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Agronomic Services — News Release


CONTACT: J. Kent Messick
Field Services Section Chief, Agronomic Division
(919) 733-2655

Agronomic testing helps organic farmer

EAGLE SPRINGS—Billy Carter grows about 600 acres of vegetables, strawberries and tobacco in Montgomery and Moore counties. With 20 years of experience, he knows farming, but when he doesn't know something, he knows where to get help. When Carter learned that a new national standard for growing organic crops would go into effect this year, he contacted David Dycus, regional agronomist with the N.C. Department of Agriculture and Consumer Service's Agronomic Division.

"I've grown organic tobacco for seven years," Carter said, "and produced my own transplants in the greenhouse. Under the old rules, I could grow transplants with commercially manufactured fertilizer. This year, a new rule requires that transplants used in organic production be grown with natural fertilizers. This is something that no one around here has ever done. There is nothing published so I started doing some experimenting last year."

Tobacco transplants, and many vegetable transplants, are grown in float beds in greenhouses. The seedlings sit in styrofoam trays that float on top of a nutrient solution. Commercially produced fertilizers are ideal for float beds because they dissolve easily in water and do not clog pumps. Organic fertilizers do not possess these same properties and using them in a float-bed situation is pretty much uncharted territory.

Carter studied the organic fertilizers available and picked two he wanted try in the float beds: a seabird manure and a bat guano. "Then I called Dycus because I knew he had the resources at the NCDA&CS agronomic laboratories to help me evaluate these fertilizers. I was going to need both solution and waste analyses."

Solution analysis is a laboratory test that measures the nutrient content and other chemical properties of water sources and nutrient solutions. It tells growers whether water is suitable for a specific agricultural purpose, such as irrigation, fish farming, and greenhouse crop production. Waste analysis measures the nutrient content and other relevant properties of composted materials, manures or other waste products that are to be used as fertilizer. Both analyses cost $4 per sample.

Carter and Dycus took samples of each fertilizer to verify the nutrient content. They took a sample of the well water they planned to mix with the fertilizer. Then, after mixing the fertilizers with well water in five-gallon buckets, they collected samples of the nutrient solution.

Carter used the results to calculate how much fertilizer to add to each 4,000-gallon float bed. It took three times as much bat guano as seabird manure to provide enough nitrogen for the seedlings, and the bat guano cost twice as much as the seabird product. With this information, it seemed obvious the seabird fertilizer would be the more economical choice, but as the "experiment" continued, other problems developed.

"After the organic fertilizers were added to the float beds, solution samples showed that nearly all the nitrogen in the seabird manure was in the ammonium form. The alkalinity of the water quickly rose to dangerously high levels. Plant roots could not even grow into the solution without being burned off. The float bed fertilized with bat guano had half its nitrogen available as nitrate and half as ammonium, and the plants rooted just fine," said Carter.

Carter and Dycus brainstormed about the alkalinity problem. "In routine float-bed culture, alkalinity problems are solved by adding battery acid to the water," said Dycus. "Battery acid, however, is not a natural product. Citric acid or vinegar are the most acceptable choices for use in organic production."

Carter added citric acid to the nutrient solution in the float bed and monitored it closely by taking solution samples. "I have a lot of confidence in solution analysis," said Carter. "It's a good way to find out exactly what's going on — alkalinity, pH, soluble salts, nutrient levels, everything you need to know."

Thanks to solution analysis, Carter was able to produce some field-ready organic transplants last year. This year, he's still experimenting and sampling—trying to resolve problems with the seabird product and adjust the float-bed alkalinity with vinegar since it is more economical and easier to obtain than citric acid.

Carter hopes, with the help of the Agronomic Division, to work out a standardized and effective fertilization method for organic transplant production. "Agronomic services are great and economical, and everybody bends over backwards to help," said Carter. "They're anxious to help because there is so much demand for this kind of information statewide."

In 2002, there were about 100 certified organic farmers in North Carolina. Organic production is one of the fastest growing segments of U.S. agriculture, and it could be a very profitable option for North Carolina farmers who are dealing with the decline of other markets. With growers like Carter who are dedicated to pioneering new ways to resolve production problems, other organic transplant producers throughout the state will benefit by not having to start from scratch.

The NCDA&CS Agronomic Division’s Field Services section offers advice and assistance in all aspects of crop nutrient management and agronomic testing, including soil testing, nematode assay, and plant, waste or solution analysis. Growers in Anson, Hoke, Lee, Montgomery, Moore, Randolph, Richmond, or Scotland counties can contact David Dycus at (919) 776-9338 or by e-mail at Growers in other North Carolina counties who would like advice on crop nutrition can visit the or contact Kent Messick at (919) 733-2655 for the name of their local regional agronomist.


Last Update February 13, 2013


NCDA&CS Agronomic Services Division, Colleen M. Hudak-Wise, Ph.D., Director
Mailing Address: 1040 Mail Service Center, Raleigh NC 27699-1040
Physical Address: 4300 Reedy Creek Road, Raleigh NC 27607-6465
Phone: (919) 733-2655; FAX: (919) 733-2837

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