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Cheng H, Xing D, Twagirayezu G, Lin S, Gu S, Tu C, Hill PW, Chadwick DR, Jones DL. Effects of field-aging on the impact of biochar on herbicide fate and microbial community structure in the soil environment. Chemosphere 2024; 348:140682. [PMID: 37952819 DOI: 10.1016/j.chemosphere.2023.140682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 10/10/2023] [Accepted: 11/08/2023] [Indexed: 11/14/2023]
Abstract
Biochar can enhance organic carbon storage and mitigate the adverse effects of pesticides in the soil. However, the mechanisms by which field-aging affects the impacts of biochar on herbicide behavior and the composition of microbial communities in the soil remain unclear. This study aimed to investigate the influences of aged and fresh biochar on herbicide behavior and microbial community structure in the soil. Herein, with 14C-labeled technology, aged treatment (soil amended with field-aged biochar), fresh treatment (soil amended with fresh biochar), and control (soil without biochar) were installed to evaluate their treatment capacities. The results showed that the average leaching out and mineralization of simazine in the aged treatment were significantly higher by 4.8% and 1.66% (P < 0.05) compared with the fresh treatment. Relative to the control, the pesticide was significantly adsorbed (P < 0.05) in the aged treatment. The abundance of arbuscular mycorrhizal fungi (AMF) significantly increased by 1.03 and 1.16-fold, whereas fungi increased dramatically by 1.02-fold and decreased by 1.21-fold in the aged and fresh treatments, respectively (P < 0.05). In addition, eukaryotes were effectively reduced by 1.02 and 1.14-fold in these treatments, respectively (P < 0.05). This study suggests that field aging can undermine the impacts of biochar on pesticides and modify the microbial community structure in the soil environment.
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Affiliation(s)
- Hongguang Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou, 550002, China; School of Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK.
| | - Dan Xing
- Guizhou Academy of Agricultural Science, Institute of Pepper Guiyang, Guiyang, 550000, China
| | - Gratien Twagirayezu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou, 550002, China
| | - Shan Lin
- School of Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shangyi Gu
- College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
| | - Chenglong Tu
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Gui'an New Region, Guiyang, 550025, China
| | - Paul W Hill
- School of Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - David R Chadwick
- School of Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - Davey L Jones
- School of Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK; SoilsWest, Centre for Sustainable Farming Systems, Food Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
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2
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Dodd RJ, Chadwick DR, Hill PW, Hayes F, Sánchez-Rodríguez AR, Gwynn-Jones D, Smart SM, Jones DL. Resilience of ecosystem service delivery in grasslands in response to single and compound extreme weather events. Sci Total Environ 2023; 861:160660. [PMID: 36464051 DOI: 10.1016/j.scitotenv.2022.160660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Extreme weather events are increasing in frequency and magnitude with profound effects on ecosystem functioning. Further, there is now a greater likelihood that multiple extreme events are occurring within a single year. Here we investigated the effect of a single drought, flood or compound (flood + drought) extreme event on temperate grassland ecosystem processes in a field experiment. To assess system resistance and resilience, we studied changes in a wide range of above- and below-ground indicators (plant diversity and productivity, greenhouse gas emissions, soil chemical, physical and biological metrics) during the 8 week stress events and then for 2 years post-stress. We hypothesized that agricultural grasslands would have different degrees of resistance and resilience to flood and drought stress. We also investigated two alternative hypotheses that the combined flood + drought treatment would either, (A) promote ecosystem resilience through more rapid recovery of soil moisture conditions or (B) exacerbate the impact of the single flood or drought event. Our results showed that flooding had a much greater effect than drought on ecosystem processes and that the grassland was more resistant and resilient to drought than to flood. The immediate impact of flooding on all indicators was negative, especially for those related to production, and climate and water regulation. Flooding stress caused pronounced and persistent shifts in soil microbial and plant communities with large implications for nutrient cycling and long-term ecosystem function. The compound flood + drought treatment failed to show a more severe impact than the single extreme events. Rather, there was an indication of quicker recovery of soil and microbial parameters suggesting greater resilience in line with hypothesis (A). This study clearly reveals that contrasting extreme weather events differentially affect grassland ecosystem function but that concurrent events of a contrasting nature may promote ecosystem resilience to future stress.
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Affiliation(s)
- Rosalind J Dodd
- UK Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Ave, Bailrigg LA1 4AP, UK; Environment Centre Wales, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK.
| | - David R Chadwick
- Environment Centre Wales, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Paul W Hill
- Environment Centre Wales, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Felicity Hayes
- UK Centre for Ecology and Hydrology, Environment Centre Wales, Bangor, Gwynedd LL57 2UW, UK
| | - Antonio R Sánchez-Rodríguez
- Environment Centre Wales, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK; Departamento de Agronomía, Universidad de Córdoba, Córdoba 14071, Spain
| | - Dylan Gwynn-Jones
- Department of Life Sciences, Aberystwyth University, Aberystwyth, Ceredigion SY23 3DA, UK
| | - Simon M Smart
- UK Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Ave, Bailrigg LA1 4AP, UK
| | - Davey L Jones
- Environment Centre Wales, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK; SoilsWest, Centre for Sustainable Farming Systems, Food Futures Institute, Murdoch University, Murdoch, WA 6105, Australia
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3
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Cheng H, Xing D, Lin S, Deng Z, Wang X, Ning W, Hill PW, Chadwick DR, Jones DL. Iron-Modified Biochar Strengthens Simazine Adsorption and Decreases Simazine Decomposition in the Soil. Front Microbiol 2022; 13:901658. [PMID: 35847072 PMCID: PMC9283092 DOI: 10.3389/fmicb.2022.901658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Currently, modified biochar has been successfully used in the remediation of soil polluted with heavy metals. However, the effects of the modified biochar on pesticides (such as simazine) are still unclear. Herein, the environmental fate of simazine, such as decomposition, leaching, and adsorption in unamended soil, in the soil amended with unmodified and modified biochar (biochar + FeCl3, biochar + FeOS, biochar + Fe) were evaluated. In addition, an incubation experiment was also performed to observe the influence of modified biochar on the microbial community and diversity in the soil. The results showed that modified biochar significantly decreased the decomposition of simazine in the soil compared to its counterpart. Modified biochar also reduced the concentration of simazine in the leachate. Compared with the control, soil microbial biomass in the soil amended with unmodified biochar, biochar + FeCl3, biochar + Fe, and biochar + FeOS was decreased by 5.3%, 18.8%, 8.7%, and 18.1%, respectively. Furthermore, modified biochar changed the structure of the microbial community. This shows that modified biochar could increase the soil adsorption capacity for simazine and change the amount and microbial community that regulates the fate of simazine in the soil. This study concludes that iron-modified biochar has positive and negative effects on the soil. Therefore, its advantages and side effects should be considered before applying it to the soil.
