Harvest is now well underway which means it is time to be thinking ahead so that key tasks are not missed in the postharvest period. Right now with the hoops you’re having to jump through as growers in today’s climate, it’ll seem crazy to be thinking that far into the future. However, planning ahead is critical to achieving your goals in this game.
If you are consistently seeing 15%+ of your crop left on the tree, it is time to ask why. Is it shading? Poor genetics? Not enough labour to get the crop off? Summer conditions? It is likely that several factors are influencing the outcome. A quick 5-minute walk in a block between-picks and once finished harvest, can give great insight into areas for improvement.
Figure 1. An example of a tree with a pickout percentage of approximately 85%
Postharvest presents a good opportunity to correct tree nutrition. Pre-harvest leaf tests can help to inform your postharvest applications (how much or how little to apply).
Leaf tests should be taken to determine the need for any nutritional replenishment. Elements that often need attention coming into the autumn season include Nitrogen, Magnesium and Boron. As an example, leaf N levels <2.2% measured at the end of Jan early Feb period mean your trees would benefit from Autumn N.
Foliar N applications are most effective in directly raising N concentrations in the floral bud. Foliar N should be applied immediately postharvest before leaf fall starts.
Where larger N inputs are required, foliar applications won’t be sufficient, with either ground applications or fertigation an effective option. If using ground application you must have the ability to wash the fertiliser into the soil solution with either rainfall or irrigation.
Boron is also most effectively applied immediately post-harvest. Boron is needed for pollen tube growth and therefore fruit-set. Adequate boron levels ensure a good seed set and the higher the seed numbers the higher the fruit size and calcium levels in the fruit.
Taking ‘large cuts’ out post-harvest can be an effective way to remove large branches and spread the labour demand later in the winter. By having your higher skilled pruners undertaking structural cuts, revisiting for winter detail has no need for loppers or saws.
It is important to note that in doing this task with leaf on, you are likely to see a vigour reduction. This type of structural pruning is most desirable on strong growing trees where a reduction in vegetative growth is desired. Renewal of the branch is less likely so keep that in mind depending on your desired result (and do not forget to paint!)
Note taking at this time of the year is worth its weight in gold. What you might notice now might be extremely useful information to you when planning for the 2023 harvest come mid-winter. Simple notes as you are driving around the orchard picking up any key outcomes which may alter your planning are important. These things are easily forgotten so let’s stay on top of it.