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Water Conservation: How Low Can You Grow?
| Jennifer Duffield White
>> Published Date: 1/31/2014
Will water be the game changer for our industry?
The issues have always lurked near the surface: the cost of water, availability, regulations, quality, pollution and the dreaded pathogen contamination. For years, we’ve been able to brush it off. Now, more than ever, water—the most crucial input for plant growers—is also tagged as a source of potential crisis.
“For most of the history of the green industry, water has been available for the cost of the pumping and distribution infrastructure and associated electrical cost. In some locales, the true cost of water has been heavily subsidized by federal projects to develop this infrastructure,” says Dr. Bill Miller, president of the Seeley board, which is organizing this year’s Seeley Summit, focusing on water in the industry. “But the value and importance of water is far greater than all this. What would happen to companies if they were forced to pay the real cost of water? How will we be impacted by prolonged droughts that lead to more stringent landscaping and home water use laws?”
According to a 2012 special report from The Economist, the focus is on moderating how much water we use. The same report, which surveyed water managers, projects that by 2030, water demand will outstrip availability by 40%. For the horticulture industry, many of our strongest-producing regions are also those that already battle water scarcity and a growing number of water regulations.
How do we change with the times? Water less. Water smarter. Recycle more. These may be the mandates of the future.
However, industry leaders aren’t talking about letting plants wilt, saving a drop here and there, or the same-old irrigation equipment. They’re talking game-changing solutions that use less water, save money, reduce disease and grow better plants. Here’s a look at a few collaborative research projects that aim to put new solutions in the hands of growers.
Use Less: Sensor Networks
Imagine an irrigation system that reduces your water use, reduces nutrient runoff and maximizes plant growth. Imagine logging onto your computer and seeing, in real time, that a specific crop is in need of water. Five universities and two companies have set out to change the way greenhouses and nurseries apply water and nutrients. Their five-year project, with a USDA Specialty Crops Research Initiative (SCRI) grant, is developing the next generation in water management with wireless sensor networks and software.
A teamwork approach to the issue is addressing all angles of viability in the commercial setting—including making sure the technology is sound and the economics work for growers. The Carnegie Mellon Robotics Institute, Decagon Devices and Antir Software are leading hardware and software development. The University of Maryland, Cornell University and the University of Georgia are focusing on micro-scale issues, researching sensing and variability issues in the root zone and using real-time information. Meanwhile, Colorado State University is working at the macro-scale level, using sensor data from both the aerial and root environments to predict real-time water use for large-scale (100+ acre) operations. Not to be forgotten: The social, economic and environmental aspects are being quantified by The University of Maryland and the University of Maryland Center for Environmental Studies.
The researchers are using wireless sensor networks in field soil, containers and soilless greenhouse substrates to monitor real-time water use of plants via sensors for moisture, temperature and electrical conductivity. Carnegie Mellon’s network monitors and controls irrigation and nutrient applications.
Thus far, their system of sensors and network monitoring has proven to reduce water use, nutrient leaching and overall runoff when compared to timed irrigation (the current best management practice). Results, including those with test commercial greenhouse operations, show that this method can reduce irrigation applications by at least 50%. In some cases, they’ve also seen the plant finish time drastically reduced and/or plant quality improved.
The end result may mean that growers save money, manage water risks and grow better plants at the same time. The sensors are portable, so growers can easily move them to different points of production, as well as add or remove sensors from the network as needed. With the ability to give short “micropulses” of water, the water has time to slowly soak in, thus reducing nutrient leaching. Set points ensure that irrigation stops once a set limit has been reached. Growers can also implement schedule-based and model-based irrigation strategies.
A few interesting notes from their 2012 research at university and commercial locations:
• At McCorkle Nurseries in Georgia, sensor-based irrigation eliminated up to 30% of plant death in gardenias typically lost to disease and it reduced the grow time from 14 to eight months. Their return on investment for the sensor network was less than three months.
• The University of Maryland recorded 37% to 69% reductions in irrigation water use through these applications.
• The University of Georgia found they could use the sensors to control poinsettia height via water deficit techniques without compromising quality.
More info: The SCRI-MINDS project has their own Smart Farms Knowledge Center (www.smart-farms.org) and project website (www.smart-farms.net).