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Affiliation(s)
- Hongguang Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
- School of Natural Science, Bangor University, Bangor, United Kingdom
- *Correspondence: Hongguang Cheng,
| | - Dan Xing
- Institute of Pepper Guiyang, Guizhou Academy of Agricultural Science, Guiyang, China
| | - Shan Lin
- School of Natural Science, Bangor University, Bangor, United Kingdom
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), College of Resources and Environment, Huazhong Agricultural University, Ministry of Agriculture, Wuhan, China
| | - Zhaoxia Deng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
- College of Resources and Environment Engineering, Guizhou University, Guiyang, China
| | - Xi Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), College of Resources and Environment, Huazhong Agricultural University, Ministry of Agriculture, Wuhan, China
| | - Wenjing Ning
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
- College of Resources and Environment, Yangtze University, Wuhan, China
| | - Paul W. Hill
- School of Natural Science, Bangor University, Bangor, United Kingdom
| | - David R. Chadwick
- School of Natural Science, Bangor University, Bangor, United Kingdom
| | - Davey L. Jones
- School of Natural Science, Bangor University, Bangor, United Kingdom
- SoilsWest, Centre for Sustainable Farming Systems, Food Futures Institute, Murdoch University, Murdoch, WA, Australia
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Simfukwe P, Hill PW, Emmett BA, Jones DL. Identification and predictability of soil quality indicators from conventional soil and vegetation classifications. PLoS One 2021; 16:e0248665. [PMID: 34679075 PMCID: PMC8535190 DOI: 10.1371/journal.pone.0248665] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 09/30/2021] [Indexed: 11/27/2022] Open
Abstract
The physical, chemical and biological attributes of a soil combined with abiotic factors (e.g. climate and topography) drive pedogenesis and some of these attributes have been used as proxies to soil quality. Thus, we investigated: (1) whether appropriate soil quality indicators (SQIs) could be identified in soils of Great Britain, (2) whether conventional soil classification or aggregate vegetation classes (AVCs) could predict SQIs and (3) to what extent do soil types and/ or AVCs act as major regulators of SQIs. Factor analysis was used to group 20 soil attributes into six SQI which were named as; soil organic matter (SOM), dissolved organic matter (DOM), soluble N, reduced N, microbial biomass, DOM humification (DOMH). SOM was identified as the most important SQI in the discrimination of both soil types and AVCs. Soil attributes constituting highly to the SOM factor were, microbial quotient and bulk density. The SOM indicator discriminated three soil type groupings and four aggregate vegetation class groupings. Among the soil types, only the peat soils were discriminated from other groups while among the AVCs only the heath and bog classes were isolated from others. However, the peat soil and heath and bog AVC were the only groups that were distinctly discriminated from other groups. All other groups heavily overlapped with one another, making it practically impossible to define reference values for each soil type or AVC. The two-way ANOVA showed that the AVCs were a better regulator of the SQIs than the soil types. We conclude that conventionally classified soil types cannot predict the SQIs defined from large areas with differing climatic and edaphic factors. Localised areas with similar climatic and topoedaphic factors may hold promise for the definition of SQI that may predict the soil types or AVCs.
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Affiliation(s)
- Paul Simfukwe
- Department of Agricultural Biotechnology and Biosciences, School of Agriculture and Natural Resources, Mulungushi University, Kabwe, Central Province, Zambia
- * E-mail: ,
| | - Paul W. Hill
- School of the Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, United Kingdom
| | - Bridget A. Emmett
- Centre for Ecology and Hydrology, Environment Centre Wales, Bangor, Gwynedd, United Kingdom
| | - Davey L. Jones
- School of the Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, United Kingdom
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5
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Greenfield LM, Hill PW, Paterson E, Baggs EM, Jones DL. Do plants use root-derived proteases to promote the uptake of soil organic nitrogen? Plant Soil 2020; 456:355-367. [PMID: 33087989 PMCID: PMC7567722 DOI: 10.1007/s11104-020-04719-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
AIMS The capacity of plant roots to directly acquire organic nitrogen (N) in the form of oligopeptides and amino acids from soil is well established. However, plants have poor access to protein, the central reservoir of soil organic N. Our question is: do plants actively secrete proteases to enhance the breakdown of soil protein or are they functionally reliant on soil microorganisms to undertake this role? METHODS Growing maize and wheat under sterile hydroponic conditions with and without inorganic N, we measured protease activity on the root surface (root-bound proteases) or exogenously in the solution (free proteases). We compared root protease activities to the rhizosphere microbial community to estimate the ecological significance of root-derived proteases. RESULTS We found little evidence for the secretion of free proteases, with almost all protease activity associated with the root surface. Root protease activity was not stimulated under N deficiency. Our findings suggest that cereal roots contribute one-fifth of rhizosphere protease activity. CONCLUSIONS Our results indicate that plant N uptake is only functionally significant when soil protein is in direct contact with root surfaces. The lack of protease upregulation under N deficiency suggests that root protease activity is unrelated to enhanced soil N capture.
