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Agronomic Services — News Release


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

Agronomic testing makes a difference

GRANITE FALLS—The Starnes brothers—Ed and Rick—have grown tobacco since 1976. For decades, they have relied on the soil testing and nematode assay services offered by the N.C. Department of Agriculture and Consumer Services. Six years ago, when they wanted to start growing their own tobacco transplants, Rick Starnes contacted NCDA&CS regional agronomist Lynn Howard and discovered another set of services especially useful in greenhouse situations—plant tissue and solution analyses.

"Gearing up for greenhouse production requires a significant financial investment," Howard said. "Growers like the Starneses who commit to that investment want to protect it the best way they can. Specialized agronomic tests let them know what nutrients the plants need and whether they are getting them."

Rick Starnes has taken Howard's 15 years of advice to heart. He starts each greenhouse transplant season by sending a sample of media to the NCDA&CS Agronomic Division in Raleigh for a standard soil test. The media, which comes in bags like potting soil, contains an unknown amount of fertilizer. If the soil test report indicates high soluble salts, Rick Starnes knows to water the plants until he can wash the excess salts out of the media. Salts can kill young seedlings.

Another precaution Rick Starnes regularly takes is testing his greenhouse source water. He is lucky to be on a city water supply so he doesn't have to worry about drastic changes in water quality. Regardless of the source, all greenhouse producers should have their water checked. Drought, like that experienced throughout most of North Carolina in recent years, can dramatically change chemical properties like mineral content and pH.

As the plants begin to grow, Rick Starnes also monitors the fertilizer solution in the float beds by taking solution samples. This way he knows if he needs to add more fertilizer, adjust the solution pH or make other changes to his production system. If plants don't green up like they should, Rick Starnes takes tissue samples to find out which nutrients are needed.

Solution analysis 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, or greenhouse crop production, and whether solutions with fertilizer added contain appropriate amounts of plant nutrients. Plant tissue analysis measures the actual nutrient content within plant tissue and can warn of a deficiency or toxicity before symptoms are evident. Both analyses cost $4 per sample.

"I send in about five sets of solution samples each year," Rick Starnes said. "For the first five years I had the greenhouse, I sent in samples and didn't have many problems. This season it was one problem after another, and things looked bad. If it hadn't been for the sampling and all the help Lynn Howard gave, I could have lost my crop this spring."

The soil test report alerted the Starneses to the first problem—unusually high soluble salts in the media. After watering the plants several days in a row to wash the salts out, he noticed the plants were still small and off- color. Results from a solution analysis ruled out a nutrient problem.

Howard soon began to suspect the problem was linked to the styrofoam float-bed trays the plants were growing in. The trays were five years old and had been cleaned with diluted chlorox at the end of each season. About the same time that problem was confirmed, the plants experienced another setback—damage by Pythium, a water-borne fungal pathogen.

Things were looking grim. It was six weeks into the growing season and the plants were still small with hardly any roots. Howard knew the only way to get the plants strong enough to plant in the field was to nurse them along with precise applications of fertilizer.

Over the next five weeks, Howard and Rick Starnes collected four sets of solution samples and one tissue sample. Reports indicated the plants were low in boron and calcium so Rick Starnes followed recommendations and added these nutrients to the float-bed solution. By the second week of May, the plants were putting on roots and looking good.

In one sense, this year's greenhouse troubles were serendipitous. Normally, tobacco plants would have been planted in the field by mid-May. This year, because the Starneses couldn't plant on time, their plants avoided almost certain damage from heavy rain and hail. By the time the land is dry enough to prepare for planting, these transplants will be big enough and strong enough for the field.

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 Alexander, Alleghany, Ashe, Avery, Burke, Caldwell, Catawba, Mitchell, Watauga or Wilkes counties can contact Lynn Howard at (828) 313-9982 or by e-mail at Growers in other N.C. counties who would like advice on crop nutrition can visit the Web site 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