Wetter farming: raising water table and biochar for reduced GHG emissions while maintaining crop productivity in agricultural peatlands

Abstract

Despite their high agricultural productivity, drained and cultivated peats are highly susceptible to degradation and significant sources of greenhouse gas (GHG) emissions. This study investigates the potential of water table manipulation and biochar application to mitigate GHG losses from agricultural peats. However, balancing the need for agricultural production with securing the ecosystem function of the peat under high water table (WT) conditions poses a significant challenge. Therefore, we grew lettuce in a controlled mesocosm experiment with either a high (HW) or low (LW) water table and monitored emissions of CO₂, CH₄ and N₂O over 4 months using a mesocosm method. Concurrent measurements of soil solution, plant measurements and microbial sequencing allowed identification of the key controls on GHG emissions. Raising the WT significantly reduced CO₂ emissions (18%), and N₂O emission (40%), but eventually increased CH₄ emission (2.5-fold) compared to the Control + LW. Biochar amendment with raised WT provided the strongest reduction in CO₂ equivalent GHG emission (4.64 t CO₂eq ha⁻¹ yr⁻¹), compared to Control + LW. We found that biochar amendment modified the microbial community composition and diversity (Shannon index 8.9–9.3), lowering the relative abundance of peat decomposers (such as Ascomycota). Moreover, biochar amendments produced 38–56% greater lettuce biomass compared to the unamended controls, irrespective of water table level, suggesting that biochar application could generate economic benefits in addition to reduced GHG emissions. Mechanisms responsible for these effects appeared to be both abiotic (e.g. via effects of the biochar physicochemical composition) and biotic via changing the soil microbiome. Overall, the combination of high-water table and biochar amendment enhanced total soil C, reduced peat decomposition, suppressed CH₄ and N₂O emissions, and enhanced crop yields.

Keywords

Peat / Biochar / Water table management / Nutrient cycling / Greenhouse gas emission / Lettuce biomass

References

[1] Anderson MJ (2003) DISTLM forward: a FORTRAN computer program to calculate a distance-based multivariate analysis for a linear model using forward selection. Department of Statistics, University of Auckland, New Zealand, pp 10

[2] AndersonMJ, LegendreP. An empirical comparison of permutation methods for tests of partial regression coefficients in a linear model. J Stat Comput Simul, 1999, 62: 271-303.

[3] AndersonCR, HamontsK, CloughTJ, CondronLM. Biochar does not affect soil N−transformations or microbial community structure under ruminant urine patches but does alter relative proportions of nitrogen cycling bacteria. Agr Ecosyst Environ, 2014, 191: 63-72.

[4] ArmstrongW, DrewMCRoot growth and metabolism under oxygen deficiency, plant roots, 2002, Boca Raton. CRC Press. 11391187

[5] BammingerC, ZaiserN, ZinsserP, LamersM, KammannC, MarhanS. Effects of biochar, earthworms, and litter addition on soil microbial activity and abundance in a temperate agricultural soil. Biol Fertil Soils, 2014, 50: 1189-1200.

[6] BiedermanLA, HarpoleWS. Biochar and its effects on plant productivity and nutrient cycling: a meta−analysis. GCB Bioenergy, 2013, 5: 202-214.

[7] CayuelaML, Sanchez-MonederoMA, RoigA, HanleyK, EndersA, LehmannJ. Biochar and denitrification in soils: when, how much and why does biochar reduce N2O emissions?. Sci Rep, 2013, 31732.

[8] ChurchillAC, TuretskyMR, McGuireAD, HollingsworthTN. Response of plant community structure and primary productivity to experimental drought and flooding in an Alaskan fen. Can J for Res, 2015, 45: 185-193.

[9] DavidsonSJ, Van BeestC, PetroneR, StrackM. Wildfire overrides hydrological controls on boreal peatland methane emissions. Biogeosciences, 2019, 16: 2651-2660.

[10] DawsonQ, KechavarziC, Leeds-HarrisonPB, BurtonRGO. Subsidence and degradation of agricultural peatlands in the Fenlands of Norfolk, UK. Geoderma, 2010, 154: 181-187.

[11] DeanJF, MiddelburgJJ, RöckmannT, AertsR, BlauwLG, EggerM, JettenMSM, de JongAEE, MeiselOH, RasigrafO. Methane feedbacks to the global climate system in a warmer world. Rev Geophys, 2018, 56: 207-250.

