Nuts about water quality outcomes from farming improvements

Recent sampling at the Centre for Tropical Horticulture in Alstonville shows promising initial results for reducing diffuse source water pollution from agricultural run-off.

“Diffuse source pollution, including nutrients and sediment, from agriculture has been identified as a priority threat to waterways across coastal NSW,” explains Dr Tracey MacDonald, Director of Water, Wetlands and Coastal Science, DPE.

The Department of Planning and Environment has been working in partnership with the Department of Primary Industries and Southern Cross University researchers to compare surface water runoff from integrated orchard management and traditionally managed macadamia plots.

Integrated Orchard Management (IOM), which was developed by DPI with support from the Australian Macadamia Society, includes a practice guide with tools for orchard management.

These concentrate on three pillars for management: drainage, orchard floor, and canopy.

“We found that compared to traditional macadamia farming practices, preliminary results from the study site suggest IOM reduces surface water runoff by half,” said Dr MacDonald.

It retains 20 times more topsoil, 8 times more phosphorus, and 4 times more nitrogen when compared to traditional farming practices.”

“Additionally, we found a reduction in the amount of chemical residue in surface water runoff.”

This study will continue to sample and analyse rainfall events throughout 2023 and 2024.

The data gathered will enable the macadamia industry to quantify the benefits of making changes that benefit farm resources and income, while improving water quality in our waterways.

This study was delivered in partnership with the Department of Planning and Environment, the Department of Primary Industries, and Southern Cross University and funded through the NSW Marine Estate Management Strategy.