Section 2 Table of Contents

At least 10 subsamples of the indicated plant part(s) should be taken to make a complete sample for submission to the lab.

Table 1.2-10. Plant part to be sampled, sampling time, and sufficiency levels for plant tissue analysis
Crop: Corn Alfalfa Small grains Soybeans
Plant part: Ear leaf Leaves, top 33% of plant Uppermost leaves Uppermost full leaves
Time: Silking Bud to 10% bloom Before heading Prior to or early flowering
Element Sufficiency range1 (percent)
  1. Sufficiency range is valid for the crop, plant part, and sampling time indicated.
  2. Aluminum is not essential. This is the normal range in plants.
Nitrogen 2.75–3.50 3.75–5.50 2.50–3.50 4.25–5.50
Phosphorus 0.25–0.50 0.25–0.70 0.20–0.40 0.25–0.50
Potassium 1.70–2.50 2.00–3.50 1.50–3.00 1.70–2.50
Calcium 0.20–1.00 1.75–3.00 0.20–1.00 0.35–2.00
Magnesium 0.20–0.60 0.30–1.00 0.15–0.60 0.25–1.00
Sulfur 0.20–0.50 0.25–0.50 0.15–0.50 0.20–0.40
Sufficiency range1 (ppm)
Manganese 20–150 30–100 25–150 21–150
Iron 20–250 30–250 20–250 50–350
Boron 4–25 30–250 6–25 20–50
Copper 6–20 10–30 6–25 10–30
Zinc 20–70 20–70 20–70 20–50
Aluminum2 10–300 10–300 10–200 10–200