Reducing nitrous oxide emissions from sugarcane soil with legume intercropping

Monica Elizabeth Salazar Cajas1, Nicole Robinson1, Adam Royle2, Lawrence Di Bella2, Weijin Wang3, Marijke Heenan3, Steven Reeves3, Susanne Schmidt1, Richard Brackin1

1 School of Agriculture and Food Sciences, The University of Queensland, QLD, 4072 Brisbane, Australia; email:

2 Herbert Cane Productivity Services Limited, 181 Fairford Rd, Ingham QLD 4850, Australia

3 Department of Science, Information Technology and Innovation, 41 Boggo Road, Dutton Park, QLD 4102 Australia


Australian sugarcane cropping has low nitrogen (N) use efficiencies, largely due to a mismatch of early-season N fertiliser application and later season peak crop N demand, in combination with poor soils and wet climate. To address the problem of N losses via run-off, leaching and N2O emissions, the sugarcane industry is evaluating several avenues. One approach is to improve N use efficiency (NUE) by reducing the use of vulnerable-to-loss N fertiliser, supplementing crop needs with biologically fixed N via sugarcane-legume intercropping. In an optimised system, decomposing legumes would deliver N to sugarcane, synchronised with sugarcane’s long N accumulation phase. We hypothesised that legume intercropping in combination with lower N fertiliser rates will reduce N losses (N2O emissions were quantified here) but not sugar yields. Here we report on one of several field trials with sugarcane grown as monoculture or intercropped with legumes at full N fertiliser or lowered rates (67 or 41% of full N). In the second year of implementation and compared to full N fertiliser, N2O emissions were reduced by 50 to 70% in the 67% N treatments irrespective of legume presence. Highest sugarcane biomass was achieved with full-N rate, 67% N, and 67% N + soybean intercropping. Sugarcane production was reduced in 67% N + mung bean intercropping, 41% N and zero N treatments. Sugar yield was variable but statistically similar across all treatments. These early results indicate that evaluation across different growing regions, fertiliser rates and planting times are needed to optimise sugarcane-legume intercropping systems.

Alternative N application strategies for reduced N2O emissions in flood-furrow irrigated cotton

Graeme Schwenke1, Annabelle Mcpherson2

1 NSW Department of Primary Industries, 4 Marsden Park Road, Tamworth, NSW, 2340,, Email

2 NSW Department of Primary Industries, 4 Marsden Park Road, Tamworth, NSW, 2340,, Email


The large inputs of N fertiliser needed for high-yielding irrigated cotton can potentially lead to substantial emissions of the greenhouse gas, nitrous oxide (N2O). We compared the impact on N2O emissions of three alternative strategies for applying the required amount of N to a commercial flood-furrow irrigated cotton crop. Compared to applying all N fertiliser pre-sowing, splitting the application between pre-sowing and in-season applications led to temporal differences in the N2O emitted, but there was no cumulative difference over the whole season. Similarly, altering the placement of the pre-sowing N fertiliser band from the non-irrigated side of the hill to the irrigated side of the hill led to a spatial difference in the N2O emission pattern, but no cumulative effect was observed. Almost all N2O emissions occurred in response to the first three of eight irrigation events, with the emissions after the second and third irrigations only observed where additional N was applied as water-run urea. The mostly low-intensity rainfall during this growing season had little impact on N2O emitted. Future research should focus on minimising N2O losses from the first irrigation, either through further reducing pre-plant N rates or by using a nitrification inhibitor with the pre-plant N application.

Mitigating indirect N2O emission from Japanese agricultural soils by reducing nitrogen leaching and runoff

Sadao Eguchi1,2, Nanae Hirano1, Shin-Ichiro Mishima1, Kazunori Minamikawa1

1 Institute for Agro-Environmental Sciences NARO (NIAES), Kannondai 3-1-3, Tsukuba, Ibaraki 305-8604, Japan

2 E-mail


Indirect nitrous oxide (N2O) emission from Japanese agricultural soils is accounted as comparable to direct N2O emission derived from inorganic or organic nitrogen (N) fertilizers in Japan. This paper tries to evaluate the mitigation potential of indirect N2O emission by reducing N leaching and runoff in different land uses at different prefectures in Japan. We used the national scale agricultural activity data of different prefectures from 1985 to 2005 and the N leaching and runoff monitoring data in Japan published after 1980. The N leaching and runoff values in vegetable and tea fields under various improved agricultural practices such as organic fertilizer application, slow release fertilizer application with reduced N application rate, cover cropping for green manure, etc., showed about 25% to 30% lower values from those under conventional practices, suggesting that such improved practices are similarly effective to mitigate indirect N2O emission from agricultural fields.

