- Fish farming creates waste that can be difficult and costly to clean up, an issue that impedes the growth of the industry in the United States.
- A new study shows that simple woodchip bioreactors can effectively and inexpensively remove nitrate pollution and solids from aquaculture wastewater.
- Bioreactors, along with pre-filtration of solid waste, could encourage growth in the domestic aquaculture industry.
URBANA, Ill. – Aquaculture, or fish farming, is one of the fastest growing sectors of agriculture in the world today. However, farmers in the United States who wish to capitalize on this momentum face regulatory hurdles when dealing with fish waste. But new research shows that a simple, organic system can clean aquaculture wastewater effectively and inexpensively.
Researchers built bioreactors—long containers filled with wood chips—to treat wastewater from a fully operational recirculating aquaculture system in West Virginia. The idea is simple: water from the fish tank enters the bioreactor at one end, flows through the wood chips, and exits through a pipe at the other end. Along the way, solids settle out and bacteria housed in the wood chips remove nitrogen, a regulated pollutant.
Laura Christianson, assistant professor of water quality at the University of Illinois and lead author of the study, is a bioreactor expert. Her research has shown just how effective they are at removing excess nitrogen from tile-drained agricultural fields across the Midwest. But this project was a different kettle of fish.
“The bioreactors that we usually promote in Illinois are for taking nitrogen out of tile drainage,” Christianson explains. “Wastewater from a fish farm is a lot gunkier. It looks brown and can be smelly. We wanted to see if we could get a bioreactor to take the nitrogen out of that kind of water without the bioreactor clogging up with solids.”
The team set up four identical bioreactors, varying only in retention time, or the amount of time it takes for water to travel from end to end. “Retention time varied from 12 to 55 hours in the four bioreactors. If you’re trying to treat a lot of water, you want a lower retention time so you can keep it moving through. But the more time you give those bacteria to take the nitrogen out, the more effective they are. We were trying to find a balance between moving water through quickly and making sure it’s staying in there long enough to get treated properly,” Christianson explains.
Solid waste in the water presented another complication. At high flow rates, more solids were entering the system, settling out, clogging the spaces between wood chips, and impeding flow. The researchers found that the optimal retention time to both treat the water and avoid immediate clogging was 24 hours.
“The long and the short of it is that the bioreactors worked great,” Christianson says. “They worked as a filter for the solids and took nitrates out. But for systems that need to move a lot of water in a short amount of time, we recommend an additional microscreen filter to settle some of the solids out before they enter and clog up the bioreactor.”
At face value, a study about clogging potential of aquaculture bioreactors might not seem revolutionary, but the results could play a part in the evolution of the agriculture industry.
“In the U.S., we import more than 80 percent of our seafood—mostly from southeast Asia and China—so it’s an important industry. If we want to increase our food security, especially around this great source of protein, we should raise more fish domestically. But to do that in an environmentally responsible way, dealing with the wastewater from fish farms will be really important,” Christianson says.
The article, “Denitrifying bioreactor clogging potential during wastewater treatment,” is published in Water Research. Christianson’s co-authors, Christine Lepine, Kata Sharrer, and Steven Summerfelt, are at The Conservation Fund’s Freshwater Institute in West Virginia. The study was supported by the USDA’s Agricultural Research Service and Tides Canada.
Anticipating the March 1 corn stocks estimate
URBANA, Ill. – USDA’s release of the Quarterly Grain Stocks report on March 31 will provide an estimate of corn stocks in storage as of March 1, 2017. This estimate provides the ability to calculate the magnitude of feed and residual use of corn during the second quarter of the marketing year.
“The calculation offers the basis for evaluating the probable feed and residual use during the entire marketing year and imparts information on the potential size of ending stocks,” says University of Illinois agricultural economist Todd Hubbs. “Although the planting intentions estimates released on the same day in the Prospective Plantings report will likely eclipse the information provided in the Quarterly Grain Stocks report, the estimated corn stocks have important implications for the current marketing year.”
The supply of corn available from December 2016 to February 2017 is the base for estimating March 1 stocks. Corn stocks at the beginning of the quarter were estimated at 12.383 billion bushels in the December Grain Stocks report. Currently, the Census Bureau estimates for corn imports are only available through December. In the first quarter of the marketing year, corn imports totaled 11.8 million bushels.
