Plant analysis indicates the nutritional status of the plant. It is used to check for hidden hunger in a good-looking crop as-well-as nutrient deficiencies in a
a poor crop.
Nutrient deficiency can occur in the plant due to:
• That nutrient being low in the soil.
• Another nutrient being high in the soil.
• Another nutrient being low in the soil.
• Environmental conditions.
•Herbicide residue or disease.
Plant analysis is not a replacement for soil sampling, but an agronomic tool that enhances the soil test.
When to Take the Plant Sample
• When the crop looks poor: If the poor crop is in patches, 2 plant samples and 2 soil samples are usually taken. 1 plant sample and 1 soil sample
from the “good” areas and 1 plant and 1 soil from the “poor” areas. If the crop is generally poor looking, 1 plant sample (and a soil sample if one
wasn’t taken earlier).
• When checking for hidden hunger early, so corrections can be made: Often from tillering to leaf sheath lengthening in cereals, rosette in oilseeds,
and vegetative stages of pulses and forages.
• When checking for hidden hunger late, to evaluate the fertility program: Often from flag leaf to head fully emerged in cereals, from late flowering to
pods formed/filling in oilseeds and pulses, and during late flowering of forages.
• High value crops: corn and sugar beets are often sample 3 to 4 times and potatoes every week or 2 during the growing season to ensure optimal
• The Plant Sampling Staging-Guide, Cereals & Oilseeds shows that samples can be taken during most growth stages, especially for cereals.
Where to Take the Sample
• Random sampling: stay out of low and high areas or take separate samples from these areas.
• Benchmark sampling.
• Transect sampling: plants are taken every so many feet along a straight line crossing the field or area of the field.
• The Plant Sampling Staging-Guide, Pulses & Potato shows the number and part of plant to sample depending on the growth stage.
How to Take the Sample
• When the plant is not under heat stress (in the morning is often best).
• Avoid plants affected by disease, pesticide, insects, hail, wind, frost and recent fertilizer application.
• Cleanliness is important: avoid contact with fertilizer, salt, grease, soil, etc.
• Cut the plants with a clean, rust-free knife or scissors and put in the ALS Environmental plant envelope.
•Keep the sample cool (do NOT freeze) and courier, bus or deliver to the laboratory.
ALS Plant Sampling Staging-Guide
The 50, 30, 20, or 15 refer to the number of plant parts that should be sampled for each specific crop at the growth stage.
If there is no number, select another plant part or growth stage.
CWRS, CPS, Durum, Malt & Oats Triticale & Fall Canaryseed
Winter & ESRS Wheats Feed Barleys & Spring Rye
Plant Part: Plant Part: Plant Part: Plant Part: Plant Part:
Whole Plant Flag Leaf Whole Plant Whole Plant Whole Plant Whole Plant
(above ground) (above ground) (above ground) (above ground) (above ground)
Growth stage: # of Plants # of Leaves # of Plants # of Plants # of Plants # of Plants
1 shoot (1 to 3 leaf stage) 50 50 50 50 50
Tillering begins 30 30 30 30 30
Tillers formed 30 30 30 30 30
Leaf sheath lengthening 20 20 20 20 20
Leaf sheaths strongly erect 20 20 20 20 20
1st node visible 20 20 20 20 20
2nd node visible 20 20 20 20 20
Flag leaf just visible 20 20 20 20 20
Flag leaf ligule just visible 15 30 15 15 15 15
In boot 15 30 15 15 15 15
Heading begins 15 30 15 15 15 15
Head 1/2 emerged 15 30 15 15 15 15
Flowering - head emerged 15 30 15 15 15 15
Ripening 15 30 15
Canola & Mustard Flax & Linola Sunflowers
Plant Part: Plant Part: Plant Part:
Whole Plant Leaves Youngest Whole Plant Whole Plant 1st to 3rd Upper
(above ground) Mature Leaf (above ground) (above ground) Mature Leaves
Growth stage: # of Plants # of Leaves # of Plants # of Plants # of Leaves
Rosette 30 30
In bud - pre-flowering 30
Bolting 15 50 20
Early flowering 15 30 20
Late flowering 15 30 20
Pods formed 15
ALS Plant Sampling Staging-Guide
Field Peas Field Beans Lentils & Chickpeas Soybeans
Plant Part: Plant Part: Plant Part: Plant Part:
Whole Plant Leaves Pods Whole Plant Leaves Whole Plant Leaves Youngest
(above ground) (above ground) (above ground) Mature Leaf
Growth stage: # of Plants # of Leaves # of Pods # of Plants # of Leaves # of Plants # of Leaves # of Leaves
Vegetative 20 50 30 30 30 50 30
In bud 15 50 20 30 20 50 30
Early flowering 15 20 20 30
Late flowering 15 20 20 30
Early pod filling 15 50 20 20 30
50% pod fill 50
Pods filled 50
Corn Total N + Minerals NO3-N (only)
Plant Part: Sugar beets
Whole Plant Leaf Leaf opp. Ear Leaf Plant Part:
(above ground) below Whorl & below Cob Blade Petiole of
Growth stage: # of Plants # of Leaves # of Leaves # of Leaves Leaves Youngest
Less than 12" tall 20 Mature Leaf
30-45 DAE 15 Growth stage: # of Leaves # of Petioles
Prior to tasseling 15 50-60 DAE 20
Full tasseling 15 Vegetative 30
Silking 15 Late July 30
3-6 wks before harvest 30
NO3-N + Minerals Alfalfa
Potatoes Plant Part: Grasses
Plant Part: Whole Plant Plant Part:
Petiole of (above ground) Whole Plant
Youngest Growth stage: # of Plants (above ground)
Mature Leaf Vegetative 20 Growth stage: # of Plants
Growth stage: # of Petioles In Bud 15 Vegetative 20
Vegetative 30 Early flowering 15 Flowering 15
Tuber initiation 30 Full Flowering 15 Prior to seed fill 15
Tuber bulking 30
Tubers 1/2 grown 30 50, 30, 20 or 15 refers to the number of that plant part that should
Tubers maturing 30 be sampled for that crop at that crop stage. If there is no number,
Tubers mature 30 select a plant part or growth stage with one.