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Fishy vegetable production methods explained through aquaponics

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COLLEGE STATION — If growing vegetables in a box with no soil and out of direct sunlight sounds a little fishy, well, it is.

“Aquaponics” is a relatively new way of intensified farming that combines aquaculture and hydroponics, according to Dr. Joe Masabni of College Station, Texas A&M AgriLife Extension Service vegetable specialist.

“We are combining fish, which is the aquaculture, and hydroponics, which is vegetable production in soilless media,” Masabni said. “Whether it’s running water through pipes or a flood-and-drain system, the idea is to combine the two where the fish waste becomes food for the plants, and the plant roots clean the water by absorbing all the nutrients. The water then is recycled back to the fish.”

Dr. Joe Masabni, Texas A&M AgriLife Extension Service vegetable specialist in College Station, demonstrates a small-scale aquaponics setup. (Texas A&M AgriLife Extension Service photo by Kathleen Phillips)
Dr. Joe Masabni, Texas A&M AgriLife Extension Service vegetable specialist in College Station, demonstrates a small-scale aquaponics setup. (Texas A&M AgriLife Extension Service photo by Kathleen Phillips)

Aquaponics methods originated at the University of the Virgin Islands in the early 1980s by Dr. James Rakocy, who retired from the university in 2010. He is still active in the industry with the book, “Aquaponics: a Comprehensive Guide to Proven Principles and Practices,” which he co-authored with his successor Dr. Wilson Lennard.

The method has been tried and even successfully used by producers in Texas since the late 1990s. But in the past five or so years, Masabni said, interest has steadily increased in Texas among vegetable producers to the point that a majority of the requests for assistance he receives pertain to hydroponics and aquaponics.

“It has become very popular, because in general with hydroponics you can produce the same crop with a lot less water because the water is recirculating. And with the addition of the fish population there is less fluctuation in the nutrients,” he said. “You don’t have to replenish the minerals, and you don’t have to worry about pH results going really high or really low.

“In theory, you can grow any vegetable because what you have is water, oxygen and nutrients,” he said. “The roots of the plants are sitting in a nutrient-rich situation with lots of water and lots of oxygen, so they will never rot. Anything can grow.”

He said the most cost-effective plants to grow might be herbs, lettuce, kale, watercress, spinach and other small plants that have a relatively fast yield. Other vegetables, such as tomatoes, also can be grown aquaponically, but may not produce quickly enough to be profitable.

Steve Sumrow, owner of Aquaponics USA in Adkins, said an aquaponic system can be “functional” in a size small enough to fit on an apartment balcony. However, he said, a much larger system would be necessary in order for the it to produce adequate food to sustain a family.

“For a family of four, I’d say a system with about 75 square feet of grow space and about 500 gallons of water would be sufficient to harvest about 10 pounds of fish a month and keep enough breeders to replace the fish used,” Sumrow said. “It would also supply the family with an adequate supply of vegetables. Basically, it could produce enough vegetables for a family of four to eat each day, but probably not enough fish for each day.”

He added that aquaponic systems can also be built to use solar or wind power, though the system he described which could produce sufficient food for a small family likely use only about $15 in electricity per month to operate.

“If it’s for fun it can be done, but if it’s for business, you may want to do the math to see what’s profitable,” Masabni said. “A lot of small acreage farmers have been making just as much money from the classes and the tours of their facilities as from the sale of the fish or the plants.”

The cost effectiveness of various methods is yet to be determined for Texas commercial producers, Masabni said.

“I don’t think on a small scale it can be profitable in terms of the production part,” he said. “If you add the tours and the ‘visit the farm,’ experience, then it could be profitable. It is just a good part of a bigger picture.

“A producer can sell produce as a Community Supported Agriculture system, and sell to restaurants and farmers markets, but can also do farm tours and lectures because people want to see the fish and visit the greenhouse where the vegetables are produced.”

Done right and depending on the size of the operation, Masabni said, a producer would harvest, transplant and seed daily.

“You keep replacing what you harvest. That’s the ultimate goal, though in reality it’s often the cycle for every third day, because the operation isn’t big enough to sell and replenish daily,” Masabni explained.

Aquaponics also lends itself to extending the product’s shelf life, which could be a marketing advantage for producers.

