Pub Date : 2024-04-24DOI: 10.5194/egusphere-2024-1125
Wolde Mekuria, Euan Phimister, Getahun Yakob, Desalegn Tegegne, Awdenegest Moges, Yitna Tesfaye, Dagmawi Melaku, Charlene Gerber, Paul Hallett, Jo Smith
Abstract. Gully erosion can be combatted in severely affected regions like sub-Saharan Africa by a range of low-cost interventions that are accessible to affected farmers. However, for successful implementation, biophysical evidence of the effectiveness of interventions needs to be combined with buy-in and input from local communities. Working with farmers in a watershed in Southern Ethiopia, we investigated (a) the effectiveness of low-cost gully rehabilitation measures to reduce soil loss and upward expansion of gully heads, (b) how farmers and communities view gully interventions, and (c) whether demonstrating gully interventions in-context changes farmers’ knowledge and perceptions of their capacity to act. On-farm field experiments, key informant interviews, focus group discussions and household surveys were used to collect and analyze data. Three gully treatments were explored, all with riprap, one also with grass planting, and one with grass planting and check-dam integration. Over a period of 26 months these low-cost practices ceased measurable gully head expansion, whereas untreated gullies had a mean upward expansion of 671 cm resulting in a calculated soil loss of 11.0 tonnes. Farmers viewed these gully rehabilitation measures positively, apart from the high cost of input materials and technical requirements of gabion check-dams. Ongoing rehabilitation activities and on-farm trials influenced knowledge and understanding of similar gully treatments among survey respondents. On-farm experiments and field day demonstrations empowered farmers to act, addressing pessimism from some respondents about their capacity to do so.
{"title":"Gully rehabilitation in Southern Ethiopia – value and impacts for farmers","authors":"Wolde Mekuria, Euan Phimister, Getahun Yakob, Desalegn Tegegne, Awdenegest Moges, Yitna Tesfaye, Dagmawi Melaku, Charlene Gerber, Paul Hallett, Jo Smith","doi":"10.5194/egusphere-2024-1125","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1125","url":null,"abstract":"<strong>Abstract.</strong> Gully erosion can be combatted in severely affected regions like sub-Saharan Africa by a range of low-cost interventions that are accessible to affected farmers. However, for successful implementation, biophysical evidence of the effectiveness of interventions needs to be combined with buy-in and input from local communities. Working with farmers in a watershed in Southern Ethiopia, we investigated (a) the effectiveness of low-cost gully rehabilitation measures to reduce soil loss and upward expansion of gully heads, (b) how farmers and communities view gully interventions, and (c) whether demonstrating gully interventions in-context changes farmers’ knowledge and perceptions of their capacity to act. On-farm field experiments, key informant interviews, focus group discussions and household surveys were used to collect and analyze data. Three gully treatments were explored, all with riprap, one also with grass planting, and one with grass planting and check-dam integration. Over a period of 26 months these low-cost practices ceased measurable gully head expansion, whereas untreated gullies had a mean upward expansion of 671 cm resulting in a calculated soil loss of 11.0 tonnes. Farmers viewed these gully rehabilitation measures positively, apart from the high cost of input materials and technical requirements of gabion check-dams. Ongoing rehabilitation activities and on-farm trials influenced knowledge and understanding of similar gully treatments among survey respondents. On-farm experiments and field day demonstrations empowered farmers to act, addressing pessimism from some respondents about their capacity to do so.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"142 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-18DOI: 10.5194/soil-10-281-2024
Lena Katharina Öttl, Florian Wilken, Anna Juřicová, Pedro V. G. Batista, Peter Fiener
Abstract. In the last decades, soils and their agricultural management have received great scientific and political attention due to their potential to act as a sink of atmospheric carbon dioxide (CO2). Agricultural management has strong potential to accelerate soil redistribution, and, therefore, it is questioned if soil redistribution processes affect this potential CO2 sink function. Most studies analysing the effect of soil redistribution upon soil organic carbon (SOC) dynamics focus on water erosion and analyse only relatively small catchments and relatively short time spans of several years to decades. The aim of this study is to widen this perspective by including tillage erosion as another important driver of soil redistribution and by performing a model-based analysis in a 200 km2 sized arable region of northeastern Germany for the period since the conversion from forest to arable land (approx. 1000 years ago). The spatially explicit soil redistribution and carbon (C) turnover model SPEROS-C was applied to simulate lateral soil and SOC redistribution and SOC turnover. The model parameterisation uncertainty was estimated by simulating different realisations of the development of agricultural management over the past millennium. The results indicate that, in young moraine areas, which are relatively dry but have been intensively used for agriculture for centuries, SOC patterns and dynamics are substantially affected by tillage-induced soil redistribution processes. To understand the landscape-scale effect of these redistribution processes on SOC dynamics, it is essential to account for long-term changes following land conversion as typical soil-erosion-induced processes, e.g. dynamic replacement, only take place after former forest soils reach a new equilibrium following conversion. Overall, it was estimated that, after 1000 years of arable land use, SOC redistribution by tillage and water results in a current-day landscape-scale C sink of up to 0.66 ‰ yr−1 of the current SOC stocks.
