide (N<sub>2</sub>O) significantly emitted from agricultural soils, is reduced to innocuous N<sub>2</sub> gas by the activity of two groups of N<sub>2</sub>O-reducing microbes (typical clade I and more recently discovered atypical clade II) having different enzymatic efficiency. Yet, basic information such as the locations of N₂O reduction hotspots and soil factors regulating their formations is still lacking. In addition, oxygen availability, which is strongly constrained by soil pore property, likely dictates their ecology in soil as N<sub>2</sub>O reductase enzyme (coded by <em>nosZ</em> genes) is inhibited by O<sub>2</sub>. Accordingly, the aim of this study was to assess the mechanistic linkage among soil pore networks, chemical microenvironments (pH, Eh, and O<sub>2</sub> and N<sub>2</sub>O abundances), ecology of N₂O-reducing microbes, and the occurrence of N₂O reduction hotspots in single soil aggregates. Using water-stable macroaggregates from two contrasting soil types (highly porous Andosol and less porous clay-rich Acrisol), we determined microscale depth profiles of N<sub>2</sub>O and O<sub>2</sub> dynamics, three-dimensional pore properties, and the two N<sub>2</sub>O reducer populations in the single aggregates after 48-hour lab incubation under a water-saturated condition. The N<sub>2</sub>O and O<sub>2</sub> depth profiles showed the increase in N<sub>2</sub>O production with O<sub>2</sub> depletion towards deeper part of the incubated aggregates, indicating denitrification N<sub>2</sub>O production especially in Andosol aggregate where O<sub>2</sub> availability was higher. The gene distribution with depth clearly showed higher abundance of <em>nosZ</em> harboring microbes (including both clades I and II) in the Acrisol aggregate than Andosol aggregate especially towards the aggregate interior. In the Acrisol aggregate, the abundance of <em>nosZ</em> clade I harboring microbes was maximum at the middle depth corresponding to N<sub>2</sub>O maxima, whereas the <em>nosZ</em> clade II harboring microbes had slightly different niche as their population monotonically increased towards the aggregate core, which were consistent with theoretical O<sub>2</sub> availability and pore connectivity. The current findings underscore the intimate connection between soil physical complexity and microbial ecology, which merits further investigation.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"28 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809591","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 : 2024-12-11DOI: 10.1016/j.soilbio.2024.109691
Johannes Wirsching, Martin-Georg Endress, Eliana Di Lodovico, Sergey Blagodatsky, Christian Fricke, Marcel Lorenz, Sven Marhan, Ellen Kandeler, Christian Poll
Microbial carbon use efficiency (CUE) is an important metric for understanding the balance between anabolic and catabolic metabolism, while energy use efficiency (EUE) provides insight into microbial energy requirements. They are linked by the ratio between released heat and respiration (calorespirometric ratio, CR), which can be used to describe the efficiency of microbial growth. In this study, microbial C and energy use during the degradation of <span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML" />' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="0.24ex" role="img" style="vertical-align: -0.12ex;" viewbox="0 -51.7 0 103.4" width="0" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"></math></span></span><script type="math/mml"><math></math></script></span>-labeled cellulose in eight different soils was investigated experimentally and simulated using a process-based model. Our results show close agreement between the cumulative C and energy balances during the incubations, with a total C and energy release equal to 30-50% of the amount added as cellulose. Both energy and C fluxes indicated that a positive priming effect of soil organic matter (SOM) increased the release of heat and CO<sub>2</sub> by 10 - 32% relative to the added substrate. The CR-CUE relationship indicated that growth on cellulose was energy limited during the early but not the later stages of the incubation, especially in soils with high SOM content. We partly observed systematic differences between estimates for CUE based either on the <span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML" />' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="0.24ex" role="img" style="vertical-align: -0.12ex;" viewbox="0 -51.7 0 103.4" width="0" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"></math></span></span><script type="math/mml"><math></math></script></span> label or on the calorespirometric ratio. Both approaches were constrained by technical and methodological limitations and agreed best during the phase of microbial growth in the SOM-rich soils, with CUE values between 0.4-0.75 indicating efficient aerobic growth. During early stages or after transition to a maintenance phase, both estimates were less meaningful for cellulose degradation, a substrate with a lower turnover rate than glucose. Still, the coupled heat and mass balances during cellulo
