Seagrass-Watch Magazine Issue 47 - March 2013 | Page 32

Improvements for the grazing industry include:
! better monitoring and management of ground cover at the end
of the dry season.
! the fencing of riparian areas.
! better construction of roads, tracks and watering points.
Farmers are being assisted in making these changes through
financial incentives and research, development and extension
support from the Australian and Queensland Governments and
Industry Groups. For information on the case studies, visit
www.reefplan.qld.gov.au/measuring-success/case-studies/casestudies.aspx

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Improved farming practises
Water quality and ecological integrity of some coastal waters are affected by
material originating in adjacent catchments as a result of agricultural activities.
Delivery of sediments and nutrients to rivers discharging into Great Barrier Reef
waters is estimated to have increased four times since 1850. Applying best
management practices such as green cane trash blanketing (right) reduces
sediment erosion into waterways. Sediments in runoff reduce water clarity,
leading to seagrass loss.
Strategic application of photosystem inhibiting (PSII) residual herbicides
(atrazine, diuron, hexazinone) can reduce their transport in runoff to the Great
Barrier Reef, impacting seagrasses and coral. Pre-emergent residual
herbicides such as diuron can suppress photosynthesis in seagrasses if
concentrations in seawater are above 0.1 µg/L. Using shielded sprayers is one
of the new tools being implemented as part of a long-term weed management
strategy as it reduces the application amount of residual by half. The strategy
also includes appropriate timing of herbicide application and suitable chemical
selection. This has facilitated a shift away from ‘residual’ herbicide control in
early crop stages to a reliance on contact (‘knockdown’) herbicides, with
significant reductions of residual PSII herbicides leaving paddocks through the
crop cycle.
Green cane trash blanketing
AD

PE

Applying herbicides with a shielded sprayer
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