Progress in quantifying coastal N2O emissions in order to close the (terrestrial) biogenic nitrogen budget

Naomi S. Wells1*, Damien Maher1, Dirk Erler1, Vera Sandel1, Badin Gibbes2, Matt Hipsey3, James Udy4, Bradley Eyre1

1Centre for Coastal Biogeochemistry, Southern Cross University, Lismore, NSW, Australia

2School of Civil Engineering, University of Queensland, Brisbane, QLD, Australia

3School of Earth and the Environment, University of Western Australia, Crawley, WA, Australia

4Healthy Waterways, Brisbane, QLD, Australia

*Corresponding author:


Aquatic nitrous oxide (N2O) emissions are both a poorly constrained component of the global greenhouse gas budget and a rarely quantified loss pathway during transport of reactive nitrogen (N) from land to sea. Quantification of N2O losses from coastal environments are particularly vital, as these regions are both biogeochemical hotspots and subject to dramatic increases in N loading from urbanisation and upstream agricultural intensification. This study aimed to link spatial intensive measurements of water-atmosphere N2O fluxes with biogeochemical controls across a land-use intensity gradient. We used recently developed cavity enhanced laser absorption spectroscopy to obtain quasi continuous (1 sec-1) measurements of dissolved N2O across the salinity gradient in eight sub-tropical estuaries subjected to varying land-use intensities. Land use had a dramatic effect: N2O fluxes from estuaries surrounded by >60% woody vegetation were an order of magnitude lower than from those surrounded by <30% woody vegetation, and the estuary mouth created a net N2O sink only in the four least impacted systems. The fact that N2O fluxes, but not nitrate concentrations, peaked at the freshwater-saltwater interface (1-5 psu) in seven of eight surveyed estuaries suggested that benthic processes, not point source pollution, controlled N2O emissions. The fact that groundwater infiltration did not drive N2O peaks supports the idea that benthic biology, rather than hydrology, regulates estuarine N2O losses. As N2O did not track the spatial patterns of the commonly measured N species (ammonium, nitrate), an accurate catchment N balance could only be achieved via directly measuring estuarine N2O emissions.

Nitrous oxide emission from N fertilizer and vinasse in sugarcane

Heitor Cantarella1, Késia Silva Lourenço1, Johnny R. Soares1, Janaína B. Carmo2, Andre C. Vitti3, Raffaella Rossetto3, Zaqueu F. Montezano1, Eiko E. Kuramae4

1 Agronomic Institute of Campinas, Av. Barao de Itapura 1487, Campinas, SP, 13020-902 Brazil, Email:
2 Federal University of São Carlos, Rod. João Leme dos Santos, Sorocaba, SP, 18052-780, Brazil
3 APTA Regional, Piracicaba Research Pole, Piracicaba, SP, 13400-970, Brazil
4 Department of Microbial Ecology, Netherlands Institute of Ecology, Wageningen, 6708 PB, The Netherlands


Nitrous oxide (N2O) emissions from nitrogen fertilizers may strongly affect the sustainability indicators of ethanol produced from sugarcane and there are evidences that the application of vinasse could enhance the emission of GHGs from N fertilizers. The strategy of separating the application of N fertilizer and vinasse in time was tested in three field experiments in Brazil. Vinasse – both regular and concentrated – was applied a) at the same time as the fertilizer, b) anticipated by one month or c) delayed by one month. Intense measurements of N2O emissions were carried out using static chambers. The N2O-N fertilizer emission factor (EF) varied from 0.08% to 0.52%, whereas the average EF of regular and concentrated vinasse were 0.68% and 0.33% respectively. Application of concentrated vinasse in the same day of the mineral N fertilization caused high N2O emissions than when the fertilizer was applied alone; simultaneous application of regular vinasse increased N2O emission in 2 out of 3 experiments. The strategy of anticipating or postponing the application of both regular and concentrated vinasse by about 30 days with respect to N fertilization in most cases granted lower N2O emissions.

Nitrous oxide emissions from wheat grown in a medium rainfall environment in SE Australia are low compared to overall nitrogen losses

Ashley Wallace1,4,5, Roger Armstrong1,2, Rob Harris3, Oxana Bellyaeva1, Peter Grace4, Clemens Scheer4

1 Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, Victoria, 3400.