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Affiliation(s)
| | - Paul W. Hill
- School of Natural Sciences, Bangor University, Gwynedd, LL57 2UW UK
| | - Eric Paterson
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH UK
| | - Elizabeth M. Baggs
- Global Academy of Agriculture and Food Security, the Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG UK
| | - Davey L. Jones
- School of Natural Sciences, Bangor University, Gwynedd, LL57 2UW UK
- SoilsWest, UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009 Australia
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6
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Alexandre A, Quintã R, Hill PW, Jones DL, Santos R. Ocean warming increases the nitrogen demand and the uptake of organic nitrogen of the globally distributed seagrass
Zostera marina. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ana Alexandre
- Marine Plant Ecology Research Group Centre of Marine Sciences (CCMAR) University of Algarve Faro Portugal
| | - Raquel Quintã
- Portuguese Institute of the Sea and Atmosphere (IPMA) Aquaculture Research Station (EPPO) Olhão Portugal
| | - Paul W. Hill
- School of Natural Sciences Bangor University Gwynedd UK
| | - Davey L. Jones
- School of Natural Sciences Bangor University Gwynedd UK
- The Oceans Institute The University of Western Australia Perth WA Australia
| | - Rui Santos
- Marine Plant Ecology Research Group Centre of Marine Sciences (CCMAR) University of Algarve Faro Portugal
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7
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Hill PW, Broughton R, Bougoure J, Havelange W, Newsham KK, Grant H, Murphy DV, Clode P, Ramayah S, Marsden KA, Quilliam RS, Roberts P, Brown C, Read DJ, Deluca TH, Bardgett RD, Hopkins DW, Jones DL. Angiosperm symbioses with non-mycorrhizal fungal partners enhance N acquisition from ancient organic matter in a warming maritime Antarctic. Ecol Lett 2019; 22:2111-2119. [PMID: 31621153 PMCID: PMC6899649 DOI: 10.1111/ele.13399] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/26/2019] [Accepted: 09/10/2019] [Indexed: 01/01/2023]
Abstract
In contrast to the situation in plants inhabiting most of the world’s ecosystems, mycorrhizal fungi are usually absent from roots of the only two native vascular plant species of maritime Antarctica, Deschampsia antarctica and Colobanthus quitensis. Instead, a range of ascomycete fungi, termed dark septate endophytes (DSEs), frequently colonise the roots of these plant species. We demonstrate that colonisation of Antarctic vascular plants by DSEs facilitates not only the acquisition of organic nitrogen as early protein breakdown products, but also as non‐proteinaceous d‐amino acids and their short peptides, accumulated in slowly‐decomposing organic matter, such as moss peat. Our findings suggest that, in a warming maritime Antarctic, this symbiosis has a key role in accelerating the replacement of formerly dominant moss communities by vascular plants, and in increasing the rate at which ancient carbon stores laid down as moss peat over centuries or millennia are returned to the atmosphere as CO2.
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Affiliation(s)
- Paul W Hill
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Richard Broughton
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 OET, UK.,Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Jeremy Bougoure
- Faculty of Science, SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, 6009, Australia.,Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, WA, 6009, Australia
| | | | - Kevin K Newsham
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 OET, UK
| | - Helen Grant
- Life Sciences Mass Spectrometry Facility, Lancaster Environment Centre, Lancaster, LA1 4AP, UK
| | - Daniel V Murphy
- Faculty of Science, SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, 6009, Australia
| | - Peta Clode
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, WA, 6009, Australia.,UWA School of Biological Sciences, University of Western Australia, Crawley, WA, 6009, Australia
| | - Soshila Ramayah
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Karina A Marsden
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Vic., 3010, Australia
| | - Richard S Quilliam
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Paula Roberts
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Caley Brown
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - David J Read
- Animal and Plant Sciences, University of Sheffield, Western bank, Sheffield, S10 2TN, UK
| | - Thomas H Deluca
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, 59812, USA
| | - Richard D Bardgett
- School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK
| | - David W Hopkins
- SRUC - Scotland's Rural College, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Davey L Jones
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,Faculty of Science, SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, 6009, Australia
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8
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Cowan N, Levy P, Drewer J, Carswell A, Shaw R, Simmons I, Bache C, Marinheiro J, Brichet J, Sanchez-Rodriguez AR, Cotton J, Hill PW, Chadwick DR, Jones DL, Misselbrook TH, Skiba U. Application of Bayesian statistics to estimate nitrous oxide emission factors of three nitrogen fertilisers on UK grasslands. Environ Int 2019; 128:362-370. [PMID: 31078005 PMCID: PMC6520472 DOI: 10.1016/j.envint.2019.04.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/04/2019] [Accepted: 04/24/2019] [Indexed: 06/09/2023]
Abstract
Trapezoidal integration by linear interpolation of data points is by far the most commonly used method of cumulative flux calculations of nitrous oxide (N2O) in studies that use flux chambers; however, this method is incapable of providing accurate uncertainty estimates. A Bayesian approach was used to calculate N2O emission factors (EFs) and their associated uncertainties from flux chamber measurements made after the application of nitrogen fertilisers, in the form of ammonium nitrate (AN), urea (Ur) and urea treated with Agrotain® urease inhibitor (UI) at four grassland sites in the UK. The comparison between the cumulative fluxes estimated using the Bayesian and linear interpolation methods were broadly similar (R2 = 0.79); however, the Bayesian method was capable of providing realistic uncertainties when a limited number of data points is available. The study reports mean EF values (and 95% confidence intervals) of 0.60 ± 0.63, 0.29 ± 0.22 and 0.26 ± 0.17% of applied N emitted as N2O for the AN, Ur and UI treatments, respectively. There was no significant difference between N2O emissions from the Ur and UI treatments. In the case of the automatic chamber data collected at one site in this study, the data did not fit the log-normal model, implying that more complex models may be needed, particularly for measurement data with high temporal resolution.
