Plant materials can be tested for mineral nutrients to monitor fertiliser programmes and identify imbalances.
About this Testing
Why Test Plants
Plant material can be tested for mineral nutrients or agrichemical residues.
Plant analysis is a valuable diagnostic and monitoring tool that should be used to complement soil analysis. A soil test shows what soil nutrients are available to the crop, while a plant test shows what nutrients the crop has actually taken up. In this way, plant tests provide a more reliable assessment of crop nutrient status.
Plant analysis can be used in two ways:
To routinely monitor nutrients to help sustain optimum levels and thus avoid nutritional disorders
To identify nutrient deficiencies, toxicities or imbalances. Low plant nutrients are often due to low soil nutrient levels, but this is not always the case.
The rate of uptake of nutrients by the plant can be influenced by:
rainfall and soil temperatures
soil structure, drainage and pH levels
interactions of mineral elements
the presence of disease or insect pests.
Interpretation criteria are specific to plant species, part of plant sampled and growth stage of the plant.
Nitrate Petiole Testing of Crops
To manage the crop fertility, the leaf petioles of crops such as potatoes, grapes and strawberries can be tested. Each sample requires forty leaf petioles to be randomly selected from plants across the block. It can also be useful to analyse for P, K and Mg. Refer to the Crop Guides below for specific sampling instructions.
Taking a Sample
Appropriate sampling methods must be used for the results to be meaningful. Horticulture, pastoral farming, arable and organic growers have specific requirements for the types of samples taken and tests performed. Sampling instructions are available on a plant species basis in our Crop Guides.
Hill Laboratories suggests that you use a consultant or fertiliser specialist to oversee your soil and plant testing program. However, you can order a complimentary soil & plant test kit (including sample bags, a courier bag, instructions and a request form) from the laboratory.
Guides and Supporting Information
For more comprehensive information such as nutrient function, deficiencies and toxicity symptoms and what tests to order, please see our Crop Guides.