Baggs, E. M., Chebii, J., and Ndufa, J. K.: A short-term investigation of trace gas emissions following tillage and no-tillage of agroforestry residues in western Kenya, Soil Till. Res., 90, 69–76, https://doi.org/10.1016/j.still.2005.08.006, 2006.
Bates, D. M.: lme4: Mixed-effects modeling with R,
http://lme4.r-forge.r-project.org/book/ (last access: 17 April 2025), 2010.
Boateng, K. K., Obeng, G. Y., and Mensah, E.: Agricultural Greenhouse Gases from Sub-Saharan Africa, in: Energy, Environment, and Sustainability, Springer Nature, 73–85, https://doi.org/10.1007/978-981-13-3272-2_6, 2019.
Borchard, N., Schirrmann, M., Cayuela, M. L., Kammann, C., Wrage-Mönnig, N., Estavillo, J. M., Fuertes-Mendizábal, T., Sigua, G., Spokas, K., Ippolito, J. A., and Novak, J.: Biochar, soil and land-use interactions that reduce nitrate leaching and N
2O emissions: a meta-analysis, Sci. Total Environ., 651, 2354–2364, https://doi.org/10.1016/j.scitotenv.2018.10.060, 2019.
Bwana, T. N., Amuri, N. A., Semu, E., Elsgaard, L., Butterbach-Bahl, K., Pelster, D. E., and Olesen, J. E.: Soil N
2O emission from organic and conventional cotton farming in Northern Tanzania, Sci. Total Environ., 785, 1–10, https://doi.org/10.1016/j.scitotenv.2021.147301, 2021.
Case, S. D. C., McNamara, N. P., Reay, D. S., Stott, A. W., Grant, H. K., and Whitaker, J.: Biochar suppresses
N2O emissions while maintaining N availability in a sandy loam soil, Soil Biol. Biochem., 81, 178–185, https://doi.org/10.1016/j.soilbio.2014.11.012, 2015.
Chapuis-Lardy, L., Metay, A., Martinet, M., Rabenarivo, M., Toucet, J., Douzet, J. M., Razafimbelo, T., Rabeharisoa, L., and Rakotoarisoa, J.: Nitrous oxide fluxes from Malagasy agricultural soils, Geoderma, 148, 421–427, https://doi.org/10.1016/j.geoderma.2008.11.015, 2009.
Cornelissen, G., Pandit, N. R., Taylor, P., Pandit, B. H., Sparrevik, M., and Schmidt, H. P.: Emissions and char quality of flame-curtain “Kon Tiki” kilns for farmer-scale charcoal/biochar production, PLoS One, 11, https://doi.org/10.1371/journal.pone.0154617, 2016.
Craine, J. M., Brookshire, E. N. J., Cramer, M. D., Hasselquist, N. J., Koba, K., Marin-Spiotta, E., and Wang, L.: Ecological interpretations of nitrogen isotope ratios of terrestrial plants and soils, Plant Soil, 396, 1–26, https://doi.org/10.1007/s11104-015-2542-1, 2015.
Daryanto, S., Wang, L., Gilhooly, W. P., and Jacinthe, P.: Nitrogen preference across generations under changing ammonium nitrate ratios, J. Plant Ecol., 12, 235–244, https://doi.org/10.1093/jpe/rty014, 2019.
Dick, J., Kaya, B., Soutoura, M., Skiba, U., Smith, R., Niang, A., and Tabo, R.: The contribution of agricultural practices to nitrous oxide emissions in semi-arid Mali, Soil Use Manag., 24, 292–301, https://doi.org/10.1111/j.1475-2743.2008.00163.x, 2008.
Falconnier, G.N., Cardinael, R., Corbeels, M., Baudron, F., Chivenge, P., Couëdel, A., Ripoche, A., Affholder, F., Naudin, K., Benaillon, E., Rusinamhodzi, L., Leroux, L., Vanlauwe, B., and Giller, K. E.: The input reduction principle of agroecology is wrong when it comes to mineral fertilizer use in sub-Saharan Africa, Outlook Agric., 52, 311–326, https://doi.org/10.1177/00307270231199795, 2023.