2 Department of Animal, Plant and Soil Sciences, LaTrobe University, Bundoora, Victoria, 3086.

3 Formerly: Department of Economic Development, Jobs, Transport and Resources, Private Bag 105, Hamilton, Victoria, 3300.

4 Institute for Future Environments, Queensland University of Technology, Brisbane, Qld, 4000.

5 Corresponding author:


Efficient management of nitrogen (N) is critical to the profitability and sustainability of agricultural systems. Losses of N can both reduce productivity and in the case of  nitrous oxide (N2O) emissions contribute to global warming and ozone depletion. The limited number of studies from medium rainfall cropping systems have indicated that N2O  losses tend to be low to moderate, but that there is the potential to reduce these losses through altered fertiliser management. This study investigated the magnitude of N2O flux from a medium rainfall cropping system in south eastern Australia and the potential to mitigate N2O losses through altered timing (at sowing compared with in-season) of N application and the use of both nitrification and urease inhibitors. This study also measured overall N fertiliser losses and crop productivity. Losses of N2O and overall fertiliser losses were measured using static chamber and 15N mass balance techniques respectively, as part of a field experiment conducted in the Victorian Wimmera during 2012. Cumulative N2O loss from sowing until harvest of the wheat crop amounted to between 75 and 270 g N2O-N/ha with  fertiliser application significantly increasing losses. In contrast, total losses of fertiliser N ranged from 7‑11 kg N/ha (14-22% of applied N), indicating that N2O losses were low in comparison to both crop requirements and overall N losses.

The effect of inhibitor use and urea fertiliser application on pasture production and nitrous oxide emissions

Kevin Kelly1, Graeme Ward2

1 Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, Tatura, Vic. 3616, Australia.,

2 Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, Warrnambool, Vic. 3280, Australia.


The application of nitrogen (N) fertilisers to pasture is known to increase nitrous oxide (N2O) emissions. There is currently little information available on emissions from N fertilised dairy pastures in Australia. The objective of this work was to quantify the effect of inhibitor coatings on urea fertiliser on pasture DM production and N2O emissions.

Field experiments (five treatments by five replicates) were conducted at two sites in south-west Victoria with contrasting drainage characteristics. Treatments were nil, urea, urea coated with dicyandiamide (DCD), urea coated with 3,4-dimethyl pyrazole phosphate (DMPP) and urea coated with N-(n-butyl) thiophosphoric triamide (nBPT). The urea+DCD treatment was replaced with urea ammonium nitrate (UAN) in Years 2 and 3. The N treatments were applied at the start of the growing season and again after every second harvest. Pasture production was measured for three years and N2O emissions were measured for two years.

Pasture responded to the application of N fertiliser at both sites every year. There were no differences in pasture production between the urea, urea plus inhibitor coatings or the UAN treatments. Cumulative N2O emissions where no N was applied varied with year and site, ranging from 0.23 to 0.53 kg N2O-N/ha/year, while emission factors for urea use ranged from 0.09 to 0.31%. The use of a nitrification inhibitor reduced emissions by 30 to 75%, with the magnitude of the reduction influenced by soil water content around the time of N application. The urease inhibitor had no effect on N2O emissions.

Effect of reduced fertiliser rates in combination with a nitrification inhibitor (DMPP) on soil nitrous oxide emissions and yield from an intensive vegetable production system in sub-tropical Australia

Clemens Scheer1, Mary Firrell2, Peter Deuter2, David Rowlings1, Ian Porter3, Peter Grace1

1Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia,

2Department of Agriculture, Fisheries and Forestry (Queensland), Gatton Research Station, QLD 4343, Australia  

3School of Life Sciences, LaTrobe University, Bundoora, Vic 3083,Australia


Vegetable production systems are characterised by intensive production with high inputs of nitrogen fertiliser and irrigation water. Consequently, high emissions of nitrous oxide have been reported. The use of nitrification inhibitors (NI) offers an effective method to reduce N2O emissions, whilst maintaining yield and increasing nitrogen use efficiency. However, only limited data are currently available on the use of NI in vegetable cropping systems. A field experiment was conducted to investigate the effect of the nitrification inhibitor 3,4-Dimethylpyrazol phosphate (DMPP) in combination with reduced N fertilizer application rates on N2O emissions and yield from a typical vegetable rotation in sub-tropical Australia. Annual N2O emissions ranged from 0.59 to 1.37 kgN/ha for the different fertiliser treatments. A 40% reduced fertilizer rate combined with DMPP reduced N2O emissions by more than half but achieved a comparable yield to the standard grower’s practice in two out of three crops. We conclude that DMPP shows a great potential for reducing N2O emissions from vegetable systems. However, further research is required to understand under what conditions reduced N rates of DMPP coated fertiliser are applicable and to determine the long-term effect of such a fertiliser regime over extended cropping cycles.

