Learning about High Tunnels
by Nicole Sanchez
My second visit to the Center for Environmental Farming Systems (CEFS) for a workshop on high tunnels, Oct. 4, did not disappoint. Since my first visit to this research farm on the outskirts of Goldsboro, N.C., I had been looking forward to my opportunity to return.
As an agriculture agent working with commercial fruit and vegetable producers, this workshop was of special interest to me. High tunnels are similar to greenhouses, but are less permanent in nature, and usually without a traditional heat source. High tunnels perform several functions depending on the crop grown within. A major function is to extend the growing season either at the beginning or end.
The three-hour session began with opportunities for hands-on demonstration and discussion. Participants learned about organic composting steps, seeding, using cold frames and ginger production in high tunnels. It was encouraging to know that so many are interested in learning more about this under-used way to extend the growing season to have vegetables available when other producers don't. High tunnels, while not for everyone, provide a unique opportunity for some growers to fill a much needed niche in our local food systems.
Extension associate Rick Holness described in detail the ongoing tunnel trials. Row after row of beautiful, large, ripening tomatoes beckoned within. The CEFS team are trying different fertilizer and composting methods to determine what resulted in the highest yield. It appeared that all treatments resulted in impressive yields. Clearly, fresh from the farm tomatoes are possible in eastern N.C. in October.
High tunnels are lots of work, but the price commanded by out-of-season vegetables means the extra effort comes with a financial return. From an environmental perspective, high tunnels are attractive because they rely less on supplemental heat, and more on making the most of heat already present in the environment. High tunnels are not heated or artificially lit all winter, so they will not provide us tomatoes in January or March. But they do enable us to have a greater variety of fresh, local produce for a longer portion of the year without additional reliance on fossil fuels.
High tunnels can also help to ward off disease. For instance, powdery and downy mildew are major problems of the cucurbit family (pumpkins, squash, cukes and melons). Using a high tunnel to minimize splashing and wind can help reduce pressure from these diseases. In this case, the crop could be drip irrigated under cover, reducing the incidence of mildew disease that comes with regular thunderstorms. High tunnels are also used in berry production in some operations.
High tunnels are intended to be movable. Some are built on skids so they can be moved back and forth along a track. This way, a grower can provide protection to plants while they are young, and then move the cover off the plants once they are established. Or, a crop can be started in the open at the end of a warm season and then given protection as the nights grow colder by moving the tunnel over the established crop. Some high tunnels are designed to be easily taken down and rebuilt. Be sure to understand the wind and snow load needs in your area if you are considering a high tunnel.
I’m already looking forward to my next opportunity to visit CEFS. There's some incredible research related to sustainable farming methods. Visit their website at www.cefs.ncsu.edu to stay informed about future workshops and classes at this facility.
For more information, click here.
There's a track devoted to high tunnels at this year’s Sustainable Ag Conference. To register, click here.
The ghoulishly named ogre-faced spider can "hear" with its legs and use that ability to catch insects flying behind it, the study published in Current Biology Thursday concluded.
"Spiders are sensitive to airborne sound," Cornell professor emeritus Dr. Charles Walcott, who was not involved with the study, told the Cornell Chronicle. "That's the big message really."
The net-casting, ogre-faced spider (Deinopis spinosa) has a unique hunting strategy, as study coauthor Cornell University postdoctoral researcher Jay Stafstrom explained in a video.
They hunt only at night using a special kind of web: an A-shaped frame made from non-sticky silk that supports a fuzzy rectangle that they hold with their front forelegs and use to trap prey.
They do this in two ways. In a maneuver called a "forward strike," they pounce down on prey moving beneath them on the ground. This is enabled by their large eyes — the biggest of any spider. These eyes give them 2,000 times the night vision that we have, Science explained.
But the spiders can also perform a move called the "backward strike," Stafstrom explained, in which they reach their legs behind them and catch insects flying through the air.
"So here comes a flying bug and somehow the spider gets information on the sound direction and its distance. The spiders time the 200-millisecond leap if the fly is within its capture zone – much like an over-the-shoulder catch. The spider gets its prey. They're accurate," coauthor Ronald Hoy, the D & D Joslovitz Merksamer Professor in the Department of Neurobiology and Behavior in the College of Arts and Sciences, told the Cornell Chronicle.
What the researchers wanted to understand was how the spiders could tell what was moving behind them when they have no ears.
It isn't a question of peripheral vision. In a 2016 study, the same team blindfolded the spiders and sent them out to hunt, Science explained. This prevented the spiders from making their forward strikes, but they were still able to catch prey using the backwards strike. The researchers thought the spiders were "hearing" their prey with the sensors on the tips of their legs. All spiders have these sensors, but scientists had previously thought they were only able to detect vibrations through surfaces, not sounds in the air.
To test how well the ogre-faced spiders could actually hear, the researchers conducted a two-part experiment.
First, they inserted electrodes into removed spider legs and into the brains of intact spiders. They put the spiders and the legs into a vibration-proof booth and played sounds from two meters (approximately 6.5 feet) away. The spiders and the legs responded to sounds from 100 hertz to 10,000 hertz.
Next, they played the five sounds that had triggered the biggest response to 25 spiders in the wild and 51 spiders in the lab. More than half the spiders did the "backward strike" move when they heard sounds that have a lower frequency similar to insect wing beats. When the higher frequency sounds were played, the spiders did not move. This suggests the higher frequencies may mimic the sounds of predators like birds.
University of Cincinnati spider behavioral ecologist George Uetz told Science that the results were a "surprise" that indicated science has much to learn about spiders as a whole. Because all spiders have these receptors on their legs, it is possible that all spiders can hear. This theory was first put forward by Walcott 60 years ago, but was dismissed at the time, according to the Cornell Chronicle. But studies of other spiders have turned up further evidence since. A 2016 study found that a kind of jumping spider can pick up sonic vibrations in the air.
"We don't know diddly about spiders," Uetz told Science. "They are much more complex than people ever thought they were."
Learning more provides scientists with an opportunity to study their sensory abilities in order to improve technology like bio-sensors, directional microphones and visual processing algorithms, Stafstrom told CNN.
"The point is any understudied, underappreciated group has fascinating lives, even a yucky spider, and we can learn something from it," he told CNN.
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In 'Road Map for a More Sustainable Future,' NY Regulator Tells Banks to Consider Climate Risks in Planning
By Brett Wilkins
Regulators in New York state announced Thursday that banks and other financial services companies are expected to plan and prepare for risks posed by the climate crisis.
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A NASA spacecraft has successfully collected a sample from the Bennu asteroid more than 200 million miles away from Earth. The samples were safely stored and will be preserved for scientists to study after the spacecraft drops them over the Utah desert in 2023, according to the Associated Press (AP).
Exxon Mobil will lay off an estimated 14,000 workers, about 15% of its global workforce, including 1,900 workers in the U.S., the company announced Thursday.
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