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Testing Corn Tissue for Nutrients
Corn Nutrient Deficiencies
Key Points
 Wet soils and other
environmental factors can
cause nutrient deficiency
symptoms
 Symptoms generally appear as
strips, lighter shades of green,
yellowing, purpling, or
browning
 Proper tissue sampling should
be followed to help avoid
erroneous information
 Soil samples should be
collected along with tissue
samples to help diagnose
nutrient deficiencies
Wet soils and other environmental interactions can
cause corn plants to develop symptoms of nutrient
deficiencies. Deficiency symptoms generally show
on the leaves as stripes, lighter shades of green,
yellowing, purpling, or browning (Figure 1). Stunting
and deformed leaves, stems, or roots can also be
symptoms. Tissue testing when used along with soil
samples can help determine if there is a true nutrient
deficiency or if the deficiency is environmentally
induced.
Nitrogen (N), phosphorus (P), potassium (K), and
magnesium (Mg) deficiencies generally appear on
older leaves as these nutrients are mobile within the
plant. Non-mobile nutrients (sulfur (S), iron (Fe),
calcium (Ca), zinc (Zn), copper (Cu), boron (B),
manganese (Mn), chlorine (Cl)) appear as
deficiencies on younger leaves.
Proper Sampling
Improper techniques for the collection and handling
of the samples can cause erroneous information.
Therefore, it is very important to follow the
procedures outlined in sampling kits. Laboratories
that conduct tissue analysis generally provide collection instructions, a grower information sheet,
and a mailing vessel.
Tissue sampling is dependent on the stage of growth of the corn. Generally for corn plants less
than 12 inches tall, the entire plant is collected except for the bottom one inch near the soil
Figure 1. Nutrient deficiencies can ap(Figure 2). If the plants are taller than 12 inches and have not tasseled, the entire (includes the
pear as necrotic areas such as nitrogen
collar or sheath that surrounds the stalk) first unrolled leaf below the whorl should be collected
(top), purpling for phosphorus (middle), or
(Figure 3). For plants with 50% of ears displaying silks that have not turned brown, the entire ear shades of yellowing as in potassium
(bottom).
leaf (not including the collar or sheath) should be collected (Figure 4). Samples should be
gathered from suspected problem plants and “normal” plants for comparison; all within the same
or very similar environments. A minimum of 20 plants should be randomly sampled throughout the area or field for proper
representation. In general, dead, diseased, insect damaged, mechanical damaged, or stressed plants (drought, flooding, high or low
temperatures) should not be collected.
Take to the field a clean, dry, or new plastic bucket(s) or paper bag(s) for collected samples; do not use plastic bags or metal
containers. Place problem and normal material into separate containers and keep separated throughout the process. Collected
samples should be free of dust or soil as they can influence the results. If samples require cleaning, brush contaminates off with soft
-bristled brush, wipe gently with a damp cloth using distilled water, or rinse with distilled water. Tap or well water can contain
contaminating elements. If the collected material was recently sprayed with pesticides or liquid fertilizer, the samples should be
cleaned with a mild detergent solution (2.5 ounces of detergent per gallon of water), then rinsed with distilled
water. Samples should not remain in the rinse or washing fluids any longer than necessary.
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Testing Corn Tissue for Nutrients
Allow the individual samples to dry for about 48 hours in a clean area or paper bag to about the dryness of cured hay. Samples
should remain loose as molding may occur if compacted together. When dry, the samples are ready for mailing. Using a clean
paper bag, break larger pieces into sections and then fold the bag over a couple of times to form a compact package and then
place into the laboratory’s mailing envelope.
Soil Sampling
Soil samples should also be collected from suspect and normal areas at the same time as tissue samples are collected. Soil
samples provide additional field nutrient information for comparison. Soil samples that show adequate fertility are an indication that
the plant symptoms are environmentally caused rather than from inadequate soil nutrients. The soil samples should be taken
adjacent to the plants that are being tissue sampled and placed into a clean plastic bucket or paper bag. Soil samples from
suspect and normal areas should not be mixed. Gloves should be worn for the soil sampling procedure to avoid contaminating the
tissue samples. Allow the soil samples to dry and submit along with the tissue samples to the laboratory per their instructions.
Summary
Tissue samples used along with soil samples can help determine if nutrients are deficient in the soil and are causing plant nutrient
deficiency symptoms during the growing season or if the cause is related to environmental factors. Nutrient deficiency symptoms
can be dependent on the seed product, the time in its life cycle, moisture content of the soil, soil pH, soil organic matter, heat, cold,
compaction, and other factors. Utilize the report from the analysis laboratory to determine what should or should not be done in
regard to the symptoms. If soil nutrient deficiency does appear to be the problem, plans should be made to apply the required
nutrient as soon as possible. Some, such as nitrogen, can be addressed during the growing season if the corn plant is not too
mature. More commonly, the deficiency will need to be addressed after harvest. Environmental factors may or may not be
managed. Compaction may be resolved through some means of tillage where possible. Tiling may be a resolution for wet areas
that consistently show nutrient deficiencies.
Break ear leaf
off at this point.
Figure 2. Submit whole plants except for
bottom one inch when plants are less than
12 inches tall.
Figure 3. Submit entire first mature leaf below the whorl
for plants that have not tasseled but are greater than 12
inches in height. Mature leaves have visible collars as
indicated by the arrow.
Figure 4. For plants that have 50% of the ears showing
green silks, break the ear leaf off at its base and submit.
The collar or sheath is not included.
Sources:
1
Stevens, G., et al. 2002. Integrated Pest Management. Crop Nutrient Deficiencies & Toxicities. IPM1016. University of Missouri.
Thom, W.O., et al. 1991.Sampling for Corn Plant Tissue Analysis. National Corn Handbook. NCH-15. Iowa State University.
Schulte, E. E. and K. A. Kelling. 1991. Plant Analysis: A Diagnostic Tool. National Corn Handbook. NCH-46. Purdue University.
4
Beegle, D. B. 2013. Plant Tissue Analysis. Part 1, Section 2: Soil Fertility Management. Penn State University.
2
3
Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local growing, soil and
weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible.
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