@article{Wang2015,
title = {Nitrogen management is the key for low-emission wheat production in Australia: A life cycle perspective},
author = {Weijin Wang and Ram C.Dalal},
doi = {10.1016/j.eja.2015.02.007},
year = {2015},
date = {2015-05-01},
journal = {European Journal of Agronomy},
volume = {66},
pages = {74–82},
abstract = {Farm management affects the global greenhouse gas (GHG) budget by changing not only soil organic
carbon (SOC) stocks and nitrous oxide (N2 O) emissions but also other pre-farm, on-farm and
off-site emissions. The life cycle assessment (LCA) approach has been widely adopted to assess the
“carbon footprint” of agricultural products, but rarely used as a tool to identify effective
mitigation strategies. In this study, the global warming impacts of no-till (NT) vs. conventional
till (CT), stubble retention (SR) vs stubble burning (SB), and N fertilization (NF) vs. no N
fertilization (N0) in an Australian wheat cropping system were assessed using in situ measurements
of N2 O fluxes over three years, SOC changes over forty years and including other supply chain GHG
sources and sinks. The results demonstrated the importance of full GHG accounting compared to
considering SOC changes or N2 O emissions alone for assessing the global warming impacts of
different management practices, and highlighted the significance of accurately accounting for SOC
changes and N2 O emissions in LCAs. The GHG footprints of wheat production were on averaged 475 kg
carbon dioxide equivalent (CO2 -e) ha−1 (or 186 kg CO2 -e t−1 grain) higher under NF than N0. Where
fertilizer N was applied (70 kg N ha−1 ), the life cycle emissions were 200 kg CO2 -e ha−1 (or 87
t−1 grain) lower under NT than CT and 364 kg CO2 -e ha−1 (or 155 t−1 grain) lower under SR than SB.
Classification of the emission sources/sinks and re-calculation of published data indicated that
under the common practices of SR combined with NT, N-related GHG emissions contributed 60–95% of
the life cycle emissions in the predominantly rain-fed wheat production systems in Australia.
Therefore, future mitigation efforts should aim to improve N use efficiency, explore non-synthetic N
sources, and most importantly avoid excessive N fertilizer use whilst practising NT and SR.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}

@article{Harris2013,
title = {Can nitrogen fertiliser and nitrification inhibitor management influence N_{2}O losses from high rainfall cropping systems in South Eastern Australia?},
author = {Robert H. Harris and Sally J. Officer and Patricia A. Hill and Roger D. Armstrong and Kirsten M. Fogarty and Reto P. Zollinger and Andrew J. Phelan},
doi = {10.1007/s10705-013-9562-0},
issn = {1385-1314},
year = {2013},
date = {2013-05-17},
journal = {Nutrient Cycling in Agroecosystems},
volume = {95},
number = {2},
pages = {269-285},
abstract = {Nitrous oxide (N2O) is a potent greenhouse gas released from high rainfall cropping soils, but the role of management in its abatement remains unclear in these environments. To quantify the relative influence of management, nitrogen (N) fertiliser and soil nitrification inhibitor was applied to separate but paired raised bed and conventionally flat field experiments in south west Victoria, to measure emissions and income from wheat and canola planted 2 and 3 years after conversion from a long-term pasture. Management included four different rates of N fertiliser, top-dressed with and without the nitrification inhibitor Dicyandiamide (DCD), which was applied in solution to the soil in the second year of experimentation. Crop biomass, grain yield, soil mineral N, soil temperature and soil water and N2O flux were measured. Static chamber methodology was used to identify relative differences in N2O loss between management. In the second crop (wheat) following conversion, N2O losses were up to 72 % lower (P�.05) in the furrows, receiving the lower rate of N fertiliser compared with the highest rate, with less frequent reductions observed in the third crop (canola); losses of N2O from the beds was unaffected by N rate, perhaps from nitrate leakage into the adjacent furrow of the raised bed experiment. On the nearby flat experiment, nitrate leaching may have diminished the effects of N rate and DCD on N2O flux. Furthermore the extra N did not significantly increase grain yield in either the wheat or canola crops on both experiments. The application of DCD in the canola crop temporarily reduced (P�.05) N2O production by up to 84 % from the beds, 83 % in the adjacent furrows and 75 % on the flat experiment. Grain yield was not significantly (P�.001) affected however, canola income was reduced by $1407/ha and $1252/ha, compared with no addition of inhibitor on the respective bed and flat experiments. Although N2O fluxes are driven by environmental episodic events, management will play a role in N2O abatement. However, DCD currently appears economically unfeasible and matching N fertiliser supply to meet crop demand appears a better option for minimising N2O losses from high rainfall cropping systems.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}

