At harvest, tissue analysis can help maximize yields and grades from desirable stalk positions. Producer contracts specify as many as five stalk positions, so several different harvest times have to be scheduled.

NCDA&CS recommends using a tissue test to ensure optimal leaf ripeness before each harvest date.

The sampling procedure used when testing for ripeness is more targeted. Leaves are collected from the appropriate stalk position from each of 12 representative plants about one week before the intended harvest.

When you plan to harvest lower leaves, plant tissue nitrogen should be at 1.3 to 1.75 percent. For middle leaves, the recommended range is 1.6 to 2.0 percent nitrogen, and for upper leaves, it is 2.0 to 2.25 percent.

To collect and submit tobacco tissue samples, follow these procedures.

• Collect the appropriate part of the plant from representative areas of the field. Place the sample in a paper bag or in the envelope provided by the Agronomic Services Division. Do not use plastic containers.

• Complete the Plant Sample Information form. To ensure the most accurate recommendations, describe the environmental conditions, fertilizer history and plant appearance on the form. When testing for ripeness and maturity, be sure your designation for “Plant Part” corresponds to the leaf stalk position sampled: L for lower, M for middle and U for upper. Also specify that the sample contains harvestable leaves (H) instead of most recent mature leaves, and indicate that the growth stage is mature (M). These designations make a big difference in how tissue analyses are evaluated. Nutrient content of leaves varies depending on stalk position.

• Enclose the $5 processing fee for each sample.

The Agronomic Services Division requires two business days to analyze plant tissue samples. Measurements include nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, zinc, copper, boron and molybdenum.

Each report, along with the agronomist’s comments, is posted on the division’s website soon after completion.

The division provides information to help growers optimize the nutritional status of tobacco, monitor and safeguard environmental quality, use fertilizers economically and determine when tobacco leaves are ripe. For assistance, call (919) 733-2655 or visit the division’s website to find your local regional agronomist.