moisture levels, is rain at harvest.
While rains cannot be avoided,
growers and custom harvesters can
mitigate moisture-related damage in
the orchard. If rain is in the forecast,
shaking should be put on hold until
after the rains have passed, as wet
nuts dry faster on the tree than on
the orchard floor. However, if rain is
in the forecast while the nuts are on
the ground to dry, a number of steps
can be taken:
• If you’ve already shaken your
orchard, but the nuts are still
too wet to pick up, blow them
away from tree trunks and
don’t windrow.
• If nuts have been windrowed,
condition them through a drop
chute of a harvest machine. This
involves picking them up and
putting them back on the ground
while blowing out leaves and
other trash. This helps dry nuts
faster even under dry conditions.
Conditioning your crop both
before and after rainfall promotes
the most rapid drying; however,
a greater benefit is seen when
conditioning after rainfall.
• Maintaining optimum moisture
levels before stockpiling is critical
to limiting mold growth and
concealed damage. If moisture
or relative humidity levels are too
high to stockpile, another option
is to move the crop to a dry
area, or machine dry.
The Trick is in the Tarp
It is important to cover a stockpile
with a tarp, but this can increase the
humidity and moisture levels within
the stockpile. When choosing a tarp,
keep the following key points in mind:
• A white-on-black tarp is
the best choice to minimize
temperature fluctuations, which
lead to condensation and
eventual mold growth.
• Clear tarps allow the greatest
temperature fluctuations, but
should only be used on dry, in-
hull almonds that are well below
the moisture threshold.
• White tarps fall between white-
on-black and clear tarps in terms
of temperature fluctuations.
Controlling the relative humidity (rH) in
a stockpile is critical to food safety.
If you find that moisture levels are
too high in a stockpile, open the tarps
in the daytime to allow moisture to
escape, and close them at night, when
relative humidity tends to increase.
Also, pay close attention to the outside
of the piles, where large changes in
temperature and condensation can
increase moisture levels.
When stockpiling is necessary, visit
almonds.com/growers/in-the-orchard
for more valuable information on
best practices for creating piles and
managing stockpile moisture.
Article contributed by the Almond Board
of California
If rainfall occurs after your crop has been windrowed, one option is to condition
the nuts by picking them up and putting them back on the ground while blowing
out leaves and other trash. Image courtesy of the Almond Board.
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