The coastal waters of Southeast Queensland (SEQ), Australia, contain areas of high ecological value, protected at state, national and international levels. Included are tidal flats and mangrove habitats used by migratory shore birds, and seagrass meadows essential for threatened species including dugong and turtles. However, diffuse source pollution from horticultural land use is one of many ongoing threats to the health of aquatic ecosystems within the region.
Monitoring of tributary creeks revealed nitrogen and herbicides in exceedance of water quality guidelines. In addition, topsoil losses are causing turbidity and sedimentation issues which are carried into the receiving waters of Moreton Bay. Working in collaboration with the horticultural industry, the Queensland Government Department of Environment and Science has engaged the Department of Agriculture and Fisheries, Healthy Land and Water, and Growcom to help determine solutions to reduce pollutant and sediment loads and improve environmental conditions, whilst being cost effective and maintaining yield. With the support of these partners and industry, the Department has invested in research and development and supported implementation of contemporary best management practices (BMPs) across SEQ.
Since commencement of the program, research has included: nitrogen budgets for pineapples and macadamias to refine fertiliser application; the efficacy of bioreactors to mitigate nitrogen leaching losses; biodegradable polymer application, cover crops, and strip tillage to reduce sediment loss; biofumigation; and improvements to existing machinery and advancement of application techniques to reduce herbicide use. Results of these studies will inform industry BMP manuals, and implementation is currently being rolled out across a larger scale.
Long term monitoring is underway to determine the impact of the practice improvements made by this committed industry to local and regional water quality.