“Harvest is different from field harvest, because we don’t cut the roots off and package it. You just remove the excess roots from the growing cup, and then you package it,” he said. “It will last a lot longer with no wilting. When the roots remain on the plant, it is still alive, so it can last a couple of weeks in the refrigerator and still taste, smell and look like it was harvested yesterday.”

Though he is concentrating on commercial aspects, Masabni said the idea is also inspiring people to try aquaponics on a smaller scale for personal consumption.

“A person might have a fish tank and have a pump that circulates the water to a small bed where vegetables are growing and then circulate the water back,” he said.

He plans to offer workshops for interested growers around the state and to do more research into production methods and economics.

“We need to answer questions such as how much nitrate is needed in the water to have a decent crop, which would determine how many fish are needed and how much to feed them,” he said. “For a commercial operation, it needs to be profitable, so you would not want to be feeding 1,000 fish if 500 is enough to give you the same vegetable crop, for example.

“A lot of research is needed as we plan for science-based programming and getting people excited about aquaponics,” he said.

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Farm & Ranch

Frog Fruit

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By Tony Dean, tonydean.tx1@gmail.com

Frog fruit is a native, low-growing perennial forb adapted to most of the eastern U.S., but few grazers know it well. It contributes more to our plant communities than we realize. It generally grows no more than a few inches tall and roots at the nodes. It can form dense mats several feet across and develop runners up to 3 feet long.

The leaves are thick, one to two inches long and 3/8 inch wide, and toothed from the middle to the tip. Tiny white flowers form a ring around a flower head, and the head then elongates into a cylinder an inch long or longer. Frog fruit has a four-angled stem.

Frog fruit can grow almost anywhere in Texas and on many soil types. It can grow in drier soils and likes good drainage, but it needs additional moisture to survive the hottest months. You can find it almost anywhere in a pasture, though it often grows in depressions and near water sources.

“Frog fruit is used as forage by livestock and deer. I recall an instance when I was moving cattle from one pasture to the next on a Jack County ranch. As I opened the gate, I stood by a beautiful green plant of switchgrass which I expected to be immediately grazed down. The cattle walked right by the switchgrass and stuck their heads in a small patch of frog fruit a few feet away,” Dean said.

Frog fruit is gaining popularity as a ground cover for homes and gardens for these reasons:

  1. Frog fruit grows quickly, maybe too quickly. If it gets out of bounds, you can always trim it back.
  2. Frog fruit is low maintenance. Once you get it established with adequate watering, it can survive with little care.
  3. Frog fruit has a long bloom period, from April to October.
  4. It is a host plant for several butterfly species and other insects.
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Farm & Ranch

Theileria orientalis

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By Barry Whitworth, DVM

Over the past few years, veterinarians have detected Theileria orientalis in Oklahoma cattle. Early cases were primarily diagnosed in adult cattle, but more recent Oklahoma cases have been identified in stocker cattle. All cattle producers should be familiar with the clinical signs of this disease and check their cattle daily for signs of trouble.

The first U.S. case of theileriosis was identified in Virginia in August 2017. Those cattle showed weakness and anemia, and veterinarians made an initial diagnosis of anaplasmosis. Blood samples from the animals were tested for Anaplasma, Babesia and Leptospira. Results were negative for all three, but the tests revealed a blood protozoan, later identified as T. orientalis genotype Ikeda. Since that first herd outbreak, the organism has been detected in several states.

Cattle sick with T. orientalis genotype Ikeda may show fever, weakness, anorexia and exercise intolerance. If forced to move, affected cattle may stagger and gasp for air. If stressed excessively, they may collapse and die. On examination, the gums, eyes or vaginal mucosa may appear pale (white) or yellow. Reproductive losses, including stillbirths and late-term abortions, may occur, along with a drop in milk production.

Clinical signs reported in adult cattle in Oklahoma include anemia, sudden death, weight loss, abortion, failure to thrive and failure to calve. In stocker cattle, producers have reported weight loss, anemia, poor performance and sudden death.

Because Anaplasma marginale and T. orientalis genotype Ikeda produce similar clinical signs, telling the two apart can be difficult. One difference is that clinical signs are more common in young cattle infected with T. orientalis than in young cattle infected with A. marginale. Cattle with anaplasmosis also often display aggression, while those with T. orientalis genotype Ikeda typically do not. A laboratory test is required to tell the two diseases apart with certainty.

