Future Orchards Project

Root PruningOakleigh Orchards

2013 - 14

Project OutlineA demonstration site was set up in a block of 3 year old Fierro Fuji’s grafted onto 10 year old M.26 rootstocks (previously Sundowner) still filling their allocated canopy area.

The trees are drip irrigated. A root pruning demonstration site was set up in the most vigorous part of the block. The site had the following treatments

• Control – no ripping• Ripped both sides• Single Ripped – North side• Single ripped – South side

Trees at ripping time

The ripping lines were a vertical incision 500mm from the trunk

and 400mm deep.

No measurements of fruit yields or characteristics

Trees in their first significant crop year whilst still developing tree canopy.

Crop yield was 24.23 t/ha

Planned netting was added to the block during the growing season.

Trellis extensions had already been added to support the leaders

The height of the net is 4.5 m above ground level.

All of the trees have attained the desired tree height in their 3rd season.

Control Trees – end of growing season

Control Trees

Trees Ripped South Side

Double Ripped

Ripped North Side

Results Summary** (averages of 20 measured trees)

Measurement Control Ripped North Side

Double Rip

Ripped South Side

Starting Circumference (cm)

15.8 16.3 16.2 15.9

End of season Circumference (cm)

17.5 17.8 17.9 17.6

% difference - tree circumference

10.8 9.2 10.5 10.7

Tree Height (m) 4.59 4.36 4.49 4.53

Number of Branches above 2.5 m*

26.2 32.9 33.5 33.3

Apart from • Slight reduction in tree circumference for the

North side ripped treatment • Slight reduction in tree height for North side

ripped treatment• and a significant (approx 27%) difference in

actual branch numbers (>5cm long and above 2.5 m) for the ripped trees there was no appreciable difference in tree

performance.

Discussion

Concluded that whilst the treatments may have had some small impacts the

3 ripping treatments did not significantly influence tree canopy

development in this season.

North side ripped treatment?

Why Not?

Where were the roots before ripping?

(Drip irrigated block)

Dig and find out where the roots are before ripping – don’t guess!

If you don’t know – you cannot get the impact you want

Or worse – you could get too severe an impact.