Reading the trees and adjusting management accordingly and attention to doing all orchard management well. This might include crop removal from sick trees, additional fertiliser for heavy cropping trees, etc.
Most negative influence on orchard performance
Nearby shelter is quite high and does shade the trees a bit but it’s unclear how much this might influence the trees. No major negative in block.
General management
Pollination, pruning and fertiliser planning is contracted out. Remainder of work is completed by owners and one part time staff member.
A weather station in on-orchard with rainfall, temperature, wind and solar radiation used to inform orchard practices.
Soil temperature is believed to be important, particularly over spring. Herbicide is used to spray out about a 30cm strip around drip line. This is often bare soil and captures sunlight well to warm soil.
Regular mowing is also carried out, particularly in spring to keep grass short and maximise sun capture to warm soil.
Canopy management
Tree spaced 7m X 7m.
Max height of trees is 4m.
Managed in rows.
Trees pruned to allow light into the middle of tree but no particular shape targeted. Try to give each limb enough space to get good light and get good light right through tree including the middle. This supports good flowering and increases the potential for new growth from the middle of the tree all the way to the edge. This maximises productive area and provides options to prune back to reduce canopy width while still having fruit on the limb after cut.
Trees are structurally pruned twice a year with larger cuts made in Spring, followed by a tidy up in autumn to select productive/replacement wood and maintain light onto these limbs. Also to ensure good light distribution through the entire canopy. About 30% of the canopy is removed each year.
Flower pruning is used on excessively flowering trees. Very rare to prune fruit off trees but will do if trees looking too stressed or carrying a heavy crop post flower pruning. Regular structural pruning means it’s unlikely to get excessively flowering trees.
Crop load is assessed in stages with intervention made if not enough leaf is coming through. Possible that two rounds of flower pruning and 2 rounds of fruit pruning carried out on a tree if it continues to look stressed. Important to balance new fruit with flush, etc
Soil and soil moisture management
Orchard is predominately sandy loam with some clay areas that aren’t planted.
Leaf litter, avocado pruning and shelter pruning are all used to mulch trees. Recently avocado mulch from another orchard has also been applied in large quantities to about 0.5m depth but this has reduced down to about 10cm now.
Soil moisture is monitored using a single site with TDT sensors at 10cm, 30cm and 50cm as well as two additional tensiometer sites. TDT reading of 30% correlates with tensiometer reading of -30kPa for 10cm probe which is used as trigger for irrigation in summer and autumn. A trigger point of -25kPa is used at full-flowering in spring. If 30cm, and 50cm soil moisture readings keep declining beyond a month, a longer irrigation may be applied.
The orchard is 100% irrigated with over-canopy micro sprinklers used for both irrigation and frost protection year round.
At peak summer it is common to irrigate for 6 hours per irrigation event once a week using sprinklers with a 6m diameter that deliver 70l/hr (15mm per irrigation event).
Sprinkler heads are chosen based on soil type, tree size and age, health, topography and irrigation is seasonally adjusted as well.
Pump pressure and flow characteristics are checked twice a year (Prior to main frost risk period and prior to main irrigation period) with ongoing inspection of pipework on orchard.
Pollination
Pollinizer species include Bacon, Ettinger, Zutano, Fuerte and Edranol at a percentage of 10-12%.
Hives are brought onto the orchard at about 20% flowering at a rate of 8 hives per hectare.
Hives are located evenly through block.
Soil and fertiliser application
Soil and leaf tests are carried out once a year in April.
A consultant provides a fertiliser plan based on test results and crop loading.
The majority of fertiliser is applied by ground application but foliar application is also used. Ground applications are assessed based on various tree characteristics e.g tree crop load, health, canopy volume. Fertiliser applications may also be split into two applications over the same time period on sick or stressed trees to maximise uptake from a potentially limited root system and to avoid shocking the roots too much. Lower yielding trees receiving less fertiliser.
Low biuret urea, magnesium sulphate and stimplex foliar sprays are applied through winter to maintain leaf colour.
Boron fertilisers are applied as ground application and foliar every year.
Calcium fertiliser is applied every year.
Fertiliser in some form is applied 12 times a year.
Tree health management
Trees are injected twice a year with phosphonate with root testing conducted to verify application has been successful. All trees are injected in late spring/early autumn and sick or stressed trees are reinjected in August (winter).
Frost protection
Over canopy sprinklers are used for frost protection. A trigger point of 4°C is used in spring to ensure flowers are protected. In winter a trigger point of 1.5°C is used.