Fang, H., Mo, J., Peng, S., Li, Z., and Wang, H.: Cumulative effects of nitrogen additions on litter decomposition in three tropical forests in southern China, Plant Soil, 297, 233–242, https://doi.org/10.1007/s11104-007-9339-9, 2007.
Fungo, B., Lehmann, J., Kalbitz, K., Tenywa, M., Thionìo, M., and Neufeldt, H.: Emissions intensity and carbon stocks of a tropical Ultisol after amendment with Tithonia green manure, urea and biochar, Field Crops Res., 209, 179–188, https://doi.org/10.1016/j.fcr.2017.05.013, 2017.
Fungo, B., Lehmann, J., Kalbitz, K., Thionìo, M., Tenywa, M., Okeyo, I., and Neufeldt, H.: Ammonia and nitrous oxide emissions from a field Ultisol amended with tithonia green manure, urea, and biochar, Biol. Fertil. Soils, 55, 135–148, https://doi.org/10.1007/s00374-018-01338-3, 2019.
Gee, G. W. and Bauder, J. W.: Particle size analysis, in: Methods of Soil Analysis, Part 1, edited by: Klute, A., Am. Soc. Agron., Madison, WI, 383–411 pp., 1986.
Giller, K. E., Andersson, J. A., Corbeels, M., Kirkegaard, J., Mortensen, D., Erenstein, O., and Vanlauwe, B.: Beyond conservation agriculture, Front. Plant Sci., 6, https://doi.org/10.3389/fpls.2015.00870, 2015.
Glaser, B., Haumaier, L., Guggenberger, G., and Zech, W.: The `Terra Preta' phenomenon: a model for sustainable agriculture in the humid tropics, Naturwissenschaften, 88, 37–41, https://doi.org/10.1007/s001140000193, 2001.
Guenet, B., Gabrielle, B., Chenu, C., Arrouays, D., Balesdent, J., Bernoux, M., Bruni, E., Caliman, J. P., Cardinael, R., Chen, S., Ciais, P., Desbois, D., Fouche, J., Frank, S., Henault, C., Lugato, E., Naipal, V., Nesme, T., Obersteiner, M., Pellerin, S., Powlson, D. S., Rasse, D. P., Rees, F., Soussana, J. F., Su, Y., Tian, H., Valin, H., and Zhou, F.: Can
N2O emissions offset the benefits from soil organic carbon storage?, Glob. Change Biol., 27, 237–256, https://doi.org/10.1111/gcb.15342, 2021.
Hao, Y., Mao, J., Bachmann, C. M., Hoffman, F. M., Koren, G., Chen, H., Tian, H., Liu, J., Tao, J., Tang, J., Li, L., Liu, L., Apple, M., Shi, M., Jin, M., Zhu, Q., Kannenberg, S., Shi, X., Zhang, X., Wang, Y., Fang, Y., and Dai, Y.: Soil moisture controls over carbon sequestration and greenhouse gas emissions: a review, npj Climate and Atmospheric Science. 8, 16, https://doi.org/10.1038/s41612-024-00888-8, 2025.
Hickman, J. E., Havlikova, M., Kroeze, C., and Palm, C. A.: Current and future nitrous oxide emissions from African agriculture, Current Opinion in Environmental Sustainability, 3, 370–378, https://doi.org/10.1016/j.cosust.2011.08.001, 2011.
Hickman, J. E., Tully, K. L., Groffman, P. M., Diru, W., and Palm, C. A.: A potential tipping point in tropical agriculture: Avoiding rapid increases in nitrous oxide fluxes from agricultural intensification in Kenya, J. Geophys. Res.-Biogeo., 120, 938–951, https://doi.org/10.1002/2015JG002913, 2015.
Hobbs, P. R., Sayre, K., and Gupta, R.: The role of conservation agriculture in sustainable agriculture, Philos. Trans. R. Soc. Lond. B., 363, 543–555, https://doi.org/10.1098/rstb.2007.2169, 2008.
Hothorn, T., Bretz, F., and Westfall, P.: Simultaneous inference in general parametric models, Biometrical J., 50, 346–363, https://doi.org/10.1002/bimj.200810425, 2008.
