Tissue Testing: Are your plants Hungry?

If you have taken a basic agronomy course or spent some time crop scouting, then you’re probably aware of visual nutrient deficiency symptoms in plants. If a plant has yellowing of lower leaves at the leaf tip developing a yellow V on the leaf, then it is a nitrogen deficiency. When there is purple coloring on the outside of lower leaves, then it is a phosphorus deficiency. If there is yellowing on the margins of older leaves, then it is a potassium deficiency; and so on.  But what about plants experiencing hidden hunger?

A plant can develop a nutrient deficiency without showing any visual symptoms, consequently hidden hunger occurs. Depending on the nutrient and the severity of the deficiency, hidden hunger can have a big impact on yield and crop quality.  Tissue testing is key to determine if hidden hunger is present, so a plant tissue sample should be taken for laboratory analysis.

How do I take a sample?

There are a couple of strategies that are used for plant tissue sampling.  First, if there are poor areas of a field, use a diagnostic approach. This serves as a tool to find deficiencies. Compare the poor area to a healthy area of the field.  Second, if plants are not showing deficiencies, use a monitoring approach. This offers a checkup and gives a farmer the opportunity to grow high quality crops and correct any hidden hungers.

When taking a sample for the lab, always note the specific growth stage of the crops as nutrient requirements vary during the growing season.

When sampling, it is important to collect the proper portion of the plant based on growth stage.  Information on sampling is in the graphic below. You can also find it here

Plant Tissue Sampling Proceedure

Watch these videos for proper tissue sampling procedure:

Dr. Nick Ward explains proper corn tissue sampling procedure.
Dr. Nick Ward explains proper soybean tissue sampling procedure.

Finally, always submit plant tissue samples in breathable paper bags to maintain sample quality.

How do I interpret my Tissue Testing results?

After submitting samples, a report will be emailed to you with the amount of each nutrient in the plant.  A bar graph shows if each nutrient is “deficient”, “low”, “sufficient”, or “high” in the plant.

The Ward Guide offers a more in-depth explanation of interpretation for many plant species also.

What do I do if I have hungry plants?

Depending on crop growth stage, equipment, amendments, and economics, there could be opportunity for in season nutrient applications. Therefore, the goal is to use this data to increase profitability.  Ward Laboratories Inc. professionals can review your report with you and help you determine specific fertilizers and application methods or other management practices that can help correct problems.

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