IoT Cuts Water Use, Boosts Yield for Asparagus Farm

By Claire Swedberg

Devine Organics saw its harvest yield almost double, even while reducing water consumption by 6 percent, based on data from a WaterBit LoRa-based system that leverages AT&T Controls' LTE network.

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Water is a precious commodity in California, no less so than during the past few years, when the state suffered a drought that lasted from 2012 to 2017. So farmers, whose water use accounts for 80 percent of all water consumption for businesses and residences, are challenged to tightly control their usage.

For organic farm Devine Organics, that meant pursuing Internet of Things (IoT) technology that measured water saturation in the soil, managed irrigation and thereby ensured water was never overused on its crops. The system in use, provided by precision irrigation technology company WaterBit, consists of solar-powered, LoRa-enabled sensors and uses the AT&T Controls‘ LTE wireless network to forward data to a hosted server.

Elvia Devine

The technology use led to a 6 percent reduction in water consumption, says Elvia Devine, the farm’s CEO and founder, amounting to a reduction of more than 750,000 gallons. In addition, Devine Organics has nearly doubled its asparagus harvest yield on the field since installing the sensors, by better managing irrigation throughout the growing season. The company says it has measured the increase from 800 to 1,500 pounds per acre.

Proper irrigation is a complex science for farmers, Devine explains, that requires more than just cutting back on watering. Underwatering can reduce the ultimate crop yield, so farms like Devine’s must keep their irrigation at a careful balance. Traditionally, this has meant expending manual labor to monitor the moisture level of soil, and to water that soil accordingly. To make it even more challenging, he notes, some soil retains water longer than others—one part of a field may have sandier soil, while another portion could have a high level of clay. As a result, the watering of the fields is an imperfect science. The organic farm had tried several sensor-based systems to address this issue, but they didn’t provide the accuracy of data it needed to meet all of these demands.

Beginning in December 2017, the company tested the WaterBit technology on 40 acres of asparagus to ensure there was a proper amount of water in the fields, without requiring human intervention. While some technology companies require towers on which gateway devices are mounted, the WaterBit system is designed to be unobtrusive and easy to install. “We showed up with a little box,” recalls Manu Pillai, WaterBit’s president and co-founder, that serves as the sensor and data transmitter. The deployment consists of several such sensors planted in the soil to test moisture levels, with built-in LoRa units to transmit that data to a single gateway. The gateway then forwards that information via AT&T’s LTE network.

Establishing a wireless network in a field is challenging—even more so around a crop such as asparagus, Pillai notes. Asparagus is a dense plant with a large amount of fluids in its stalks. The sensors, which are at the height of the crop itself, are still able to transmit reliably. He says they are designed so that farm machinery can be operated around them without doing any damage, and are built to operate without requiring maintenance. “Our key value is the highly reliable product,” Pillai states. “The biggest complement we get is that it just works.”

The number of sensors needed varies according to the fields being monitored. In open areas, two sensors can be sufficient to cover 40 acres, but if farmers require more granular information about soil moisture content in very small zones, they could use as many as 21 sensors for a single acre. The WaterBit system comes with an automatic link to the irrigation system, allowing the sprinklers to start and stop according to sensor data. Devine, however, has been using the solution to view soil moisture, and then, based on personal analysis, to remotely control the irrigation valve using WaterBit’s remote valve controllers.

AT&T also offers the LTE-M network, which enables battery-powered sensors to have life spans of up to 10 years, says Mobeen Khan, the company’s IoT strategy and product-management executive. The use of LTE-M, he explains, allows sensor modules to be less complex and, therefore, lower in cost. In addition to enabling lower-cost deployments and longer battery life for the sensors, he says, LTE-M can penetrate barriers such as concrete walls with 10 to 12 inches more distance. During the past few years, the firm has also been offering end-to-end solutions for agriculture, as well as for customers in all sectors that need a customized solution.

The AT&T Controls Center platform enables companies like WaterBit to program settings and alerts based on an end user’s particular needs, such as turning sensors on and off depending on the season or time of day. The solution has also enabled geofences to detect when a sensor moves from one location to another, and to issue an alert accordingly.

Since launching its IoT network and solutions, AT&T reports 41 million connected devices. In the future, Devine says, the WaterBit and AT&T Controls system can be used to automate its own irrigation valves, and can be customized to the watering schedules required throughout a crop’s lifetime. For instance, she says, at some times of the year, the harvest goes dormant and requires very little water, while 30 days before harvesting, the soil’s water content needs to be increased. She notes that customer requirements add further complexities. For instance, some retailers purchase asparagus at different sizes than others, and the farm must carefully monitor how the crop is watered, as well as when it is harvested, in order to meet those needs.

In addition to increasing yields and reducing water consumption, Devine says, the system has reduced greenhouse gas emissions from fuel use by 5 percent, since workers no longer need to drive the fields as often to check the soil manually. This has led to a 5 percent drop in labor costs—and because of a reduction in leaching from over-watering, the company has been able to decrease the amount of nutrients used in the soil.

With the technology, Devine says “I haven’t had any problems, just benefits.” She reports that the asparagus yields the farm experienced with the WaterBit system in place were the highest it has had to date. “We did great this year,” she says. Devine Organics will next deploy the system for its pistachio and almond crops in California—which span more than 75 acres in total—as well as 2,000 hectares of asparagus fields in Mexico. Devine says she expects the system to reduce water consumption both in California and in Mexico.