IPCC:
N2O emissions from managed soils, and
CO2 emissions from lime and urea application, in: 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, edited by: Buendia, E. C., Tanabe, K., Kranjc, A., Jamsranjav, B., Fukuda, M., Ngarize, S., Osako, A., Pyrozhenko, Y., Shermanau, P., and Federici, S., IPCC, Switzerland, ISBN 978-4-88788-232-4, 2019.
Jantalia, C. P., Dos Santos, H. P., Urquiaga, S., Boddey, R. M., and Alves, B. J. R.: Fluxes of nitrous oxide from soil under different crop rotations and tillage systems in the South of Brazil, Nutr. Cycl. Agroecosyst., 82, 161–173, https://doi.org/10.1007/s10705-008-9178-y, 2008.
Jeffery, S., Bezemer, T. M., Cornelissen, G., Kuyper, T. W., Lehmann, J., Mommer, L., Sohi, S. P., van de Voorde, T. F. J., Wardle, D. A., and van Groenigen, J. W.: The way forward in biochar research: Targeting trade-offs between the potential wins, GCB Bioenergy, 7, 1–13, https://doi.org/10.1111/gcbb.12132, 2015.
Jensen, E. S., Peoples, M. B., Boddey, R. M., Gresshoff, P. M., Henrik, H. N., Alves, B. J. R., and Morrison, M. J.: Legumes for mitigation of climate change and the provision of feedstock for biofuels and biorefineries. A review, Agron. Sustain. Dev., 32, 329–364, https://doi.org/10.1007/s13593-011-0056-7, 2012.
Jeuffroy, M. H., Baranger, E., Carrouée, B., de Chezelles, E., Gosme, M., Hénault, C., Schneider, A., and Cellier, P.: Nitrous oxide emissions from crop rotations including wheat, oilseed rape and dry peas, Biogeosciences, 10, 1787–1797, https://doi.org/10.5194/bg-10-1787-2013, 2013.
Kaizzi, K. C., Byalebeka, J., Semalulu, O., Alou, I., Zimwanguyizza, W., Nansamba, A., Musinguzi, P., Ebanyat, P., Hyuha, T., and Wortmann, C. S.: Maize response to fertilizer and nitrogen use efficiency in Uganda, Agron. J., 104, 73–82, https://doi.org/10.2134/agronj2011.0181, 2012.
Kammann, C., Ippolito, J., Hagemann, N., Borchard, N., Cayuela, M. L., Estavillo, J. M., Fuertes-Mendizabal, T., Jeffery, S., Kern, J., Novak, J., Rasse, D., Saarnio, S., Schmidt, H. P., Spokas, K., and Wrage-Mönnig, N.: Biochar as a tool to reduce the agricultural greenhouse-gas burden–knowns, unknowns and future research needs, J. Environ. Eng. Landsc., 25, 114–139, https://doi.org/10.3846/16486897.2017.1319375, 2017.
Kanissery, R., Gairhe, B., Kadyampakeni, D., Batuman, O., and Alferez, F.: Glyphosate: Its environmental persistence and impact on crop health and nutrition, Plants, 8, 1–11, https://doi.org/10.3390/plants8110499, 2019.
Kim, D.-G., Thomas, A. D., Pelster, D., Rosenstock, T. S., and Sanz-Cobena, A.: Greenhouse gas emissions from natural ecosystems and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further research, Biogeosciences, 13, 4789–4809, https://doi.org/10.5194/bg-13-4789-2016, 2016.
Kumar Rao, J. V. D. K. and Dart, P. J.: Nodulation, nitrogen fixation and nitrogen uptake in pigeonpea (
Cajanus cajan (L.) Millsp) of different maturity groups, Plant Soil, 99, 255–266, 1987.
Lehmann, J.: A handful of carbon, Nature, 143–144, https://doi.org/10.1038/447143a, 2007.
Lenth, R. V.: Least-Squares Means: The R Package lsmeans, J. Stat. Softw., 69, 1–33, https://doi.org/10.18637/jss.v069.i01, 2016.
Lentz, R. D., Ippolito, J. A., and Spokas, K. A.: Biochar and Manure Effects on Net Nitrogen Mineralization and Greenhouse Gas Emissions from Calcareous Soil under Corn, Soil Sci. Soc. Am. J., 78, 1641–1655, https://doi.org/10.2136/sssaj2014.05.0198, 2014.