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Affiliation(s)
- N Cowan
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK.
| | - P Levy
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK
| | - J Drewer
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK
| | - A Carswell
- Rothamsted Research, Sustainable Agriculture Sciences, North Wyke, Devon, UK
| | - R Shaw
- School of Natural Sciences, Bangor University, Gwynedd, UK
| | - I Simmons
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK
| | - C Bache
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK
| | - J Marinheiro
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK; Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, Lisboa, Portugal
| | - J Brichet
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK
| | - A R Sanchez-Rodriguez
- School of Natural Sciences, Bangor University, Gwynedd, UK; Departamento de Agronomía, Universidad de Córdoba, ETSIAM, Córdoba, Spain
| | - J Cotton
- School of Natural Sciences, Bangor University, Gwynedd, UK
| | - P W Hill
- School of Natural Sciences, Bangor University, Gwynedd, UK
| | - D R Chadwick
- School of Natural Sciences, Bangor University, Gwynedd, UK
| | - D L Jones
- School of Natural Sciences, Bangor University, Gwynedd, UK; UWA School of Agriculture and Environment, University of Western Australia, Crawley, Australia
| | - T H Misselbrook
- Rothamsted Research, Sustainable Agriculture Sciences, North Wyke, Devon, UK
| | - U Skiba
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, UK
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9
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Hill PW, Jones DL. Plant-microbe competition: does injection of isotopes of C and N into the rhizosphere effectively characterise plant use of soil N? New Phytol 2019; 221:796-806. [PMID: 30196574 DOI: 10.1111/nph.15433] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 07/17/2018] [Indexed: 05/09/2023]
Abstract
Despite considerable attention over the last 25 yr, the importance of early protein breakdown products to plant nitrogen (N) nutrition remains uncertain. We used rhizosphere injection of 15 N-, 13 C- and 14 C-labelled inorganic N and amino acid (l-alanine), with chase periods from 1 min to 24 h, to investigate the duration of competition for amino acid between roots (Triticum aestivum) and soil microorganisms. We further investigated how microbial modification of l-alanine influenced plant carbon (C) and N recovery. From recovery of C isotopes, intact alanine uptake was 0.2-1.3% of added. Soil microbes appeared to remove alanine from soil solution within 1 min and release enough NH4+ to account for all plant 15 N recovery (over 24 h) within 5 min. Microbially generated inorganic or keto acid C accounted for < 25% of the lowest estimate of intact alanine uptake. Co-location of C and N labels appears a reasonable measure of intact uptake. Potential interference from microbially modified C is probably modest, but may increase with chase period. Similarly, competition for l-alanine is complete within a few minutes in soil, whereas NO3- added at the same rate is available for > 24 h, indicating that long chase periods bias outcomes and fail to accurately simulate soil processes.
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Affiliation(s)
- Paul W Hill
- School of Environment, Natural Resources and Geography, Environment Centre Wales, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - Davey L Jones
- School of Environment, Natural Resources and Geography, Environment Centre Wales, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
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10
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de Sosa LL, Glanville HC, Marshall MR, Schnepf A, Cooper DM, Hill PW, Binley A, Jones DL. Stoichiometric constraints on the microbial processing of carbon with soil depth along a riparian hillslope. Biol Fertil Soils 2018; 54:949-963. [PMID: 30956377 PMCID: PMC6413827 DOI: 10.1007/s00374-018-1317-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 09/11/2018] [Accepted: 09/27/2018] [Indexed: 06/01/2023]
Abstract
Soil organic matter (SOM) content is a key indicator of riparian soil functioning and in the provision of ecosystem services such as water retention, flood alleviation, pollutant attenuation and carbon (C) sequestration for climate change mitigation. Here, we studied the importance of microbial biomass and nutrient availability in regulating SOM turnover rates. C stabilisation in soil is expected to vary both vertically, down the soil profile and laterally across the riparian zone. In this study, we evaluated the influence of five factors on C mineralisation (Cmin): (i) substrate quantity, (ii) substrate quality, (iii) nutrient (C, N and P) stoichiometry, (iv) soil microbial activity with proximity to the river (2 to 75 m) and (v) as a function of soil depth (0-3 m). Substrate quality, quantity and nutrient stoichiometry were evaluated using high and low molecular weight 14C-labelled dissolved organic (DOC) along with different nutrient additions. Differences in soil microbial activity with proximity to the river and soil depth were assessed by comparing initial (immediate) Cmin rates and cumulative C mineralised at the end of the incubation period. Overall, microbial biomass C (MBC), organic matter (OM) and soil moisture content (MC) proved to be the major factors controlling rates of Cmin at depth. Differences in the immediate and medium-term response (42 days) of Cmin suggested that microbial growth increased and carbon use efficiency (CUE) decreased down the soil profile. Inorganic N and/or P availability had little or no effect on Cmin suggesting that microbial community growth and activity is predominantly C limited. Similarly, proximity to the watercourse also had relatively little effect on Cmin. This work challenges current theories suggesting that areas adjacent to watercourse process C differently from upslope areas. In contrast, our results suggest that substrate quality and microbial biomass are more important in regulating C processing rates rather than proximity to a river.
