Irrigation and Conservation
Watering without wasting
Our approach to using water to irrigate lawns should be that
of conservation. The supply is not endless-in fact only 1 percent of the
earth’s water is available for human consumption and use. The objective is to
supplement only what the lawn requires and use this precious resource wisely.
How well soil absorbs water is a key factor in determining a
lawns “personality” in regard to length of time and day interval for
irrigation. Factors affecting absorption are:
Soil type:
Clay soils absorb water more slowly than sandy soils.
Organic matter:
The amount in the soil helps balance air space and moisture
retention.
Grade/slope:
Obviously, runoff occurs more quickly the steeper the slope.
Exposure to sun and
wind:
Formulate a plan according to your environment, observing
the lawn and how it responds after a rain and making allowances for unique
situations.
What criteria indicate when a lawn needs to be watered? The
simplest method is to walk across the lawn and look back at the path just
taken. Visible foot impressions indicate the early stages of moisture stress
and irrigation will be needed if adequate rainfall does not occur.
Another means is to use a trowel or screwdriver to loosen
the soil surface then judge the moisture level of the soil by touch. Remember,
the soil surface dries out quickly, while the top inch of soil may be plenty
moist to sustain the turf.
The goal is to stretch out the time between watering as long
as possible. This will encourage deep root growth from 4 to 6 inches and is
advantageous in case of prolonged drought or water restrictions. The recovery
of a lawn from a dry period is much better if the turf has a deep,
well-established root system. Other benefits to the lawn by infrequent watering
include minimizing disease problems and unnecessary water loss due to
evaporation.
Apply 1-1-1/2 inches of water deeply every 7-10 days during
dry periods. In July and August, it may be necessary to water on a 5-7 day
interval.
Efficient use of water means irrigating to the point of
runoff, stopping until the water has been absorbed, and then resuming. To
accomplish this, set a rain gauge or a tuna can on the lawn. Start the
irrigation system, whether it is an automatic (underground system) or manual
(hose and sprinkler). Note when excessive water runoff starts to occur, stop
the water.
Let’s say you watered for 10 minutes and the gauge measures
.25 inches of water. To minimize runoff with a manual system, water each area
for 10 minutes, and then move the sprinkler to another area to allow water to
soak into the soil. Alternate sites until each area has been watered 40 total
minutes or 1 inch.
Automatic systems, given the above scenario, should be set
for 10 minutes per turf zone and programmed for 4 consecutive start times on
the same day. This will give 40 minutes or 1 inch of water to the lawn. With 5
turf zones that would be 50 total minutes for one cycle of irrigation to all
turf zones. The first start time might be 4
a.m. , the second at 5 a.m.
The third and fourth cycles will continue the progression established between
the first and second start times.
Consideration and time should be taken to ensure that your
irrigation process is wasting as little water as possible. Especially with
automatic systems, this means testing periodically to make sure there is no
missing heads shooting up into the air or misaligned heads spraying into the
street instead of the lawn. Repair leaks and make adjustments in a timely
manner to minimize unnecessary water loss. Make sure that spray patterns are
not being interfered with by a tree, shrub or foliage of some type.
Be diligent stewards of our water. Take the time to manage
your water use. Don’t take the easy way out and water daily for your convenience.
This precious resource does not have an endless supply! Until next time……Happy gardening!!!
Jimmie
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