@article{Wang2010,
title = {Assessment of the boundary line approach for predicting N_{2}O emission ranges from Australian agricultural soils},
author = {Weijin Wang and Ram Dalal},
url = {http://soilscienceaustralia.com.au/19th-world-congress-of-soil-science},
year = {2010},
date = {2010-08-01},
pages = {1-4},
abstract = {This study aimed to assess the feasibility of predicting ranges in N_{2}O emission with a boundary line approach using a few key driving factors. Intact soil cores (9 cm dia. and ~20 cm in depth) were collected from pasture, cereal cropping and sugarcane lands and incubated at various temperature and moisture conditions after addition of different forms of mineral nitrogen (NH_{4}+ and NO_{3}). The pasture and sugarcane soils showed greater N_{2}O production capacity than the cropping soils with similar mineral N and organic C contents or under similar temperature and water filled pore space (WFPS%), and thus different model parameters need to be used. The N_{2}O emission rates were classified into three ranges: low (< 16 g N_{2}O/ha/day), medium (16 -160 g N_{2}O/ha/day) and high (> 160 g N2O/ha/day). The results indicated that N_{2}O emissions were in the low range when soil mineral N content was below 10 mg N/kg for the cropping soils and below 2 mg N/kg for the pasture and sugarcane soils. In soils with mineral N content exceeding the above thresholds, the emission rates were largely regulated by soil temperature and WFPS and the emission ranges could be estimated using linear boundary line models that incorporated both temperature and WFPS. Using these key driving factors (land use, temperature, WFPS and mineral N content), the boundary line models correctly estimated the emission ranges for 85% of the 247 data points for the cropping soils and 59% of the 271 data points for the pasture and sugarcane soils. In view of the fact that N_{2}O emissions from soil are often very variable and difficult to predict and that the soil and environmental conditions applied in this study differed substantially, the above results suggested that, in terms of accuracy and feasibility, the boundary line approach provides a simple and practical alternative to the use of a single emission factor and more complex process-based models.},
note = {Gilkes, R.J, Prakongkep, N. (Eds.). Proceedings 19th World Congress of Soil Science 2010; Published on DVD; http://www.iuss.org; Congress Symposium 4; Greenhouse gases from soils, IUSS, Brisbane, pp. 1-4.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}

@article{Schwenke2010b,
title = {Soil nitrous oxide emissions under dryland N-fertilised canola and N_{2}-fixing chickpea in the northern grains region, Australia},
author = {G. D. Schwenke and Bruce Haigh and Guy McMullen and David Herridge},
url = {http://soilscienceaustralia.com.au/19th-world-congress-of-soil-science},
year = {2010},
date = {2010-08-01},
pages = {228-231},
abstract = {Nitrous oxide (N_{2}O) emissions from cropping soils contribute to increasing atmospheric N_{2}O. Planning to reduce emissions requires real-world measurements. Crop production systems that partially rely on nitrogen (N) fixed by legumes may emit less N_{2}O than systems that are totally dependent on fertiliser N inputs. We measured N_{2}O emissions from a dryland vertosol in northwest NSW, Australia during the growth of Nfertilised canola ( ) and N_{2}-fixing chickpea (Cicer arietinum). At sowing, canola received 80 kg N/ha as urea, and chickpea was inoculated with effective rhizobia. Emissions of N_{2}O were monitored seven times per day using an automated system of chambers connected to a gas chromatograph. Daily N_{2}O emissions ranged from -1.7 to 39.6 g N_{2}O-N/ha/day in canola plots and -1.6 to 12.5 g N_{2}O-N/ha/day for chickpea. During crop growth, the N-fertilised canola plots emitted a total of 293 g N_{2}O-N/ha, equivalent to 0.37% of the urea N applied. Chickpea plots emitted 29 g N_{2}O-N/ha. The canola plots emitted a further 241 g N_{2}O-N/ha in the first months of the post-crop fallow, mostly during a short period of high rainfall, compared with 58 g N_{2}O-N/ha for chickpea. We hypothesise that the canola residue may have mineralised N earlier than chickpeas.},
note = {Gilkes, R.J, Prakongkep, N. (Eds.). Proceedings 19th World Congress of Soil Science 2010; Published on DVD; http://www.iuss.org; Congress Symposium 4; Greenhouse gases from soils, IUSS, Brisbane, pp. 228-231.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}

