Tissue sampling has become very popular in recent years as it more accurately represents plant nutrition. That’s why tissue samples should be taken as early in the season as possible to properly detect nutrient deficiencies and make adjustments during the growing season.
For accurate results, avoid testing plants that show severe signs of stress from factors not related to nutrients. This includes damage from insects, drought or flooding, temperature, chemicals or machinery. Also be sure to test normal plants in addition to affected plants in the same stage of growth.
When testing alfalfa plants from beginning stages until the first flower, it’s important to sample from the top six inches of the plant. Collect about 35 samples. When sampling alfalfa closer to or at harvest for comparison, test about 25 whole plants. Collecting soil samples simultaneously can be helpful when paired with the plant analysis to identify nutrient deficiencies, toxicities and imbalances. Take soil samples, at a six- or seven-inch depth, from the same areas where plant samples were collected.
Once samples have been collected, remove foreign particles like dirt but do so without washing the plant. Place the samples in a paper bag or a large envelope to help prevent them from developing mold during shipping. Soil samples also may be placed in a waterproof container with a correlating label to the field and tissue sample with which it was taken.
Depending on the lab you use, some reports for plant samples will reveal the concentration of N, P, K, Ca, Mg, S, Zn, Mn, B, Cu, Fe, Al, and Na within the plant. Soil samples submitted with the plant sample will be analyzed for pH, organic matter, P, K as well as special soil test results. Nutrient levels will also be interpreted for soil and plant samples to identify any nutrient issues and potentially offer recommendations. It’s important to note that nutrients can then be soil, seed and foliar applied.
The ability to apply timely nutrition and reach new yield levels is so exciting! Experiment on your farm.