微生物的碳利用效率（CUE）是了解合成代谢和分解代谢之间平衡的重要指标，而能量利用效率（EUE）则能让人深入了解微生物的能量需求。它们通过释放热量和呼吸作用之间的比率（卡路里呼吸比，CR）联系在一起，可用于描述微生物的生长效率。本研究对八种不同土壤中-标记纤维素降解过程中微生物的碳和能量利用进行了实验研究，并使用基于过程的模型进行了模拟。结果表明，培养过程中累积的碳和能量平衡非常接近，总的碳和能量释放量相当于纤维素添加量的 30-50%。能量和碳通量都表明，相对于添加的基质，土壤有机质（SOM）的正向引导效应使热量和二氧化碳的释放量增加了 10 - 32%。CR-CUE关系表明，纤维素上的生长在培养早期阶段受到能量限制，而在培养后期阶段则不受能量限制，尤其是在SOM含量较高的土壤中。我们在一定程度上观察到了基于标签或热量呼吸比的 CUE 估算值之间的系统性差异。这两种方法都受到技术和方法的限制，在富含 SOM 的土壤中微生物生长阶段，这两种方法的一致性最好，CUE 值在 0.4-0.75 之间，表明有效的有氧生长。在早期阶段或过渡到维持阶段后，这两个估计值对纤维素降解的意义不大，因为纤维素是一种周转率比葡萄糖低的基质。不过，与单独考虑质量平衡相比，纤维素降解过程中的热平衡和质量平衡耦合与基于过程的建模相结合，提供了有关生长产量以及 SOM 对微生物生长的贡献的更多信息。
{"title":"Coupling energy balance and carbon flux during cellulose degradation in arable soils","authors":"Johannes Wirsching, Martin-Georg Endress, Eliana Di Lodovico, Sergey Blagodatsky, Christian Fricke, Marcel Lorenz, Sven Marhan, Ellen Kandeler, Christian Poll","doi":"10.1016/j.soilbio.2024.109691","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109691","url":null,"abstract":"Microbial carbon use efficiency (CUE) is an important metric for understanding the balance between anabolic and catabolic metabolism, while energy use efficiency (EUE) provides insight into microbial energy requirements. They are linked by the ratio between released heat and respiration (calorespirometric ratio, CR), which can be used to describe the efficiency of microbial growth. In this study, microbial C and energy use during the degradation of <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\" />' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"0.24ex\" role=\"img\" style=\"vertical-align: -0.12ex;\" viewbox=\"0 -51.7 0 103.4\" width=\"0\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"></math></span></span><script type=\"math/mml\"><math></math></script></span>-labeled cellulose in eight different soils was investigated experimentally and simulated using a process-based model. Our results show close agreement between the cumulative C and energy balances during the incubations, with a total C and energy release equal to 30-50% of the amount added as cellulose. Both energy and C fluxes indicated that a positive priming effect of soil organic matter (SOM) increased the release of heat and CO<sub>2</sub> by 10 - 32% relative to the added substrate. The CR-CUE relationship indicated that growth on cellulose was energy limited during the early but not the later stages of the incubation, especially in soils with high SOM content. We partly observed systematic differences between estimates for CUE based either on the <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\" />' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"0.24ex\" role=\"img\" style=\"vertical-align: -0.12ex;\" viewbox=\"0 -51.7 0 103.4\" width=\"0\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"></math></span></span><script type=\"math/mml\"><math></math></script></span> label or on the calorespirometric ratio. Both approaches were constrained by technical and methodological limitations and agreed best during the phase of microbial growth in the SOM-rich soils, with CUE values between 0.4-0.75 indicating efficient aerobic growth. During early stages or after transition to a maintenance phase, both estimates were less meaningful for cellulose degradation, a substrate with a lower turnover rate than glucose. Still, the coupled heat and mass balances during cellulo","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"6 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142804871","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}
The combination of biochar and nitrogen (N) addition has been proposed as a potential strategy to sustain crop productivity and mitigate climate change by increasing soil fertility, sequestering carbon (C), and reducing soil greenhouse gas emissions. However, our current knowledge about how biochar and N additions interactively alter mineralization of native soil organic C (SOC), which is referred to priming effects (PEs), is largely limited. To address this uncertainty, C3 biochar (pyrolyzing rice straw at 300, 550, and 800 °C) and its combination with N fertilizer (urea) were incubated in a C4-derived soils at 25 °C. All these 3 types of biochar with different addition rates caused positive priming of native soil organic matter decomposition (up to +58.4%). The maximum negative priming effects (up to −25.4%) occurred in soil treated with 1% of N-bound biochar pyrolyzed at 300 °C. In addition, a negative correlation was found between the priming intensity and soil inorganic N content across all treatments. The decrease in biochar-induced PEs was related with a shift in microbial community composition and reduction in microbial biomass determined by chloroform-fumigation. Such a reduction, however, was not confirmed by PLFA analysis. These findings advance our understanding on the microbial mechanisms mediating net soil C balance with the adequate biochar use for blending traditional mineral fertilizers.
