REFERENCE SUFFICIENCY RANGES
FRUIT & NUT CROPS
 |
Apple |
C. O. Plank |
None established.
Sample 50–100 healthy, mid-terminal leaves on current season's growth in mid-season (8 to 10 weeks after full bloom).
| Macronutrients | |||||
| N § | P | K | Ca | Mg | S |
| 1.80–2.10% | 0.15–0.50% | 1.25–1.80% | 1.00–2.00% | 0.20–0.50% | NA |
| § These values apply to ‘Golden Delicious’. For all other varieties, the values are 1.90–2.30%. | |||||
| Micronutrients | ||||
| Fe | Mn | Zn | Cu | B |
| 50–400 ppm | 25–200 ppm | 20–50 ppm | 5–20 ppm | 25–60 ppm |
DRIS norms have not been established for apple.
Plant analysis is an excellent means of determining the nutritional status and fertilizer needs of apple. As with many fruit crops, low nutrient levels and/or nutrient imbalances in apple are often manifested in the fruit before deficiency symptoms show on the leaves. Examples are bitter pit due to inadequate Ca and internal corking due to low B. Therefore, it is important to maintain the nutrient level within the sufficiency range to prevent abnormal growth, fruit color, texture, or shelf life.
In order to make a successful diagnosis, the sample submitted to the laboratory must represent the overall growing conditions and be properly taken. Always follow the sampling instructions provided by the laboratory performing the analysis. In addition, there are several other growth factors that can also influence the nutrient status of the trees. Apple is a poor accumulator of Ca, and many producers routinely apply foliar Ca sprays. If the leaf samples are not properly washed off or if the application of foliar sprays is not noted on the information sheet accompanying the sample, the analytical results for Ca can be easily misinterpreted. Therefore, to aid the diagnostician in evaluating the plant analysis data, it is essential that all available information on cultural and climatic conditions, as well as the symptomology, be known. Most laboratories provide plant analysis kits containing history sheets for recording this information.
Hanson E. 1993. Apples and pears. In: Bennett WF, editor. Nutrient deficiencies & toxicities in crop plants. St Paul (MN): American Phytopathological Society Press. p 159–63.
Jones JB Jr, Wolf B, Mills HA. 1991. Plant analysis handbook: a practical sampling, preparation, analysis, and interpretation guide. Athens (GA): Micro-Macro Publishing. 213 p.
Mulder D. 1950. Magnesium deficiency in fruit trees on sandy soils and clay soils in Holland. Plant Soil 2:145–57.
Plank CO. 1989. Plant analysis handbook for Georgia. Athens (GA): University of Georgia Cooperative Extension Service. 64 p.
Shear CB, Faust M. 1980. Nutritional ranges in deciduous tree fruits and nuts. Hort Rev 2:142–64.
Electronic Document Prepared by:
Catherine Stokes, Communication Specialist
Agronomic Division of the N.C. Department of Agriculture and Consumer Services. July 2000.