Time of flowering and pollination relevant to orchard weather conditions in northern NSW – a growers trial group (MC12011)

What was it all about?

Climatic conditions during peak flowering have often been related to poor macadamia yields in northern rivers NSW but whether it is heat, rain or wind that causes poor yields is not known.

This project, which ran from 2011 to 2016, investigated the effect of weather events in the orchard on the success of pollination at time of flowering. It used grower-based trials to gather on-farm data in the Northern Rivers region of New South Wales (Newrybar, Knockrow, Rosebank, Alstonville Plateau and Tregeagle).

All of the growers in the macadamia Grower Trials Group already had on-farm canopy management trials underway to improve pollination and yield. These trials were absorbed into this project, adding a control condition for comparison where needed.

Each grower collected data on climatic conditions, timing of flowering and commercial yields over six seasons. This valuable information fed into the development of the ‘integrated orchard management’ (IOM) concept, which showed a positive effect on production over the last three years of the project.

One finding of relevance to growers was that the flower location in the canopy had a stronger influence on timing of flowering, more so than regional differences. As most northern rivers NSW orchards are tall and mature, with the majority of the productive zone (where flowers turn into mature nuts) is in the top 2m of the canopy, this project found that making timing decisions based on flowers lower in the canopy risks missing key crop protection periods.

Once the IOM system was developed, the group supported its extension to the wider industry by acting as host orchards for annual field trips.