@article{Scheer2010b,
title = {Greenhouse Gas Emissions From Intensive Pasture On Ferrosol In Northern Nsw, Australia: Impact Of Biochar Amendment},
author = {Clemens Scheer and Peter R. Grace and Dave Rowling and Stephen Kimber and Lukas Van Zwieten},
url = {http://soilscienceaustralia.com.au/19th-world-congress-of-soil-science},
year = {2010},
date = {2010-08-01},
pages = {96-98},
abstract = {An intensive field campaign was performed from April to June 2009 to assess the effect of biochar amendment on the emission of soil-borne GHGs from a sub-tropical pasture on acidic ferrosol. Over the whole measurement period high emissions of N_{2}O and high fluxes of CO_{2} could be observed, whereas a net uptake of CH_{4} was measured. Only small differences in the fluxes of N_{2}O and CH_{4} from the biochar amended plots (35.33 ± 4.83 µg N_{2}O-N/m2/h, -6.76 ± 0.20 µg CH_{4} -C/m2/h) vs. the control plots (31.08 ± 3.50 µg N_{2}O-N/m_{2}/h, -7.30 ± 0.19 µg CH_{4} -C/m2/h) could be observed, while there was no significant difference in the fluxes of CO_{2}. However, it could be observed that N_{2}O emissions were significantly lower from the biochar amended plots during periods with low emission rates (< 50 µg N_{2}O-N/m_{2}/h). Only during an extremely high emission event following heavy rainfall N_{2}O emissions from the biochar amended plots were higher than from the control plots. Our results demonstrate that pastures on ferrosols in Northern NSW are a significant source of GHG and that the amendment of biochar can alter those emissions. However, more field and laboratory incubation studies covering prolonged observation periods are needed to clarify the impact of biochar amendment on soil microbial processes and the emission of soil-borne GHGs.},
note = {Gilkes, R.J, Prakongkep, N. (Eds.). Proceedings 19th World Congress of Soil Science 2010; Published on DVD; http://www.iuss.org; Congress Symposium 4; Greenhouse gases from soils, IUSS, Brisbane, pp. 96-98.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}

@article{Rowlings2010b,
title = {Quantifying N_{2}O and CO_{2} emissions from a subtropical pasture},
author = {David Rowlings and Peter R. Grace and Ralf Kiese and Clemens Scheer},
url = {http://soilscienceaustralia.com.au/19th-world-congress-of-soil-science},
year = {2010},
date = {2010-08-01},
pages = {199-201},
abstract = {Greenhouse gas emissions from a well established, unfertilized tropical grass-legume pasture were monitored over two consecutive years using high resolution automatic sampling. Nitrous oxide emissions were highest during the summer months and were highly episodic, related more to the size and distribution of rain events than WFPS alone. Mean annual emissions were significantly higher during 2008 (5.7 ± 1.0 g N_{2}O-N/ha/day) than 2007 (3.9 ± 0.4 and g N_{2}O-N/ha/day) despite receiving nearly 500 mm less rain. Mean CO_{2} (28.2 ± 1.5 kg CO_{2} C/ha/day) was not significantly different (P < 0.01) between measurement years, emissions being highly dependent on temperature. A negative correlation between CO_{2} and WFPS at >70% indicated a threshold for soil conditions favouring denitrification. The use of automatic chambers for high resolution greenhouse gas sampling can greatly reduce emission estimation errors associated with temperature and WFPS changes.},
note = {Gilkes, R.J, Prakongkep, N. (Eds.). Proceedings 19th World Congress of Soil Science 2010; Published on DVD; http://www.iuss.org; Congress Symposium 4; Greenhouse gases from soils, IUSS, Brisbane, pp. 199-201.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}

@article{Grace2010,
title = {Nitrous Oxide Emissions From Irrigated Cotton Soils Of Northern Australia},
author = {Peter R. Grace and David Rowlings and Ian Rochester and Ralf Kiese and Klaus Butterbach-Bahl},
url = {http://soilscienceaustralia.com.au/19th-world-congress-of-soil-science},
year = {2010},
date = {2010-08-01},
pages = {179-182},
abstract = {An automated gas sampling methodology has been used to estimate nitrous oxide (N_{2}O) emissions from heavy black clay soil in northern Australia where split applications of urea were applied to furrow irrigated cotton. Nitrous oxide emissions from the beds were 643 g N/ha over the 188 day measurement period (after planting), whilst the N_{2}O emissions from the furrows were significantly higher at 967 g N/ha. The DNDC model was used to develop a full season simulation of N_{2}O and N_{2} emissions. Seasonal N_{2}O emissions were equivalent to 0.83% of applied N, with total gaseous N losses (excluding NH_{3}) estimated to be 16% of the applied N.},
note = {Gilkes, R.J, Prakongkep, N. (Eds.). Proceedings 19th World Congress of Soil Science 2010; Published on DVD; http://www.iuss.org; Congress Symposium 4; Greenhouse gases from soils, IUSS, Brisbane, pp. 179-182.},
keywords = {Reducing emissions through improved nitrogen use efficiency},
pubstate = {published},
tppubtype = {article}
}