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Affiliation(s)
- Laura L. de Sosa
- Environment Centre Wales, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW UK
| | - Helen C. Glanville
- Environment Centre Wales, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW UK
- School of Geography, Geology and the Environment, Keele University, Keele, Staffordshire ST5 5BG UK
| | - Miles R. Marshall
- Environment Centre Wales, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW UK
| | - Andrea Schnepf
- Department of Forest and Soil Sciences, University of Natural Resources and Applied Life Sciences, Vienna, Austria
| | - David M. Cooper
- Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW UK
| | - Paul W. Hill
- Environment Centre Wales, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW UK
| | - Andrew Binley
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
| | - Davey L. Jones
- Environment Centre Wales, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW UK
- UWA School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 Australia
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Sánchez-Rodríguez AR, Hill PW, Chadwick DR, Jones DL. Crop residues exacerbate the negative effects of extreme flooding on soil quality. Biol Fertil Soils 2017; 53:751-765. [PMID: 32009699 PMCID: PMC6961515 DOI: 10.1007/s00374-017-1214-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/17/2017] [Accepted: 05/26/2017] [Indexed: 06/10/2023]
Abstract
Extreme flood events are predicted to have a negative impact on soil quality. Currently, there is a lack of information about the effect of agricultural practices on soil functioning and microbial processes under these events. We hypothesized that the impact of flooding on soil quality will be exacerbated when crop residues are present in the soil as they will induce more extreme anaerobicity. A spring extreme flood event (10 °C, 9 weeks) was simulated in mesocosms containing an arable sandy-loam soil low in nutrients. The main treatments were (1) with and without flooding and (2) with and without maize residue addition (8 Mg ha-1). We monitored changes in soil chemical quality indicators (e.g. pH, salinity, Fe3+, P, C, NH4 +, NO3 - and organic N), greenhouse gas (GHG) emissions (CO2, CH4, N2O) and soil microbial community composition (PLFAs) during a prolonged flood period (9 weeks) and an 8-week "recovery" period after flooding. In comparison to the other treatments, flooding in the presence of crop residues resulted in a dramatic drop in soil redox potential. This was associated with the enhanced release of Fe and C into solution and an increase in CH4 emissions. In contrast, maize residues reduced potential nitrate losses and N2O emissions, possibly due to complete denitrification and microbial N immobilization. Both flooding and maize residues stimulated microbial growth and promoted a shift in microbial community composition. Following floodwater removal, most of the soil quality indicators returned to the levels of the control treatment within 5 weeks. After this short recovery phase, no major impact of flooding could be observed on plant growth (maize pot-grown). Overall, we conclude that both extreme flooding and management regime negatively impact upon a range of soil quality indicators (e.g. redox, GHG emissions); however, the soil showed high resilience and recovered quickly after floodwater removal. Further work is required to investigate the impact of repeated extreme flood events on soil quality and function over longer timescales.
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Affiliation(s)
| | - Paul W. Hill
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd LL57 2UW UK
| | - David R. Chadwick
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd LL57 2UW UK
| | - Davey L. Jones
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd LL57 2UW UK
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Hill PW, Garnett MH, Farrar J, Iqbal Z, Khalid M, Soleman N, Jones DL. Living roots magnify the response of soil organic carbon decomposition to temperature in temperate grassland. Glob Chang Biol 2015; 21:1368-75. [PMID: 25351704 PMCID: PMC4365897 DOI: 10.1111/gcb.12784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 09/18/2014] [Accepted: 10/18/2014] [Indexed: 05/20/2023]
Abstract
Increasing atmospheric carbon dioxide (CO2 ) concentration is both a strong driver of primary productivity and widely believed to be the principal cause of recent increases in global temperature. Soils are the largest store of the world's terrestrial C. Consequently, many investigations have attempted to mechanistically understand how microbial mineralisation of soil organic carbon (SOC) to CO2 will be affected by projected increases in temperature. Most have attempted this in the absence of plants as the flux of CO2 from root and rhizomicrobial respiration in intact plant-soil systems confounds interpretation of measurements. We compared the effect of a small increase in temperature on respiration from soils without recent plant C with the effect on intact grass swards. We found that for 48 weeks, before acclimation occurred, an experimental 3 °C increase in sward temperature gave rise to a 50% increase in below ground respiration (ca. 0.4 kg C m(-2) ; Q10 = 3.5), whereas mineralisation of older SOC without plants increased with a Q10 of only 1.7 when subject to increases in ambient soil temperature. Subsequent (14) C dating of respired CO2 indicated that the presence of plants in swards more than doubled the effect of warming on the rate of mineralisation of SOC with an estimated mean C age of ca. 8 years or older relative to incubated soils without recent plant inputs. These results not only illustrate the formidable complexity of mechanisms controlling C fluxes in soils but also suggest that the dual biological and physical effects of CO2 on primary productivity and global temperature have the potential to synergistically increase the mineralisation of existing soil C.
