Continual population growth has no doubt put a tax on resources. Water conservation is mandated in many states. But conservation shouldn’t have to be forced. It makes good business sense to save water. Many growers have already put in place water-saving devices such as runoff collection ponds, drip irrigation and high-efficiency nozzles for overhead irrigation.
Here’s a look at three practical applications nurseries can implement to save water.
Drip directive
When Doug and Ina Lukas founded Blooming Valley Perennial Nursery in Avoca, Wis., they made a serious commitment to minimize any negative environmental impact. They opted for a Netafim drip system, which Ina said was “well worth the investment.” Each plant gets its own drip stake equipped with four-way emitters.
“We’re able to mix and match perennials on the same drip line based on their watering needs,” Ina said. “We don’t have water sitting on the flowers, so our blooms are much nicer and healthier than if we used overhead irrigation.”
Maintenance is simple with easy-to-handle snap-on and snap-off emitters, she said. But she suggests getting an irrigation company to design the set up for even better efficiency.
The Lukases have emitters on 12, 18 and 24 inches on center, based on plant spacing needs. Containers from 6 inch to 2 gallons are on drip.
“The system grows amazing perennials. There is no overwatering and the irrigation is very consistent,” she said. “We typically water once a day, but may water twice in the heat of the summer.”
Fortunate flood
Water conservation was an unexpected benefit when Spring Meadow Nursery in Grand Haven, Mich., equipped 2 acres of greenhouses with flood floors for its young woodies. The nursery’s initial intention was to get crops prone to leaf-borne diseases off of overhead irrigation, said Jeremy Deppe, general manager at Spring Meadow.
“We were having to spray certain crops like roses, cornus, hibiscus, hydrangea and cotinus on a regular basis for things like blackspot and anthracnose,” he said.
The flood floors virtually eliminated bacterial leaf spot, he said.
Then Deppe and grower Dave Joeright realized the flood floors used up to 50 percent less water compared to overhead irrigation.
“When it’s really hot, with overhead we’re watering every day. But with flood floors we’re watering two or three times per week,” Deppe said.
The nursery has spent about two years testing varieties on the flood floors. Joeright found viburnum and lilac don’t perform well on the flood floors.
“With flood floors, you’re basically saturating all the plants at the same time,” Joeright said. “We group plants together that have similar water requirements.”
With flood floors the root system tends to stay wet for a few days then dry for a few days.
“And with a dry environment on top, you have to keep a close eye on spider mites,” Deppe said.
It’s a big investment, but a good long-term approach, Deppe said.
“Flood floors are a good option for reducing runoff and for complying with water regulations, which haven’t hit Michigan yet,” Deppe said. “The cost of a flood floor essentially doubles the cost of a greenhouse. But when you’re using half the amount of water and fertilizer, eliminating certain fungicides and increasing the amount of salable plants, the payback isn’t that long.”
Acclaim for reclaimed water
The Shadetree Partnership Nursery in Irvine, Calif., is a nonprofit organization cosponsored by the Irvine Ranch Water District (IRWD). After almost a decade of growing trees, the nursery is a model for using water reclaimed from the IRWD treatment plant. The reclaimed water promotes conservation and lowers operating costs.
Reclaimed water piped from the IRWD treatment plant has been trusted as an irrigation alternative to domestic water for many years by the agricultural community, said Dale Skidmore, Shadetree manager. And the use of recycled water also lessens the demand for nitrogen additives, he said.
The nursery uses data from the local California Irrigation Management Information System (CIMIS) station to measure evapotranspiration rates. CIMIS evapotranspiration data is reviewed daily. Knowing the local evapotranspiration enables the nursery water manager to know exactly how much water the seedlings need.
The nursery grows several varieties, including California oaks, sycamores and Monterey pines for placement in public areas.
For more: Blooming Valley Perennial Nursery, (608) 583-2427; www.bloomingvalley.com. Spring Meadow Nursery, (800) 633-8859; www.springmeadownursery.com. Shadetree Partnership Nursery; (949) 453-5817; www.shadetreepartnership.org.
Growing media characteristics impact water conservation
The aeration, drainage and water-holding capacity of growing media are key elements affecting irrigation management, according to the Texas A&M University Soil and Water Testing Laboratory.
Here’s a step-by-step method and worksheet to evaluate those characteristics. Keep in mind, each substrate or substrate combination will have different properties and must be evaluated separately. Container size and shape affect aeration and water-holding characteristics. Repeat this procedure a minimum of three times for each container size/type and media combination.
