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Completed project

Better tree performance and water use efficiency through root system resilience (AL13009)

Key research provider: CSIRO Agriculture and Food
Publication date: Monday, June 21, 2021

What was it all about?

This investment, which ran from 2014 until 2020, combined various studies on almond root systems, from commercial orchards to research greenhouses, to provide growers with information aimed at maximising production through the efficient use of inputs, such as irrigation and nutrition.

In collaboration with Hort Innovation project Identifying factors that influence spur productivity in almond (AL14005), work took place over four seasons within a 2.2 ha field trial at Lindsay Point in north east Victoria.

The team examined root system dynamics and tree water use in response to a 30 per cent reduction in irrigation, a 40 per cent reduction in nitrogen application, and a combination of the two.

Input reduction showed minimal impact on the root system, in line with the lack of any significant effect on yield reported by AL14005. This suggests that almond root systems can maintain adequate nutrition in a broad range of input scenarios, creating the potential for more efficient input use compared with current practices.

Detailed greenhouse studies were also conducted, using the stable isotope 15N as a label so that nitrogen uptake could be quantified and tracked very quickly (as little as a few hours). This work used six rootstocks and three scions in eight combinations, showing that:

  • The fine root system swiftly reached maximum nitrogen uptake rate with little difference between rootstocks, meaning that shoot demand was likely the major driver of whole plant nitrogen uptake
  • Despite having little effect on nitrogen uptake rate, rootstock genotype did appear to influence whole tree nitrogen allocation, meaning that if this effect is also present in mature trees it has implications for rootstock choice and tree management.

Finally, the team adapted a plant growth analysis method to create a rapid pre-screen for rootstock resilience to soil abiotic stress. The process was tested and simplified to ensure its reliable use by tree nurseries and importers of new genetic material to assess and categorise genotypes prior to selection for long-term field trials.


Related levy funds


Funding statement:
This project was funded through the Hort Innovation Almond Fund using the Almond R&D levy and contributions from the Australian government.

Copyright © Horticulture Innovation Australia Limited 2021. The Final Research Report (in part or as a whole) cannot be reproduced, published, communicated or adapted without the prior written consent of Hort Innovation, except as may be permitted under the Copyright Act 1968 (Cth).