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Affiliation(s)
- Paul W Hill
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
- Correspondence: Paul W. Hill, tel. +44 1248 382632, fax +44 1248 354997, e-mail:
| | - Mark H Garnett
- NERC Radiocarbon Facility, Scottish Enterprise Technology ParkEast Kilbride, G75 0QF, UK
| | - John Farrar
- School of Biological Sciences, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
| | - Zafar Iqbal
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
- Nuclear Institute for Agriculture and BiologyFaisalabad, Pakistan
| | - Muhammad Khalid
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
- Institute of Soil and Environmental Sciences, University of AgricultureFaisalabad, Pakistan
| | - Nawaf Soleman
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
| | - Davey L Jones
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
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Wilkinson A, Hill PW, Vaieretti MV, Farrar JF, Jones DL, Bardgett RD. Challenging the paradigm of nitrogen cycling: no evidence of in situ resource partitioning by coexisting plant species in grasslands of contrasting fertility. Ecol Evol 2015; 5:275-87. [PMID: 25691957 PMCID: PMC4314261 DOI: 10.1002/ece3.1244] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 07/18/2014] [Accepted: 07/25/2014] [Indexed: 11/12/2022] Open
Abstract
In monoculture, certain plant species are able to preferentially utilize different nitrogen (N) forms, both inorganic and organic, including amino acids and peptides, thus forming fundamental niches based on the chemical form of N. Results from field studies, however, are inconsistent: Some showing that coexisting plant species predominantly utilize inorganic N, while others reveal distinct interspecies preferences for different N forms. As a result, the extent to which hypothetical niches are realized in nature remains unclear. Here, we used in situ stable isotope tracer techniques to test the idea, in temperate grassland, that niche partitioning of N based on chemical form is related to plant productivity and the relative availability of organic and inorganic N. We also tested in situ whether grassland plants vary in their ability to compete for, and utilize peptides, which have recently been shown to act as an N source for plants in strongly N-limited ecosystems. We hypothesized that plants would preferentially use NO3 (-)-N and NH4 (+)-N over dissolved organic N in high-productivity grassland where inorganic N availability is high. On the other hand, in low-productivity grasslands, where the availability of dissolved inorganic N is low, and soil availability of dissolved organic N is greater, we predicted that plants would preferentially use N from amino acids and peptides, prior to microbial mineralization. Turves from two well-characterized grasslands of contrasting productivity and soil N availability were injected, in situ, with mixtures of (15)N-labeled inorganic N (NO3 (-) and NH4 (+)) and (13)C(15)N labeled amino acid (l-alanine) and peptide (l-tri-alanine). In order to measure rapid assimilation of these N forms by soil microbes and plants, the uptake of these substrates was traced within 2.5 hours into the shoots of the most abundant plant species, as well as roots and the soil microbial biomass. We found that, contrary to our hypothesis, the majority of plant species across both grasslands took up most N in the form of NH4 (+), suggesting that inorganic N is their predominant N source. However, we did find that organic N was a source of N which could be utilized by plant species at both sites, and in the low-productivity grassland, plants were able to capture some tri-alanine-N directly. Although our findings did not support the hypothesis that differences in the availability of inorganic and organic N facilitate resource partitioning in grassland, they do support the emerging view that peptides represent a significant, but until now neglected, component of the terrestrial N cycle.
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Affiliation(s)
- Anna Wilkinson
- Lancaster Environment Centre, Lancaster UniversityBailrigg, Lancaster, LA1 4YQ, U.K
- Faculty of Life Sciences, Michael Smith Building, The University of ManchesterOxford Road, Manchester, M13 9PT, U.K
| | - Paul W Hill
- School of Environment, Natural Resources and Geography, College of Natural Sciences, Bangor UniversityGwynedd, LL57 2UW, U.K
| | - María V Vaieretti
- Instituto Multidisciplinario de Biología Vegetal (IMBIV)Casilla de Correo 495, 5000, Córdoba, Argentina
| | - John F Farrar
- School of Environment, Natural Resources and Geography, College of Natural Sciences, Bangor UniversityGwynedd, LL57 2UW, U.K
| | - Davey L Jones
- School of Environment, Natural Resources and Geography, College of Natural Sciences, Bangor UniversityGwynedd, LL57 2UW, U.K
| | - Richard D Bardgett
- Lancaster Environment Centre, Lancaster UniversityBailrigg, Lancaster, LA1 4YQ, U.K
- Faculty of Life Sciences, Michael Smith Building, The University of ManchesterOxford Road, Manchester, M13 9PT, U.K
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Affiliation(s)
- Johannes Rousk
- Section of Microbial Ecology Department of Biology Lund University Lund Sweden
| | - Paul W. Hill
- School of Environment Natural Resources and Geography Bangor University Bangor UK
| | - Davey L. Jones
- School of Environment Natural Resources and Geography Bangor University Bangor UK
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Jones DL, Simfukwe P, Hill PW, Mills RTE, Emmett BA. Evaluation of dissolved organic carbon as a soil quality indicator in national monitoring schemes. PLoS One 2014; 9:e90882. [PMID: 24633085 PMCID: PMC3954595 DOI: 10.1371/journal.pone.0090882] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 02/03/2014] [Indexed: 11/19/2022] Open
Abstract
Background Monitoring the properties of dissolved organic carbon (DOC) in soil water is frequently used to evaluate changes in soil quality and to explain shifts in freshwater ecosystem functioning. Methods Using >700 individual soils (0–15 cm) collected from a 209,331 km2 area we evaluated the relationship between soil classification (7 major soil types) or vegetation cover (8 dominant classes, e.g. cropland, grassland, forest) and the absorbance properties (254 and 400 nm), DOC quantity and quality (SUVA, total soluble phenolics) of soil water. Results Overall, a good correlation (r2 = 0.58) was apparent between soil water absorbance and DOC concentration across the diverse range of soil types tested. In contrast, both DOC and the absorbance properties of soil water provided a poor predictor of SUVA or soluble phenolics which we used as a measure of humic substance concentration. Significant overlap in the measured ranges for UV absorbance, DOC, phenolic content and especially SUVA of soil water were apparent between the 8 vegetation and 7 soil classes. A number of significant differences, however, were apparent within these populations with total soluble phenolics giving the greatest statistical separation between both soil and vegetation groups. Conclusions We conclude that the quality of DOC rather than its quantity provides a more useful measure of soil quality in large scale surveys.