Liu, Q., Zhang, Y., Liu, B., Amonette, J. E., Lin, Z., Liu, G., Ambus, P., and Xie, Z.: How does biochar influence soil N cycle? A meta-analysis, Plant Soil, 426, 211–225, https://doi.org/10.1007/s11104-018-3619-4, 2018.
Mapanda, F., Wuta, M., Nyamangara, J., and Rees, R. M.: Effects of organic and mineral fertilizer nitrogen on greenhouse gas emissions and plant-captured carbon during maize cropping in Zimbabwe, Plant Soil, 343, 67–81, https://doi.org/10.1007/s11104-011-0753-7, 2011.
Martinsen, V., Mulder, J., Shitumbanuma, V., Sparrevik, M., Børresen, T., and Cornelissen, G.: Farmer-led maize biochar trials: Effect on crop yield and soil nutrients under conservation farming, J. Plant Nutr. Soil Sci., 177, 681–695, https://doi.org/10.1002/jpln.201300590, 2014.
Martinsen, V., Shitumbanuma, V., Mulder, J., Ritz, C., and Cornelissen, G.: Effects of hand-hoe tilled conservation farming on soil quality and carbon stocks under on-farm conditions in Zambia, Agric. Ecosyst. Environ., 241, 168–178, https://doi.org/10.1016/j.agee.2017.03.010, 2017.
Meier, E. A., Thorburn, P. J., Bell, L. W., Harrison, M. T., and Biggs, J. S.: Greenhouse Gas Emissions From Cropping and Grazed Pastures Are Similar: A Simulation Analysis in Australia, Front. Sustain. Food Syst., 3, 1–18, https://doi.org/10.3389/fsufs.2019.00121, 2020.
Millar, N., Ndufa, J. K., Cadisch, G., and Baggs, E. M.: Nitrous oxide emissions following incorporation of improved fallow residues in the humid tropics, Global Biogeochem. Cycles, 18, 1–9, https://doi.org/10.1029/2003GB002114, 2004.
Mubiru, D. N., Komutunga, E., Agona, A., Apok, A., Ngara, T., and Mubiru, D.: Characterising agrometeorological climate risks and uncertainties: Crop production in Uganda, S. Afr. J. Sci., 108, https://doi.org/10.4102/sajs, 2012.
Munera-Echeverri, J. L., Martinsen, V., Strand, L. T., Cornelissen, G., and Mulder, J.: Effect of conservation farming and biochar addition on soil organic carbon quality, nitrogen mineralization, and crop productivity in a light textured Acrisol in the sub-humid tropics, PLoS One, 15, 1–17, https://doi.org/10.1371/journal.pone.0228717, 2020.
Munera-Echeverri, J. L., Martinsen, V., Dörsch, P., Obia, A., and Mulder, J.: Pigeon pea biochar addition in tropical Arenosol under maize increases gross nitrification rate without an effect on nitrous oxide emission, Plant Soil, 474, 195–212, https://doi.org/10.1007/s11104-022-05325-4, 2022.
Namatsheve, T.: Biological N
2-fixation, grain yield and
N2O emissions: the role of conservation agriculture and biochar in unfertilized tropical soils, PhD thesis, Norwegian University of Life Sciences, 2025.
Namatsheve, T., Chikowo, R., Corbeels, M., Mouquet-Rivier, C., Icard-Vernière, C., Cardinael, R., Icard-Verniere, C., and Cardinael, R.: Maize-cowpea intercropping as an ecological intensification option for low input systems in sub-humid Zimbabwe: Productivity, biological N2-fixation and grain mineral content, Field Crops Res., 263, 1–21, https://doi.org/10.1016/j.fcr.2020.108052, 2021.
Namatsheve, T., Martinsen, V., Obia, A., and Mulder, J.: Grain yield and nitrogen cycling under conservation agriculture and biochar amendment in agroecosystems of sub-Saharan Africa. A meta-analysis, Agric. Ecosyst. Environ., 376, https://doi.org/10.1016/j.agee.2024.109243, 2024.