{"title":"A millennium of arable land use – the long-term impact of tillage and water erosion on landscape-scale carbon dynamics","authors":"Lena Katharina Öttl, Florian Wilken, Anna Juřicová, Pedro V. G. Batista, Peter Fiener","doi":"10.5194/soil-10-281-2024","DOIUrl":"https://doi.org/10.5194/soil-10-281-2024","url":null,"abstract":"Abstract. In the last decades, soils and their agricultural management have received great scientific and political attention due to their potential to act as a sink of atmospheric carbon dioxide (CO2). Agricultural management has strong potential to accelerate soil redistribution, and, therefore, it is questioned if soil redistribution processes affect this potential CO2 sink function. Most studies analysing the effect of soil redistribution upon soil organic carbon (SOC) dynamics focus on water erosion and analyse only relatively small catchments and relatively short time spans of several years to decades. The aim of this study is to widen this perspective by including tillage erosion as another important driver of soil redistribution and by performing a model-based analysis in a 200 km2 sized arable region of northeastern Germany for the period since the conversion from forest to arable land (approx. 1000 years ago). The spatially explicit soil redistribution and carbon (C) turnover model SPEROS-C was applied to simulate lateral soil and SOC redistribution and SOC turnover. The model parameterisation uncertainty was estimated by simulating different realisations of the development of agricultural management over the past millennium. The results indicate that, in young moraine areas, which are relatively dry but have been intensively used for agriculture for centuries, SOC patterns and dynamics are substantially affected by tillage-induced soil redistribution processes. To understand the landscape-scale effect of these redistribution processes on SOC dynamics, it is essential to account for long-term changes following land conversion as typical soil-erosion-induced processes, e.g. dynamic replacement, only take place after former forest soils reach a new equilibrium following conversion. Overall, it was estimated that, after 1000 years of arable land use, SOC redistribution by tillage and water results in a current-day landscape-scale C sink of up to 0.66 ‰ yr−1 of the current SOC stocks.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"27 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140607641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-16DOI: 10.5194/egusphere-2024-1047
Eunji Byun, Fereidoun Rezanezhad, Stephanie Slowinski, Christina Lam, Saraswati Saraswati, Stephanie Wright, William L. Quinton, Kara L. Webster, Philippe Van Cappellen
Abstract. The adverse impacts of excessive soil nutrients on water quality and carbon sequestration have been recognized in tropical and temperate regions, with already widespread industrial farming and urbanization, but rarely in subarctic regions. However, recent studies have shown significant increases in porewater nitrogen (N) and phosphorus (P) concentrations in burned subarctic peatlands and downstream waters, which is a growing concern as climate change leads to increasing wildfires, permafrost thaws, and waterlogged peatlands. In this study, we present the results of a short-term incubation experiment conducted on soils from subarctic bogs and fens, aimed at evaluating the effects of high levels of nutrients on carbon gas production rates. We divided aliquots of the peatland soil samples into separate containers and added artificial porewater to each, enriching them with dissolved inorganic nitrogen (N), phosphorus (P), both, or none for controls. Overall, the fen samples showed higher carbon dioxide (CO2) and methane (CH4) production rates at 1, 5, 15, and 25 °C compared to the bog samples, which we attributed to differences in soil properties and initial microbial biomass. The bog sample with added N produced more CO2 compared to its control, while the fen sample with added P produced more CO2 compared to its control. It was unexpected that the addition of both N and P reduced CO2 but increased CH4 production in both soils compared to their controls. After a month, the pore water C, N, and P stochiometric ratios approached the initial soil microbial biomass ratios, suggesting microbial nutrient recycling in an inherently nutrient-poor soil environment. These preliminary results imply a complex response of carbon turnover in peatland soils to nutrient enrichment.
摘要过多的土壤养分对水质和碳封存的不利影响已在工业化耕作和城市化已经普及的热带和温带地区得到公认，但在亚北极地区却鲜有发现。然而，最近的研究表明，在烧毁的亚北极泥炭地和下游水域中，孔隙水氮（N）和磷（P）的浓度显著增加，随着气候变化导致野火、永久冻土融化和泥炭地积水的增加，这种情况日益受到关注。在本研究中，我们介绍了在亚北极沼泽和沼泽土壤上进行的短期培养实验的结果，该实验旨在评估高浓度养分对碳气体产生率的影响。我们将泥炭地土壤样本等分到不同的容器中，并分别加入人工孔隙水，同时加入溶解的无机氮（N）、磷（P）或两者，或不加入任何无机氮（N）、磷（P）作为对照。总体而言，与沼泽样本相比，沼泽样本在 1、5、15 和 25 °C 温度下的二氧化碳 (CO2) 和甲烷 (CH4) 生成率更高，我们认为这是由于土壤特性和初始微生物生物量的差异造成的。与对照组相比，添加了氮的沼泽样本产生了更多的二氧化碳，而添加了磷的沼泽样本则产生了更多的二氧化碳。令人意想不到的是，与对照组相比，添加 N 和 P 会减少两种土壤中的 CO2 生成量，但会增加 CH4 生成量。一个月后，孔隙水的碳、氮和磷计量比率接近土壤微生物生物量的初始比率，这表明在固有养分贫乏的土壤环境中微生物进行了养分循环。这些初步结果表明泥炭地土壤中的碳周转对养分富集有复杂的反应。
{"title":"Complexity of nutrient enrichment on subarctic peatland soil CO2 and CH4 production under increasing wildfire and permafrost thaw","authors":"Eunji Byun, Fereidoun Rezanezhad, Stephanie Slowinski, Christina Lam, Saraswati Saraswati, Stephanie Wright, William L. Quinton, Kara L. Webster, Philippe Van Cappellen","doi":"10.5194/egusphere-2024-1047","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1047","url":null,"abstract":"<strong>Abstract.