Plant tissue analysis is a powerful tool for assessing the nutritional status of crops. By analyzing plant tissues, growers and agronomists can identify nutrient deficiencies, excesses, or imbalances. But, you have to know how to read a plant tissue test. The correct sampling techniques, optimal sampling timing, and the relationship between plant tissue and soil tests for testing all need to be understood to be beneficial for farm ecosystem health.
Why Plant Tissue Analysis Matters
Plant tissue analysis complements soil testing by providing real-time information on nutrient availability within the plant. Unlike soil tests, which assess nutrient levels in the soil, plant tissue analysis directly evaluates the plant’s nutrient uptake and utilization. Here’s why it matters:
- Early Detection: Plant tissue analysis detects nutrient deficiencies before visible symptoms appear.
- Precision: It guides targeted fertilization, preventing over-application and reducing costs.
- Crop-Specific Recommendations: Different crops have varying nutrient requirements, and tissue analysis tailors recommendations accordingly.
Taking Plant Tissue Samples
When to Sample
- Vegetative Growth Stage: Sample during active vegetative growth (before flowering or fruiting).
- Sampling Frequency: Regularly sample throughout the growing season (e.g., every 2-4 weeks).
- Critical Growth Stages: Sample during critical growth stages (e.g., pre-bloom, fruit set).
Where to Sample
- Collect Representative Samples: Randomly select plants from different areas of the field.
- Avoid Edge Effects: Avoid sampling near field edges or areas with different soil conditions.
- Composite Samples: Combine multiple plant parts (leaves, stems) to create a composite sample.
How to Sample
Select the Right Plant Part:
○ Leaves: Young, fully expanded leaves are ideal.
○ Avoid Old Leaves: Old leaves may not reflect the current nutrient status.
- Sample Quantity:
○ Collect enough material (e.g., 20-30 leaves) to represent the entire plant. - Avoid Contamination:
○ Use clean tools and containers.
○ Avoid touching samples with bare hands. - Label and Document:
○ Label each sample with relevant information (field, date, crop).
○ Keep detailed records.
Interpreting Plant Tissue Test Results
This is an example from Waypoint Analytical and the tests you get back may be in a different format.
This plant analysis of soybeans shows levels of iron and zinc higher than sufficient, but not quite toxic. It also shows low levels of sulfur. Often nutrients interact with each other, causing excesses and deficiencies that can only be remedied by balancing the ratios of soil nutrient levels. Regenerative agricultural practices help achieve balance in soil and plants.
Nutrient Ratios
- Nutrient Ratios: Compare nutrient levels (e.g., N:P:K, micronutrients) to optimal ratios.
- Imbalances: High N and low K may indicate excessive vegetative growth but poor fruiting.
Nutrient Concentrations
- Macronutrients: Evaluate N, P, K, Ca, Mg, and S levels.
- Micronutrients: Assess Fe, Mn, Zn, Cu, B, and Mo concentrations.
Critical Levels
- Critical Levels: Compare results to established critical levels.
- Deficient, Adequate, Excessive: Interpret nutrient levels accordingly.
The Connections Between Plant Tissue and Soil Tests
- Complementary Information: Soil tests provide the foundation, while plant tissue analysis offers real-time insights.
- Correlations: Correlate soil nutrient levels with plant nutrient uptake.
- Adjusting Fertilization: Use both tests to fine-tune fertilization strategies.
When using plant tissue analysis and soil tests from a lab you need interpretative guidance. Our team of crop consultants at ST Biologicals has spent years guiding farmers and ranchers in reading these test results for optimum nutrient management.
Contact us for more information. We’re here to help you succeed. When soil speaks, we listen.
