SOIL AND PLANT ANALYSIS (1+1)

What plant tissue analysis shows and its interpretation

What plant tissue analysis shows?

Plant tissue analysis shows the nutrient status of plants at the time of sampling.

• This, in turn, shows whether soil nutrient supplies are adequate. In addition, plant tissue analysis will detect unseen deficiencies and may confirm visual symptoms of the deficiencies.Toxic levels also may be detected. Though usually used as a diagnostic tool for future correction of nutrient problems, plant tissue analysis from young plants will allow a corrective fertilizer application during the same season. Not all abnormal appearances are due to a deficiency.
• Some may be due to too much of certain elements. Also, symptoms of one deficiency may look like those of another.
• A plant tissue analysis can pinpoint the cause, if it is nutritional.

A plant analysis is of little value

• if the plants come from fields that are infested with weeds, insects, and disease organisms;
• if the plants are stressed for moisture; or
• if the plants have some mechanical injury.


 
The most important use of plant analysis is as a monitoring tool for determining the adequacy of current fertilization practices. Sampling a crop periodically during the season or once each year provides a record of its nutrient content that can be used through the growing season or from year to year. With soil test information and a plant analysis report, a producer can closely tailor fertilization practices to specific soil-plant needs. It also may be possible to prevent nutrient stress in a crop if the plant analysis indicates a potential problem developing early in the season. Corrective measures can be applied during the season or, if the crop is perennial, during the next year. Combined with data from a soil analysis, a tissue analysis is an important tool in determining nutrient requirements of a crop.
Download Recommended plant tissue nutrient levels: sufficiency values and ranges

INTERPRETATION

• The sufficiency ranges are given for plant tissues of the crops at ages (or stages in the crop cycle) that research has found appropriate for sampling.
• The analysis data can be used as a guide for attaining improved crop quality and yield.
• For long-term orchard crops, plant tissue nutrient levels can be logged over time and used as a diagnostic tool to assist in developing a fertilizer programme.
• If a tissue level of a nutrient is below the lower end of the sufficiency range, the nutrient should be considered deficient, whereas if the level is above the upper end of the range, the nutrient can be considered as approaching a toxic level.
• The midpoint of the sufficiency range is the target to aim at.
• As the level approaches the lower limit, the nutrient should be added.
• As the level approaches the upper limit, additions of the nutrient should be withheld. It is important to be near the midpoint for most nutrients, because imbalances in the ratios of nutrients can affect crop growth.
• Because environment plays a major role in nutrient uptake and crop development, the sufficiency ranges given here should be considered as general guides.
• In addition to variation due to environment effects, different crop cultivars may have different critical levels.