“Imports for the second quarter might have been around 14 million bushels,” Hubbs says. “When imports are combined with the beginning stocks, total available supply for the second quarter comes in at 12.397 billion bushels.”
An estimate of corn exports for the second quarter is based on the cumulative weekly export inspections estimate available for the entire quarter. Cumulative marketing-year export inspections through February totaled approximately 975 million bushels. During the first four months of the marketing year, total Census Bureau corn exports were greater than cumulative export inspections by 70 million bushels.
“Assuming the margin is maintained through February, corn exports during the first half of the year equaled 1.04 billion bushels,” Hubbs says. “Because exports in the first quarter totaled 551 million bushels, the estimate for second-quarter corn exports equals 493 million bushels.”
The Grain Crushing and Co-Products Production report released on March 1 estimated corn used for ethanol and co-product production during December 2016 and January 2017 at 950 million bushels. Weekly estimates of ethanol production provided by the Energy Information Administration indicates ethanol production increased by 6.1 percent in February 2017 from the preceding year. Hubbs says by calculating the amount of corn used to produce ethanol from these February numbers, corn used for ethanol production in February was approximately 436 million bushels. Total use for the quarter is estimated at 1.386 million bushels.
Corn used to produce other food and industrial products during the 2016-17 marketing year is projected at 1.44 billion bushels by the USDA.
“Using historical corn use data, typically around 49 percent of the final marketing-year food and industrial products use occurs in the first half of the marketing year,” Hubbs says. “If this historical pattern holds and the USDA projection is correct, corn use for the first half of the marketing year totaled 708 million bushels.” Corn use during the first quarter equaled 347 million bushels which set the second-quarter use estimate at 361 million bushels.
The current USDA projection for feed and residual use sits at 5.6 billion bushels. In January, the projection was lowered by 50 million bushels due to a smaller-than-expected corn crop, increased corn use for ethanol, and the disappearance associated with the December 1 stocks report.
Hubbs says the historical pattern of feed and residual use in corn may provide some indication of the second-quarter use. For the five previous marketing years, use during the first half of the marketing year ranged from 69.5 to 75.4 percent with an average of 72 percent. Second-quarter feed and residual use ranged from 25 to 34 percent of the total use over this time span. For this analysis, the 72 percent average during the first half of the previous five marketing years is used to calculate expected feed and residual use during the second quarter. If the USDA projection is correct, feed and residual use during the first half of the 2016-17 marketing year totaled 4.057 billion bushels. Feed and residual use equaled 2.275 billion bushels in the first quarter. Therefore, the second-quarter estimate totals 1.782 billion bushels.
By adding the estimates for exports and domestic uses, Hubbs says the total use of corn during the second quarter is 4.022 billion bushels. The total use estimate for the second quarter places March 1 corn stocks at 8.37 billion bushels. At this level, March 1 stocks come in 556 million bushels larger than the estimated 2016 March 1 corn stocks.
“Although it can be difficult to anticipate the quarterly stocks estimate in corn, it provides a basis for the magnitude of stocks that is considered neutral for corn prices,” Hubbs says. “A corn stocks estimate that supports the USDA projection of 5.6 billion bushels of feed and residual use during the 2016-17 marketing year is neutral. An estimate of March 1 corn stocks that deviates significantly from market expectations will trigger a price reaction. This analysis indicates an estimate near 8.37 billion bushels should not alter expectations that feed and residual use is on track to meet the marketing-year projection.”
Decoding the secret language of flowers
URBANA, Ill. – Do you give flowers to your loved one on holidays and birthdays? Flowers are a great way to communicate your love and affection, and some can convey a specific message, according to a horticulture educator with University of Illinois Extension.
“Flowers can represent everything from friendship to true love,” says Rhonda Ferree. “For example, chrysanthemums show friendship. Gardenias represent secret love. Give a primrose to say, ‘I can’t live without you.’ Lilies, a traditional wedding flower, convey chastity, innocence, and purity, while Stephanotis shows happiness in marriage. Tulips are given to the perfect lover, and a red tulip declares your love. Orchids are commonly given as corsages to show love and beauty.”
But, Ferree says, no other flower shows more meaning than a rose. All roses symbolize love, but certain colors of roses have special meanings. “What’s more, when several colors in various stages of bloom are combined in one arrangement, your floral bouquet can speak a whole sentence instead of just one thought!”
