IN YOUR ORCHARD
TIME TO CONSIDER
What an interesting winter and early spring. Warmer than normal temperatures in January increased the rate of almond
tree development leading to an earlier than expected bloom. This proved to be unfortunate when a cold air mass dropped
down from the arctic creating several nights below freezing temperatures leading to crop loss in many orchards. The cold
temperatures persisted and then it rained, impacting bee hours and creating disease conditions for the remaining viable
flowers. This was all on top of one of the driest years on record. A challenging start to 2018.
It is a common misconception that the tree will
compensate for crop loss with an increase in set
percentage of the surviving flowers. This is not exactly
true. There is some mild compensation due to a slightly
higher set percentage of undamaged buds (around two
percent or so increase) as well as a gain from increased
kernel size due to more energy directed to the embryo
during the period of cell division. These two factors,
however, are not enough to compensate for flower loss
that may have occurred during bloom.
At this time, the impacts of the widespread freeze event
and following weather conditions that occurred during
bloom should be visible. To farm efficiently in 2018,
the crop size should be estimated to determine which
orchard operations are needed. This includes the amount
of fertilizer, fungicide applications as well as other farm
practices. Some farm practices, such as irrigation, will
have to be maintained regardless of crop status to have
a productive orchard for 2019.
Spring-time Nitrogen Management
Fertilization will be most impacted by reduced crop
loads. New nitrogen regulations require a crop estimate
to determine the seasonal amount of nitrogen to apply.
Crop removal studies have indicated that around 65
pounds of nitrogen are removed with every 1,000 kernel
pounds of harvest. Considering nitrogen application
inefficiencies, 85 pounds of nitrogen must be applied
to replace the removed amount. Further research has
indicated that multiple applications of nitrogen should
be made through the season with 80 percent of the
total budget being applied prior to kernel fill and the
remaining 20 percent applied in the postharvest period.
The rate of spring fertilizer applications should be split
to reduce the potential of plant toxicity and leaching
from spring rains or over-irrigation. In coarser or soils with
lower water holding capacities, smaller, more frequent
applications should be applied. Young trees are more
sensitive to toxicity. Rates for each application should be
reduced to levels that are equal to one ounce of actual
nitrogen per tree for newly established trees, and two
ounces of actual nitrogen per tree for years two and
three after establishment. Multiple applications may occur
through the season to hit the targeted nitrogen budget.
Irrigation timing/Saturated Soils
In many operations, water is over-applied in the spring.
This is due to the occurrence of rains, variable ranges of
wetted soil profiles, weather conditions, and general lack
of understanding of how much water trees utilize at this
period. Prior to the first irrigation, it is best to make sure
the soil profile is beginning to dry before applying water.
This can be determined with the use of a shovel or auger,
pressure chamber, or soil moisture sensors. If using the
pressure chamber, irrigation should be considered if trees
are 1.5-2 bars more negative than baseline. As an example,
for the past three years (2015–2017) in a local research
plot of mature Butte and Padre trees in a very sandy soil,
3 0
A L M O N D F A C T S
