Winter 2021 - 38

IRRIGATION
Growers manage
irrigation and nitrogen
with CropManage
BY CRYSTAL NAY
WESTERN EDITOR
A
gtech is aggressively transforming the tech space to
include growers and applied professionals who have
quite a bit to manage in the day-to-day.
CropManage is a decision support tool that was developed
for water and nutrient management, looking at them together
in order to solve the problem of nutrient overuse, irrigation
scheduling and the protection of groundwater.
" You can't do good nutrient management unless you're
doing good water management, " said Michael Cahn, irrigation
and water resources farm advisor with University of California
Cooperative Extension. " There's a lot of nitrogen applied that
causes downstream and groundwater impacts. "
CropManage has been on the scene for the better part
of a decade. It currently has about 2,500 users covering
7,200 plantings, 1,600 ranches or farms, and is used on
roughly 6,000 acres of almonds alone. With funding from
the California Department of Food and Agriculture and
the California Department of Water Resources, it uses
extensive research from the University of California
conducted in commercial fields to build algorithms to
provide decision support to growers. CropManage can
customize recommendations on how much water and
nitrogen to apply for a grower's particular operation based
on various data inputs.
Originally developed for use in vegetables in California,
CropManage has expanded to include more permanent
crops, such as strawberry, raspberry and alfalfa. More
notably, however, is its expansion into almond, walnut
and pistachio.
The art of scheduling
Irrigation management in tree nuts is becoming
increasingly more important, especially concerning
California's Sustainable Groundwater Management Act, the
inability to rely on groundwater to supplement cutbacks on
surface water allocations, and when more acres of permanent
crops are being planted, which need year-round water in
38 WINTER 2021
a place that is prone to drought. Not only is irrigation
management a vital component of maximizing production
and yield, it's also key to operating within the requirements
of water availability and regulation.
When and how much are the key factors in scheduling and
can be weather-, plant-, or soil-based. Each has its pros and
cons, and one may take priority over another.
The weather-based option works with the California
Irrigation Management Information System (CIMIS),
which are weather stations located in different agriculture
zones throughout the state, and have a reference crop
with consistent cover throughout the year. CropManage
automatically pulls the reference evapotranspiration (ET)
data from CIMIS, which is then adjusted for the crop of
interest by using a crop coefficient. And crop coefficients
change over time; they start low when trees are small, rise
with canopy growth, then lower later in the season as leaves
senesce and fall.
For fields with their own weather stations, CropManage
can use that data instead.
Factoring in ET since last irrigation, leaching, application
rates and other aspects can result in involved calculations.
Spread across multiple fields, it can be time consuming.
Winter 2021

Table of Contents for the Digital Edition of Winter 2021