Here are some of the most widely accepted meanings for different rose colors, blooms, and arrangements:
- Red roses show love, respect, or courage.
- Yellow roses represent joy, gladness, or freedom.
- Pink/peach roses exude gratitude, appreciation, admiration, or sympathy.
- White roses demonstrate purity or secrecy.
- Two roses joined together display engagement.
- Red and white roses together indicate unity.
Additionally, rosebuds say, “you are young and beautiful.” A single rose stands for simplicity. In full bloom, a rose means “I love you” or “I love you still,” and a bouquet of roses in full bloom signifies gratitude.
If you receive fresh flowers from your loved one, follow the following guidelines to ensure the longest vase life. Add water containing floral food to the vase every day. The best flower food can be obtained from your floral retailer.
Once the flowers are past their prime, discard them or make the memory last by creating a potpourri out of your rose petals. You can also press and dry the flowers for your memory book. “The uses of flowers are endless,” Ferree says.
For a complete fact sheet on the meaning of flowers, visit the horticulture program page at web.extension.illinois.edu/fmpt.
Managing pests in your garden with IPM
URBANA, Ill. – When trying to manage pests in your garden this year, consider using integrated pest management (IPM) practices.
“As the saying goes, the only things guaranteed in life are death and taxes, and if you’re a gardener you can also include pests in the list of life’s guarantees,” says University of Illinois Extension educator Ken Johnson. “IPM is an approach to reducing pest and disease populations to an acceptable level using a variety of techniques. There are four types of techniques used with IPM: cultural, physical/mechanical, biological, and chemical.”
The idea behind cultural management, Johnson says, is growing and maintaining a healthy plant. A healthy plant is less susceptible to disease and is better able to withstand attacks from pests. This means growing the right plant in the right place at the right time.
“You want to make sure you are planting plants that are appropriate for the site they will be planted in,” Johnson explains. “Don’t plant something that needs full sun in shade, or that requires acidic soils in alkaline or neutral soils. Placing a plant in the wrong environment can prevent the plant from reaching its full potential and will likely lead to a weak plant that is disease and insect riddled.”
In addition to selecting the right site for your plant, Johnson says to make sure it is getting the proper fertilization and enough, but not too much, water. “You can also alter the time of your planting to avoid a particular pest. For example, plant summer squash in early July to avoid squash vine borer, because they have finished laying eggs by then.” Additional management techniques used in cultural management include pruning, sanitation, and mulching.
The goal for physical/mechanical management is to physically eliminate pests. This can be done in a variety of different ways, such as hand picking caterpillars or bag worms; pruning out diseased branches, webworms, or galls; pulling or hoeing weeds in flower beds or vegetable gardens; or putting up barriers to prevent pests from getting to your plants, such as bird netting or fencing for rabbits and deer.
In biological management, pests are managed with other living organisms—their natural enemies. Insects like ladybugs will eat small soft-bodied insects like aphids, scale, and mealybugs. Lacewing larvae, sometimes referred to as aphid lions, will feed on aphids, scale, mealybugs, small caterpillars, and occasionally mites. In addition, some tiny parasitic wasps lay eggs inside of aphids and when the eggs hatch, the larvae will eat the aphid. Other parasitic wasps lay eggs on caterpillars such as horn worms.
“You may have seen these in your garden before if you grow tomatoes. Infected caterpillars will have a mass of what looks like eggs on them, but they are actually cocoons,” Johnson says. “If you see this, don’t get rid of that caterpillar. Eventually the wasps will emerge from the cocoon and will go on to attack more caterpillars.” Insects can also be killed by fungus and bacteria. For example, milky spore, a bacterium, can be used to control Japanese beetle larvae.
Chemical techniques round out the IPM practitioner’s toolkit. The goal is to manage pest populations by using pesticides, whether they are insecticides, fungicides, or herbicides. “If you are using IPM, chemicals are used as a last resort,” Johnson explains. “You want to use the three other techniques – cultural, physical/mechanical, and biological – before reaching for the pesticide bottle. If you do go the pesticide route, you want to try and use the least toxic chemical possible.”
Before using any pesticide product, make sure to read the label. “The label will tell you where you can legally use it, what it will control, how much you should use, how often you should use it, and any precautions you need to take while using the product,” explains Johnson.