[12] Downie A, Crosky A, Munroe P (2009) Physical properties of biochar. In: Lehmann J, Joseph S (eds) Biochar for Environmental Management: Science and Technology, Earthscan, London, pp 13–32

[13] EvansCD, PeacockM, BairdAJ, ArtzRRE, BurdenA, CallaghanN, ChapmanPJ, CooperHM, CoyleM, CraigE. Overriding water table control on managed peatland greenhouse gas emissions. Nature, 2021, 593: 548-552.

[14] EvansCD, RoweRL, FreemanBWJ, RhymesJM, CummingA, LloydIL, MortonD, WilliamsonJL, MorrisonR. Biomethane produced from maize grown on peat emits more CO2 than natural gas. Nat Clim Chang, 2024, 14: 1030-1032.

[15] Evans C, Artz R, Moxley J, Smyth M-A, Taylor E, Archer E, Burden A, Williamson J, Donnelly D, Thomson A (2017) Implementation of an emissions inventory for UK peatlands. Centre for Ecology and Hydrology

[16] Evans CD, Morrison R, Cumming A, Bodo A, Burden A, Callaghan N, Clilverd H, Cooper H, Cowan N, Crabtree D (2023) Defra Lowland Peat 2: Managing agricultural systems on lowland peat for decreased greenhouse gas emissions whilst maintaining agricultural productivity. Report to Defra for Project SP1218

[17] Fierer N, Jackson RB (2006) The diversity and biogeography of soil bacterial communities. Proc National Acad Sci 103:626–631

[18] FreemanC, LiskaG, OstleNJ, LockMA, ReynoldsB, HudsonJ. Microbial activity and enzymic decomposition processes following peatland water table drawdown. Plant Soil, 1996, 180: 121-127.

[19] FreemanBWJ, EvansCD, MusarikaS, MorrisonR, NewmanTR, PageSE, WiggsGFS, BellNGA, StylesD, WenY, ChadwickDR, JonesDL. Responsible agriculture must adapt to the wetland character of mid−latitude peatlands. Glob Change Biol, 2022, 28: 3795-3811.

[20] FuY, LuoY, AuwalM, SinghBP, Van ZwietenL, XuJ. Biochar accelerates soil organic carbon mineralization via rhizodeposit−activated actinobacteria. Biol Fertil Soils, 2022, 58: 565-577.

[21] GaoJ, HouH, ZhaiY, WoodwardA, VardoulakisS, KovatsS, WilkinsonP, LiL, SongX, XuL, MengB, LiuX, WangJ, ZhaoJ, LiuQ. Greenhouse gas emissions reduction in different economic sectors: Mitigation measures, health co−benefits, knowledge gaps, and policy implications. Environ Pollut, 2018, 240: 683-698.

[22] GüntherA, BarthelmesA, HuthV, JoostenH, JurasinskiG, KoebschF, CouwenbergJ. Prompt rewetting of drained peatlands reduces climate warming despite methane emissions. Nat Commun, 2020, 111644.

[23] HouJ, PugazhendhiA, SindhuR, VinayakV, ThanhNC, BrindhadeviK, Lan ChiNT, YuanD. An assessment of biochar as a potential amendment to enhance plant nutrient uptake. Environ Res, 2022, 214113909.

[24] IPCC, Gutiérrez JM, Jones RG, Narisma GT (2024) IPCC Sixth Assessment Report (AR6) Technical Summary. NERC EDS Centre for Environmental Data Analysis

[25] JaatinenK, TuittilaES, LaineJ, YrjäläK, FritzeH. Methane−oxidizing bacteria in a Finnish raised mire complex: effects of site fertility and drainage. Microb Ecol, 2005, 50: 429-439.

[26] JeewaniPH, BrownRW, RhymesJM, McNamaraNP, ChadwickDR, JonesDL, EvansCD. Greenhouse gas removal in agricultural peatland via raised water levels and soil amendment. Biochar, 2025, 739.

[27] Jeffery S, Verheijen FG, van der Velde M, Bastos AC (2011) A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agric Ecosyst Environ 144(1):175–187

[28] JiangC-Y, LiuY, LiuY-Y, YouX-Y, GuoX, LiuS-J. Alicyclobacillus ferrooxydans sp. nov., a ferrous−oxidizing bacterium from solfataric soil. Int J Syst Evolut Microbiol, 2008, 58: 2898-2903.

[29] JoostenH, SirinA, CouwenbergJ, LaineJ, SmithPThe role of peatlands in climate regulation, 2016, Cambridge. Cambridge University Press. .

