HARVESTING AROUND RAIN

By Andrew Cutfield, GM Investor Relations and Supply, Darling Group

[Video content included below]

Pre-pick protocol

Why: Over the last three years, the avocado industry has faced a number of quality claims which costs the industry significantly in money and reputation. As we develop new markets, we need to instill confidence in our customer about our product. Typically our developing Asian markets are a green fruit market (where small blemishes are very evident as the fruit is green rather than closer to being ripe) and have an increased travel time, increasing the potential for blemishes to express themselves. Just Avocados is looking to support our marketing team to develop these new and high value markets through being able to present a very high visual quality avocado to the market. Damage caused during harvest whether through mechanical causes or poor vigilance around rain not only costs us in the markets but cost you in your packout and bottom line. Based on our 2019-20 OGR at a glance report, the “average” grower could increase their total orchard return by circa $700 + per ha – worth staying vigilant.

One of the key ways you can assist our marketers and help to protect your potential return is to be vigilant at the time of picking and especially around rainfall events. Below are our guidelines for harvesting around rain. Many of these come from NZ Avocado’s guidelines but have also been amended with our experience as a grower, harvester and packer. We have also included some top tips for reducing other types of damage at harvest.

Prior to picking start:

Please use our decision tree to help guide you through protocols for harvesting around rain.  Key points are also listed below.

  • Ensure you have a rain gauge on your property – cheap, practical solutions can be sourced at any rural supplies store. There is a high variability within in many regions, so the local on-line rain gauge may not accurately reflect your actual orchard rainfall in this very key period.
  • If you have more than 5mm of rain in the previous 24 hours, please stop harvest.
  • Prior to the start of picking complete a roll test. This should be completed when fruit are dry to the touch and at least two hours after rainfall has stopped.
  • The period of time to wait before harvest recommences will vary on the drying conditions and soil types. But as a general rule for every 5-10mm of rain you will need to wait at least 24 hours before a roll test will pass e.g. 20mm of cumulative rain you will need to wait 48 hours from the cessation of rain before a roll test will be passed.

VIDEO – HOW TO: ROLL TEST

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The industry standard is “more than 5mm in 24 hours”. Why are we adding the 20mm in 48 hour rule?
Many markets, including some channels in Australia, but more significantly in our developing markets in Asia, are requiring hard green fruit.  This shorter time-frame protocol (5mm in 24 hours), in our experience, will not deliver the desired outcome the marketing team are looking for and won’t improve the variable poor quality experiences the industry has had over the last three + years. There are too many variables from orchard to orchard around a rain event and any lenticel turgidity will cause variable outcome and therefore will not meet spec..

Other industry recommendations say use a smooth sided 10L bucket. Why are we saying use a “fish bin”?
You can use a bucket, but there are a number of variables that “rolling fruit for 15 to 20 seconds” can produce. We are looking to create something that is easy and clear for all growers to implement that provides a consistent outcome.

What will influence orchard drying time?
There are a number of factors that will influence the time that you can start harvest after rain:

  • Soil saturation: If your soil is saturated, even a small amount of rain will influence the fruit moisture content. Sandy soil will obviously dry sooner than say a heavier loam.
  • Wind: If you have steady, warm wind your soil will dry faster.
  • Canopy structure: The more open, the higher the drying rate, especially in combination with above.
  • Aspect/orchard temperature.

Why stop harvest when already started if it rains? and will this influence harvest costs?
Generally, it won’t influence your harvest cost as most contractors work on an “hours worked basis”. The key reason why you want to stop is that you have invested heavily in getting your crop to this point. If you are at risk of say getting an 14.3% downgrade in packout (the average we saw from last season) then there is a good economic rationale to pause.

Other areas to vigilant on during picking:

  • Ensure you or your contractor are not filling the mobile elevating work platform pick bags beyond the bottom of the cage (no drop bags used). This has a tendency to:
    • Increase rubbing/bruising and lenticel damage.
    • Increase incidence of mechanical damage as fruit below the “cage” is knocked in the tree’s as picking occurs.
  • Drop height is no greater than 10cm from the bottom of the picking bag to the fruit in the bin. A higher drop height will cause bruising leading to localised softening.
  • Keep bins in the shade and out of direct sunlight. Use bin covers if possible. This not only prevents sunburn and reduces the chance of any external contaminant’s coming in (food safety) but will also reduce heat build up and moisture and weight loss in the fruit. This will increase your pack out and increase the time that we have to get your fruit into the hands of the end consumer.
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