Mar_Apr_PCC_2017_Web

IRRIGATION
Integrating Key Water
Management Information
to Better Manage Irrigation
Miro-sprinkler irrigation system in a
young almond orchard.
Photo Credit: Dan Munk
Surface irrigated plum orchard.
Post-filtration pressure monitoring in
drip irrigation.
Dan Munk
UCCE Farm Advisor, Fresno County
Jeff Mitchell
UCCE Cropping Systems Specialist
Over the past several years, few
irrigated regions of the country
have escaped the impacts of drought
and in many places this has translated to
increased costs and reduced availability
of irrigation water. California growers
in particular have experienced dramatic
reductions in surface water deliveries
and have increasingly turned to using
groundwater to make up the surface
water shortfall. Consequently growers
have experienced unprecedented water
table level reductions that have increased
the price of pumping and maintenance
on their water wells. Growers have also
responded to the drought by increasing
personal and personnel resources
dedicated to water management and have
increased their efforts to better understand
the complexities of irrigation water
management. Efforts to improve onfarm
water management practices must
include these key elements:
Page 28 Progressive Crop Consultant March/April 2017
• Elevating irrigation system design
and management expectations.
• Better exploit our understanding of
crop development and physiology
including crop sensitivity to water
stress.
• Increasing our capacities to measure
and manage soil water storage.
Proper evaluation and integration of
these key water management elements
can be complex but can result in operating
whole farm and field irrigation
systems at peak efficiency over time. For
example, it may not help us to increase
the monitoring and measurement soil
moisture if we do not have a more
complete understanding of how specific
changes in soil moisture content influence
crop water stress and crop performance.
Similarly it would not be difficult
to misinterpret plant water stress or soil
moisture information in a field where
water is not applied in a uniform manner.
And how might field indicators of
soil water availability be used in different
field management settings? Interpreting
soil moisture readings in a drip irrigated
field that applies water multiple times
per week will differ from that of a furrow
or flood irrigated field that is irrigated
using two to three week intervals. These
complexities help to point out that each
field is unique from a water management
standpoint and that irrigation decision
makers should not rely too heavily on
any one piece of information to guide
their water management program without
also considering broader systems
information.
Irrigation System Design and
Management
Improperly designed irrigation systems
are incapable of achieving high performance
levels making efficient water
management an impossibility regardless
of how well water might be scheduled.
Application efficiency is a fundamental
measure of irrigation system performance
defined as the amount of beneficially
applied water in relation to the
amount of total irrigation water applied
to the field. One of the biggest obstacles
to developing field systems with high
application efficiency comes from the
fact that many irrigation systems do not
apply water uniformly. Water applied in
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