REFERENCE SUFFICIENCY RANGES
FIELD CROPS
 |
Tobacco, Burley |
C. R. Campbell |
| Limited published information: | |
| Magnesium (Mg) | 0.2% (whole plant) |
| Molybdenum (Mo) | 0.38% (whole plant), 0.42% (cured leaves) |
The most recent mature or fully expanded leaf (MRML) is the best indicator of nutritional status. This is the first leaf back from the growing point that is fully developed. Cell division is complete, but cell expansion will continue. The MRML is generally the 4th or 5th leaf back from the bud.
A total of 6 to 10 leaves are required for analysis, depending on size. As leaves become larger, the lamina from one side of the midrib can be removed from several leaves for a representative sample. In either case, midribs should be removed before grinding.
Diagnostic samples should be taken at first signs of a problem. Comparative samples from "good" and "bad" plants should be taken along with matching soil samples from the root zones. If symptoms are zonal on the plant, it is helpful to take the MRML sample and a separate sample of leaves showing the symptoms.
To monitor nutritional status, samples should be taken at lay-by and/or flowering.
After topping, the 2nd or 3rd leaf from the top of the stalk is the best indicator sample of nutritional status.
Samples are shipped to the laboratory in paper containers.
| Macronutrients | ||||||
| Growth Stage | N (%) | P (%) | K (%) | Ca (%) | Mg (%) | S (%) |
| Seedling | 4.0–6.0 | 0.2–0.5 | 3.0–4.0 | 0.6–1.5 | 0.2–0.6 | 0.15–0.6 |
| Early growth | 4.0–5.0 | 0.2–0.5 | 2.5–3.5 | 0.75–1.5 | 0.2–0.6 | 0.15–0.6 |
| Flowering | 3.5–4.5 | 0.2–0.5 | 2.5–3.5 | 0.75–1.5 | 0.2–0.6 | 0.15–0.6 |
| Maturity | 3.0–4.0 | 0.2–0.5 | 2.5–3.5 | 0.75–1.5 | 0.2–0.6 | 0.15–0.6 |
| Micronutrients | ||||||
| Growth Stage | Fe (ppm) | Mn (ppm) | Zn (ppm) | Cu (ppm) | B (ppm) | Mo (ppm) |
| All | 50–300 | 20–250 | 20–60 | 5–10 | 18–75 | 0.2–1.0 |
| Excessive or Toxic Nutrient Levels |
| Manganese toxicity can occur at approximately 1000 ppm but is temperature dependent. Toxicity occurs most often at low temperatures and is generally associated with low pH. |
| Important Ratios |
| The N:S ratio should be less than 18 at all growth stages. |
DRIS norms for cured burley have been developed by Evanylo and others (1988).
Sufficiency ranges were established based on available references and experience interpreting analytical results.
Evanylo GK, Sims JL, Grove JH. 1988. Nutrient norms for cured burley tobacco. Agron J 80(4):610–4.
Mills HA, Jones JB Jr. 1996. Plant analysis handbook II: a practical sampling, preparation, analysis, and interpretation guide. Athens (GA): Micro-Macro Publishing.
Miner GS, Tucker MR. 1990. Plant analysis as an aid in fertilizing tobacco. In: Westerman RL, editor. Soil testing and plant analysis. 3rd ed. Madison (WI): Soil Science Society of America, Inc [SSSA]. p 645–57. (SSSA book series; 3).
Electronic Document Prepared by:
Catherine Stokes, Communication Specialist
Agronomic Division of the N.C. Department of Agriculture and Consumer Services. July 2000.