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Agronomic Services — News Release


Contact: J. Kent Messick, Field Services Section Chief
NCDA&CS Agronomic Division
(919) 733-2655

NCDA&CS services take guesswork out of organic tobacco fertilization and harvest.

Johnny Slade (left) and regional agronomist Robin Watson select the correct tobacco leaf for a tissue sample from Jane Iseley's crop by counting nodes from the bottom of the stalk.
Johnny Slade (left) and regional agronomist Robin Watson select the correct tobacco leaf for a tissue sample from Jane Iseley's crop by counting nodes from the bottom of the stalk.

BURLINGTON—Eight years ago when Jane Iseley began growing organic tobacco, there were no established guidelines for fertilization. Her first attempt was, to a large extent, guesswork. Today, Iseley is confident in her approach to organic fertilization. She has come to rely on plant tissue analysis and advice from her regional agronomist—services available to her through the N.C. Department of Agriculture and Consumer Services’ Agronomic Division.

“I started out following the rule of thumb that only 45 percent of the nitrogen present in an organic fertilizer would be available,” said Iseley. “I applied 80 units of nitrogen and that proved to be too much. Santa Fe suggested that I contact NCDA&CS regional agronomist Robin Watson.”

Watson made a visit to Iseley’s farm and walked through the fields with her. He explained the various factors that could affect the availability of the fertilizer—formulation, soil type and weather conditions. He showed her how to collect leaf tissue samples, submit them for analysis, access her reports online, download the results and use them to adjust fertilizer application more precisely.

“I pointed out that the 45 percent rule is not hard and fast,” said Watson. “Actual nutrient availability is affected by many factors, such as weather and soil type. Red clay has finer particles and holds water better than some soils. By holding water, it also holds nitrogen better. The only way to get a really good handle on crop nutrient use is through tissue analysis.”

“For the most part, tissue testing is an underused tool,” Watson went on. “It is potentially useful for any crop, but for high-value crops, it really is indispensable. And in the case of organic tobacco, it has two important uses. It enables a grower not only to fertilize more precisely but also to time harvest more precisely.”

Iseley is a long-time customer of the Agronomic Division’s soil testing service. However, she had not used tissue analysis until she began consulting with Watson. Now she tissue samples other crops regularly as well, especially strawberry and tomato.

“Watson’s advice made all the difference in the world,” said Iseley. “Organic fertilizers cost about three times as much as conventional fertilizers. By using tissue analysis to adjust fertilization rates, I was able to save money by using less fertilizer. By using it to decide when to harvest, I was able to produce quality leaf as well. Without it, I would have primed a week earlier. Tissue analysis is a wonderful tool.”

Tissue analysis is one of the most valuable, and little known, agronomic tests available to tobacco growers. By measuring the nitrogen content of the leaf, the test indicates whether leaves from the sampled stalk position are ripe enough for harvest. Achieving the best-cured leaf, grade and yield is important for all growers, and tissue analysis ensures that this goal is reached.

"There was a time in North Carolina when growers relied on visual cues to decide when to harvest," Watson said. "However, there were a lot of false readings with this approach. For example, leaves that were sun baked and off color could look ready to harvest. Today there’s no reason to rely on visual cues when a quick, accurate test can easily eliminate the guesswork.”

Tissue samples to predict optimum harvest should be collected and submitted every two weeks throughout the harvest period. Laboratory analysis requires about two working days. At a cost of $5 per sample ($25 per out-of-state sample), tissue analysis is an economical investment. Whether using tissue analysis to time harvest or to monitor and adjust fertilization, growers should contact their NCDA&CS regional agronomist for details on how to collect and submit samples and how to interpret results.

North Carolina growers have access to one of the most comprehensive agronomic testing and advisory services in the nation. Although best known for its soil testing services, the Agronomic Division also checks plant tissue, composted materials, animal wastes, industrial and municipal wastes, fertilizer solutions and source water for nutrient content and other chemical properties relevant to agricultural production. To support these testing services, it has a staff of 13 regional agronomists who visit growers, evaluate suspected nutrient problems, help take samples, give advice on liming and fertilization, and help identify and manage nematode problems.

Information on collecting and submitting agronomic samples is available online at For more help, contact your local NCDA&CS regional agronomist. A list of regional agronomists, their assigned counties and contact information is available online at

Agronomist Robin Watson is available to provide advice on fertilization, nutrient management or nematode problems in Alamance, Caswell, Chatham, Durham, Granville, Orange, Person, Rockingham and Stokes counties. He can be reached by phone at (336) 570-6850 or by e-mail at


Last Update June 10, 2011


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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