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IMG_1601The three-year SunCoast Enhanced Compost Project was designed to reduce greenhouse gas emissions by diverting organics from municipal landfill for composting and application with/without a biological nitrogen enhancer to cane, macadamia and olives, in an effort to demonstrate increased soil carbon and reduced need for synthetic fertilisers and possibly reduction in nitrous oxide emissions.

ECOllaboration were involved in the cane trials.  The project  consisted of nitrous Oxide emission measurement  being undertaken on the small plot replicated trials at a cane farm on the Maroochy River.   Manual field sampling was undertaken over the summer (November – February) following compost and fertiliser application.

Methodology

The round PVC manual sampling chambers (diameter = 0.235 m) were used for this trial. Chambers were  inserted to a depth of 10 cm.  The height of the chambers from the ground was measured and recorded. A PVC cap with a gas sampling port (a three-way valve.) and rubber septum was placed on the PVC base to initiate the gas sampling measurement period. Samples were drawn from the flux chamber by extracting 25 ml of gas with a syringe via the three-way valve. After expelling 5 ml of the gas, 20 ml was transferred into a 10 ml evacuated vial with a septum lid, which was subsequently transported to the laboratory for analysis.

Gas sampling was undertaken 2 times per week during the high emission period ( the first 2 months after fertiliser application, and high rainfall season from November to March.).  After the first two high rainfall events (exceeding 10mm in a 24 hour period), sampling was undertaken 3 times a week.  Sampling occurred between 9 am and 11 am, when emissions are close to daily average. This same start time was used throughout the season except on one occasion where sampling was conducted between 8am-10am due to extreme weather conditions. 

For this trial, only 6 time zero samples were collected each sampling event to represent the ambient condition for all chambers. Samples of all 64 chambers were collected after closing for approximately 60 mins. Gas samples (28 mls) were extracted with a 50 mL syringe and injected into evacuated glass vials. The laboratory calculated the flux.

Gas samples were stored in a cool environment and analysed within 7-14 days where possible.