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Affiliation(s)
- David L. Jones
- School of the Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, United Kingdom
- * E-mail:
| | - Paul Simfukwe
- School of the Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, United Kingdom
| | - Paul W. Hill
- School of the Environment, Natural Resources & Geography, Bangor University, Bangor, Gwynedd, United Kingdom
| | - Robert T. E. Mills
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Laboratory of Ecological Systems (ECOS), Lausanne, Switzerland
| | - Bridget A. Emmett
- Centre for Ecology and Hydrology, Environment Centre Wales, Bangor, Gwynedd, United Kingdom
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Hill PW, Marsden KA, Jones DL. How significant to plant N nutrition is the direct consumption of soil microbes by roots? New Phytol 2013; 199:948-955. [PMID: 23718181 PMCID: PMC3838624 DOI: 10.1111/nph.12320] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/07/2013] [Indexed: 05/13/2023]
Abstract
The high degree to which plant roots compete with soil microbes for organic forms of nitrogen (N) is becoming increasingly apparent. This has culminated in the finding that plants may consume soil microbes as a source of N, but the functional significance of this process remains unknown. We used (15) N- and (14) C-labelled cultures of soil bacteria to measure rates of acquisition of microbes by sterile wheat roots and plants growing in soil. We compared these rates with acquisition of (15) N delivered as nitrate, amino acid monomer (l-alanine) and short peptide (l-tetraalanine), and the rate of decomposition of [(14) C] microbes by indigenous soil microbiota. Acquisition of microbe (15) N by both sterile roots and roots growing in soil was one to two orders of magnitude slower than acquisition of all other forms of (15) N. Decomposition of microbes was fast enough to account for all (15) N recovered, but approximately equal recovery of microbe (14) C suggests that microbes entered roots intact. Uptake of soil microbes by wheat (Triticum aestivum) roots appears to take place in soil. If wheat is typical, the importance of this process to terrestrial N cycling is probably minor in comparison with fluxes of other forms of soil inorganic and organic N.
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Affiliation(s)
- Paul W Hill
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
| | - Karina A Marsden
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
| | - Davey L Jones
- School of Environment, Natural Resources and Geography, Bangor UniversityBangor, Gwynedd, LL57 2UW, UK
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Glanville HC, Hill PW, Maccarone LD, N. Golyshin P, Murphy DV, Jones DL. Temperature and water controls on vegetation emergence, microbial dynamics, and soil carbon and nitrogen fluxes in a high Arctic tundra ecosystem. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.02056.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Helen C. Glanville
- School of Environment; Natural Resources and Geography; Bangor University; Gwynedd LL57 2UW UK
| | - Paul W. Hill
- School of Environment; Natural Resources and Geography; Bangor University; Gwynedd LL57 2UW UK
| | - Linda D. Maccarone
- Soil Biology Group; School of Earth and Environment; The University of Western Australia; Crawley WA Australia
| | - Peter N. Golyshin
- School of Biological Sciences; Bangor University; Gwynedd LL57 2UW UK
| | - Daniel V. Murphy
- Soil Biology Group; School of Earth and Environment; The University of Western Australia; Crawley WA Australia
| | - Davey L. Jones
- School of Environment; Natural Resources and Geography; Bangor University; Gwynedd LL57 2UW UK
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Farrell M, Hill PW, Farrar J, DeLuca TH, Roberts P, Kielland K, Dahlgren R, Murphy DV, Hobbs PJ, Bardgett RD, Jones DL. Oligopeptides Represent a Preferred Source of Organic N Uptake: A Global Phenomenon? Ecosystems 2012. [DOI: 10.1007/s10021-012-9601-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Williamson JC, Rowe EC, Hill PW, Nason MA, Jones DL, Healey JR. Alleviation of Both Water and Nutrient Limitations is Necessary to Accelerate Ecological Restoration of Waste Rock Tips. Restor Ecol 2011. [DOI: 10.1111/j.1526-100x.2009.00575.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Hill PW, Klapatch TR, Lynd LR. Bioenergetics and end-product regulation of Clostridium thermosaccharolyticum in response to nutrient limitation. Biotechnol Bioeng 2010; 42:873-83. [PMID: 18613135 DOI: 10.1002/bit.260420712] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Fermentation of xylose by Clostridium thermosaccharolyticum was studied in batch and continuous culture in which the limiting nutrient was either xylose, phosphate, or ammonia. Transient results obtained in continuous cultures with batch grown inoculum and progressively higher feed substrate concentrations exhibited ethanol selectivities (moles ethanol/moles other products) in excess of 11. The hypothesis that this high ethanol selectivity was a general response to mineral nutrient limitation was tested but could not be supported. Growth and substrate consumption were related by the equation q(s)(1 - Y(x) (c))G(ATP) = (mu/Y(ATP) (max)) + m, with q(s) the specific rate of xylose consumption (moles xylose/hour . g cells), Y(x) (c) the carbon based cell yield (g cell carbon/g substrate carbon), G(ATP) the ATP gain (moles ATP produces/mol substrate catabolized), micro the specific growth rate (1/h), Y(ATP) (max) the ATP-based cell yield (g cells/mol ATP), and m the maintenance coefficient (moles ATP/hour . g cells). Y(ATP) (max) was found to be 11.6 g cells/mol ATP, and m 9.3 mol ATP/hour . g cells for growth on defined medium. Different responses to nutrient limitation were observed depending on the mode of cultivation. Batch and immobilized cell continuous cultures decreased G(ATP) by initiating production of the secondary metabolites, propanediol, and in some cases, D-lactate; in addition, batch cultures increased the fractional allocation of ATP to maintenance and/or wastage. Nitrogen-limited continuous free-cell cultures maintained a constant cell yield, whereas phosphate-limited continuous free-cell cultures did not. In the case of phosphate limitation, the decreased ATP demand associated with the lowered cell yield was accompanied by an increased rate of ATP consumption for maintenance and/or wastage. Neither nitrogen or phosphorus-limited continuous free-cell cultures exhibited an altered G(ATP) in response to mineral nutrient limitation, and neither produced secondary metabolites.