Strategies for GHG mitigation in Mediterranean cropping systems. A review

Sanz-Cobeña1, A., Lassaletta, L.2, Aguilera, E.3, del Prado, A.4, Garnier, J.5,6, Billen, G. 5,6, Iglesias, A.1, Sánchez, B.1, Guardia, G.1, Abalos, D.7, Plaza-Bonilla, D.8, Puigdueta, I1, Moral, R.9, Galán, E.4, Arriaga, H.10, Merino, P.10, Infante-Amate, J.3, Meijide, A.11, Pardo, G.4, Alvaro-Fuentes, J.12, Gilsanz, C.13, Báez, D.13, Doltra, J.14, González-Ubierna, S.15, Cayuela, M.L.16, Menendez, S.17, Diaz-Pines, E.18, Le-Noe, J.4, Quemada, M.1, Estellés, F.19, Calvet, S.19, van Grinsven, H.2, Westhoek, H.2, Sanz, M.J.6, Sánchez-Jimeno, B.20, Vallejo, A.1, Smith, P.21

1 ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain
2 PBL Netherlands Environmental Assessment Agency, Bilthoven, PO Box 303, 3720 AH Bilthoven, the Netherlands
3 Universidad Pablo de Olavide, Ctra. de Utrera, km. 1, 41013, Sevilla, Spain
4 Basque Centre for Climate Change (BC3), Alameda Urquijo 4-4, 48008, Bilbao, Spain CNRS, UMR
5 CNRS,, UMRMetis 7619, BP105, 4 place Jussieu, 75005, Paris, France
6 UPMC, UMR Metis 7619, BP105, 4 place Jussieu, 75005, Paris, France
7 Department of Soil Quality, Wageningen University, PO Box 47, Droevendaalsesteeg 4, Wageningen 6700AA, The Netherlands
8 INRA, UMR-AGIR, 24 Chemin de Borde Rouge –Auzeville, CS 52627, 31326 Castanet-Tolosan cedex, France
9 Department of Agrochemistry and Environment, EPSO, Miguel Hernandez University, 03312 Orihuela, Alicante, Spain
10 NEIKER-Tecnalia, Conservation of Natural Resources, Bizkaia Technology Park, P. 812, 48160, Derio, Bizkaia, Spain
11 Bioclimatology, Georg-August-Universität Göttingen, Büsgenweg 2, 37077, Göttingen, Germany
12 Soil and Water Dpt, Estacion Experimental de Aula Dei (EEAD), Spanish National Research Council (CSIC,), Av. Montañana, 1005, 50059 Zaragoza, Spain
13 Mabegondo Agricultural Research Centre (CIAM-INGACAL), Xunta de Galicia, Carretera AC-542 de Betanzos a Mesón do Vento, km 7, 15318 Abegondo, A Coruña, Spain
14 Cantabrian Agricultural Research and Training Centre, CIFA, c/Héroes 2 de Mayo 27, 39600 Muriedas, Spain
15 Faculty of Pharmacy. Complutense University of Madrid. Ciudad Universitaria. Pza. Ramón y Cajal s/n, 28040 Madrid, Spain
16 Departamento de Conservación de Suelos y Aguas y Manejo de Residuos Orgánicos. CEBAS-CSIC. Campus Universitario de Espinardo. 30100 Murcia. Spain.
17 University of the Basque Country UPV/EHU, Department of Plant Biology and Ecology, Apdo. 644, 48080, Bilbao, Spain
18 Institute of Meteorology and Climate Research, Atmospheric Environmental Research. Karlsruhe Institute of Technology. Kreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen, Germany.
19 ICTA, Universitat Politècnica de València, Camino de Vera s/n 46022, Valencia
20 Dirección General de Investigación Científica y Técnica. Ministerio de Economía y Competitividad. Gobierno de España. Pº. de la Castellana, 162, 28046 Madrid, España.
21 Institute of Biological and Environmental Sciences, University of Aberdeen, 23 St Machar Drive,Aberdeen, AB24 3UU, UK


