REFERENCE SUFFICIENCY RANGES
FRUIT & NUT CROPS

Strawberry, Annual Hill Culture

C. R. Campbell and G. S. Miner

• Critical Values

  None established.

• Sampling Procedures

  The most recent mature trifoliate and petiole are the best indicator samples. Concentrations of essential elements are determined on the trifoliate. Nitrate nitrogen is determined on the petioles.

  Fifteen trifoliates and petioles are required for a representative sample.

  Samples are collected during fall growth as needed to solve problems and monitor crop development. Intensive biweekly sampling is initiated when spring growth begins and continued throughout flowering and harvest (approximately March 1–May 30) in North Carolina. Petioles are removed from trifoliates at the sampling site.

  Samples are shipped to the laboratory in paper containers.

• Sufficiency Ranges
  
  
  • Most Recent Mature Trifoliate
    All growth stages
    
    

    Macronutrients
    N	P	K	Ca	Mg	S
    3.0–4.0%	0.2–0.4%	1.1–2.5 %	0.5–1.5%	0.25–0.45%	0.15–0.40%

    
    

    Micronutrients
    Fe	Mn	Zn	Cu	B
    50–300 ppm	30–300 ppm	15–60 ppm	3–15 ppm	25–50 ppm

    
    

    Excessive or Toxic Nutrient Levels

    Boron becomes toxic as concentrations approach 200 ppm B. Excess boron results in a marginal leaf burn beginning first on lower leaves and progressing up the plant. Severe cases result in >10% yield loss.

  • Petioles from Most Recent Mature Trifoliate
    Spring growth
    
    

    Petiole nitrate nitrogen zone of sufficiency

• DRIS Norms

  DRIS norms have not been reported for strawberry.

• Remarks

  Sufficiency ranges were adopted from California studies and modified for North Carolina conditions based on numerous field studies.

  Petiole nitrate nitrogen values well above the sufficient zone during fruiting result in soft fruit.

• References

  Hockmuth G, Albregts E. 1994. Fertilization of strawberries in Florida. Gainesville (FL): University of Florida Cooperative Extension Service. Circular 1141. 4 p.

  Miner GS, Poling EB, Carroll DE, Nelson LA, Campbell CR. 1997. Influence of fall nitrogen and spring nitrogen-potassium applications on yield and fruit quality of ‘Chandler’ strawberry. J Am Soc Hort Sci 122(2):290–5.

Electronic Document Prepared by:
Catherine Stokes, Communication Specialist
Agronomic Division of the N.C. Department of Agriculture and Consumer Services. July 2000.