Namatsheve, T., Mulder, J., Obia, A., and Martinsen, V.: Biological N
2-fixation and grain yield of pigeon pea: The role of biochar and conservation agriculture in low-input systems, Field Crops Res., 328, 109923, https://doi.org/10.1016/j.fcr.2025.109923, 2025.
Namatsheve, T., Martinsen, V., Mulder, J, Obia, A., and Dörsch, P.: Data for: Nitrous oxide emissions from pigeon pea–maize rotation in response to conservation agriculture and biochar amendments in a Ferralsol, northern Uganda, NMBU dataverse [data set], https://doi.org/10.18710/CNP8TF, 2026.
Namoi, N., Pelster, D., Rosenstock, T. S., Mwangi, L., Kamau, S., Mutuo, P., and Barrios, E.: Earthworms regulate ability of biochar to mitigate CO
2 and
N2O emissions from a tropical soil, Appl. Soil Ecol., 140, 57–67, https://doi.org/10.1016/j.apsoil.2019.04.001, 2019.
Nguyen, T. T. N., Xu, C. Y., Tahmasbian, I., Che, R., Xu, Z., Zhou, X., Wallace, H. M., and Bai, S. H.: Effects of biochar on soil available inorganic nitrogen: A review and meta-analysis, Geoderma, 288, 79–96, https://doi.org/10.1016/j.geoderma.2016.11.004, 2017.
Oriangi, G., Mukwaya, P. I., Luwa, J. K., Menya, E., Malinga, G. M., and Bamutaze, Y.: Variability and Changes in Climate in Northern Uganda, African Journal of Climate Change and Resource Sustainability, 3, 81–97, https://doi.org/10.37284/ajccrs.3.1.1830, 2024.
Pittelkow, C. M., Liang, X., Linquist, B. A., Van Groenigen, L. J., Lee, J., Lundy, M. E., Van Gestel, N., Six, J., Venterea, R. T., and Van Kessel, C.: Productivity limits and potentials of the principles of conservation agriculture, Nature, 517, 365–368, https://doi.org/10.1038/nature13809, 2015.
Portmann, R. W., Daniel, J. S., and Ravishankara, A. R.: Stratospheric ozone depletion due to nitrous oxide: Influences of other gases, Philos. T. R. Soc. B, 367, 1256–1264, https://doi.org/10.1098/rstb.2011.0377, 2012.
Powlson, D. S., Whitmore, A. P., and Goulding, K. W. T.: Soil carbon sequestration to mitigate climate change: A critical re-examination to identify the true and the false, Eur. J. Soil Sci., 62, 42–55, https://doi.org/10.1111/j.1365-2389.2010.01342.x, 2011.
Raji, S. G. and Dörsch, P.: Effect of legume intercropping on N
2O emissions and CH
4 uptake during maize production in the Great Rift Valley, Ethiopia, Biogeosciences, 17, 345–359, https://doi.org/10.5194/bg-17-345-2020, 2020.
Rochette, P., Angers, D. A., Bélanger, G., Chantigny, M. H., Prévost, D., and Lévesque, G.: Emissions of
N2O from Alfalfa and Soybean Crops in Eastern Canada, Soil Sci. Soc. Am. J., 68, 493–506, https://doi.org/10.2136/sssaj2004.4930, 2004.
Ruan, L. and Philip Robertson, G.: Initial nitrous oxide, carbon dioxide, and methane costs of converting conservation reserve program grassland to row crops under no-till vs. conventional tillage, Glob. Chang. Biol., 19, 2478–2489, https://doi.org/10.1111/gcb.12216, 2013.
Rusinamhodzi, L., Corbeels, M., Van Wijk, M. T., Rufino, M. C., Nyamangara, J., and Giller, K. E.: A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions, Agron. Sustain. Dev., 31, 657–673, https://doi.org/10.1007/s13593-011-0040-2, 2011.
Saggar, S., Jha, N., Deslippe, J., Bolan, N. S., Luo, J., Giltrap, D. L., Kim, D. G., Zaman, M., and Tillman, R. W.: Denitrification and
N2O: N
2 production in temperate grasslands: Processes, measurements, modelling and mitigating negative impacts, Sci. Total Environ., 465, 173–195, https://doi.org/10.1016/j.scitotenv.2012.11.050, 2013.
