Plant analysis is the second tool after soil testing that is critical to improving crop nutrition and yield. Only plant analysis can identify the actual nutrient status of a plant or crop. While soil testing identifies the nutrients offered to the crop, plant analysis identifies how well the plants are utilizing soil and applied nutrients. Plant analysis allows the crop or plant to tell us what nutrition it lacks. It is critical that the correct plant part and stage of growth be sampled and that the lab be clearly informed of this. The normal nutrient concentration differs between the various plant parts. Also, the normal nutrient concentration of each plant part changes as the plant matures. Plant analysis is calibrated to these norms, so correct identification of which nutrients are low or high depends on accurate information.
Effective Uses For Plant Tissue Analysis
- Confirm visual deficiency symptoms.
- Reveal "hidden" nutrient stresses.
- Check on the effectiveness of a fertility program.
- Improve yield goals and fertilizer needs for future crops.
Some Tissue Analysis Do's & Don'ts
- Do collect a representative sample.
- Do always collect sufficient plant material.
- Do fill out the "Tissue Test Request Sheet" as completely and accurately as possible.
- Do always identify the age and growth stage as accurately as possible.
- Do always collect a soil sample from problem areas.
- Don't sample dead plants.
- Don't wash leaf tissue.
- Don't use galvanized equipment in any way.
- Don't sample severely insect damaged plants.
- Don't sample severely mechanically injured plants.
- Don't sample plants that are too old.
- Don't sample plants during severe drought.
- Don't include roots, branches or loose soil with any plant sample.
- Don't ship samples in plastic bags or containers.
Where To Take Samples
1. In Uniform Fields: Where plant growth is uniform over the entire area, one composite sample, taken from at least 10 widely scattered areas in the field. One plant sample is necessary. One soil sample is recommended.
2. In Problem Fields: These are where the growth or appearance of one area differs from the rest of the field. Plant analysis can often determine the cause of these differences and indicate the best method to correct the problem. Sample when abnormalities are discovered. Two plant and two soil samples are recommended. This includes collecting soil and plant samples from the normal and abnormal areas. All plant samples taken from abnormal areas should be taken from just inside of the abnormal area. Soil samples should be taken throughout the abnormal area. A separate plant analysis history must be recorded on the "Tissue Test Request Sheet" for each sample taken.
When to Take Samples
Crops can be sampled during much of the season. See the "Crop Codes" document below for a list of the preferred plant parts and growth stages to sample for many crops.
Amount of Plant Material
Plant analysis requires at least a rounded double handful (softball size) of plant tissue. We cannot analyze a sample that is too small. Refer to the tables on the following pages for the proper number of plants parts to sample.
Preparing Samples For Shipping
Use a large paper bag or clean plastic bucket to collect the sample. Remove any dust or residue from the leaf surface with a clean, dry, soft-bristle brush. Do not wash the sample. Improper washing can affect the nutrient content of some elements. Samples should be dry to touch, and strongly wilted before shipping. Wilting is not critical if overnight shipping is used.
Complete The Tissue Test Request Sheet
Perhaps the most important part of a plant sample is its accompanying history. It must be complete to permit a meaningful interpretation. Keep a copy of the "Tissue Test Request Sheet" for your files. Agri-Labs Plant Tissue Submittal Form- Crop Codes
Place the dry, wilted plant tissue sample in a paper bag. Do not send fresh samples or put them into plastic bags. They may decompose during shipment, making them useless for analysis purposes. The sample must not decompose in transit. It is strongly recommended that either 2-day, or next-day delivery service be used.