Use Less: Recycle
One practical way to reduce your dependence on well or municipal water? Capture runoff and reuse it again. Yet, many growers balk at the idea, worried about sanitation issues, logistics and costs. In a survey of growers in Maryland, Pennsylvania and Virginia, Jim Pease at Virginia Tech found that 70% of the large firms captured at least some runoff, but few of those recycled it. However, among small and medium growers, 60% to 70% do not capture runoff at all.
Another collaborative research project, funded by a USDA Specialty Crops Research Initiative grant, is focusing on irrigation pathogens and water quality. Their mission: to help growers recycle irrigation water without recycling plant pathogens, such as pythium, phytophtora and ralstonia.
This project, which is currently underway, will significantly increase the understanding of water quality dynamics, its impact on plant pathogens and their interactions with other microbes in irrigation systems. They’ll use this new information to develop best management practices that reduce sources of inoculum and negate the pathogen dissemination via recycling irrigation systems.
As with the water sensor project, this is a collaborative effort, with several universities and commercial growers participating, including Virginia Tech, Penn State, University of Maryland, University of California—Riverside, Christopher Newport University and Rutgers. More info: www.irrigation-pathogens.info.
Use Less: In Propagation
Young plant propagators can look to new research being conducted by Jim Faust and a team at Clemson University. Their project, funded by the USDA-ARS Floriculture/Nursery Research Initiative, has been developing benchmarks for water use during propagation, creating a Propagation Weather Station (PaWS), and identifying target soil moisture content and target mist practices during propagation.
Jim reports that the PaWS part of the project, with a data logger and sensors that send data over the Internet on a real-time basis, is nearly complete and the target soil moisture data is ongoing. They’re getting a better understanding of the water requirements of unrooted cuttings and have, for example, observed that mist requirements decline each day the cuttings spend time in propagation, even before roots are formed. Next up, they’re working on target mist practices so that water isn’t being wasted.
(A summary of this project is also available in the November 2012 issue of GrowerTalks.)
Slowly, the growing community is raising its vision to the problems that may lie ahead. Whether you’re eager to adapt or just “toeing the waters,” the academic community is stepping up to work with producers and provide new strategies.
Want to understand more about the issues, some of the regulatory challenges and how industry members are adapting? Check out the Seeley Summit (www.seeleysummit.com) this June and be part of the conversation. GT
2014 Seeley Summit to Address Water Issues
The 2014 Seeley Summit, “Water: Horticulture’s Next Game Changer,” will be held June 22-24, 2014, near Chicago, featuring round-table discussions, Q&A with speakers and panelists, and face-to-face networking.
A few of the questions they aim to explore:
• What if you had to deal with the real cost, including distribution, of water?
• What if the direct cost of water to grow a pot plant, flat or hanging basket was equal to or exceeded the cost of the plastic or growing medium used?
• What would this do to your business?
• How do we make changes in our business to accommodate ever-increasing costs of water?
• In drought conditions, how do we convince the legislators (and consumers) to factor the environmental, social, economic, health/wellness benefits of plants, trees and flowers into restriction guidelines they’re considering?
“This year’s Seeley is a can’t-miss program for the entire green industry and we have made a concerted effort to invite speakers from across the industry: greenhouse, nursery, landscape and allied trade. We expect that a topic relevant to all users of floral and landscape products, a new, easier-to-access location, and a reduced registration cost will be attractive to many leaders in the industry,” says Dr. Bill Miller, president of the Seeley board.
For more information, visit www.seeleysummit.com.
How Sensors Save Water & Reduce Leaching
The sensors and software may be high tech, but how this technology saves water and reduces nutrient leaching is pretty simple:
1 Reduces irrigation duration with multiple, short micropulses of water.
2 Reduces unnecessary irrigations, particularly in the spring and fall.
3 Reduces the substrate moisture level required for good root growth.
3 Things You Can Do Right Now To reduce pathogens:
1 Make sure your irrigation system works correctly.
2 Make irrigation uniformity a priority in order to reduce overwatering.
3 Know when to irrigate.
Source: Irrigation Pathogens and Water Quality, webinar series, Gary Moorman, Penn State, www.irrigation-pathogens.ppws.vt.edu/webinar/
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