Understanding the question
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| Why is it important to me as a farmer?
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- Soil tests are a valuable tool for identifying the macronutrient status of paddocks on the
farm. However, research has shown that using soil tests to indicate trace-element
deficiencies can be very inaccurate, especially on acid soils
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- Plant tissue testing is the preferred method for diagnosing trace element toxicities,
deficiencies, and imbalances for plants
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- Plant tissue testing involves the sampling of plant parts, chemical extraction to
determine their nutrient concentration, and the relation of this to plant production
Figure 1 - Example of plant tissue analysis using a section of clover to sample. - Source: DEPI, Victoria [View larger image]
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| How can it be used in farm nutrient management?
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- The information that plant tissue testing provides on the nutrient status of plants can play
an important role in nutrient management by:
- identifying plant nutrient deficiencies, toxicity or production limitations where
no visible symptoms occur
- determining if applied nutrients have been taken up by plants
- predicting nutrient problems likely to affect crop production between sampling
and harvest
- allowing the calculation of nutrient export in hay or produce, or the dietary
intake by animals
- providing information on the variation in plant demand for nutrients with time
- As with soil testing, plant tissue testing depends on reliable sampling, analytical and
interpretation procedures:
- Take plant samples from an area representative of the area being grazed
- Use transects
- Take the samples in late winter to spring
- Do not take samples until about 8 weeks after the last fertiliser application
- Any soil should be quickly washed off the plant material with cold water
- Send tissue samples to an accredited
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- It is important to ask when choosing a plant-testing laboratory whether they are a member of the Australian Soil Plant Analysis Council (ASPAC) and if this accreditation applies to all the tests they offer
- ASPAC accredited laboratories meet quality assurance standards for one or more of the tests carried out in their laboratory
- Equally important is asking whether the laboratory has accreditation with the National Association of Testing Authorities (NATA). NATA is an association, which sets and maintains the high standards for the various analytical methods
- Remember to clarify whether they are ASPAC accredited for the particular test you want
- See the ASPAC website - http://www.aspac-australasia.com - to identify if your laboratory is ASPAC accredited
- Tissue testing can be unreliable for testing for some trace elements required for
animal nutrition
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Other related questions in the Brown Book
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Brown Book content has been based on published information listed in the Resources and References sections below
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- Plant Tissue Testing - Section 3.2. Guidelines for developing a Nutrient Management
Code of Practice (2001) - Fertiliser Industry Federation of Australia
- Minor nutrients or trace elements - Section 6.4. What Nutrients do Plants Require?�
Department of Environment and Primary Industries, Victoria
- Trace Minerals - Fertilisers for pastures � Department of Primary Industries, NSW
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- Guidelines for developing a Nutrient Management Code of Practice. (2001) - Section 3.2
Plant Tissue Testing. Fertiliser Industry Federation of Australia.
- Assessing the Nutrient Status of Dairy Pastures. (See Section 7.3 Plant tissue testing) �
Department of Primary Industries, Victoria.
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- What Nutrients do Plants Require?. Section 6.4 Minor nutrients or trace elements �
Department of Primary Industries, Victoria.
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