</strong> The adverse impacts of excessive soil nutrients on water quality and carbon sequestration have been recognized in tropical and temperate regions, with already widespread industrial farming and urbanization, but rarely in subarctic regions. However, recent studies have shown significant increases in porewater nitrogen (N) and phosphorus (P) concentrations in burned subarctic peatlands and downstream waters, which is a growing concern as climate change leads to increasing wildfires, permafrost thaws, and waterlogged peatlands. In this study, we present the results of a short-term incubation experiment conducted on soils from subarctic bogs and fens, aimed at evaluating the effects of high levels of nutrients on carbon gas production rates. We divided aliquots of the peatland soil samples into separate containers and added artificial porewater to each, enriching them with dissolved inorganic nitrogen (N), phosphorus (P), both, or none for controls. Overall, the fen samples showed higher carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) production rates at 1, 5, 15, and 25 °C compared to the bog samples, which we attributed to differences in soil properties and initial microbial biomass. The bog sample with added N produced more CO<sub>2</sub> compared to its control, while the fen sample with added P produced more CO<sub>2</sub> compared to its control. It was unexpected that the addition of both N and P reduced CO<sub>2</sub> but increased CH<sub>4</sub> production in both soils compared to their controls. After a month, the pore water C, N, and P stochiometric ratios approached the initial soil microbial biomass ratios, suggesting microbial nutrient recycling in an inherently nutrient-poor soil environment. These preliminary results imply a complex response of carbon turnover in peatland soils to nutrient enrichment.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"37 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140556455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-15DOI: 10.5194/soil-10-275-2024
Johan Six, Sebastian Doetterl, Moritz Laub, Claude R. Müller, Marijn Van de Broek
Abstract. The concept of soil organic carbon (SOC) saturation emerged a bit more than 2 decades ago as our mechanistic understanding of SOC stabilization increased. Recently, the further testing of the concept across a wide range of soil types and environments has led some people to challenge the fundamentals of soil C saturation. Here, we argue that, to test this concept, one should pay attention to six fundamental principles or “rights” (R's): the right measures, the right units, the right dispersive energy and application, the right soil type, the right clay type, and the right saturation level. Once we take care of those six rights across studies, we find a maximum of C stabilized by minerals and estimate based on current data available that this maximum stabilization is around 82 ± 4 g C kg−1 silt + clay for 2 : 1-clay-dominated soils while most likely being only around 46 ± 4 g C kg−1 silt + clay for 1 : 1-clay-dominated soils. These estimates can be further improved using more data, especially for different clay types across varying environmental conditions. However, the bigger challenge is a matter of which C sequestration strategies to implement and how to implement them in order to effectively reach this 82/46 g C kg−1 silt + clay in soils across the globe.
摘要。二十多年前，随着我们对土壤有机碳（SOC）稳定机理认识的加深，土壤有机碳（SOC）饱和度的概念应运而生。最近，随着这一概念在多种土壤类型和环境中的进一步验证，一些人对土壤有机碳饱和度的基本原理提出了质疑。在此，我们认为，要检验这一概念，应该注意六项基本原则或 "权利"（R）：正确的措施、正确的单位、正确的分散能量和应用、正确的土壤类型、正确的粘土类型以及正确的饱和度。一旦我们在各项研究中都考虑到了这六项权利，我们就会发现矿物稳定的碳的最大值，并根据现有数据估计，对于 2 ：而对于 1 ：而对于 1 : 1-粘土为主的土壤，则很可能只有约 46 ± 4 g C kg-1 淤泥 + 粘土。利用更多数据，特别是不同环境条件下不同粘土类型的数据，可以进一步改进这些估计值。然而，更大的挑战在于要实施哪些固碳策略以及如何实施这些策略，以便在全球土壤中有效地达到 82/46 克 C kg-1 淤泥+粘土的固碳水平。
{"title":"The six rights of how and when to test for soil C saturation","authors":"Johan Six, Sebastian Doetterl, Moritz Laub, Claude R. Müller, Marijn Van de Broek","doi":"10.5194/soil-10-275-2024","DOIUrl":"https://doi.org/10.5194/soil-10-275-2024","url":null,"abstract":"Abstract. The concept of soil organic carbon (SOC) saturation emerged a bit more than 2 decades ago as our mechanistic understanding of SOC stabilization increased. Recently, the further testing of the concept across a wide range of soil types and environments has led some people to challenge the fundamentals of soil C saturation. Here, we argue that, to test this concept, one should pay attention to six fundamental principles or “rights” (R's): the right measures, the right units, the right dispersive energy and application, the right soil type, the right clay type, and the right saturation level. Once we take care of those six rights across studies, we find a maximum of C stabilized by minerals and estimate based on current data available that this maximum stabilization is around 82 ± 4 g C kg−1 silt + clay for 2 : 1-clay-dominated soils while most likely being only around 46 ± 4 g C kg−1 silt + clay for 1 : 1-clay-dominated soils. These estimates can be further improved using more data, especially for different clay types across varying environmental conditions. However, the bigger challenge is a matter of which C sequestration strategies to implement and how to implement them in order to effectively reach this 82/46 g C kg−1 silt + clay in soils across the globe.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"8 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140553631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-11DOI: 10.5194/egusphere-2024-804
Samuel Franco-Luesma, María Alonso-Ayuso, Benjamin Wolf, Borja Latorre, Jorge Álvaro-Fuentes
