Reduced fertiliser use linked to cleaner water flowing to Great Barrier Reef

A new study reveals that reduced use of fertilizers in farm management practices has led to cleaner water flowing into the Great Barrier Reef. This research marks the largest and most comprehensive analysis of its kind, utilizing 100 years of data. The findings are crucial as Australia prepares to report on its progress under the Reef 2050 water quality plan to UNESCO in 2028.

Two separate studies have demonstrated a correlation between improved water quality in catchments and farmers changing their fertilization methods. Researchers from CSIRO and James Cook University used this data to show that nitrogen and phosphorus fertilizer application across the Great Barrier Reef catchment area has decreased by up to 25 to 50 percent over the past 20 years.

The improved water quality could help the reef recover from climate change impacts such as coral bleaching. Aaron Davis from TropWATER at James Cook University noted the clear link between the reduced fertiliser use and the subsequent improvements in water quality. Stephen Lewis highlighted that the data spans 100 years, with a marked reduction in synthetic nitrogen and phosphorus fertiliser application in most basins.

Rebecca Bartley, a CSIRO researcher, emphasized that nearly 40 years of water-quality data from nine sites showed improvements in water quality over a 40-year period, with 75 percent of these sites exhibiting positive trends. Dr. Bartley stressed the importance of landholders in maintaining water quality, which would aid the reef, especially during coral bleaching events.

The Great Barrier Reef Marine Authority welcomed the study's findings, highlighting the significance of long-term monitoring in conservation efforts.