JULY | AUGUST 2016
Almond Facts
37
Critical threshold levels for boron hull values are
as follows:
Hull Boron Level (PPM)
Deficiency
<80 PPM
Sufficient
100 - 160 PPM
Toxicity
>300 PPM
To determine if an orchard is deficient in or showing toxicity
from boron, hull samples must be collected. Since the hulls
serve as the primary boron sink, they tend to accumulate
the nutrient, and provide a consistent reading. Leaf values
are not effective in determining adequate boron levels. Leaf
tissues cannot reliably detect toxicities and are inconsistent at
the lower end of the sufficiency levels.
Boron deficiency can be alleviated through applications of
boron to the soil. Caution should be used when determining
the rate of material applied, as high rates of application may
cause toxicity. There have been some reports that boron
applied in the summer may lead to stick-tights at harvest,
suggesting that it may be better to apply boron after harvest.
A foliar spray of boron should always be considered between
postharvest and pinkbud.
Postharvest Irrigation
and Nutrition
The initiation of fruit bud formation
occurs for most almond varieties in mid-
to late August. Severe stress imposed
during this period can reduce floral
bud count and fertility in the following
years. Trees should be irrigated as
soon as possible after harvest to reduce
stress. During this period, the tree is
also building nitrogen stores for the
following year. Approximately 20
percent of the nitrogen budget should
be applied in the post-harvest period.
The rate may be reduced if mid-July
leaf samples were above 2.5 percent.
No more than 50 pounds of nitrogen
should be applied, however, as research
has shown that the shorter days and
lower ETc demands limits the amount
of nitrogen uptake to about this much.
Rates for later harvesting varieties
should be less.
The Final Thought
Over the past few years there has been an increase of almond
thefts. These include from stockpile yards and missing
truckloads. Although it is a busy time, be mindful of the
activity and stick to the protocol of verifying drivers and
receiving signed pickup sheets. With that in mind, consider
assigning only the most trustworthy employees to handling
trucking and delivery information.
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Ant damage to an almond kernel.
Ants often consume the meat of
the kernel, leaving only the pellicle.
Often times, the pellicle is light
enough to be blown out through
harvesting and the full extent of ant
damage often goes undetected.