Abstract. Over the last decades and due to the current climate change situation, the study of the impacts of human activities on climate has reached great importance, being agriculture one of the main sources of soil greenhouse gas. There are different techniques to quantify the soil gas fluxes, such as micrometeorological techniques or chamber techniques, being the last one capable to assess different treatment at the same site. Manual chambers are the most common one. However, due to the low sampling frequency, this approach cannot resolve short-term emission events, like fertilization or rewetting. For this reason, automated chamber systems are an opportunity to improve soil gas flux determination, but their distribution is still scarce due to the cost and challenging technical implementation. The objective of this study was to develop an automated chamber system for agricultural systems under Mediterranean conditions and compare measured GHG flux rates to those derived using manual chambers. A comparison between manual and automated chamber systems was conducted to evaluate the soil gas fluxes obtained by the automated system. Moreover, over a period of one month the soil gas fluxes were determined by both systems to compare their capabilities to capture the temporal variability of soil gas emissions. The automated system reported higher soil GHG fluxes compared to the manual chamber system. Additionally, the higher sampling frequency of the automated chamber system allowed for the capture of daily flux variations, resulting in a more accurate estimation of cumulative soil gas emissions. The study emphasises the importance of chamber dimension and shape, as well as sampling frequency, in the development of chamber systems, especially when using the manual chamber system.
{"title":"Measurement of greenhouse gas fluxes in agricultural soils with a flexible, open-design automated system","authors":"Samuel Franco-Luesma, María Alonso-Ayuso, Benjamin Wolf, Borja Latorre, Jorge Álvaro-Fuentes","doi":"10.5194/egusphere-2024-804","DOIUrl":"https://doi.org/10.5194/egusphere-2024-804","url":null,"abstract":"<strong>Abstract.</strong> Over the last decades and due to the current climate change situation, the study of the impacts of human activities on climate has reached great importance, being agriculture one of the main sources of soil greenhouse gas. There are different techniques to quantify the soil gas fluxes, such as micrometeorological techniques or chamber techniques, being the last one capable to assess different treatment at the same site. Manual chambers are the most common one. However, due to the low sampling frequency, this approach cannot resolve short-term emission events, like fertilization or rewetting. For this reason, automated chamber systems are an opportunity to improve soil gas flux determination, but their distribution is still scarce due to the cost and challenging technical implementation. The objective of this study was to develop an automated chamber system for agricultural systems under Mediterranean conditions and compare measured GHG flux rates to those derived using manual chambers. A comparison between manual and automated chamber systems was conducted to evaluate the soil gas fluxes obtained by the automated system. Moreover, over a period of one month the soil gas fluxes were determined by both systems to compare their capabilities to capture the temporal variability of soil gas emissions. The automated system reported higher soil GHG fluxes compared to the manual chamber system. Additionally, the higher sampling frequency of the automated chamber system allowed for the capture of daily flux variations, resulting in a more accurate estimation of cumulative soil gas emissions. The study emphasises the importance of chamber dimension and shape, as well as sampling frequency, in the development of chamber systems, especially when using the manual chamber system.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"163 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140545013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-11DOI: 10.5194/soil-10-251-2024
Christophe Djemiel, Samuel Dequiedt, Walid Horrigue, Arthur Bailly, Mélanie Lelièvre, Julie Tripied, Charles Guilland, Solène Perrin, Gwendoline Comment, Nicolas P. A. Saby, Claudy Jolivet, Antonio Bispo, Line Boulonne, Antoine Pierart, Patrick Wincker, Corinne Cruaud, Pierre-Alain Maron, Sébastien Terrat, Lionel Ranjard
Abstract. The fungal kingdom is among the most diversified kingdoms on Earth, with estimations of up to 12 million species. However, it remains poorly understood, with only 150 000 fungal species currently described. Given the major ecological role of fungi in ecosystem functioning, these numbers stress the importance of investigating fungal diversity description across different ecosystem types. Here, we explored the spatial distribution of the soil fungal diversity on a broad geographical scale, using the French Soil Quality Monitoring Network that covers the whole French territory (2171 soils sampled along a systematic grid). Fungal alpha diversity was assessed directly from soil DNA using a meta-barcoding approach by targeting the 18S rDNA gene. The total accumulated fungal diversity across France included 136 219 operational taxonomic units (OTUs), i.e., about 1 % of worldwide soil fungal diversity (based on a maximum diversity estimate of 12 million) for a territory representing only 0.3 % of the terrestrial surface on Earth. Based on this dataset, the first extensive map of fungal alpha diversity was drawn and showed a heterogeneous and spatially structured distribution in large biogeographical patterns of 231 km radius for richness (Hill diversity of order 0) and smaller patterns of 36 km radius for dominant fungi (Hill diversity of order 2). As related to other environmental parameters, the spatial distribution of fungal diversity (Hill numbers based on different orders of diversity) was mainly influenced by local filters such as soil characteristics and land management and also by global filters such as climate conditions with various relative influences. Interestingly, cropped soils exhibited the highest pool of fungal diversity relative to forest and vineyard soils. To complement this, soil fungal OTU network interactions were calculated for the different land uses across France. They varied hugely and showed a loss of 75 % of the complexity in crop systems and grasslands compared to forests and up to 83 % in vineyard systems. Overall, our study revealed that a nationwide survey with a high spatial-resolution approach is relevant for deeply investigating the spatial distribution and determinism of soil fungal diversity. Our findings provide novel insights for a better understanding of soil fungal ecology across the 18S rDNA gene and upgrade biodiversity conservation policies by supplying representative repositories dedicated to soil fungi.
