title: Reducing dissolved inorganic nitrogen in surface runoff water from sugarcane production systems.
abstract: Nitrogen (N) lost from farms, especially as the highly bioavailable dissolved inorganic form, may be damaging Australia's Great Barrier Reef (GBR). As sugarcane is the dominant cropping system in GBR catchments, its N management practises are coming under increasing scrutiny. This study measured dissolved inorganic N lost in surface runoff water and sugarcane productivity over 3 years. The experiment compared the conventional fertiliser N application rate to sugarcane (average 180kg N/ha/year) and a rate based on replacing N exported in the previous crop (average 94kg N/ha/year). Dissolved inorganic N losses in surface water were 72%, 48% and 66% lower in the three monitored years in the reduced N fertiliser treatment. There was no significant difference in sugarcane yield between the two fertiliser N treatments, nor any treatment difference in soil mineral N - both of these results are indicators of the sustainability of the lower fertiliser N applications.
authors.affiliation: CSIRO Ecosystem Sciences and Sustainable Agriculture Flagship, P.O. Box 12139, Earville BC 4870, Australia. tony.webster@csiro.au
authors.forename: A J
authors.initials: AJ
authors.lastname: Webster
authors.forename: R
authors.initials: R
authors.lastname: Bartley
authors.forename: J D
authors.initials: JD
authors.lastname: Armour
authors.forename: J E
authors.initials: JE
authors.lastname: Brodie
authors.forename: P J
authors.initials: PJ
authors.lastname: Thorburn
mesh_terms: D000383:Agriculture / Q000379:methods / Q000706:statistics & numerical data*; D001315:Australia; D003247:Conservation of Natural Resources; D057894:Coral Reefs; D004784:Environmental Monitoring; D005308:Fertilizers / Q000706:statistics & numerical data*; D009584:Nitrogen / Q000032:analysis*; D058458:Nitrogen Cycle; D031786:Saccharum; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000517:prevention & control* / Q000706:statistics & numerical data
chemical_list: D005308:Fertilizers; D014874:Water Pollutants, Chemical; D009584:Nitrogen