ontario sugar beet growers - Atrium - University of Guelph

IRRIGATION STRATEGIES FOR SUGAR BEETS IN
MICHIGAN - 2005
Dr. Ron Pitblado, University of Guelph Ridgetown Campus
Ian Nichols, Julia Lok and Rob Danford, Ontario Weather Network
Ridgetown, ON NOP 2C0
EXECUTIVE SUMMARY
Two grower locations were used to monitor the soil moisture profiles at soil depths of 10,
30 (-1 ft) and 60 cm (-2 ft). A capacitance probe (C-probe) was used in each of the three
treatments. Treatments included the grower's normal irrigation practice, using a pivot
system, the researcher's hand irrigated plot to time irrigation events at critical periods and
a non-irrigated control plot. Graphics of the C-probe information provided a visual
account of the soil moistures, giving the grower a clearer understanding of the stage of
sugar beet root growth at the various depths and the significance of their irrigation
practices. At location A, the grower kept the soil moisture profile high, resulting in
increased sugar beet yields but lowered beet quality with less sugar content per beet.
Timing irrigation events, based on the soil moisture graphs from the C-probes, provided
by the Ontario Weather Network, provided equal yields to the grower's regime while
significantly increasing % sugar accumulation. Critical irrigation events were identified
that could have improved both yield and sugar content in sugar beets. At location B, with
a much heavier soil type, irrigation was used to oxygenate the soil, softening it up after
early season near-flood conditions. Yields were considerably depressed in this location
however with timely irrigation, yields were improved with no loss in sugar quantities.
Sugar beet roots were forced to grow more deeply into the soil where less nutrients are
available resulting in low yields. A water budget approach, where critical information
such as evapotranspiration values along with grower inputs of rainfall and irrigation
timings and quantities, was deemed a less effective method for timing irrigation events,
due to missing or false data inputs. On the other hand, the soil moisture profile, read
through graphics derived from the C-probes provided a more accurate account of what
was happening at these particular farm locations allowing growers to make more
effective irrigation management decisions. Where irrigation was deemed excessive the
practice provided more hours of leaf wetness resulting in a slight increase in the
incidence of Cercospora Leafspot foliar disease.