Table 1.2-9. Plant part to be sampled, sampling time, and sufficiency levels for plant tissue analysis
At least 10 subsamples of the indicated plant part(s) should be taken to make a complete sample for submission to the lab.
| Crop: | Corn |
Corn | Alfalfa | Small grains | Soybeans |
|---|---|---|---|---|---|
| Plant part: | Whole Plant |
Ear leaf | Leaves, top 33% of plant | Uppermost leaves | Uppermost full leaves |
| Time: | 12 inches tall |
Silking | Bud to 10% bloom | Before heading | Prior to or early flowering |
|
|||||
| Element | Sufficiency range¹ (percent) | ||||
| Nitrogen | 3.50-5.00 |
2.75–3.50 | 3.75–5.50 | 2.50–3.50 | 4.25–5.50 |
| Phosphorus | 0.30-0.50 |
0.25–0.50 | 0.25–0.70 | 0.20–0.40 | 0.25–0.50 |
| Potassium | 2.50-4.00 |
1.70–2.50 | 2.00–3.50 | 1.50–3.00 | 1.70–2.50 |
| Calcium | 0.30-0.70 |
0.20–1.00 | 1.75–3.00 | 0.20–1.00 | 0.35–2.00 |
| Magnesium | 0.15-0.45 |
0.20–0.60 | 0.30–1.00 | 0.15–0.60 | 0.25–1.00 |
| Sulfur | 0.20-0.50 |
0.20–0.50 | 0.25–0.50 | 0.15–0.50 | 0.20–0.40 |
| Sufficiency range¹ (ppm) | |||||
| Manganese | 20-300 |
20–150 | 30–100 | 25–150 | 21–150 |
| Iron | 50-250 |
20–250 | 30–250 | 20–250 | 50–350 |
| Boron | 5-25 |
4–25 | 30–250 | 6–25 | 20–50 |
| Copper | 5-20 |
6–20 | 10–30 | 6–25 | 10–30 |
| Zinc | 20-60 |
20–70 | 20–70 | 20–70 | 20–50 |