{"title":"Unraveling biogeographical patterns and environmental drivers of soil fungal diversity at the French national scale","authors":"Christophe Djemiel, Samuel Dequiedt, Walid Horrigue, Arthur Bailly, Mélanie Lelièvre, Julie Tripied, Charles Guilland, Solène Perrin, Gwendoline Comment, Nicolas P. A. Saby, Claudy Jolivet, Antonio Bispo, Line Boulonne, Antoine Pierart, Patrick Wincker, Corinne Cruaud, Pierre-Alain Maron, Sébastien Terrat, Lionel Ranjard","doi":"10.5194/soil-10-251-2024","DOIUrl":"https://doi.org/10.5194/soil-10-251-2024","url":null,"abstract":"Abstract. The fungal kingdom is among the most diversified kingdoms on Earth, with estimations of up to 12 million species. However, it remains poorly understood, with only 150 000 fungal species currently described. Given the major ecological role of fungi in ecosystem functioning, these numbers stress the importance of investigating fungal diversity description across different ecosystem types. Here, we explored the spatial distribution of the soil fungal diversity on a broad geographical scale, using the French Soil Quality Monitoring Network that covers the whole French territory (2171 soils sampled along a systematic grid). Fungal alpha diversity was assessed directly from soil DNA using a meta-barcoding approach by targeting the 18S rDNA gene. The total accumulated fungal diversity across France included 136 219 operational taxonomic units (OTUs), i.e., about 1 % of worldwide soil fungal diversity (based on a maximum diversity estimate of 12 million) for a territory representing only 0.3 % of the terrestrial surface on Earth. Based on this dataset, the first extensive map of fungal alpha diversity was drawn and showed a heterogeneous and spatially structured distribution in large biogeographical patterns of 231 km radius for richness (Hill diversity of order 0) and smaller patterns of 36 km radius for dominant fungi (Hill diversity of order 2). As related to other environmental parameters, the spatial distribution of fungal diversity (Hill numbers based on different orders of diversity) was mainly influenced by local filters such as soil characteristics and land management and also by global filters such as climate conditions with various relative influences. Interestingly, cropped soils exhibited the highest pool of fungal diversity relative to forest and vineyard soils. To complement this, soil fungal OTU network interactions were calculated for the different land uses across France. They varied hugely and showed a loss of 75 % of the complexity in crop systems and grasslands compared to forests and up to 83 % in vineyard systems. Overall, our study revealed that a nationwide survey with a high spatial-resolution approach is relevant for deeply investigating the spatial distribution and determinism of soil fungal diversity. Our findings provide novel insights for a better understanding of soil fungal ecology across the 18S rDNA gene and upgrade biodiversity conservation policies by supplying representative repositories dedicated to soil fungi.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"38 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140544760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-10DOI: 10.5194/soil-10-231-2024
Simon Oberholzer, Laura Summerauer, Markus Steffens, Chinwe Ifejika Speranza
Abstract. Conventional laboratory analysis of soil properties is often expensive and requires much time if various soil properties are to be measured. Visual and near-infrared (vis–NIR) spectroscopy offers a complementary and cost-efficient way to gain a wide variety of soil information at high spatial and temporal resolutions. Yet, applying vis–NIR spectroscopy requires confidence in the prediction accuracy of the infrared models. In this study, we used soil data from six agricultural fields in eastern Switzerland and calibrated (i) field-specific (local) models and (ii) general models (combining all fields) for soil organic carbon (SOC), permanganate oxidizable carbon (POXC), total nitrogen (N), total carbon (C) and pH using partial least-squares regression. The 30 local models showed a ratio of performance to deviation (RPD) between 1.14 and 5.27, and the root mean square errors (RMSE) were between 1.07 and 2.43 g kg−1 for SOC, between 0.03 and 0.07 g kg−1 for POXC, between 0.09 and 0.14 g kg−1 for total N, between 1.29 and 2.63 g kg−1 for total C, and between 0.04 and 0.19 for pH. Two fields with high carbonate content and poor correlation between the target properties were responsible for six local models with a low performance (RPD < 2). Analysis of variable importance in projection, as well as of correlations between spectral variables and target soil properties, confirmed that high carbonate content masked absorption features for SOC. Field sites with low carbonate content can be combined with general models with only a limited loss in prediction accuracy compared to the field-specific models. On the other hand, for fields with high carbonate contents, the prediction accuracy substantially decreased in general models. Whether the combination of soils with high carbonate contents in one prediction model leads to satisfying prediction accuracies needs further investigation.