In this review we aimed to synthetize and analyze the most promising GHGs mitigation strategies for Mediterranean cropping systems. A description of most relevant measures, based on the best crop choice and management by farmers (i.e., agronomical practices), was firstly carried out. Many of these measures can be also efficient in other climatic regions, but here we provide particular results and discussion of their efficiencies for Mediterranean cropping systems. An integrated assessment of management practices on mitigating each component of the global warming potential (N2O and CH4 emissions and C sequestration) of production systems considering potential side-effects of their implementation allowed us to propose the best strategies to abate GHG emissions, while sustaining crop yields and mitigating other sources of environmental pollution (e.g. nitrate leaching and ammonia volatilization).

Nitrous oxide emission factors across Mediterranean regions: a meta-analysis of available data from field studies

Maria L. Cayuela1*, Eduardo Aguilera2, Alberto Sanz-Cobena3, Dean C. Adams4,5, Diego Abalos6, Louise Barton7, Rebecca Ryals8, Whendee L. Silver9, Marta A. Alfaro10, Valentini A. Pappa11,12, Pete Smith13, Josette Garnier14, Gilles Billen14, Lex Bouwman15,16, Alberte Bondeau17, Luis Lassaletta15

1Departamento de Conservación de Suelos y Aguas y Manejo de Residuos Orgánicos. CEBAS-CSIC. Campus Universitario de Espinardo. 30100 Murcia. Spain.

2 Universidad Pablo de Olavide, Ctra. de Utrera, km. 1, 41013, Sevilla, Spain

3 ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain

4 Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames IA, USA, 50010

5 Department of Statistics, Iowa State University, Ames IA, USA, 50010                                                                   

6 Department of Soil Quality, Wageningen University, PO Box 47, Droevendaalsesteeg 4, Wageningen 6700AA, The Netherlands

7 Soil Biology and Molecular Ecology Group, School of Geography and Environmental Sciences, UWA Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia

8 Department of Natural Resources and Environmental Sciences, University of Hawaii, Manoa, Honolulu HI, 96822, USA

9 Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94707, USA

10Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Remehue, Casilla 24-O, Osorno, Chile

11 Agricultural University of Athens, Department of Crop Science, Iera Odos 75, 11855 Athens, Greece

12 Texas A&M University, 302H Williams Administration Bldg, College Station, TX 77843-3372, USA

13 Institute of Biological and Environmental Sciences, University of Aberdeen, 23 St Machar Drive, Aberdeen, AB24 3UU, UK

14 CNRS/UPMC, UMR Metis, 4 Place Jussieu, 75005 Paris, France

15 PBL Netherlands Environmental Assessment Agency, Bilthoven, PO Box 303, 3720 AH Bilthoven, The Netherlands

16 Department of Earth Sciences – Faculty of Geosciences, Utrecht University, PO Box 80021, 3508 TA Utrecht, The Netherlands

17 Institut Méditerranéen de Biodiversité et d’Ecologie marine et continentale (IMBE) Aix Marseille Université, CNRS, IRD, Avignon Université. Aix-en-Provence, France.


Studies on soil N2O emissions from Mediterranean climate regions are less abundant than in other temperate areas and they are often not included in recent reviews and meta-analyses. In this paper we aimed at collecting and synthesizing all available current data from field studies on N2O emissions across Mediterranean climate regions. We calculated through meta-analytical methods the averaged emission factor (EF, the percentage of fertilizer N applied that is transformed and emitted as N2O) for Mediterranean cropping systems, which was found to be significantly lower (0.5%) than the IPCC default value (1%). We found that soil properties had no significant effect on N2O emissions, but the irrigation system and the type and rate of applied N fertilizer influenced EFs. Rain-fed crops in Mediterranean regions had, in average, lower emissions (EF: 0.27%) than irrigated crops (EF: 0.63%). Drip irrigation systems showed 44% lower emission factors than sprinkler irrigation methods. Regarding the different N fertilizers, liquid slurries showed the highest EF, slightly lower, but not significantly different to 1%, whereas the remainder of the fertilizer types were significantly lower than 1%. Increasing the rate of nitrogen fertilizer led to higher EFs. The use of nitrification and ammonification inhibitors significantly reduced emissions (EF: 0.14%) and therefore seems a good strategy to mitigate direct N2O emissions under Mediterranean conditions.