Northeast Region Certified Crop Adviser (NRCCA) Study Resources

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In This Section

• Introduction
• PO 15 Fertilizer analysis conversions
• PO 16 Soil sampling
• PO 17 Variability in soil test results
• PO 18 Fertilizer recommendations
• PO 19 Soil test interpretation
• PO 20 Soil sampling strategies
• PO 21 Pre-sidedress nitrogen test
• PO 22 Plant tissue analysis
• PO 23 Plant nutrient level
• Summary

Competency Area 3: Soil Testing and Plant Tissue Analysis

PO 22. Describe how to use plant tissue analysis.

1. Problem-solving and diagnosis
2. Nutrient program monitoring
3. In-season nutrient management

Analyzing plant tissue can indicate the success of a soil fertility program and uncover potential problems. Plant tissue analysis complements soil testing by measuring the nutrients actually taken up by the plant. In addition, secondary nutrients and micronutrients that currently are not routinely measured in soils can be measured reliably in plants. It should be noted, however, that plant nutrient content represents the effects of not only soil nutrient status but also all the factors controlling plant growth. Therefore, a single year's information may not be useful for planning a soil fertility management program. But as results are accumulated over a period of years, the information will become more valuable.

Sampling plant tissues allows for diagnosis of nutrient problems, whether deficiency, sufficiency, excess, or toxicity. The information may be used to change aspects of the current nutrient management plan, or to alter future plans. 

Tissue analysis allows for nutrient program monitoring by following the concentration and amount of a nutrient in a crop during the growing season. Deficiencies or excesses may change the current plan, or may influence nutrient amendments for future years. The nutrient concentration in a plant varies with the plant's age and the part of the plant sampled. If plant analyses are to be meaningful, the appropriate plant part must be collected for the age of the plant, and a number of plants must be included to obtain a representative sample. Specific directions on plant sampling generally are available with each sampling kit from the plant analysis laboratory.

Plant tissue analyses also are used to fine-tune the current season's nutrient management. Recommendations based on plant tissues usually involve application of specific fertilizers at key times during the cropping season.