Wireless Irrigation Technology
PORTAGEVILLE, MO.
Center pivot irrigation accounts for 40 percent
of all irrigated acreage in Missouri.
There are approximately 4,000 pivots in the
state, most in the Bootheel. It is estimated that
yields on center
pivots could be
increased 10-15
percent if better
irrigation management,
specifically
irrigation
s c h e d u l i n g ,
were used. One
viable scheduling
method is
the use of soil
moisture sensing
(SMS) devices,
however,
for a host of reasons
Missouri
farmers are not
using SMS. Missouri irrigators would
probably increase the use of SMS
technology if SMS data could be automatically
collected and made available
to them at a reasonable price. Telemetric
SMS systems are being tested
at the Delta Center.
Irrigators in Missouri who do use irrigation
scheduling out-yield their
counterparts who do not schedule. Although
use of soil moisture sensors
was only reported by 1 percent of corn
growers and 1 percent of cotton growers,
the results from this small sample
were outstanding. Table 1 shows
the increased amount of yield enjoyed
by irrigators who employ the
Arkansas Scheduler computer program,
the Woodruff charts, or soil
moisture sensing devices over their
counterparts who do not schedule
their irrigation.
To properly use SMS on center pivots at least
three locations should be monitored to account
for distribution differences in the pivot. It is recommended
that each location have a 6-, 12-,
and an 18-inch sensor. Two types of sensors
seem to be feasible due to their cost, ease of use,
and reliability. These are WaterMarks and small
capacitance sensors. It is desired that no wires
be strung out in the field, so all communication
of data is done telemetrically.
Sensors are installed at the beginning of the
season after the crop has first emerged. Readings
from the sensors are sent telemetrically to
either the farmer’s own PC via repeaters or to a
website via cell phone modem. The University is
exploring developing a hosting site at its AgEBB
website.
Figure 1 shows the components of a SMS monitoring
system hosted at the university.
The initial investment cost varies on company
used and whether the system sends data to your
PC or to the web. A reliable system can be set
up for $3,000. The annual per-acre cost of this
setup would only be about $5.07 per acre for the
PC system or $6.79 per acre for the web-based
system. These costs would decrease if a farmer
has two or more pivots next to each other.
If one compares those costs to the yield increases
farmers experience through irrigation
scheduling, it appears that this investment
could well pay for itself time and time again. The
Delta Center is testing equipment from various
companies and it can be seen on the walking
tour. These include:
• SmartField
• Decagon Devices, Inc.
• Irrometer Company, Inc.
• Onset Computer Corp. Δ
DR. JOE HENGGELER: Irrigation Specialist,
University of Missouri
Table 1. The yield increase from using various irrigation scheduling methods over
that of irrigators who do not schedule, 2000-2008.
Fig. 1. Components of a Missouri telemetric soil moisture sensing program.