Test micronutrients to diagnose deficiencies.
Agronomy Bulletin 106 ─ Corn Tissue Sampling
Nutrient deficiency symptoms are not always caused by a lack of nutrients in the soil. Other factors can be to blame, such as poor root development, unfavorable soil conditions or weather. Plant tissue sampling helps identify the problem and determine corrective action.
Factors to Consider
- Sampling method
- Preparing and mailing the sample
- Field history
- Corrective action
- WHY TISSUE SAMPLING? A plant tissue analysis, or tissue sampling, will detect unseen deficiencies as well as confirm visual deficiency symptoms in corn. Typically used as a diagnostic tool for future correction of nutrient problems, a plant tissue analysis from young plants also helps with corrective fertilizer applications during the season.
- WHAT AND WHERE TO SAMPLE. How to sample depends on field conditions. Be sure to collect a sufficient amount of plant material — about the size of a softball. Samples need to be from similar areas of corn plants in the same growth stage. See Figure 1.
• Uniform fields: On acres with uniform stands in fields or for routine testing, combine plant samples from at least 10 different areas of the field into one composite tissue sample.
• Problem fields: On acres with varying or abnormal growth and plant appearance, tissue samples will help determine cause and corrective action. Take tissue samples and soil samples from affected and normal areas. This will help show the difference in plant and soil nutrients. A representative sample should include 10 to 20 individual samples.
- PREPARING AND MAILING THE SAMPLE. Use a large, clean paper bag or clean plastic bucket to collect the sample(s). Remove any dust or residue from the leaf surface. Mail samples using envelopes supplied by the laboratory. If samples cannot be shipped immediately, place them in a refrigerator. Laboratories cannot process samples that are deteriorated or moldy.
- FIELD HISTORY. Perhaps the most important information you supply to the lab is the plant history form. It provides background of your fields and a more meaningful interpretation of the results. File a separate form for each sample taken. Make copies for your records.
- CORRECTIVE ACTION. Tissue analysis can help make decisions about nutrient applications such as nitrogen and micronutrients. If fertilizer is required to correct a deficiency, use the information from these tests to adjust your fertility plan. Contact your trusted agronomic adviser or use laboratory services for recommendations.
After soil testing, plant tissue analysis is the second-best tool to help improve crop nutrition and yield. While soil testing identifies the nutrients offered to the crop, tissue sampling identifies how well the plants utilize the soil and applied nutrients. The test confirms visual deficiency symptoms and reveals hidden nutrient stresses. Use tissue testing to check the effectiveness of fertility programs, improve yield goals and determine future fertilizer needs. For more information, contact your local Mycogen Seeds customer agronomist or trusted agronomic adviser.