[30] Keiluweit M, Nico PS, Johnson MG, Kleber M (2010) Dynamic molecular structure of plant biomass-derived black carbon (Biochar). Environ Sci Technol 44:1247–1253

[31] Kirkby E (2012) Introduction, definition and classification of nutrients. In: Marschner H (ed) Marschner's mineral nutrition of higher plants,3rd edn. Academic, Amsterdam, pp 3–5

[32] KlemedtssonL, Von ArnoldK, WeslienP, GundersenP. Soil CN ratio as a scalar parameter to predict nitrous oxide emissions. Glob Change Biol, 2005, 11: 1142-1147.

[33] KochJ, ElsgaardL, GreveMH, GyldenkærneS, HermansenC, LevinG, WuS, StisenS. Water−table−driven greenhouse gas emission estimates guide peatland restoration at national scale. Biogeosciences, 2023, 20: 2387-2403.

[34] Lehmann J, Joseph S (2015) Biochar for environmental management: an introduction. In: Biochar for environmental management. Routledge, pp 1–13

[35] Lehmann J, Rondon M (2006) Bio-char soil management on highly weathered soils in the humid tropics. Biol Approaches Sust Soil Syst 113(517):e530

[36] LehmannJ, RilligMC, ThiesJ, MasielloCA, HockadayWC, CrowleyD. Biochar effects on soil biota–a review. Soil Biol Biochem, 2011, 43: 1812-1836.

[37] LeifeldJ, MenichettiL. The underappreciated potential of peatlands in global climate change mitigation strategies. Nat Commun, 2018, 91071.

[38] LeifeldJ, MüllerM, FuhrerJ. Peatland subsidence and carbon loss from drained temperate fens. Soil Use Manag, 2011, 27: 170-176.

[39] LeifeldJ, Wüst-GalleyC, PageS. Intact and managed peatland soils as a source and sink of GHGs from 1850 to 2100. Nat Clim Change, 2019, 9: 945-947.

[40] LiimatainenM, VoigtC, MartikainenPJ, HytönenJ, ReginaK, ÓskarssonH, MaljanenM. Factors controlling nitrous oxide emissions from managed northern peat soils with low carbon to nitrogen ratio. Soil Biol Biochem, 2018, 122: 186-195.

[41] LinC-C, LiuY-T, ChangP-H, HsiehY-C, TzouY-M. Inhibition of continuous cropping obstacle of celery by chemically modified biochar: an efficient approach to decrease bioavailability of phenolic allelochemicals. J Environ Manag, 2023, 348119316.

[42] LiuR, HuH, SuterH, HaydenHL, HeJ, MeleP, ChenD. Nitrification is a primary driver of nitrous oxide production in laboratory microcosms from different land−use soils. Front Microbiol, 2016, 71373.

[43] LiuS, HeF, KuzyakovY, XiaoH, HoangDTT, PuS, RazaviBS. Nutrients in the rhizosphere: a meta−analysis of content, availability, and influencing factors. Sci Total Environ, 2022, 826153908.

[44] LladóS, ŽifčákováL, VětrovskýT, EichlerováI, BaldrianP. Functional screening of abundant bacteria from acidic forest soil indicates the metabolic potential of Acidobacteria subdivision 1 for polysaccharide decomposition. Biol Fertil Soils, 2016, 52: 251-260.

[45] LópezMJ, JuradoMM, López-GonzálezJA, Estrella-GonzálezMJ, Martínez-GallardoMR, ToribioA, Suárez-EstrellaF. Characterization of thermophilic lignocellulolytic microorganisms in composting. Front Microbiol, 2021, 12697480.

[46] LuY, LiuQ, FuL, HuY, ZhongL, ZhangS, LiuQ, XieQ. The effect of modified biochar on methane emission and succession of methanogenic archaeal community in paddy soil. Chemosphere, 2022, 304135288.

[47] LuoY, DurenkampM, De NobiliM, LinQ, BrookesPC. Short term soil priming effects and the mineralisation of biochar following its incorporation to soils of different pH. Soil Biol Biochem, 2011, 43: 2304-2314.

[48] LuoL, MengH, GuJ-D. Microbial extracellular enzymes in biogeochemical cycling of ecosystems. J Environ Manag, 2017, 197: 539-549.

[49] LyuH, ZhangH, ChuM, ZhangC, TangJ, ChangSX, MašekO, OkYS. Biochar affects greenhouse gas emissions in various environments: a critical review. Land Degrad Dev, 2022, 33: 3327-3342.

[50] MaL, ZhuG, ChenB, ZhangK, NiuS, WangJ, CiaisP, ZuoH. A globally robust relationship between water table decline, subsidence rate, and carbon release from peatlands. Commu Earth Environ, 2022, 3254.

