TIME TO CONSIDER
40
Almond Facts
MARCH | APRIL 2016
Irrigation timing/Saturated Soils
Annually, several calls regarding poor tree growth and
“pale trees” are received. This is often due to saturated
soils. Too wet of soils reduces the movement of oxygen
into the soil, killing fine feeder roots. This impacts
the ability for the tree to uptake water and nutrients,
leading to micro-nutrient deficiencies, impacting nut set
and tree growth. Later-season effects are also observed
and include a limited rootzone, leading to severe water
stress during hull-split and harvest. The problem is
often compounded by fertigation or chemigation in
attempts to manage the symptoms. Often, however,
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.
Importance of Irrigation
Irrigation is the most important practice within the
farm operation. This is due to the close relationship
between water applications and yield. Preliminary
data from regional water trials suggests that yield
is a linear response to water applications with a 1:1
relationship until 85 percent of the calculated almond
evapotranspirational demand (ET
c
) is applied. Although
there is some debate in methodology, all agree that water
should be applied to match the tree’s usage. ET
c
should
be calculated using real time weather, if possible. Thirty
year average ET
c
values can be used, but they tend to
vary significantly in the spring and don’t account for
rainy or cool periods. Summer values, however, are more
consistent. Once the demand is calculated, water should
be applied to match the tree’s demand without overfilling
the water holding capacity of the wetted area of the field.
More on scheduling irrigation can be found at your local
extension office.
Anthracnose can be a
problematic spring-time
disease. Warm, spring rains
can create environmental
conditions conducive
for disease. The variety
“Monterey” is highly
susceptible to this disease.
