SYSTEM INTEGRATION & AUTOMATION
The primary variable Heeren and his team collected was canopy temperature gathered with an infrared thermometer placed on the pivot lateral moving around the field. He then compared that with ground-based IRTs.
a standard size 60-hectare center pivot-irrigated field at the University of Nebraska-Lincoln Eastern Nebraska Research and Extension Center. The treatments included infrared temperature sensors (IRT) and granular matrix sensors for full irrigation and deficit irrigation, irrigation system supervisory control and data acquisition (ISSCADA) system (IRTs and soil water sensors, developed by USDA ARS), spatial evapotranspiration model, common practice and rainfed (no irrigation). The research was done in partnership with Valmont Industries, to which the ISSCADA treatment is specific. The other research models are pre- competitive.
Preliminary data from the research showed significant yield differences for the irrigation refill treatments (including 0%-rainfed, 50%, 100% and 150%) with refill levels implemented by switching nozzles on the pivot lateral at the beginning of the season. The ISSCADA system was able to detect stress in the crop canopy. The threshold value for integrated Crop Water Stress Index for when to trigger irrigation needed to be adjusted from the default values, possibly due to different climate factors.
Reaching results
Merging the science with technology in an easy-to-use solution has been a rewarding approach for Heeren, bringing expertise to applications that give growers more options that can be implemented to fit their situations. He found that working with the manufacturer gave his team the chance to not only test current technology
16 Irrigation TODAY | Winter 2022
By using uncrewed aircraft flights, Bhatti was able to get the temperatures across the whole field within a point in time as a data quality check.
but to provide input on how to improve it. For example, Heeren was looking to test its algorithm in more subhumid areas rather than arid climates where it would be easier to determine crop stress. Using the trigger thresholds that had been determined in a drier atmosphere would have resulted in fewer watering events over the course of the summer and the potential for crop stress, he says.
“The first summer, we adjusted the threshold during the season to make sure we put on enough water,” he says. “Over the winter, we took time to do a more in- depth data analysis to fine-tune what the threshold should be for eastern Nebraska and implemented it the next summer. That would be an example of positive synergy.”
The primary variable Heeren and his team collected was canopy temperature gathered with an infrared thermometer placed on the pivot lateral moving around the field, he says. He then compared that with ground-based IRTs.
“It’s this idea that the pivot is a preexisting robot that already goes around the field several times a year,” he says. “Let’s take advantage of it as a platform to mount sensors on. We were comparing that to traditional IRT sensors mounted on the ground.” His team also used uncrewed aircraft flights to get the temperatures across the whole field as a data quality check.
“The usefulness is that the thermal signal is a signal of crop stress in the way that, if we’re low on water, we can’t sweat and we
It’s this idea that the pivot is a preexisting robot that already goes around the field several times a year. Let’s take advantage of it as a platform to mount sensors on.”
— Derek Heeren
irrigationtoday.org
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