Sampling for apple tree foliar analysis must be done by February 15

Apple tree foliar analysis is one of the recommended practices for correctly planning orchard fertilization, as it provides a picture of the plant's nutritional status. Leaf collection must be done from January 15th to February 15th. The researcher at the Epagri Experimental Station in Caçador Leandro Hahn explains the procedures for this collection, which will offer a more accurate and reliable result.

“Foliar analysis is something similar to what the doctor asks the patient to do, like a blood test or an MRI. Through leaf analysis, it is possible to identify any nutrient that is deficient or in excess. Both situations interfere with productivity and quality of production”, describes the researcher.

Leandro explains that care when collecting leaves is essential. First, it is important to define what a sample is. It is necessary to separate the cultivars – that is, the sampling of Gala is different from Fuji, for example. It is also necessary to distinguish the rootstock: for each one, it is a sample of leaves. And, finally, separate by orchard age.

“For each of these variables, there is a different collection, a different sample”, explains the researcher. Each sample is made up of one hundred leaves collected from 20 plants in the orchard, that is, five leaves from each plant.

It is essential to avoid collecting plant leaves from the edge of the orchard – it is recommended to remove all plant leaves from the inside. Leaves should also not be taken from the lower or upper parts of the plant: always in the middle part. The fruit grower has to collect the entire leaf, made up of the blade (the green part of the leaf) and the petiole (the branch that attaches the leaf to the tree).

Another precaution is to avoid collection after heavy rain. You have to wait at least a week to harvest the leaves. This same period must be respected after the application of pesticides or foliar fertilization. Leaves that are mechanically damaged, attacked by a disease or insect should not be part of the sample. Another recommendation is not to collect leaves in orchards close to roads, because of the dust. It is also recommended to avoid collecting leaves from thieving branches.

The hundred leaves that form a sample must be packed in a paper bag and placed to dry in the shade for about five days. After that, this sample must be delivered to one of Epagri's municipal offices.

The result of the analysis will be released in about a month and the interpretation must be made with the help of an agronomist. “Based on the results of the foliar analysis, the professional who assists the producer must make a recommendation for corrective fertilization, if necessary, either during the crop cycle, especially via foliar use, or in the following production cycle, via soil correction”, concludes Leandro.