[51] MaX, LiS, PanR, WangZ, LiJ, ZhangX, AzeemM, YaoY, XuZ, PanJ, ZhangZ, LiR. Effect of biochar on the mitigation of organic volatile fatty acid emission during aerobic biostabilization of biosolids and the underlying mechanism. J Clean Prod, 2023, 390136213.

[52] MatysekM, LeakeJ, BanwartS, JohnsonI, PageS, KadukJ, SmalleyA, CummingA, ZonaD. Impact of fertiliser, water table, and warming on celery yield and CO2 and CH4 emissions from fenland agricultural peat. Sci Total Environ, 2019, 667: 179-190.

[53] MatysekM, LeakeJ, BanwartS, JohnsonI, PageS, KadukJ, SmalleyA, CummingA, ZonaD. Optimizing fen peatland water-table depth for romaine lettuce growth to reduce peat wastage under future climate warming. Soil Use Manag, 2022, 38: 341-354.

[54] McNicol G, Fluet‐Chouinard E, Ouyang Z, Knox S, Zhang Z, Aalto T, Bansal S, Chang KY, Chen M, Delwiche K (2023). Upscaling wetland methane emissions from the FLUXNET‐CH4 eddy covariance network (UpCH4 v1. 0): Model development, network assessment, and budget comparison. AGU Adv 4:e2023AV000956

[55] MengL, SunT, LiM, SaleemM, ZhangQ, WangC. Soil−applied biochar increases microbial diversity and wheat plant performance under herbicide fomesafen stress. Ecotoxicol Environ Saf, 2019, 171: 75-83.

[56] Miranda KM, Espey MG, Wink DA (2001) A rapid, simple spectrophotometric method for simultaneous detection of nitrate and nitrite. Nitric Oxide 5:62–71

[57] MohantySR, KollahB, SharmaVK, SinghAB, SinghM, RaoAS. Methane oxidation and methane driven redox process during sequential reduction of a flooded soil ecosystem. Ann Microbiol, 2014, 64: 65-74.

[58] Mulvaney RL (1996) Nitrogen—inorganic forms. Methods Soil Anal Part 3 Chem Methods 5:1123–1184

[59] MusarikaS, AthertonCE, GomersallT, WellsMJ, KadukJ, CummingAMJ, PageSE, OechelWC, ZonaD. Effect of water table management and elevated CO2 on radish productivity and on CH4 and CO2 fluxes from peatlands converted to agriculture. Sci Total Environ, 2017, 584: 665-672.

[60] Oomes MJM, Olff H, Altena HJ (1996) Effects of vegetation management and raising the water table on nutrient dynamics and vegetation change in a wet grassland. J Appl Ecol 576–588

[61] Page S, Baird A, Cumming A, High KE, Kaduk J, Evans C (2020) An assessment of the societal impacts of water level management on lowland peatlands in England and Wales: Report to Defra for Project SP1218: Managing agricultural systems on lowland peat for decreased greenhouse gas emissions whilst maintaining agricultural productivity

[62] PalansooriyaKN, OkYS, AwadYM, LeeSS, SungJ-K, KoutsospyrosA, MoonDH. Impacts of biochar application on upland agriculture: a review. J Environ Manag, 2019, 234: 52-64.

[63] PärnJ, VerhoevenJTA, Butterbach-BahlK, DiseNB, UllahS, AasaA, EgorovS, EspenbergM, JärveojaJ, JauhiainenJ. Nitrogen-rich organic soils under warm well−drained conditions are global nitrous oxide emission hotspots. Nat Commun, 2018, 9: 1-8

[64] Philippot L, Raaijmakers JM, Lemanceau P, Van Der Putten WH (2013) Going back to the roots: the microbial ecology of the rhizosphere. Nat Rev Microbiol 11(11):789–799

[65] PranantoJA, MinasnyB, ComeauLP, RudiyantoR, GraceP. Drainage increases CO2 and N2O emissions from tropical peat soils. Glob Change Biol, 2020, 26: 4583-4600.

[66] Schmidt KB, Treu T, Trenti M, Bradley LD, Kelly BC, Oesch PA, Holwerda BW, Shull JM, Stiavelli M (2014) The luminosity function at z∼ 8 from 97 Y-band dropouts: Inferences about reionization. Astrophys J 786(1):57

[67] SinghBK, BardgettRD, SmithP, ReayDS. Microorganisms and climate change: terrestrial feedbacks and mitigation options. Nat Rev Microbiol, 2010, 8: 779-790.

[68] SohiSP, KrullE, Lopez-CapelE, BolR. A review of biochar and its use and function in soil. Adv Agron, 2010, 105: 47-82.

