Beth Grafton-Cardwell and her team at Lindcove - Citrus Research ...

Citrograph asks:
8 Citrograph July/August 2011
INDUSTRY VIEWS
Irrigation efficiencies: How much more growth can we obtain from our
citrus groves with the introduction of these new precision irrigation
measuring devices? Fertilizer placement, saving water, groundwater
contamination are all reasons for adapting this new technology, but how
much more growth and production can be affected?
T o date, we see the use of precision irrigation monitoring devices in mature,
established groves as a defensive mechanism in terms of crop production and
tree growth. While we have seen improvements in irrigation efficiency, nutrient
timing and other issues, we have not yet determined if the sensors will enable us
to set bigger crops or have better tree vigor. What we do know is that during high
stress events throughout the growing season (e.g., high temperatures during crop
set, etc.), we have the ability to see exactly how much water the trees use and
need. This information helps us better ensure that we don’t lose crop volume, size
or quality due to environmental stressors. So while we cannot yet say that this
technology has led to larger crop volumes, better sizing, higher quality, or better
tree growth, we can say that it offers us another layer of protection against Mother
Nature’s worst. In the future, as our understanding becomes more refined, we hope
that these devices will lead to better production, but for now we are happy with
them helping us ensure that the crop volumes, sizes and quality we would expect
are indeed present at harvest. – Randy Skidgel, General Manager, Mittman-
Denni Citrus Management
Intuitively, growers understand the importance of irrigation management and
the need for timely, accurate information that is easily interpreted. Precision
irrigation monitoring equipment, such as capacitance probes, offers growers access
to this information. Water is the single largest input that is applied to a field.
With precision irrigation equipment, growers have “eyes beneath the soil”, which
allows them to accurately define the active root zone and minimize stress events
attributed to over/under irrigation. By creating an optimal environment for root
growth and root health, trees are able to access the needed nutrients, oxygen
and moisture early in the season, which in turn promotes productive growth and
increased fruit holding capacity. Managing water stress through the spring and
summer allows the trees to build on early-season momentum and encourages
early fruit sizing, while reducing fruit shedding through heat events. Going into
the fall, as temperatures begin to decrease, timely irrigations help to finish the
fruit and reduce issues with fruit quality. Combining stress management through
irrigation monitoring with variable rate irrigation system design (VR) and a strong
nutritional program, growers have the tools needed to not only increase growth
and productivity but also field uniformity. – Kris Tomlinson, Tulare Ag Products