Plant material analysis is an extremely useful tool in agricultural production. It is not only used to monitor plant nutrition, but can also identify nutrient deficiencies and/or imbalances. This enables farmers to apply fertilizers more efficiently in order to meet the plant’s nutrient requirements. In addition to improving crop production and avoiding unnecessary use of large amounts of fertilizer, correcting nutrient deficiencies also helps reduce production costs.
Soil analysis or plant material analysis?
Soil analysis is necessary when establishing a new orchard or plantation, as well at regular intervals to monitor nutrient levels in the soil. It is recommended to perform soil analysis every 3–5 years. Due to the physical and chemical properties of the soil that influence the plant’s ability to absorb nutrients, differences often occur between nutrient levels in the soil and in the plant. For this reason, plant material analysis becomes essential.
When should plant material be analysed?
- Routine analyses – Analysis of leaf and/or petiole samples collected during the appropriate period, every 2–3 years, for the purpose of monitoring nutrient levels in the plant and adjusting the fertilization program for a specific crop.
- Problem diagnostics – In cases where visible changes (symptoms) appear on the leaves indicating nutrient deficiencies, samples are collected from plants showing symptoms as well as from those without symptoms (“healthy plants”).
Which nutrient concentrations are measured?
Analysis results include the concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, copper, iron, manganese, zinc, and molybdenum.
Recommended Sampling Procedures for Fruit and Vegetable Crops
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Crop
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Growth stage
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Plant part to sample
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Number of leaves (plants) per sample
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Fruit Trees and Grapevines
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Olive
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1. Winter dormancy
2. Summer dormancy
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Youngest fully developed leaf from the middle part of the current season’s shoot (without fruits)
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50–100 leaves (5–10 plants)
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Cherry, Sour Cherry, Apple, Apricot
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Mid-season – summer
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Leaves from the middle part of the new shoot
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50–75 leaves (5–25 plants)
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Pear, Plum
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Mid-season – summer
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Leaves from the middle part of the new shoot
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50–75 leaves (5–25 plants)
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Peach, Nectarine
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Spring – fruit set
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Leaves from the middle part of the shoot
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25–50 leaves (5–20 plants)
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Strawberry
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Flowering
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Youngest fully developed leaves
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25–50 leaves (10–25 plants)
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Grapevine
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1. End of flowering
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Petioles and leaves opposite the first cluster
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50–100 petioles and leaves
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2. Beginning of veraison
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Youngest fully developed leaves
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15–25 leaves (15–25 plants)
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Crop
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Growth stage
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Plant part to sample
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Number of leaves (plants) per sample
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Tomato (protected cultivation)
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1. From flowering to fruit set
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Leaf and petiole opposite the terminal flower cluster
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15–20 leaves (15–20 plants)
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2. From fruit set to fruiting
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Youngest fully developed leaf
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Tomato (open field)
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From flowering to fruit set
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Leaf opposite or below the terminal flower cluster
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15–20 leaves (15–20 plants)
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Pepper
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Entire growing season
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Youngest fully developed leaves
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25–30 leaves (25–30 plants)
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Cucumber, Watermelon, Melon
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1. Before fruit set
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Leaves on the main vine near the base of the plant
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15–20 leaves (15–20 plants)
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2. Rest of the growing season
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Youngest fully developed leaves
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Leafy Vegetables (lettuce, spinach, etc.)
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Entire growing season
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Youngest fully developed leaves
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25–30 leaves (25–30 plants)
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Potato
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Before or at the beginning of flowering
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Youngest fully developed leaves (3rd–6th leaf from the top of the plant)
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25–35 leaves (15–20 plants)
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Leaves should be delivered fresh or dried at room temperature. Before drying, the leaves should be quickly washed (< 1 min) in a highly diluted detergent solution, rinsed several times (with tap or distilled water), and placed on paper towels to dry.
For all other crops, sampling procedures and timing, please contact:
Dr. Branimir Urlić
Tel.: +385 21 434 478
E-mail: usluge-tlo@krs.hr
Laboratory for Soil and Plant Nutrition
Institute for Adriatic Crops and Karst Reclamation
Put Duilova 11
21000 Split