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Affiliation(s)
- P W Hill
- R. W. Johnson Pharmaceutical Research Institute, Raritan, New Jersey, USA
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Hill PW, Handley L, Raven J. Juniperus communisL. ssp.communisat Balnaguard, Scotland: Foliar carbon discrimination (δ13C) and 15-N natural abundance (δ15N) suggest gender-linked differences in water and N use. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/03746609608684842] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Koerber GR, Edwards-Jones G, Hill PW, Canals LMI, Nyeko P, York EH, Jones DL. Geographical variation in carbon dioxide fluxes from soils in agro-ecosystems and its implications for life-cycle assessment. J Appl Ecol 2009. [DOI: 10.1111/j.1365-2664.2009.01622.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hill PW, Marshall C, Williams GG, Blum H, Harmens H, Jones DL, Farrar JF. The fate of photosynthetically-fixed carbon in Lolium perenne grassland as modified by elevated CO2 and sward management. New Phytol 2007; 173:766-777. [PMID: 17286825 DOI: 10.1111/j.1469-8137.2007.01966.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Prediction of the impact of climate change requires the response of carbon (C) flow in plant-soil systems to increased CO(2) to be understood. A mechanism by which grassland C sequestration might be altered was investigated by pulse-labelling Lolium perenne swards, which had been subject to CO(2) enrichment and two levels of nitrogen (N) fertilization for 10 yr, with (14)CO(2). Over a 6-d period 40-80% of the (14)C pulse was exported from mature leaves, 1-2% remained in roots, 2-7% was lost as below-ground respiration, 0.1% was recovered in soil solution, and 0.2-1.5% in soil. Swards under elevated CO(2) with the lower N supply fixed more (14)C than swards grown in ambient CO(2), exported more fixed (14)C below ground and respired less than their high-N counterparts. Sward cutting reduced root (14)C, but plants in elevated CO(2) still retained 80% more (14)C below ground than those in ambient CO(2). The potential for below-ground C sequestration in grasslands is enhanced under elevated CO(2), but any increase is likely to be small and dependent upon grassland management.
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Affiliation(s)
- P W Hill
- School of Biological Sciences, University of Wales Bangor, Robinson Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - C Marshall
- School of Biological Sciences, University of Wales Bangor, Robinson Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - G G Williams
- School of Biological Sciences, University of Wales Bangor, Robinson Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - H Blum
- Federal Institute of Technology (ETH) Zurich, Institute of Plant Sciences, Experimental Station Eschikon 33, CH-8315 Lindau, Switzerland
| | - H Harmens
- Centre for Ecology and Hydrology, Orton Building, Deiniol Road, Bangor, Gwynedd LL57 2UP, UK
| | - D L Jones
- School of the Environment and Natural Resources, University of Wales Bangor, Thoday Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - J F Farrar
- School of Biological Sciences, University of Wales Bangor, Robinson Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
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Hill PW, Raven JA, Sutton MA. Leaf age-related differences in apoplastic NH(4)(+) concentration, pH and the NH(3) compensation point for a wild perennial. J Exp Bot 2002; 53:277-286. [PMID: 11807131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Extracts of the foliar apoplast of leaves of different ages of Luzula sylvatica (Huds.) Gaud. were prepared by vacuum infiltration and centrifugation. Measurements of pH and concentration were performed on extracts. From these bioassay measurements the relative magnitude of NH(3) compensation points for leaves of different ages were inferred. Young leaves were found to have much higher apoplast pH than old leaves, leading to the calculation of 4-10-fold higher NH(3) compensation points. Such age-related differences in the NH(3) compensation point are considerably larger than those previously reported. Apoplast pH and concentration were found to increase during leaf expansion before declining prior to senescence. Bulk foliar tissue pH, and total N concentrations were also found to be generally higher in young leaves than in old leaves. Where a significant correlation was found, total foliar N, bulk tissue foliar and the calculated NH(3) compensation point were all found to increase with N supplied to roots, whilst apoplast and bulk tissue H(+) concentrations were found to decline. The potential of bulk foliar tissue measurements to act as simple predictors of the NH(3) compensation point is discussed.
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Affiliation(s)
- P W Hill
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK.
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Hill PW, Raven JA, Loubet B, Fowler D, Sutton MA. Comparison of gas exchange and bioassay determinations of the ammonia compensation point in Luzula sylvatica (Huds.) Gaud. Plant Physiol 2001; 125:476-87. [PMID: 11154355 PMCID: PMC61028 DOI: 10.1104/pp.125.1.476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2000] [Revised: 07/13/2000] [Accepted: 09/09/2000] [Indexed: 05/23/2023]
Abstract
Determinations of the NH(3) compensation point for the understory plant of semi-natural woodlands Luzula sylvatica (Huds.) Gaud. were carried out by measurements of gas exchange and by calculation from the NH(4)(+) concentration and pH of extracts of the foliar apoplast. Compensation points determined by gas exchange measurements were among the lowest yet reported (0.51-1.10 microg NH(3) m(-3)) and those calculated from apoplast extracts were lower than any yet reported (0.017-0.54 microg NH(3) m(-3)). Those determined by gas exchange were consistently found to be between 2 and 30 times higher than those determined from apoplast extracts. Consideration of possible causes of this discrepancy, which is not confined to this investigation, showed that all likely errors would result in an increase in the discrepancy, or were insufficient to account for observed differences. It is suggested that spatial variability of pH and NH(4)(+) concentration within the foliar apoplast represents the most promising line for further investigation. It is also shown that the foliar apoplast of L. sylvatica is sufficiently buffered to eliminate the need for correction of H(+) concentration for dilution during extraction, but that it is necessary to correct the NH(4)(+) concentration of apoplast extracts for dilution.
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Affiliation(s)
- P W Hill
- Department of Biological Sciences, University of Dundee, Dundee, Scotland DD1 4HN, United Kingdom.
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Abstract
A commercial kit for the radioisotopic assay of folate in serum, the Bio-Rad 'Quanta Count' folate kit, produced lower results than the Lactobacillus casei microbiological assay method. Its normal range was 2-0-13-0 microng/l and the reproducibility was similar to that of the microbiological assay method. The kit was also satisfactory for whole bood folate assays. The cost requires careful consideration before the kit is used for routine purposes.
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