Shaping Smarter Cities: IIoT Irrigation Monitoring Key to Indoor Agriculture Success

Steven Keeping gained a BEng (Hons.) degree at Brighton University, U.K., before working in the electronics divisions of Eurotherm and BOC for seven years. He then joined Electronic Production magazine and subsequently spent 13 years in senior editorial and publishing roles on electronics manufacturing, test, and design titles including What’s New in Electronics and Australian Electronics Engineering for Trinity Mirror, CMP and RBI in the U.K. and Australia. In 2006, Steven became a freelance journalist specializing in electronics. He is based in Sydney.

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Steven Keeping
Steven Keeping

All too often engineers pejoratively describe a technology as “agricultural” to imply that it’s limited or outdated. But this is unfair; agribusiness—the sector that concerns itself with commercializing crop and livestock production, and delivering foodstuffs to our plates—is a habitually early adopter of high tech. A modern combine harvester, for example, employs GPS, laser guidance, self levelling, and hydrostatic drive among its many computer-controlled attributes. And now agribusiness is embracing the Industrial Internet of Things(IIoT) to enhance the commercial viability of Controlled Environment Agriculture (CEA, or “indoor farming”).

CEA uses fully-enclosed and climate-controlled facilities to eliminate external environmental factors such as disease, pests, or poor weather. The technology is not dependent on expensive, fertile arable land and can be established anywhere—including the center of urban communities. Growing food close to consumers is particularly advantageous considering transporting food from traditional farms to city dwellers consumes up 10percent of the total U.S. energy budget, according to a 2012 study.

The Critical Role of Water

Early adoption of technology has enabled the agricultural sector to dramatically boost yields. According to the U.S. Department of Agriculture (USDA), for example, in 2000, farmers produced 12 times as much per person-hour as a farmer did in 1950. However, these gains have come at a cost, most notably high water usage. That’s perhaps no surprise, considering water is the critical factor in maximizing plant yield; even if everything else is perfectly balanced to boost plant growth, without a reliable water supply, plants soon curl up and die.

Although agribusiness has made great strides in recent years, traditional farm irrigation is a wasteful process, primarily because 70 to 90 percent of the water applied to the soil drains away before it can be taken up by plant roots. Globally, agriculture is the biggest consumer of water—in some arid countries heavily reliant on irrigation to sustain crops, up to 85 percent of the water supply is to grow food.

Slashing excessive water use is one of the biggest advantages of CEA. But economizing water use is not just driven by an environmental imperative; it is also encouraged by an economic one. Setting up a CEA facility is devilishly expensive and reasonable return on investment only comes if input costs are contained and plant growth optimized. Water use significantly influences the outcome of both these objectives.

The IIoT Brings Control

An agribusiness company that isn’t reliant on Mother Nature to irrigate plants can turn to the IIoT to dramatically cut water usage—by up to 90 percent compared to traditional farming. The incoming water can have particulate, fluoride, and heavy metal contaminants removed, and controlled amounts of nutrients added before delivery, while water from transpiration can be minimized, harvested, and reused (a closed environment simplifies recycling). Drained water can be processed for reuse as well. Techniques include drip irrigation to keep soil permanently moist and even systems that dispense with soil completely, operating by directly misting the plants’ naked roots.

Sensors wirelessly connected to the IIoT help agribusiness precisely control water use by closely monitoring how much plants are taking in and how much is being lost. Sensors can also correlate plant growth to water volume supplied and nutrient concentration. The data gathered can be analyzed in real-time to control closed-loop systems which can even adjust water usage for individual plants.

Building IIoT Irrigation Systems

IIoT irrigation systems take advantage of advances in wireless sensors and actuators, wireless sensor networks, and Cloud resources to meet the engineering challenges of a CEA process control system. Wireless sensors using technology such as Bluetooth low energy monitor the growth parameters. The sensors in turn form part of mesh network, improving reliability and supporting rapid scaling as the indoor farm grows. Depending on the output of the sensors, signals sent back across the mesh network instruct actuators to increase or decrease irrigation.

Despite these proven systems, designing mesh network-based irrigation systems is not trivial. However, the most difficult part—constructing the wireless system—is considerably eased by using chip vendors’ development tools. For example, Microchip, a leading supplier of microcontroller and analog semiconductors, offers a range of components and tools—including a starter kit, development kit extension boards, and Bluetooth low energy System-on-Chips (SoCs)—which permit engineers with little or no RF experience to design practical wireless networks for CEA applications.

The greatest advantage of IIoT connectivity is the access it opens to Cloud resources that could be used to run powerful algorithms to analyze the constant stream of data from the indoor farm to continually refine the growth process. Over time, information could be built into a database to provide instant answers as to what effect a minor change in a specific growth parameter would have on input costs, plant quality, and, ultimately, indoor farm profitability.

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