摘要如果要测量各种土壤特性，传统的实验室土壤特性分析往往成本高昂且需要大量时间。可见光和近红外（vis-NIR）光谱法提供了一种互补且具有成本效益的方法，可在高空间和时间分辨率下获取各种土壤信息。然而，应用可见近红外光谱仪需要对红外模型的预测准确性有信心。在这项研究中，我们使用了来自瑞士东部六块农田的土壤数据，并使用偏最小二乘回归法校准了（i）针对特定农田的（局部）模型和（ii）针对土壤有机碳（SOC）、高锰酸盐氧化碳（POXC）、全氮（N）、全碳（C）和 pH 值的一般模型（结合所有农田）。30 个本地模型的性能偏差比（RPD）介于 1.14 和 5.27 之间，均方根误差（RMSE）介于 1.07 和 2.43 g kg-1 之间（SOC）、0.03 和 0.07 g kg-1 之间（POXC）、0.09 和 0.14 g kg-1 之间（总氮）、1.29 和 2.63 g kg-1 之间（总碳）以及 0.04 和 0.19 之间（pH 值）。两块碳酸盐含量较高且目标属性之间相关性较差的田块导致 6 个本地模型性能较低（RPD < 2）。对投影中变量重要性以及光谱变量与目标土壤特性之间相关性的分析证实，碳酸盐含量高会掩盖 SOC 的吸收特征。碳酸盐含量低的田地可与一般模型相结合，但与特定田地模型相比，预测精度损失有限。另一方面，对于碳酸盐含量较高的田地，一般模型的预测准确性大幅下降。在一个预测模型中结合碳酸盐含量高的土壤是否会带来令人满意的预测精度，还需要进一步研究。
{"title":"Best performances of visible–near-infrared models in soils with little carbonate – a field study in Switzerland","authors":"Simon Oberholzer, Laura Summerauer, Markus Steffens, Chinwe Ifejika Speranza","doi":"10.5194/soil-10-231-2024","DOIUrl":"https://doi.org/10.5194/soil-10-231-2024","url":null,"abstract":"Abstract. Conventional laboratory analysis of soil properties is often expensive and requires much time if various soil properties are to be measured. Visual and near-infrared (vis–NIR) spectroscopy offers a complementary and cost-efficient way to gain a wide variety of soil information at high spatial and temporal resolutions. Yet, applying vis–NIR spectroscopy requires confidence in the prediction accuracy of the infrared models. In this study, we used soil data from six agricultural fields in eastern Switzerland and calibrated (i) field-specific (local) models and (ii) general models (combining all fields) for soil organic carbon (SOC), permanganate oxidizable carbon (POXC), total nitrogen (N), total carbon (C) and pH using partial least-squares regression. The 30 local models showed a ratio of performance to deviation (RPD) between 1.14 and 5.27, and the root mean square errors (RMSE) were between 1.07 and 2.43 g kg−1 for SOC, between 0.03 and 0.07 g kg−1 for POXC, between 0.09 and 0.14 g kg−1 for total N, between 1.29 and 2.63 g kg−1 for total C, and between 0.04 and 0.19 for pH. Two fields with high carbonate content and poor correlation between the target properties were responsible for six local models with a low performance (RPD < 2). Analysis of variable importance in projection, as well as of correlations between spectral variables and target soil properties, confirmed that high carbonate content masked absorption features for SOC. Field sites with low carbonate content can be combined with general models with only a limited loss in prediction accuracy compared to the field-specific models. On the other hand, for fields with high carbonate contents, the prediction accuracy substantially decreased in general models. Whether the combination of soils with high carbonate contents in one prediction model leads to satisfying prediction accuracies needs further investigation.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"136 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140541595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. It is still difficult to precisely quantify and predict the effects of drying-rewetting cycles (DWCs) on soil carbon dioxide (CO2) release due to the paucity of studies using constant moisture conditions equivalent to the mean water content during DWC incubation. The present study was performed to evaluate overall trends in the effects of DWCs on CO2 release and to explore environmental and soil predictors for variations in the effect size in 10 Japanese forests and pastureland soils variously affected by volcanic ash during their pedogenesis. Over an 84-day incubation period including three DWCs, CO2 release was 1.3- to 3.7-fold greater than under continuous constant moisture conditions (p < 0.05) with the same mean water content as in the DWC incubations. Analysis of the relations between this increasing magnitude of CO2 release by DWCs (IFCO2) and various environmental and soil properties revealed significant positive correlations between IFCO2 and soil organometal complex contents (p < 0.05), especially pyrophosphate extractable aluminum (Alp) content (r = 0.74). Molar ratios of soil total carbon (C) and pyrophosphate-extractable C (Cp) to Alp contents and soil carbon content-specific CO2 release rate under continuous constant moisture conditions (qCO2_soc) were also correlated with IFCO2 (p < 0.05). The covariations among Alp, total C, and Cp to Alp molar ratios and qCO2_soc suggested Alp as the primary predictor of IFCO2. Whereas soil microbial biomass C and nitrogen (N) levels were significantly lower in DWCs than under continuous constant moisture conditions, there was no significant relation between the microbial biomass decrease and IFCO2. The present study showed a comprehensive increase in soil CO2 release by DWC in Japanese forests and pastureland soils, suggesting that Alp is a predictor of the effect size likely due to vulnerability of organo-Al complexes to DWC.
