Source: NCDA&CS, 3/4/15

The work strawberry growers put in now will set the stage for the quality of fruit and berry yields they will see at harvest time. Agronomists from the N.C. Department of Agriculture and Consumer Services encourage growers to consider tissue testing as part of their fertilization and production practices.

“The strawberry season is relatively short, so growers need to be sure their fertilization program is adequate for optimal production or it could affect the bottom line of the business,” said Aaron Pettit, NCDA&CS agronomist. “A plant tissue analysis offers the most accurate way to monitor strawberry nutrition and gives growers the information in a timely manner to modify fertilizer rates if needed.”

The department recommends that growers submit strawberry tissue samples every two weeks throughout the bloom and fruiting stages. The test costs $7 per sample for North Carolina growers and $27 for out-of-state growers. The turnaround time for results and recommendations is typically two working days. Growers can find their results online at www.ncagr.gov/agronomi/uyrplant.htm.

Leaf samples need to be collected and handled in a specific way to ensure best results from the tests.

It is important to collect the most recently mature, trifoliate leaves (MRMLs). These leaves are full-sized and green and consist of one petiole (leaf stalk) with three leaflets. They are usually located three to five leaves back from the growing point. Avoid collecting leaves that are damaged or dull in color.

When MRMLs are being collected, the petioles need to be detached from the leaves immediately. This action halts nutrient transfer between the two plant parts, which will be analyzed separately for different purposes. Analysis of the leaves can reveal nutrient imbalances within the plant. Analysis of petioles indicates the amount of soil nitrogen currently available for crop growth and development, and serves as a basis for the nitrogen rate recommendation.

Each sample should include MRMLs from 20 to 25 plants randomly selected within a uniform area. For example, all of the plant material in a single sample should be the same variety, growing on the same soil type, planted at the same time and having the same management history. This is known as a representative sample.

To provide accurate recommendations, the Agronomic Services Division asks growers to provide specific information about each crop sample. Details about fertilization history, environmental conditions and the name of the variety being grown should be written on the NCDA&CS “Plant Sample Information” form, which is available on the division’s website. On the form, it is important to indicate the appropriate growth-stage code (B1 through B12) based on the week of bloom.

To help with the process, information on collecting and submitting strawberry tissue samples is available online at www.ncagr.gov/agronomi/pictorial.htm. Also, refer to the Strawberry Fertility Manual available at the Agronomic Services Highlights box at www.ncagr.gov/agronomi/.

“Agronomists are also available to help strawberry growers interested in starting a sampling program,” said Dr. Kristin Hicks, Plant/Waste/Solution/Media Section chief with the Agronomic Services Division. “They can explain tissue sample collection and fertilization strategies for strawberries, and help growers implement any recommendations made from testing. They can be a valuable resource for these high-value crops.”

To identify the agronomist for your area, visit www.ncagr.gov/agronomi/rahome.htm, or call Michelle McGinnis at 919-733-2655.