Denmead, O. T.MacDonald, B. C.T.Bryant, G.White, I.Wang, W.Moody, P.Dalal, R. C.Stainlay, W.2025-03-262025-03-26Scopus:85047725458https://dspace-test.anu.edu.au/handle/1885/733738571WE PRESENT the results of two investigations into greenhouse gas emissions from acid-sulfate (ASS) sugarcane soils, one recent and one current, and evaluate the measurement techniques employed. Both projects have employed micrometeorological methods and the current one also uses chambers to verify the micrometeorological measurements. Both measurement systems have been found to be reliable and mutually consistent for carbon dioxide (CO2) and nitrous oxide (N2O), but differences between them in the case of methane (CH4) need to be resolved. The aim of the current project is to obtain continuous, season-long, verified data sets for emissions of CO2, N2O and CH4from sugarcane soils, both the ASS of northern NSW and the non-ASS more representative of the Queensland cane producing areas. Results to date indicate that emissions of CO2from ASS are in the top of the range for agricultural soils, while emissions of N2O from N-fertilised soils appear to be much higher than expected from agricultural soils, amounting at times to > 0.4 kg N/ha/d. Results for CH4are equivocal: chambers indicate small emissions; micrometeorological measurements suggest emissions are non-trivial. Both soil heterogeneity and instrument resolution may be involved. A bigger data base is needed.Allowing for this, the increase in N2O emission due to fertiliser addition in the first 2 weeks of measurement in Series 2, equals the total emission of 1.25% of the N applied or 2 kg N/ha expected by the Australian and IPCC greenhouse gas inventories for the whole growing season. Acknowledgements Some of the work reported here was carried out as part of an Australian Research Council Linkage Grant on ‘Interactions between Sulfur, Nitrogen, Iron and Carbon cycles in the Sustainable Management and Use of Acid Sulfate Soils’. We acknowledge the financial support of the Australian Research Council and the Tweed Shire Council for that work. Our current work is funded by the Australian Greenhouse Office and the SRDC with substantial in-kind support provided by our respective institutions. We are grateful to Robert Quirk for assistance and advice, to Ron Teo, Graham Kettlewell and Steven Reeves for technical support, and Andrew Kinsela, Mira Durr, Annabelle Keene and Marty Hancock for valuable assistance in the field.EnglishPublisher Copyright: © 2006 28th Annual Conference of the Australian Society of Sugar Cane Technologists, ASSCT 2006. All rights reserved.Carbon DioxideChambersMethaneMicrometeorologyNitrous Oxide2006http://www.scopus.com/inward/record.url?scp=85047725458&partnerID=8YFLogxK