Taking Plant Samples

The acquisition of leaf samples at various stages of plant development is essential for ascertaining the nutritional status of plants and evaluating the efficacy of implemented fertilization programs. This process enables the identification of deficiencies, excesses, or imbalances in nutrient elements present within plant leaves. To ensure the acquisition of meaningful data, it is imperative that the collected plant samples accurately represent the sampled area. The purpose for which the plant samples are collected significantly influences the interpretation of the plant analysis results.

Considerations for Plant Sample Collection:

• Typically, the youngest fully expanded leaves are selected for sampling.
• Plants within the sampling area should exhibit a uniform growth stage.
• In cases where a nutrient deficiency is suspected, it is advisable to collect a separate sample from healthy plants in the vicinity for comparative analysis.
• To ensure representativeness, sampling should encompass approximately 20% of the total area.
• Leaf samples can be collected at any time of day. If any fertilizer or pesticide application has been made to the leaves, it should be explicitly stated on the label. It is recommended to avoid sampling from these plants if possible.

The most reliable approach involves annual collection of plant samples during the same growth stage, followed by data storage and subsequent revision of the fertilization program based on the obtained results. This practice facilitates the detection of latent deficiencies and mitigation of potential yield losses.

Sample Bagging and Storage:

If plant samples are stored in nylon bags, it is necessary to perforate the bags at multiple points using a pen. This allows for the escape of moisture, preventing damage to the enclosed paper label. Additionally, this measure helps to prevent the overheating of plant samples. In situations where plant samples cannot be transported to the laboratory on the same day, they can be temporarily stored in the vegetable compartment of a refrigerator.

Specific considerations should be taken into account when selecting leaves for sampling from different plant species. Sampling procedures for certain plants are outlined below:

Grapevine:

During the flowering or fruit-set period, the leaf opposite the first cluster is sampled. Sampling should be conducted by encircling the plant and collecting leaves from all directions.

Olive:

In November and December, leaves should be collected along with their petioles from the current year’s terminal shoots.

Citrus:

Sampling should be carried out in September and October, targeting leaves from non-fruiting shoots of the current growth flush.

Tomato:

Leaf samples are collected when the first fruit reaches the size of a walnut. Fully expanded leaves located closest to the growing point should be selected for sampling.

It is crucial to transport the collected leaf samples to the laboratory promptly and without causing any damage or overheating. Any foliar applications made to the plants in the sampled area must be clearly indicated. It is important to emphasize that the successful utilization of leaf analysis results hinges upon adherence to proper sampling procedures and objectives. The collected samples must accurately represent the area from which they were obtained.