Tissue testing: Are your plants hungry?

If you have taken a basic agronomy course or spent some time crop scouting, then you are 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 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.

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

How do I interpret my Tissue Testing result?

After sending samples, you will get a report on the analysis result, indicating the level of supply of each element in the sample.