1. Place a piece of duct tape over the drain holes.
2. Fill the container with selected substrate.
3. Fill a graduated cylinder with water and note the initial volume.
4. Slowly pour the water in the container until it reaches the substrate’s surface. (This is Line A on the worksheet.)
5. Place the saturated container over a bucket, remove the duct tape and collect all of the water draining water. Do not force the water out of the container. (This is Line B on the worksheet.)
Worksheet
A. _______________ = Total porosity
B. _______________ = Air space at saturation
C. Water retention = A-B ______________
D. (B x [MULTIPLICATION SIGN] 100) [DIVISION SIGN] A = Percent air space at saturation _______________
E. (C x [MULTIPLICATION SIGN] 100) [DIVISION SIGN] A = Percent water retention
For more:
When it comes to water conservation, start with the basics
Have you lost site of some important factors -- like saving water -- because of production routines? Go back to the basics and see where you can improve water conservation.
Reduce runoff
* Group plants with similar water needs together to improve irrigation efficiency.
* Space containers under fixed overhead irrigation to maximize plant irrigation and reduce waste between containers.
* Use drip tubes for each container when reasonably practical.
* Check growing media. Make sure it’s well-drained and has a good water-holding capacity.
Improve efficiency
* Plug sprinkler heads that are not in use, keep sprinkler heads as low as possible to the plants and use larger water droplet size to reduce irrigation time.
* Install rain sensors or other devices such as check valves, pressure regulators, soil moisture sensors and wind sensors.
* Irrigate plants when needed based on media moisture levels with one of these methods: appearance or feel of media; tensiometers; weight of media moisture; light accumulators; or soil moisture conductivity.
* Properly maintain existing irrigation systems including replacing washers, leaky pipes, hoses or sprinklers, and clean spray heads.
Beyond the basics
* Consider subirrigation systems such as a capillary mat or ebb and flood system.
* Reuse water by installing retention basins or storage ponds.
- Kelli Rodda
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A snapshot of water-conservation products for the nursery
* Aquamat: A subirrigation system for containers. The multilayered textile mat uses less than 60 percent of water required by overhead irrigation. The top layer is algae resistant; next is an evaporation block layer that prevents salt buildup; then an absorbent felt layer for even watering; and at the bottom is a total containment barrier that prevents runoff. For more: www.aquamatsystem.com.
* Dramm Pressure Compensated Drip System: This system uses chemical-tolerant silicone diaphragms and slim metal weights. The pressure compensated anti-siphoning (PCAS) system improves on existing pressure compensated systems. Two- and four-way assemblies are available. PCAS emitters operate between 15 and 60 psi allowing for higher head pressures while still maintaining accurate flow. For more: www.dramm.com.
* Spraying Pot Stake: This stake from Maxijet keeps water in the pot with a 160@ down spray, which helps prevent overspray. It has a jet-style orifice. Flow rates include 6.4 gallons per hour (gph), 10.5 gph and 16 gph. The Spraying Pot Stake measures 7.25 inches long. For more: www.maxijet.com.
* Constant pressure valve (CPV): This pump control valve from Cycle Stop Valves takes a standard constant speed pump and creates a variable flow pump. The CPV maintains a constant pressure regardless of the amount of water being used. The CPV stops pump cycling and eliminates water hammer. For more: www.cyclestopvalves.com.
* Flo-Wise Meters: Senninger Irrigation offers Flo-Wise Meters for 1/2- to 12-inch pipe. The sensors deliver repeatable flow measurement. Senninger Flo-Wise meters offer on-site data reading or transmission to a remote location. The meters are available as a battery-operated, self-contained model or an analog output model that requires external power. For more: www.senninger.com.
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* Growstones: Made from recycled glass, Growstones help retain moisture and reduce the amount of fine particles traditionally found in soil amendments, ensuring drain holes are not clogged. Growstones provide more water-holding capacity than rice hulls or perlite. Growstones are sterile and recyclable, and are free of weeds and disease. For more: http://growstone.com/horticulture.
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Biomimicry: A science that studies natural processes and models to imitate the designs to solve human problems, i.e. studying a leaf to better understand and design solar cells.
Carbon trading: A trading system for countries, companies and individuals designed to offset carbon emissions from one activity with another, whereby those who cannot meet their emissions goals may purchase credits from those who surpass their goals.
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Dematerialization: The reduction of total materials used in providing customers with products or services.
Meta-trend: A global and overarching force that will affect many multidimensional changes; for example, environmental impacts on business, individuals and countries.
Source: BrownFlynn
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