U of I students design galactic greenhouse
URBANA, Ill. - Two University of Illinois engineering students have designed a miniature lunar greenhouse which they hope will enable humans to grow crops in lunar soil. They will present their design at the Lab2Moon Challenge in Bangalore, India in March. If they win the competition? Next stop – the moon.
Alex Darragh, a freshman in agricultural and biological engineering, and Matt Steinlauf, a freshman in mechanical engineering, won’t be traveling to the moon themselves, but their galactic greenhouse might.
The device is about the size of a beverage can and has an Archimedes screw that drills into the ground, lifts lunar soil (also called regolith) into the shell, and drops it into rotating cups. When the screw retracts, the hole closes and the device pressurizes and heats up. Tubes deposit seeds, water and fertilizer into the cups.
Darragh and Steinlauf will present their project to TeamIndus, an aerospace research organization sponsoring the Lab2Moon Challenge. TeamIndus is one of four privately owned companies traveling to the moon in December, hoping to win the Google Lunar XPrize, a global competition to challenge and inspire engineers and entrepreneurs to develop low-cost methods of robotic space exploration. To win the $30 million prize, a privately funded team must successfully place a robot on the moon, travel at least 500 meters, and transmit high-definition video and images back to earth.
To increase the opportunity for lunar research, TeamIndus challenged college students world-wide to design and build an experiment that would help develop sustainable life on the moon. There were more than 3,000 applicants from 15 countries and 300 cities.
Phase II of the competition narrowed the field to 25 teams. Darragh and Steinlauf’s team, Regolith Revolution, is one of three from the United States to make the cut. Several teams are from India, and Italy, Mexico, Peru, Spain, and the United Kingdom will also be represented. TeamIndus will manufacture the winning design and include it on their lunar voyage.
“Right now we’re conducting experiments in the lab and growing different plants in the lunar soil simulant,” said Darragh. “We’ve worked with Arabidopsis, the first plant that was grown in space. We’re also testing different fertilizer solutions to find the one that will work the best with lunar soils and plants and minimize the amount of nutrients you would have to bring to the moon.”
The team’s faculty mentors are Prasanta Kalita, a professor in agricultural and biological engineering and associate dean for academic programs in the College of Agricultural, Consumer and Environmental Sciences, and Sameh Tawfick, assistant professor in mechanical engineering in the College of Engineering.
Darragh says they are excited to be chosen as finalists in the competition, and regardless of the outcome, “It’s been an amazing experience to be part of a project that has so much potential.”
You can follow Regolith Revolution’s journey through video logs on their website at www.regolithrevolution.com.
Benefits of intergenerational gardening
URBANA, Ill. – Like many life skills, gardening is often learned directly from family members. Grandparents might recruit the grandkids to help water transplants or drop in seeds, setting the stage for a lifetime love of gardening.
“Gardening is classified as a life skill because it not only allows you to grow food for yourself and family, but it also incorporates many skills such as math, reading, science, and even history,” says University of Illinois Extension horticulture educator Bruce J. Black.
“Like many people, I got bit by the gardening bug while learning how to grow vegetables and flowers from my grandparents and my mother,” Black says. “When I was learning this skill and developing my passion, I did not realize the full benefits or how this passion would impact my life.”
Intergenerational gardening is the act of older adults passing along plant information, gardening skills, and cultural traditions to younger generations. Participants need not be related. For example, when Master Gardeners teach classes in their community, they may be engaging in intergenerational gardening.
The benefits of intergenerational gardening include:
- An increased interest in gardening in the younger generation.
- Relationships between elders and children, while helping to counteract negative stereotypes.
- Improvements in physical and mental well-being and life satisfaction in elder participants.
- A safe environment for cultural and life experience sharing.
- An exploration of skills, such as reading, math, science, geography, and life lessons, such as responsibility, accountability, life/death, and patience.
“Not everything that grows in a garden is a plant,” Black says. “Gardening is just one of the many common-ground activities where intergenerational transfers can happen. In my experiences as not only the child but also now as a garden educator, the learning opportunities do happen on both sides.”
With 35 percent of American households growing food in gardens in 2014, the opportunities for intergenerational gardening are abundant.
To learn about a volunteer opportunity that incorporates plenty of intergenerational education, check out the University of Illinois Extension’s Master Gardener Program at web.extension.illinois.edu/mg.