March/April 2024 - 26

Photo courtesy of the
Almond Board of California.
nitrogen to almond trees
Maximizing your investment and minimizing inefficiencies
utrient application, such
as nitrogen application, is
undoubtedly one of the most
important " make or break " economic
and environmental decisions almond
growers make. Not only can nitrogen
affect yields and productivity, but
growers can see a huge difference
in their profit margins if applied
" When we think about managing
nutrients such as nitrogen, our goal
is the balance between supply, all
of the inputs of nitrogen into the
system, and the demand of the tree
with the goal of maximizing your
efficiency, " said Patrick Brown,
professor at UC Davis during a 2023
Almond Conference session.
Because nitrogen application can
differ from one crop to the next,
Brown encouraged growers to fully
understand the conditions of their
individual orchard before applying
fertilizer. This includes when it
is needed, how much should be
applied, the placement and source.
Minimizing losses
The goal when using these
considerations is to minimize losses,
with environmental concerns being
top of mind.
" Any loss is a lack of efficiency,
but any loss is also a source of
greenhouse gasses for pollution or a
source of nitrates for pollution into
the groundwater, " Brown said.
Research has shown that nitrates
move through the soil very rapidly,
and as growers increase application,
uptake of nutrients from the soil
is not uniform. For example,
if fertigation is infrequent and
application exceeds a certain rate,
saturation can occur causing waste
or leaching.
" A large proportion of that
nitrogen will sit in the root zone
waiting for the plant to catch up, " he
said. " This is an important principle
because it underlies where and how
inefficiencies occur. "
Growers can avoid these scenarios
if they follow the 4 Rs of nutrient
management: right rate, at the right
time and in the right place, using the
right source of nutrients. An in-depth
explanation of the 4 Rs can be found
on the Almond Board of California's
(ABC) website,
Right time
First, it's important to understand
the ideal time to apply nitrogen to
an almond orchard. Studies show
there is no nitrogen uptake from the
soil at 70% leaf out because the tree
is still utilizing reserves established
in the previous year. Until those
reserves are consumed, new uptake
doesn't occur, and that's where loss
transpires, Brown explained.
" Those early excesses are
particularly prone to losses from
rainfall, irrigation, and other events,
so you have an increasing number
of periods where there's excess
availability of nutrients and hence,
the potential for loss, " he said.
Instead, optimal fertilization will
occur with multiple applications in
a season, timed accordingly with the
demand of the tree.
Active root zone placement
Another key aspect of nitrogen
application is placement. This is
where growers must be educated
in understanding the relationship
between irrigation and nitrogen
movement. Nitrogen that sits on the
surface of the soil and remains in the
top five inches will be lost if water
moves through the profile.
In order to be utilized properly,
nitrogen must be kept within the
active root zone, which through

March/April 2024

Table of Contents for the Digital Edition of March/April 2024

Editor's Letter
The blight phase of Botryosphaeria diseases in nut crops of California
Tree nut outlook for 2024
From the top
Water stress
Buzz pollination
Hazelnut crop concerns
Almond Board of California
Ad Index
March/April 2024 - 1
March/April 2024 - 2
March/April 2024 - 3
March/April 2024 - Editor's Letter
March/April 2024 - 5
March/April 2024 - The blight phase of Botryosphaeria diseases in nut crops of California
March/April 2024 - 7
March/April 2024 - 8
March/April 2024 - 9
March/April 2024 - Tree nut outlook for 2024
March/April 2024 - 11
March/April 2024 - 12
March/April 2024 - 13
March/April 2024 - From the top
March/April 2024 - 15
March/April 2024 - 16
March/April 2024 - 17
March/April 2024 - Water stress
March/April 2024 - 19
March/April 2024 - Buzz pollination
March/April 2024 - 21
March/April 2024 - Hazelnut crop concerns
March/April 2024 - 23
March/April 2024 - Business
March/April 2024 - 25
March/April 2024 - Almond Board of California
March/April 2024 - Events
March/April 2024 - 28