Researchers have identified Haemaphysalis longicornis as a possible vector of T. orientalis genotype Ikeda. In 2017, the U.S. Department of Agriculture’s (USDA) National Veterinary Services Laboratories (NVSL) confirmed the presence of H. longicornis, commonly called the Asian longhorned tick (ALT) or bush tick. While trying to determine how the tick arrived in the United States, USDA officials discovered it had been present in West Virginia as early as 2010. The tick has now been confirmed in at least 26 states, including Oklahoma. Some evidence suggests other insect vectors may also transmit T. orientalis genotype Ikeda. Needle transfer is another possible route of transmission.

The ALT has been identified in Craig and Mayes counties in Oklahoma. This tick thrives in areas with high humidity, such as wooded regions, brush or tall grass. Ticks are often found where large numbers of wildlife gather, such as along deer trails. Producers can find more information about the ALT on the USDA website at https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/asian-longhorned.

Other countries have developed treatments for T. orientalis, but no approved treatments are available in the United States, and no vaccine exists for this disease. The best defense is prevention: buying cattle free of the organism, avoiding blood transfer between animals and using effective tick control. Producers should purchase cattle from reputable sources. Clean instruments between animals during procedures such as castration or dehorning, and change needles between every animal. Control external parasites with appropriate insecticide treatments. Pasture management also helps, such as rotating cattle away from wooded or brushy areas where ticks thrive. Patch burning may also help reduce tick populations.

Theileria orientalis remains a concern for some cow/calf and stocker producers in Oklahoma. Producers who want more information about T. orientalis genotype Ikeda should contact their local veterinarian or Oklahoma State University County Extension agriculture educator.

References

Hammer, J. F., Emery, D., Bogema, D. R., & Jenkins, C. (2015). Detection of Theileria orientalis genotypes in Haemaphysalis longicornis ticks from southern Australia. Parasites & Vectors, 8, 229.

Oakes, V. J., Yabsley, M. J., Schwartz, D., LeRoith, T., Bissett, C., Broaddus, C., Schlater, J. L., Todd, S. M., Boes, K. M., Brookhart, M., & Lahmers, K. K. (2019). Theileria orientalis Ikeda genotype in cattle, Virginia, USA. Emerging Infectious Diseases, 25(9), 1653-1659.

Spickler, Anna Rovid. (2019). Theileriosis. Retrieved from http://www.cfsph.iastate.edu/DiseaseInfo/factsheets.php.

Watts, J. G., Playford, M. C., & Hickey, K. L. (2016). Theileria orientalis: A review. New Zealand Veterinary Journal, 64(1), 3-9.

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Farm & Ranch

Is the Pond Safe for Livestock?

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By OKFR Staff

During the hottest part of summer, a farm pond can look like a welcome source of water. Cattle may be standing belly-deep along the bank, and the pond may still hold enough water to seem dependable. Looks alone won’t tell you whether that water is safe.

Hot weather, limited rainfall and falling pond levels can create water-quality problems. As water evaporates, salts, minerals, nutrients and other substances become more concentrated. Warm, still water can also encourage blue-green algae, and some forms can produce toxins capable of killing livestock.

Producers sometimes treat water as an afterthought compared to grass, hay and supplemental feed. Livestock need a dependable supply of clean water to maintain feed intake, regulate body temperature and support production. Poor-quality water can reduce consumption and performance even when it does not cause obvious poisoning.

A pond that has watered cattle for years is not safe under every set of conditions. Pay particular attention during drought, extreme heat or any period when the water level drops significantly.

Watch the Water and the Livestock

One of the most serious late-summer concerns is a bloom of cyanobacteria, commonly called blue-green algae. These organisms live naturally in many bodies of water, and most do not produce dangerous toxins. The risk rises when certain toxin-producing species multiply rapidly under favorable conditions.

According to Oklahoma State University Extension, toxic blue-green algal blooms typically develop in standing water after periods of hot, dry, calm weather. Nutrients such as nitrogen and phosphorus can fuel excessive growth. Those nutrients may reach a pond through manure, fertilizer runoff, soil erosion and decaying vegetation.

