Tissue testing provides valuable insights into the nutrient status of the sampled plants. It is not a substitute for soil testing. Instead it is most effective when used in conjunction with soil testing.
Reasons to test plant tissue
- Tissue testing assists with nutrient decisions to drive the dry matter yield of subsequent hay cuts or grazing rotations.
- Test results provide some real data on nutrient removal to assist in future nutrient budgeting.
- Tissue testing provides nutrient information for next autumn’s fertiliser application (especially with regard to micronutrients and potassium).
When and how to perform tissue testing
Collect plant tissue samples any time after emergence until the beginning of flowering.
Nutrient levels within the tissue change as the plant ages. In addition, nutrient concentration tends to decrease as the plant grows because nutrients are being diluted within larger volumes of plant tissue.
Tissue testing can also be used as an aid for diagnosing problems in a field. In this case, take samples from ‘good’ and ‘bad’ to allow for realistic comparison.
Sample the same plant part in each area and be sure that both areas are comparable in terms of variety, planting date, treatment etc. concentration tends to decrease as the plant grows because nutrients are being diluted within larger volumes of plant tissue.
Collect 200 grams of plant material for each leaf tissue sample. Use clean food-grade gloves and keep samples in clearly identified paper bags. Keep samples in a cool location prior to sending. Where possible, sample and post in the same day.
Sample during a period of active growth, before flowering. Take the top 15 cm of the whole plant.
Sample in spring to early summer. In white and strawberry clovers, take the green leaves with petioles at pre-flowering stage. For all other varieties, take all the green leaves and stems from 5 to 7cm above ground at pre-flowering stage.
Sample during the active growing season, when moisture is adequate for two to three weeks. Take 40 to 50 tillers at random from over the paddock. All growth – cut 3 to 5cm above the ground after two to five weeks of regrowth.
Sample when plant is showing signs of unusual change in colour. Take samples from the actively growing leaf of the plant. Preferably the youngest mature leaves.
Reference: Agronomic insight, Incitec Pivot Fertilisers, 2016
Valley sees regional sales managers can assist with tissue sampling and interpreting results.