Chestnut trees are drought tolerant. If you are not dependent on the size of
the chestnut harvest then irrigating chestnut trees could be more harmful to
the chestnut trees than helping. If chestnut trees get their roots saturated
with water when they are actively growing there is a good chance the tree(s)
could die. Only water chestnut trees if the leaves are looking like they are
sad and limp.
Water is one of the most important components of the soil in the chestnut
orchard. Soil nutrients are carried to the chestnut tree root system through
soil moisture. When there is sufficient water in the soil, water forms a
microscopic layer over the soil particles. When present, this microscopic
layer of water, aids in the interaction of the soil particles with each other.
In a simple way, the water helps the soil come alive by filling the gaps
between particles allowing them to interact with each other. When the soil
particles can interact they cause each other to change a little bit. As these
changes take place nutrients are released into the microscopic layer of water.
As the nutrients enter the water the chestnut tree roots uptake of water will
bring the nutrients into the tree.
The challenge then is to keep the amount of water in the soil in a range that
best benefits the chestnut trees. Soil moisture is measured in percentage.
When evaluating soil moisture content there are 3 important parts to the
evaluation. Most important is the soil type. Fine sandy soils have a very low
capacity for holding water. Clay soils have the highest capacity for storing
water. The water capacity of the soil if often described as inches of
available water per foot of soil. The higher the water capacity of a soil the
more water it takes to rehydrate. The next part of the evaluation is the
wilt point of the soil. This is where there is still water in the soil but
none of it is available to the plant roots. The final part is of the evaluation
is determining if the water in the soil is in what is called "readily
available water" range. The goal with irrigation is to always keep the soil
water in the readily available water range. Once the soil water goes above
the 100 percent available water is wasted, becomes run off and possible cause
the soil to become saturated. Water saturated soils kills trees. The only way
to know if the water content of the soil is in the readily available range is
to measure it.
Measuring water in the soil can be as simple as taking a handful of soil and
feeling it. It could also be simply weighing the soil sample, drying the soil,
weighing it again and then calculating the percent moisture. There are meters
for measuring soil moisture that are either permanently installed in the ground
or are inserted at the time the measurement is taken. For help with measuring
soil moisture content contact your local extension agent. They know the soils
in your area the best and can help determine the soil moisture capacity.
As the soil moisture is depleted, water will be required once the moisture
drops below the readily available range. Determining how much water is required
is simple if you know the soil water capacity and the current soil moisture
readings. Watering simply refills the spaces between the soil particles.
Available water in the soil can be expressed in inches of water. Fine and
very fine soils including clays have a moisture available of 1.6 - 2.5 inches
of water per foot. Medium soils described as silt loam, clay loam, and sandy
loam have a range of 1.4 - 2.4 inches of water per foot of soil. Moderately
coarse soils, those soils having larger soil particles, have a range of
1.0 to 1.6 inches of water per foot of soil. If the soil moisture measurement
of available soil moisture indicated the soil to have 50% of the moisture
depleted then the amount of water needed to bring it back up to 100% available
would be half the total soil capacity. For example, a medium soil with an
available moisture capacity of 2 inches with half of this depleted would require
1 inch of water to refill the soil.
There are many methods of irrigating chestnut trees. Please contact your local
extension agent for guidance. There are a few tips that can help avoid trouble
when considering irrigating chestnut trees. When it comes to applying water
from overhead, leave this to the clouds. Overhead sprinklers damage the leaves
of the trees to much. Whenever you do irrigate measure the amount of water
applied. You can do this using a bucket and putting a drip emitter in it or if
using sprinklers place the bucket near a tree where the water is applied. Check
the bucket every 1/2 hour or so to see if the amount of water applied is what
you expected or needed. If you have the resources to place a timer on the
irrigation system this can help prevent "I forgot to turn off the water"
As a final word about irrigation, water travels at different speeds through
the soil. The more compact the soil the slower the water moves. Try to set your
application rate of water equal to or less than the rate the soil can accept
water. This is the one area where the most water is wasted. When checking the
orchard while water is being applied, any puddling, running water over the
surface, or saturated soil even if it is only in the top inch or two of soil,
you are applying to much water to fast. Slow down the application rate of the
water. Most sprinklers have changeable nozzles so the volume of water passing
through can be changed.
6160 Everson Goshen Rd
Everson, WA 98247
Ph: (360) 966-7158
Fax: (360) 966-7994
Washington Chestnut Company
6160 Everson Goshen Rd.
Everson, WA 98247
Ph: (360) 966-7158