[69] SpokasKA, KoskinenWC, BakerJM, ReicoskyDC. Impacts of woodchip biochar additions on greenhouse gas production and sorption/degradation of two herbicides in a Minnesota soil. Chemosphere, 2009, 77: 574-581.

[70] Spokas KA, Cantrell KB, Novak JM, Archer DW, Ippolito JA, Collins HP, Boateng AA, Lima IM, Lamb MC, McAloon AJ, Lentz RD (2012) Biochar: a synthesis of its agronomic impact beyond carbon sequestration. J Environ Qual 41(4):973–989.

[71] SunT, GuzmanJJL, SewardJD, EndersA, YavittJB, LehmannJ, AngenentLT. Suppressing peatland methane production by electron snorkeling through pyrogenic carbon in controlled laboratory incubations. Nat Commun, 2021, 124119.

[72] TaftHE, CrossPA, JonesDL. Efficacy of mitigation measures for reducing greenhouse gas emissions from intensively cultivated peatlands. Soil Biol Biochem, 2018, 127: 10-21.

[73] Taghizadeh-ToosiA, CloughTJ, SherlockRR, CondronLM. Biochar adsorbed ammonia is bioavailable. Plant Soil, 2012, 350: 57-69.

[74] Taghizadeh-ToosiA, ElsgaardL, CloughTJ, LabouriauR, ErnstsenV, PetersenSO. Regulation of N 2 O emissions from acid organic soil drained for agriculture. Biogeosciences, 2019, 16: 4555-4575.

[75] ThauerRK. Biochemistry of methanogenesis: a tribute to Marjory Stephenson. 1998 marjory stephenson prize lecture. Microbiology, 1998, 144: 2377-2406.

[76] TiemeyerB, Albiac BorrazE, AugustinJ, BechtoldM, BeetzS, BeyerC, DröslerM, EbliM, EickenscheidtT, FiedlerS, FörsterC, FreibauerA, GiebelsM, GlatzelS, HeinichenJ, HoffmannM, HöperH, JurasinskiG, Leiber-SauheitlK, Peichl-BrakM, RoßkopfN, SommerM, ZeitzJ. High emissions of greenhouse gases from grasslands on peat and other organic soils. Glob Change Biol, 2016, 22: 4134-4149.

[77] van BeekCL, PleijterM, KuikmanPJ. Nitrous oxide emissions from fertilized and unfertilized grasslands on peat soil. Nutr Cycl Agroecosyst, 2011, 89: 453-461.

[78] WangG, MaY, CheniaHY, GovindenR, LuoJ, RenG. Biochar−mediated control of phytophthora blight of pepper is closely related to the improvement of the rhizosphere fungal community. Front Microbiol, 2020, 111427.

[79] WangY, CalancaP, LeifeldJ. Sources of nitrous oxide emissions from agriculturally managed peatlands. Glob Change Biol, 2024, 30e17144.

[80] WenY, ZangH, FreemanB, MaQ, ChadwickDR, JonesDL. Rye cover crop incorporation and high watertable mitigate greenhouse gas emissions in cultivated peatland. Land Degrad Dev, 2019, 30: 1928-1938.

[81] XiongB-J, KleinsteuberS, SträuberH, DusnyC, HarmsH, WickLY. Impact of fungal hyphae on growth and dispersal of obligate anaerobic bacteria in aerated habitats. Mbio, 2022, 13: e00769-00722.

[82] YaoQ, LiuJ, YuZ, LiY, JinJ, LiuX, WangG. Three years of biochar amendment alters soil physiochemical properties and fungal community composition in a black soil of northeast China. Soil Biol Biochem, 2017, 110: 56-67.

[83] YinJ, ZhaoL, XuX, LiD, QiuH, CaoX. Evaluation of long−term carbon sequestration of biochar in soil with biogeochemical field model. Sci Total Environ, 2022, 822153576.

[84] ZhangA, CuiL, PanG, LiL, HussainQ, ZhangX, ZhengJ, CrowleyD. Effect of biochar amendment on yield and methane and nitrous oxide emissions from a rice paddy from Tai Lake plain, China. Agr Ecosyst Environ, 2010, 139: 469-475.

[85] Zimmerman AR, Gao B, Ahn MY (2011) Positive and negative carbon mineralization priming effects among a variety of biochar-amended soils. Soil Biol Biochem 43(6):1169–1179

[86] ZubHW, Brancourt-HulmelM. Agronomic and physiological performances of different species of Miscanthus, a major energy crop. A review. Agron Sustain Dev, 2010, 30: 201-214.

Funding

Biotechnology and Biological Sciences Research Council(grant BB/V011561/1)

RIGHTS & PERMISSIONS

Crown