She'll be apples with right timing

An innovative trial in Tasmania is aiming to predict the nutrient and water use of apple trees which would help industry maximise their productivity.

The trial is being conducted by the Tasmanian Institute of Agriculture (TIA) as part of a four-year research project, funded by Hort Innovation using the Apple and Pear levy and funds from the Australian Government.

TIA Research Fellow Dr Nigel Swarts is leading the team researching the seasonal use of nitrogen and water for apple tree growth. He said research into optimising nitrogen-use efficiency has the potential to boost productivity in apple growing.

“Growers are keen to efficiently use their nutrients – not only to improve their productivity and yield – but also to support positive environmental outcomes,” Dr Swarts said.

The trial involves looking at when and how the tree uses applied nitrogen. Applied nitrogen is detectable via a nitrogen tracer and it is the first time in Australia that this technology has been used in apple orchards.

Dr Swarts said the research involved two main components, including field work and the development of a model by New Zealand collaborators Plant and Food Research, which would be used to produce an online tool that strategically predicts apple tree growth and productivity in a season.

“There are few models that predict tree growth and this technology will be designed specifically for the Australian horticulture industry,” Dr Swarts said.

The online tool will be called SINATA (Strategic Irrigation and Nitrogen Assessment Tool for Apples).  

“We’re trying to get as much information as possible about the tree response to nitrogen which will inform the model,” Dr Swarts said.

“In the first two months of growth an apple tree uses nitrogen from storage reserves and as the tree’s leaves, branches and crop develops, it starts getting hungry for nitrogen and other nutrients,” Dr Swarts said.

“It’s mid-November to early-December that the tree really needs its nitrogen, however when you’re putting on nitrogen pre-harvest, there’s a risk of impacting fruit quality. The model will help growers understand the right time to apply nitrogen that optimises uptake efficiency.”

Dr Nigel Swartz & PhD Candidate Bi Tan

PhD candidate, Bi Zheng Tan, is conducting research for this project over the next two years and is currently setting up new trials with Dr Swarts. Originally from Malaysia, Bi relocated to Hobart to undertake a bachelor’s degree with Honours in Agricultural Science and has stayed in Tasmania to complete his PhD.

Bi will be investigating the conditions in which apple trees use nitrogen most efficiently. The practical work involves excavating 30 trees over winter next year and during the 2019 apple harvest.  

“It’s a technique that allows us to look at the movement of the nitrogen that we apply to the soil, through the tree. We’re analysing all its parts – the fruit, leaves, branches, trunk, and roots – to see where the applied nitrogen has been allocated and how much has been absorbed,” Dr Swarts said.

“The growers are very generous letting us use their field sites. For our work to be relevant it has to be completed in commercial sites,” Dr Swarts said.

This is the full version of an article that appeared in Tasmanian Country on Friday 6 October 2017.

Published on: 06 Oct 2017 10:25am