In A Nutshell Autumn 2025 | Page 30

RESEARCH & EVENTS

Trial to test cover crop mixes

Growers can visit a cover crop trial site in the Riverina, where researchers are testing the economic feasibility of cover crop mixes in almond rows.
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ALMOND growers will have the
Darlington Point has higher rainfall
opportunity to visit a cover crop trial site
than Loxton, so treatment five was
in a Riverina almond orchard this winter.
altered because the Riverina site
The Hort Innovation funded project
could handle more water demanding
is being run by Dr Thomas Lines
species.
at the University of Adelaide, and
University of Adelaide Research
the findings will test the economic
Fellow Doctor Thomas Lines said
feasibility of cover crop mixes in
canopy temperature and humidity
almond rows.
data that’ s been collected so far
The project aims to evaluate the
is showing significant differences
impact of these cover crops on
between treatments in heating and
yield, soil health, water status /
cooling.
stress, temperature, humidity, soil
“ The tree canopies next to the bare
physiochemistry, carbon stocks and
earth treatments are warming and
soil microbiomes.
drying faster at the start of the day.
The two trials are being run at the
This is likely to influence some
Almond Centre of Excellence at
phenology of the trees,” he said.
Loxton, and the other at Darlington
“ More detail is being explored, and
Point in the Riverina, where the first
the addition of the microtensiometers
year of seeding took place in May
next season will really help
2023.
demonstrate whether there is a real
At each site there’ s five different
world effect on water usage and
treatments:
stress.”
1.
A herbicide control with no
Dr Lines said the trials are generally
cover crop
sown in early May but timing is
2. A legume( medic, clover,
important, especially if orchards get
vetch) mix
waterlogged or, conversely, get very
3. A medic / rye / clover mix
little rain.
4. A pollinator mix
“ Try to sow as late as possible without
5. A barley / vetch / radish mix( at
missing the first serious rains of the
the ACE orchard) and‘ big
season,” he said.
blend’ mix at Darlington Point
“ If in doubt, sow early. Late sowing
consisting of a chicory, vetch,
might miss rain and may not give the
plantain radish, brassica, rye,
cover crop time to flower.”
clover, quinoa and oat.
The majority of Australian almond
In A Nutshell- Autumn 2025 Vol 26 Issue 1
orchards have drip irrigation and Dr Lines said it is still viable to grow a mid row cover crop.“ While full-floor planting would be ideal to maximise the ecosystem services of cover crops,( such as improvements in water retention, heat reflectance, soil structure improvement) current harvesting methods mean it is not practical,” he said. Dr Lines said it ' s still too early to make a call about the best cover crop mix to use in an almond orchard.“ In addition to looking at water usage in the different treatments, we also expect there will be differences in soil characteristics, but these can be slow to change,” he said. Dr Lines said harvest can continue as normal, but slashing or terminating the cover crop at the right time is important.“ Cover crop selection is also critical in defining the challenges you might have at the busy end of the season,” he said. The cover crop workshop will be held on Wednesday, 27 August at Darlington Point. Keep an eye on the ABA’ s events page for further details, including the registration link.