A suspicious bloom may turn the water bright green, blue-green, pea-soup green or even brownish. Scum, foam or mats may collect along the shoreline, particularly where the wind pushes floating material into one area. Some blooms look like spilled paint.

Not every green pond is poisonous. Common aquatic plants and harmless algae can also change the color or surface of the water. You usually cannot tell whether a bloom is toxic by looking at it, and a pond can contain toxin-producing cyanobacteria without showing every commonly described warning sign.

Keep livestock, horses, pets and people away from water that has an unusual color, heavy surface scum, a bad odor or unexplained dead fish or wildlife nearby. Do not let livestock drink from another part of the same pond on the assumption that the water is safe there. Wind can move a bloom, and toxin levels may vary across the pond.

Blue-green algae can produce toxins that affect the nervous system or liver. Depending on the toxin and the amount consumed, affected animals may develop weakness, staggering, difficulty breathing, tremors, convulsions, diarrhea or collapse. In severe cases, owners find animals dead near the water before realizing anything is wrong. Treatment often fails, which makes prevention especially important.

Treat any suspected poisoning as an emergency. Move the herd away from the water source without driving or stressing animals that may already be affected. Provide another clean water supply and contact a veterinarian immediately. Your county Extension office can also help you determine where and how to submit a water sample.

Blue-green algae is not the only potential problem. Pond water may contain elevated levels of dissolved salts, sulfates, nitrates, bacteria or other contaminants. Runoff can carry manure, fertilizer, pesticides and organic matter into the pond. Low water levels make some of these problems worse because the remaining water grows more concentrated.

Water with excessive dissolved solids may taste bitter or salty, so animals drink less of it. Depending on the substances involved and their concentrations, poor-quality water may contribute to diarrhea, reduced feed intake, poor weight gain or other health concerns. Young animals and livestock that are not used to the water may be more vulnerable.

Watch the cattle themselves, too. Are they reluctant to drink? Are they crowding around a different water source? Has feed intake or weight gain dropped without an obvious explanation? Are several animals having digestive problems? Changes across multiple animals can be an early clue that you need to look at the feed or water.

OSU Extension recommends collecting a representative sample and submitting it for a livestock water test whenever you suspect a water supply is harming animal health or performance. A standard livestock water test covers several characteristics, but blue-green algae can require different sampling and testing procedures. Contact the laboratory or county Extension office before collecting the sample so you take it from the right location, use the proper container and handle it correctly.

Reduce Problems Before They Develop

Good pond management cannot eliminate every water-quality problem, but it can lower the risk. One of the most effective steps is limiting the manure, soil and nutrients that enter the water.

Cattle with unrestricted access to an entire pond can damage the banks, muddy the water and deposit large amounts of manure in or near it. Hoof traffic strips vegetation and speeds erosion. Sediment fills the pond over time, while manure supplies nutrients that can encourage excessive algae growth.

Where practical, fence livestock away from most of the pond and provide a limited-access watering point. Another option is piping water to a trough below the dam or elsewhere in the pasture. OSU notes that reducing cattle manure in the pond can reduce the conditions that favor toxic algae and make the water more palatable.

A vegetated buffer around the pond can slow runoff and trap soil and nutrients before they reach the water. Apply fertilizer and manure carefully in the watershed, particularly before heavy rain, and do not let large amounts of hay, feed or organic debris pile up at the water’s edge.

Alternative watering systems need maintenance, too. Check troughs for algae, manure, drowned animals and other contamination. Install wildlife escape ramps in tanks so birds and small animals can climb out instead of drowning and fouling the water.

Be cautious about treating a pond on your own. Some owners use copper sulfate and other algaecides for algae control, but improper treatment can create new problems. Killing a large amount of algae or aquatic vegetation at once can deplete dissolved oxygen as the material decomposes, which can lead to a fish kill. Treatment may also release toxins from affected cyanobacteria into the water. Base any chemical application on proper identification and professional recommendations, not guesswork.

Livestock should always have enough water for the weather, their size and their stage of production. Demand rises sharply in hot weather, and a pond that barely meets the herd’s needs in spring may fall short in August. Check the source regularly instead of waiting for cattle to gather around a muddy shoreline.

Ponds can fool you. Crystal-clear water isn’t always safe, and a green pond doesn’t always mean toxic algae. Regular observation, testing and prevention are the best ways to keep a pond safe for your herd.

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