{"title":"Comprehensive increase in CO2 release by drying-rewetting cycles among Japanese forests and pastureland soils and exploring predictors of increasing magnitude","authors":"Yuri Suzuki, Syuntaro Hiradate, Jun Koarashi, Mariko Atarashi-Andoh, Takumi Yomogida, Yuki Kanda, Hirohiko Nagano","doi":"10.5194/egusphere-2024-419","DOIUrl":"https://doi.org/10.5194/egusphere-2024-419","url":null,"abstract":"<strong>Abstract.</strong> It is still difficult to precisely quantify and predict the effects of drying-rewetting cycles (DWCs) on soil carbon dioxide (CO<sub>2</sub>) release due to the paucity of studies using constant moisture conditions equivalent to the mean water content during DWC incubation. The present study was performed to evaluate overall trends in the effects of DWCs on CO<sub>2</sub> release and to explore environmental and soil predictors for variations in the effect size in 10 Japanese forests and pastureland soils variously affected by volcanic ash during their pedogenesis. Over an 84-day incubation period including three DWCs, CO<sub>2</sub> release was 1.3- to 3.7-fold greater than under continuous constant moisture conditions (<em>p</em> < 0.05) with the same mean water content as in the DWC incubations. Analysis of the relations between this increasing magnitude of CO<sub>2</sub> release by DWCs (IF<sub><em>CO</em>2</sub>) and various environmental and soil properties revealed significant positive correlations between IF<sub><em>CO</em>2</sub> and soil organometal complex contents (<em>p</em> < 0.05), especially pyrophosphate extractable aluminum (Alp) content (<em>r</em> = 0.74). Molar ratios of soil total carbon (C) and pyrophosphate-extractable C (Cp) to Alp contents and soil carbon content-specific CO<sub>2</sub> release rate under continuous constant moisture conditions (qCO<sub>2</sub>_soc) were also correlated with IF<sub><em>CO</em>2</sub> (<em>p</em> < 0.05). The covariations among Alp, total C, and Cp to Alp molar ratios and qCO<sub>2</sub>_soc suggested Alp as the primary predictor of IF<sub><em>CO</em>2</sub>. Whereas soil microbial biomass C and nitrogen (N) levels were significantly lower in DWCs than under continuous constant moisture conditions, there was no significant relation between the microbial biomass decrease and IF<sub><em>CO</em>2</sub>. The present study showed a comprehensive increase in soil CO<sub>2</sub> release by DWC in Japanese forests and pastureland soils, suggesting that Alp is a predictor of the effect size likely due to vulnerability of organo-Al complexes to DWC.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"47 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140538470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-02DOI: 10.5194/egusphere-2024-848
Sergio Aranda-Barranco, Penélope Serrano-Ortiz, Andrew S. Kowalski, Enrique P. Sánchez-Cañete
Abstract. Soil respiration (Rs) is an important carbon flux in terrestrial ecosystems and knowledge about this CO2 release process and the drivers involved is a key topic in the context of global change. However, temporal, and spatial variability has not been extensively studied in semiarid systems such as olive groves. In this study, we show a full year of continuous measurements of Rs with six automatic chambers in a fertirrigated olive grove with bare soil in the Mediterranean accompanied by ecosystem respiration (Reco) obtained using the eddy covariance (EC) technique. To study spatial variability, the automatic chambers were distributed equally under the canopy (Rs Under-Tree) and in the center of the alley (Rs Alley), and the gradient of Rs between both locations was measured in several manual campaigns in addition to azimuthal changes about the center of the olive trees. The results indicate that Rs Under-Tree was three times larger than Rs Alley in the annual computations. Higher Rs was found on the south face, and an exponential decay of Rs was observed until the alley's center was reached. These spatial changes were used to weigh and project Rs to the ecosystem scale, whose annual balance was 1.6–2.3 higher than Reco estimated using EC-derived models. The daytime Reco model performs better the greater the influence of Rs Under-Tree and the night-time Reco model and Rs covaried more the higher the fraction of Rs Alley. We found values of Q10 < 1 in the vicinity of the olive tree and Rs Under-Tree represented 39 % of the Rs of the olive grove. CO2 pulses associated with precipitation events were detected, especially in the alley, during dry periods, and after extended periods without rain, but were not accurately detected by EC-derived models. We point out an interaction between several effects that vary in time and are different under the canopy than in the alleys that the accepted models to estimate Q10 and Reco do not consider. These results show a high spatial and temporal heterogeneity in soil respiration and the factors involved, which must be considered in future work in semi-arid agrosystems.
