FOR IMMEDIATE RELEASE
WEDNESDAY, MARCH 21, 2007
Brenda Cleveland, Plant/Waste/Solution Section chief
NCDA&CS Agronomic Division
Improve strawberry fruit quality with tissue analysis
Download a high res version
RALEIGH - Strawberries grown on black plastic require intensive and precise fertility management. Nutrients such as potassium, calcium, magnesium and boron affect fruit firmness, taste and appearance. The best way to decide how much fertilizer to apply is to collect leaf and petiole samples and have them tested for nutrient content. The Agronomic Division of the N.C. Department of Agriculture and Consumer Services recommends collecting tissue samples at first bloom and continuing to do so every two weeks throughout flowering and fruiting.
The NCDA&CS laboratory measures actual concentrations of essential nutrients within the plant. Nutrient ranges for optimal production are well established. When nutrient levels are outside these ranges, decreases in quality will eventually occur. Tissue analysis can identify nutrient shortages early, before symptoms appear, thus giving growers time to adjust fertilization appropriately.
To collect a tissue sample from strawberry plants, select the most recently mature, trifoliate leaves (MRMLs). Those leaves are full-sized and green and consist of one petiole or leaf stalk with three leaflets. MRMLs are usually located three to five leaves back from the growing point. Avoid collecting damaged tissue. Detach the petioles from the leaves as you collect them, but submit them together as one sample.
Each sample should include leaves and petioles from 20 to 25 locations 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.
When submitting tissue samples, be sure to fill out the information sheet completely, including fertilization history and environmental conditions. It is particularly important to provide the name of the strawberry variety being grown as well as its stage of growth at the time of sampling. Stage of growth refers to week of bloom and can be coded B1 through B12 (first through 12th week of bloom). Accurate management recommendations depend on this information.
Strawberry tissue analysis costs $7 per sample and requires both leaves and petioles. Analysis of leaf blades reveals nutrient deficiencies or excesses. Analysis of petioles gives a good indication of the amount of nitrate nitrogen currently available for crop growth and development. When test results show nutrient levels to be out of the optimal ranges, the plant analysis report provides recommendations for corrective action.
A guide to collecting and submitting strawberry tissue samples is available online at http://www.ncagr.com/agronomi/pictorial.htm. NCDA&CS regional agronomists are also available throughout the state to offer guidance and answer question about sampling and fertilization. Visit http://www.ncagr.com/agronomi/rahome.htm to find contact information for your regional agronomist, or call Kent Messick at (919) 733-2655.