Plant sap analysis

More in this section

• Green Maintenance
• Regenerative Agriculture
• The pyramid of plant health
• Plant sap analysis
• Foliar fertilisation

Today, it is possible to quickly find out about the health of the plant through plant sap analysis, which provides information about the actual uptake of nutrients by the plant. This reveals important information about the health of the plant. An optimal and balanced uptake of nutrients has a positive effect on the natural disease resistance of the plant and, for example, on the quality, consistency and shelf life of the fruit.

The method of correct analysis is the starting point

Enables immediate correction of nutritional excesses or deficiencies

In the past, dry matter analysis has always been used, but in this case, a deficiency in nutrient uptake will only be revealed 4 to 6 weeks after the actual nutrient deficiency has been caused. This is why fertilization adjustments often come too late. By analyzing the sap of the plant, a nutrient deficiency will be revealed within a few days. This is why plant sap analysis is a powerful tool for managing and adjusting fertilization strategies quickly and accurately.

How to perform the analysis

Collect at least 150 g of old leaves and at least 150 g of mature young leaves by 09:00 in the morning and close them. Make sure that they are dry and seal them separately in a transparent bag so that the air is extracted. In the case of herbaceous essences, collect at least 150 g of the aerial part of the plant above the colander. Apply the label with the botanical name of the culture and send it to the laboratory.

How to interpret the results

Depending on the crop, in addition to the absolute value measured, the graph offers three colons with concentration bars for each element. The first column indicates deficiencies, the second is the correct average values ​​and the third is excessive values.

As a general rule, you should always check that the values ​​are in the range of the average column, with the exception of sugars and nitric and ammoniacal nitrogen.

In fact, the greater the amount of sugars present in the plant, the greater the plant's energy reserves. Conversely, an excess of nitric and ammoniacal nitrogen makes plants fragile.

To optimize photosynthesis, all elements must be kept in balance.

In particular:

1. Avoid excess nitrogen because it often creates imbalances, causing overgrowth, diluting sugars and therefore reducing the plants' resistance to disease and attracting insects in particular. The total value of nitrogen must remain within the average range; the less ammoniacal and nitric nitrogen the better the health of the plant and its ability to transform nitrogen into amino acids and therefore into proteins. They must not exceed 30%.
2. Another aspect concerns the four bases (K, Ca, Mg and Na) and above all the ratio between K/Ca, K/(Ca+Mg) and K/Mg because an excess of potassium for example can create imbalances in the absorption of another element such as magnesium or in calcium and ammonium. When forming fruit a good strategy is to supply the calcium by day 9-12 and then supply the potassium afterwards. In this way a fruit is formed with a tough skin due to the abundance of calcium and then increases in volume due to the abundance of potassium. A contrary strategy would create fruit with a fragile skin that would not keep well and would be more attractive to insects.
3. Nitrogen should be combined with sulfur in a 10:1 ratio and molybdenum to fix it in the soil along with humic substances.
4. There is no need to add sodium (Na), chlorine (Cl) and aluminum (AL) because the plants do without.
5. On the other hand, it is very useful to keep the trace elements in balance because they have different functions within the plant and even make them resistant to biotic environmental stresses.