Scheer, C., Fuchs, K., Pelster, D. E., and Butterbach-Bahl, K.: Estimating global terrestrial denitrification from measured
N2O:(
N2O + N
2) product ratios, Current Opinion in Environmental Sustainability, 47, 72–80, https://doi.org/10.1016/j.cosust.2020.07.005, 2020.
Schmidt, H. P., Kammann, C., Hagemann, N., Leifeld, J., Bucheli, T. D., Sánchez Monedero, M. A., and Cayuela, M. L.: Biochar in agriculture – A systematic review of 26 global meta-analyses, GCB Bioenergy, 13, 1708–1730, https://doi.org/10.1111/gcbb.12889, 2021.
Shakoor, A., Shahbaz, M., Farooq, T. H., Sahar, N. E., Shahzad, S. M., Altaf, M. M., and Ashraf, M.: A global meta-analysis of greenhouse gases emission and crop yield under no-tillage as compared to conventional tillage, Sci. Total Environ., 750, https://doi.org/10.1016/j.scitotenv.2020.142299, 2021.
Turmel, M. S., Speratti, A., Baudron, F., Verhulst, N., and Govaerts, B.: Crop residue management and soil health: A systems analysis, Agric. Syst., 134, 6–16, https://doi.org/10.1016/j.agsy.2014.05.009, 2015.
Wang, H., Yan, Z., Ju, X., Song, X., Zhang, J., Li, S., and Zhu-Barker, X.: Quantifying nitrous oxide production rates from nitrification and denitrification under various moisture conditions in agricultural soils: Laboratory study and literature synthesis, Front. Microbiol., 13, https://doi.org/10.3389/fmicb.2022.1110151, 2023.
Wang, Y., Guo, J., Vogt, R. D., Mulder, J., Wang, J., and Zhang, X.: Soil pH as the chief modifier for regional nitrous oxide emissions: New evidence and implications for global estimates and mitigation, Glob. Chang. Biol., 24, e617–e626, https://doi.org/10.1111/gcb.13966, 2018.
Weldon, S., van der Veen, B., Farkas, E., Kocatürk-Schumacher, N. P., Dieguez-Alonso, A., Budai, A., and Rasse, D.: A re-analysis of NH4
+ sorption on biochar: Have expectations been too high?, Chemosphere, 301, 134662, https://doi.org/10.1016/j.chemosphere.2022.134662, 2022.
Wickham, H.: ggplot2: Elegant Graphics for Data Analysis, Springer-Verlag, New York, https://doi.org/10.1007/978-0-387-98141-3, 2016.
Wrage-Mönnig, N., Horn, M. A., Well, R., Müller, C., Velthof, G., and Oenema, O.: The role of nitrifier denitrification in the production of nitrous oxide revisited, Soil Biol. Biochem., 123, A3–A16, https://doi.org/10.1016/j.soilbio.2018.03.020, 2018.
Yao, Z., Guo, H., Wang, Y., Zhan, Y., Zhang, T., Wang, Zheng, X., Butterbach-Bahl, K.: A global meta-analysis of yield-scaled
N2O emissions and its mitigation efforts for maize, wheat, and rice, Glob. Change Biol., 30, e17177, https://doi.org/10.1111/gcb.17177, 2024.
Zhang, L., Jing, Y., Chen, C., Xiang, Y., Rezaei Rashti, M., Li, Y., Deng, Q., and Zhang, R.: Effects of biochar application on soil nitrogen transformation, microbial functional genes, enzyme activity, and plant nitrogen uptake: A meta-analysis of field studies, Glob. Change Biol., 13, 1859–1873, https://doi.org/10.1111/gcbb.12898, 2021.
Žurovec, O., Sitaula, B. K., Čustović, H., Žurovec, J., and Dörsch, P.: Effects of tillage practice on soil structure,
N2O emissions and economics in cereal production under current socio-economic conditions in central Bosnia and Herzegovina, PLoS One, 12, https://doi.org/10.1371/journal.pone.0187681, 2017.
Zuur, A. F., Ieno, E. N., Walker, N., Saveliev, A. A., and Smith, G. M.: Mixed effects models and extensions in ecology with R, Springer New York, New York, NY, https://doi.org/10.1007/978-0-387-87458-6, 2009.