{"title":"Spatial and temporal heterogeneity of soil respiration in a bare-soil Mediterranean olive grove","authors":"Sergio Aranda-Barranco, Penélope Serrano-Ortiz, Andrew S. Kowalski, Enrique P. Sánchez-Cañete","doi":"10.5194/egusphere-2024-848","DOIUrl":"https://doi.org/10.5194/egusphere-2024-848","url":null,"abstract":"<strong>Abstract.</strong> Soil respiration (R<sub>s</sub>) is an important carbon flux in terrestrial ecosystems and knowledge about this CO<sub>2</sub> release process and the drivers involved is a key topic in the context of global change. However, temporal, and spatial variability has not been extensively studied in semiarid systems such as olive groves. In this study, we show a full year of continuous measurements of R<sub>s</sub> with six automatic chambers in a fertirrigated olive grove with bare soil in the Mediterranean accompanied by ecosystem respiration (R<sub>eco</sub>) obtained using the eddy covariance (EC) technique. To study spatial variability, the automatic chambers were distributed equally under the canopy (R<sub>s Under-Tree</sub>) and in the center of the alley (R<sub>s Alley</sub>), and the gradient of R<sub>s</sub> between both locations was measured in several manual campaigns in addition to azimuthal changes about the center of the olive trees. The results indicate that R<sub>s Under-Tree </sub>was three times larger than R<sub>s Alley</sub> in the annual computations. Higher R<sub>s</sub> was found on the south face, and an exponential decay of R<sub>s</sub> was observed until the alley's center was reached. These spatial changes were used to weigh and project R<sub>s </sub>to the ecosystem scale, whose annual balance was 1.6–2.3 higher than R<sub>eco</sub> estimated using EC-derived models. The daytime R<sub>eco</sub> model performs better the greater the influence of R<sub>s Under-Tree </sub>and the night-time R<sub>eco</sub> model and R<sub>s</sub> covaried more the higher the fraction of R<sub>s Alley</sub>. We found values of Q<sub>10</sub> < 1 in the vicinity of the olive tree and R<sub>s Under-Tree </sub>represented 39 % of the R<sub>s</sub> of the olive grove. CO<sub>2</sub> pulses associated with precipitation events were detected, especially in the alley, during dry periods, and after extended periods without rain, but were not accurately detected by EC-derived models. We point out an interaction between several effects that vary in time and are different under the canopy than in the alleys that the accepted models to estimate Q<sub>10</sub> and R<sub>eco</sub> do not consider. These results show a high spatial and temporal heterogeneity in soil respiration and the factors involved, which must be considered in future work in semi-arid agrosystems.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"76 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140340535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-03-26DOI: 10.5194/egusphere-2024-593
Laura Kuusemets, Ülo Mander, Jordi Escuer-Gatius, Alar Astover, Karin Kauer, Kaido Soosaar, Mikk Espenberg
Abstract.Fertilised soils are a significant source of nitrous oxide (N2O), a highly active greenhouse gas and stratospheric ozone depleter. Nitrogen (N) fertilisers, while boosting crop yield, also lead to N2O into the atmosphere, impacting global warming. We investigated relationships between mineral N fertilisation rates and additional manure amendment with different crop types through the analysis of abundances of N cycle functional genes, soil N2O and N2 emissions, nitrogen use efficiency (NUE), soil physicochemical analysis and biomass production. Our study indicates that N2O emissions are predominantly dependent on the mineral N fertilisation rate and enhance with increased mineral N fertilisation rate. Higher N2O emissions were attained with the application of manure. Manure amendment also increased the number of N cycle genes that are significant in the change of N2O. Contrary to our hypothesis, there was no significant influence of crop type on soil N2O emissions. The study indicated dominance of nitrification over denitrification in the soil. Microbial analyses also showed the potential role of comammox and DNRA processes as a source of N2O. Our study did not find soil moisture to be significantly linked to N2O emissions. Results of the study provide evidence that for wheat, a fertilisation rate of 80 kg N ha−1 is closest to the optimal rate for balancing biomass yield, N2O emissions, and achieving high NUE. Sorghum showed potential for cultivation in temperate climate, as sorghum maintained low N2O emissions and N losses on mineral N fertilisation rate of 80 kg N ha−1.
{"title":"Interactions of fertilisation and crop productivity on soil nitrogen cycle microbiome and gas emissions","authors":"Laura Kuusemets, Ülo Mander, Jordi Escuer-Gatius, Alar Astover, Karin Kauer, Kaido Soosaar, Mikk Espenberg","doi":"10.5194/egusphere-2024-593","DOIUrl":"https://doi.org/10.5194/egusphere-2024-593","url":null,"abstract":"<strong>Abstract.</strong> <span>Fertilised soils are a significant source of nitrous oxide (N<sub>2</sub>O), a highly active greenhouse gas and stratospheric ozone depleter. Nitrogen (N) fertilisers, while boosting crop yield, also lead to N<sub>2</sub>O into the atmosphere, impacting global warming. We investigated relationships between mineral N fertilisation rates and additional manure amendment with different crop types through the analysis of abundances of N cycle functional genes, soil N<sub>2</sub>O and N<sub>2</sub> emissions, nitrogen use efficiency (NUE), soil physicochemical analysis and biomass production. Our study indicates that N<sub>2</sub>O emissions are predominantly dependent on the mineral N fertilisation rate and enhance with increased mineral N fertilisation rate. Higher N<sub>2</sub>O emissions were attained with the application of manure. Manure amendment also increased the number of N cycle genes that are significant in the change of N<sub>2</sub>O. Contrary to our hypothesis, there was no significant influence of crop type on soil N<sub>2</sub>O emissions. The study indicated dominance of nitrification over denitrification in the soil. Microbial analyses also showed the potential role of comammox and DNRA processes as a source of N<sub>2</sub>O. Our study did not find soil moisture to be significantly linked to N<sub>2</sub>O emissions. Results of the study provide evidence that for wheat, a fertilisation rate of 80 kg N ha<sup>−1</sup> is closest to the optimal rate for balancing biomass yield, N<sub>2</sub>O emissions, and achieving high NUE. Sorghum showed potential for cultivation in temperate climate, as sorghum maintained low N<sub>2</sub>O emissions and N losses on mineral N fertilisation rate of 80 kg N ha<sup>−1</sup>. </span>","PeriodicalId":48610,"journal":{"name":"Soil","volume":"31 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140291503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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