| Data Set Citation |
Rowlings D of Institute for Sustainable Resources, Queensland University of Technology and Grace P of Institute for Sustainable Resources, Queensland University of Technology.N2O and N2 emissions from irrigated cotton. Dalby, Queensland, 2007-2008 [GCRC].
Rowlings.33.9
(http://www.n2o.net.au/knb/metacat/Rowlings.33.9/default).
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| Data Set Owner(s): |
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Individual: | Dr. David Rowlings |
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Organization: | Institute for Sustainable Resources, Queensland University of Technology |
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Position: | Principal Investigator |
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| Gardens Point campus, 2 George St, |
| Brisbane, Queensland 4001 Australia |
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Email Address:
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Individual: | Professor Peter Grace |
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Organization: | Institute for Sustainable Resources, Queensland University of Technology |
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Position: | Director ISR |
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Address: |
| 2 George St, |
| Brisbane, Queensland 4001 Australia |
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| Associated Party: |
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Individual: | Ms. Siobhann McCafferty |
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Organization: | Institute for Future Environments, Queensland University of Technology |
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Position: | Data Librarian |
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Address: |
| 2 George Street, |
| Brisbane, QLD 4000 Australia |
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| Abstract: |
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| Cotton is one of many agricultural industries in Australia heavily reliant on nitrogenous fertilizers and water storages to maintain high levels of production. Cotton-based farming systems are therefore labelled as potentially high-risk agricultural systems with respect to gases losses of nitrogen to the atmosphere.
The on-farm study was undertaken at Dalby in the Darling Downs region of Queensland in north eastern Australia. The field was furrow irrigated and had been under continuous cotton (with winter bare fallow) for 10 years. An automated greenhouse gas measuring system (developed by Butterbach-Bahl et al.) was utilised that consisted of six chambers connected to sequential sampling unit, a gas chromatograph (equipped with both electron capture and flame ionization detectors for nitrous oxide and methane analysis respectively), and a Licor for carbon dioxide. The experiment also directly measured the specific losses of N2O and N2 from a single application of N fertiliser using 15N isotopically labelled urea.
As there was little residual N in the profile after the previous crop, the grower applied 200 kg starter N in August 2006, and planted in late October, 2006. An application of 15N labelled urea (99% atom excess 15N) was made on 2 November in three (of the six) gas sampling chambers equivalent to 120 kg N/ha (treatment A), and 60 kg N/ha equivalent in the remaining three chambers (Treatment B). The grower applied 23 and 46 kg N as urea in the irrigation water, 98 and 135 days after the 15N urea was applied. |
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| Keywords: |
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- Cotton
- Furrow irrigation
- Subtropical
- N2O
- Nitrous oxide
- CO2
- Fertilisation
- 15N labelled urea
- Auto Chambers
- Dalby
- QLD
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| Thesaurus: | anzsrc-for |
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| License and Usage Rights: |
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| Permission required from data owner |
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| Geographic Coverage: |
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Geographic Description: | Dalby, Queensland |
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Bounding Coordinates:
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| West: | 151.28 degrees
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| East: | 151.28 degrees
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| North: | -27.17 degrees
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| South: | -27.17 degrees
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| Temporal Coverage: |
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Begin:
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End:
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| Contact: |
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Individual: | Dr. David Rowlings |
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Organization: | Institute for Sustainable Resources, Queensland University of Technology |
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Position: | Principal Investigator |
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Address: |
| Gardens Point campus, 2 George St, |
| Brisbane, Queensland 4001 Australia |
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Phone:
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Email Address:
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| Methods Info: |
| Step 1: |
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Description:
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| Automatic Chambers |
For determination of soil borne CH4, N2O and CO2 fluxes an automated gas sampling system was utilized, similar to the one described in detail by Breuer et al. (2000) and Kiese et al. (2003) This system consisted of pneumatically operated static chambers (non-steady-state, non-through-flow), linked to an automated sampling system and a gas chromatograph. The clear acrylic glass chambers covered a surface area of 0.25 m2 (500 mm x 500 mm) with a height of 150 mm and were secured to stainless steel bases inserted permanently into the soil to a depth of 100 mm. In the row, chambers covering plants were increased in height incrementatlly as the crop grew from 150mm, to 450 mm to 650mm. A transparent tinted plastic coating was placed on the lids to reduce heat build-up within the chambers when closed. A tipping bucket rain gauge (Davis Instruments Corp. CA, USA) connected to the system allowed for automated opening of the lids during rainfall events.
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| Step 2: |
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Description:
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| Greenhouse Gas Flux Measurement |
Nitrous oxide and CH4 concentrations were determined using a gas chromatograph (SRI GC8610, Torrance, CA, USA) equipped with 63Ni Electron Capture Detector for N2O and a Flame Ionisation Detector for CH4. Carbon dioxide was measured continuously with a non dispersive infrared CO2 analyser (LI-820; LI-COR, Lincoln Nebraska, USA). To minimize interference from moisture vapour and CO2 on N2O measurement, a precolumn filled with sodium hydroxide coated silica was installed ahead of the analytical column and changed regularly.
A full measurement cycle for flux determination commenced with lid closure and finished when the lids opened 96 minutes later. The lids remained open for a further 96 minutes before the commencement of the next cycle, allowing 7 or 8 cycles per day. Fluxes of N2O, CH4 and CO2 were calculated from the slope of the linear increase or decrease in concentrations within the chambers over the closure time.
Flux rates were discarded if the r2 was <0.81 for N2O and CH4 and <0.90 for CO2. The flux rate was then calculated and corrected for air temperature during measurement and site pressure using the procedure outline by Barton et. al. (2008).
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Instrument(s):
| Gas chromatograph (SRI GC8610, Torrance, CA, USA) equipped with 63Ni Electron Capture Detector for N2O and a Flame Ionisation Detector for CH4. |
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Instrument(s):
| Non dispersive infrared CO2 analyser (LI-820; LI-COR, Lincoln Nebraska, USA). |
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Description:
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| Water Content and Soil Temperature |
A FDR (EnviroSCAN Sentek, Stepney, South Australia) moisture probe located centrally to the chambers within both the row and furrow. This recorded half-hourly readings of volumetric water content (5-10 cm) while soil temperature (10 cm) was measured at 30 minute intervals (PT100).
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Instrument(s):
| FDR moisture probe (EnviroSCAN Sentek, Stepney, South Australia) |
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Description:
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| Climate Data Collection |
For climate data an automatic weather station (Davis Instruments Corp. CA, USA) installed nearby recorded half-hourly rainfall, temperature, relative humidity and wind speed and direction values.
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Instrument(s):
| Automatic weather station (Davis Instruments Corp. CA, USA). |
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Sampling Area And Frequency:
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| 17/09/2007 to 05/05/2008 Darling Downs (near Dalby), Southern Queensland, Australia (-27.3536, 151.4416) |
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Sampling Description:
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| Two sets of (3) chambers were placed (over plants) on 2 rows of irrigated cotton (3 per row) approximately 7 m apart and managed as per farmer practice.
Over the season a total of 155 kg N was added as both anhydrous ammonia and water run urea. An additional application of 99% enriched 15N labled urea was applied on the 28.12.2007 at rates of 40 kg N (chambers 1-3) and 80 kg N (chambers 4-6). In conjuction with the automatic sampling system for N2O, manual samples were taken using sample ports inserted into the existing sampling lines. Immediately after the end of each chambers automated sampling cycle, 10ml samples were collected for determination of 15N-N2O and 15N-N2 via mass spectrometry. Samples were taken daily for the inital week, then twice daily, weekly and fortnightly for 80 days following the labelled fertiliser application. |
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