{"title":"Nitrogen input alleviates the priming effects of biochar addition on soil organic carbon decomposition","authors":"Xuhui Zhou, Zhiqiang Feng, Yixian Yao, Ruiqiang Liu, Junjiong Shao, Shuxian Jia, Yining Gao, Kui Xue, Hongyang Chen, Yuling Fu, Yanghui He","doi":"10.1016/j.soilbio.2024.109689","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109689","url":null,"abstract":"The combination of biochar and nitrogen (N) addition has been proposed as a potential strategy to sustain crop productivity and mitigate climate change by increasing soil fertility, sequestering carbon (C), and reducing soil greenhouse gas emissions. However, our current knowledge about how biochar and N additions interactively alter mineralization of native soil organic C (SOC), which is referred to priming effects (PEs), is largely limited. To address this uncertainty, C<sub>3</sub> biochar (pyrolyzing rice straw at 300, 550, and 800 °C) and its combination with N fertilizer (urea) were incubated in a C<sub>4</sub>-derived soils at 25 °C. All these 3 types of biochar with different addition rates caused positive priming of native soil organic matter decomposition (up to +58.4%). The maximum negative priming effects (up to −25.4%) occurred in soil treated with 1% of N-bound biochar pyrolyzed at 300 °C. In addition, a negative correlation was found between the priming intensity and soil inorganic N content across all treatments. The decrease in biochar-induced PEs was related with a shift in microbial community composition and reduction in microbial biomass determined by chloroform-fumigation. Such a reduction, however, was not confirmed by PLFA analysis. These findings advance our understanding on the microbial mechanisms mediating net soil C balance with the adequate biochar use for blending traditional mineral fertilizers.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"48 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793593","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 : 2024-12-09DOI: 10.1016/j.soilbio.2024.109688
C. Vermeiren, J. Ceulemans, Y. Thiry, E. Smolders
In recent years, a global interest in selenium (Se) has arisen, both in the light of crop biofortification and risk assessments of 79Se present in nuclear waste. In both cases, a profound understanding of the fate of Se in soils is required. The objectives of this study were to evaluate the fate of selenate (Se(VI)) added to soil and to relate the rate and extent of its immobilisation in the months after soil spiking, termed ageing, to soil properties. The underlying hypothesis is that Se mobility can be reduced by incorporation in microbial biomass and by pH-dependent adsorption to oxyhydroxides. Ageing of Se was studied in 14 soils with contrasting properties after spiking with an enriched 77Se(VI) isotope tracer. During six months of incubation, subsamples of the soils were collected and extracted to monitor the mobile, adsorbed and NaOH-extractable fractions of soil-native Se and spiked 77Se. After 182 days, the mobile concentration of the 77Se spike was reduced by a factor 2-300, with the largest factors consistently found in soils with a pH above 6. The decrease in Se availability with time was described by first-order kinetics, which allowed to derive a rate and extent of Se ageing in soils. Distinct but gradual ageing was mainly promoted by high soil pH, whereas Se immobilisation was faster but less pronounced in low pH soils. Amendment of five soils with a carbon source enhanced microbial activity, thereby increasing the rate and/or extent of Se ageing. Also among the unamended soils, the immobilisation rate constant increased with increasing measured soil respiration rates. This study showed a pronounced effect of both soil pH and biochemical reactions on the time-dependent solid:liquid distribution of Se, which should be considered in biofortification practices and risk assessments.
{"title":"Increased soil pH and enhanced microbial activity stimulate the gradual immobilisation of selenate added to soils","authors":"C. Vermeiren, J. Ceulemans, Y. Thiry, E. Smolders","doi":"10.1016/j.soilbio.2024.109688","DOIUrl":"https://doi.org/10.1016/j.soilbio.2024.109688","url":null,"abstract":"In recent years, a global interest in selenium (Se) has arisen, both in the light of crop biofortification and risk assessments of <sup>79</sup>Se present in nuclear waste. In both cases, a profound understanding of the fate of Se in soils is required. The objectives of this study were to evaluate the fate of selenate (Se(VI)) added to soil and to relate the rate and extent of its immobilisation in the months after soil spiking, termed ageing, to soil properties. The underlying hypothesis is that Se mobility can be reduced by incorporation in microbial biomass and by pH-dependent adsorption to oxyhydroxides. Ageing of Se was studied in 14 soils with contrasting properties after spiking with an enriched <sup>77</sup>Se(VI) isotope tracer. During six months of incubation, subsamples of the soils were collected and extracted to monitor the mobile, adsorbed and NaOH-extractable fractions of soil-native Se and spiked <sup>77</sup>Se. After 182 days, the mobile concentration of the <sup>77</sup>Se spike was reduced by a factor 2-300, with the largest factors consistently found in soils with a pH above 6. The decrease in Se availability with time was described by first-order kinetics, which allowed to derive a rate and extent of Se ageing in soils. Distinct but gradual ageing was mainly promoted by high soil pH, whereas Se immobilisation was faster but less pronounced in low pH soils. Amendment of five soils with a carbon source enhanced microbial activity, thereby increasing the rate and/or extent of Se ageing. Also among the unamended soils, the immobilisation rate constant increased with increasing measured soil respiration rates. This study showed a pronounced effect of both soil pH and biochemical reactions on the time-dependent solid:liquid distribution of Se, which should be considered in biofortification practices and risk assessments.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"17 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793590","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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