Celebrating CCC macadamia nutrient research on World Water Day
22 March 2022
Researchers and Development Officers from the NSW DPI - Clean Coastal Catchments (CCC) project are working on ways to reduce fertiliser waste and stop nutrient pollution from ending up in groundwater, creeks and rivers in the marine estate.
Funded by the NSW Marine Estate Management Strategy, the CCC project team are working with horticultural and livestock industries on the NSW coast, including macadamia growers in northern NSW.
The team has installed soil moisture and ground water monitoring equipment at a CCC research site on a commercial macadamia farm near Brooklet.
The CCC scientists are tracking the movement of nitrate, phosphate, and ammonium in the soil profile.
Moisture probes measure water content in the soil and wick lysimeters are used to extract water samples at a two-metre depth below the macadamia trees.
The samples are tested for nutrient concentrations and nitrates have been detected at 2 metres, however it’s not clear whether these nutrients are naturally occurring, have leached deep into the soil following fertiliser application, or have been transported into the soil from another nitrogen source.
The researchers are also analysing farm nutrient application and rainfall data to better understand how much nutrient is escaping the target root zone of the macadamia trees, and how nutrient leaching might be exacerbated by seasonal conditions and by weather events such as heavy rainfall. This includes measuring the amount of nutrients lost in surface run off from the orchard floor.
Work is underway to design and test practical farming strategies that will reduce nutrient leaching into both surface and groundwater flows.
The aim of this research is to better manage on farm fertiliser application to reduce the amount of nutrients leaving the farm and ending up in the NSW Marine Estate.
