How to Improve Fertilization by Plant Biochemical Analysis?

The biochemical analysis of plants for the content of macro and microelements performed during the growing season is the key method determining the yielding capacity of plants. Find out what it is all about and what benefits it brings.

How to Improve Fertilization by Plant Biochemical Analysis?

What is plant biochemical analysis?

The biochemical analysis of plants allows for a precise reflection of the current state of plant nutrition and the determination of precise fertilization of crops. Visual inspection of the specimens allows only the identification of typical disease symptoms or mineral deficiencies.

The problem arises when the changes are the result of the loss of several elements. In such situations, it is worth using fertilization diagnostics of plant material. Most often, the leaves are subjected to biochemical analysis, but the chemical composition of the roots, fruits and even buds can also be examined.

It should be remembered that the content of nutrients also depends on the soil in which the plant grows, species, cultivars and the time of sampling for analysis. And in the case of fruit plants, also from the rootstock. All of these factors can play a key role in plant nutrition.

What is plant biochemical analysis?

What are the benefits of plant biochemical analysis?

Chemical diagnostics of the plant illustrates the current nutritional status, and therefore it is used to determine the doses of pre-sowing fertilizers and helps to determine the doses of top dressing fertilizers, both in field and greenhouse cultivation of plants. Hence, the chemical analysis of plants will also be helpful in the hydroponic cultivation of herbs and vegetables.

Often, despite the fact that the fertilization of the crop is carried out correctly, plants may show the effects of an excess or deficiency of certain nutrients. The lack or excess of individual elements may appear in the form of changes in the leaf blade or the entire plant and deformation of the growth tips.

In the case of an imbalance in the uptake of several nutrients, biochemical analysis of leaves, buds, and sometimes, as in the case of grapes, leaf petioles, becomes more and more popular.

The effects of poor fertilization of plants

Too high content of macroelements such as N, P, K, Ca, Mg in the plant is the effect of over-fertilization. An excess of even a single element may result in blocking the uptake of other elements by plants.

On the other hand, reducing the bioavailability of even a single microelement results in deterioration of health and increased susceptibility of plants to diseases and pest attacks, and thus lower and worse yield.

The effects of poor fertilization of plants
It should be emphasized that the excess is more harmful to plants than the deficiency of a given ingredient

Both excess and deficiency of nutrients can be identified by visual changes on the leaf surface. The problem arises when plants are influenced by several factors giving ambiguous symptoms at the same time.

Poor fertilization of plants - effects
Iron and magnesium deficiency causes leaf discoloration

How to correctly take plant samples for analysis?

The reliability of plant material test results largely depends on correct sampling, as the limit numbers developed for a given crop species are closely related to specific plant development phases.

Usually the so-called indicator parts which show the greatest difference in terms of the nutrient part are selected for the analyzes. Most often they are fully developed, healthy leaves, less often leaf blades, petioles, even the main leaf nerve.

Older, lower leaves are selected for the determination of reutilized ingredients, i.e. those that move easily in the plant (N, P, K, Mg). Younger leaves are selected to determine the remaining components (Ca, Fe, Zn, B, Mo). For fertilization diagnostics, we do not use the youngest leaves collected from the shoot tip and the older, first true leaves. Plant parts infested with insects and burned by chemical treatments are also not suitable for diagnosis.

The aggregate sample is taken from places characteristic for arable plants according to the selected scheme.

Scheme for taking plant material
Sampling schemes for analyzes

Samples collected according to the scheme are combined into a collective sample of plant material, which should weigh a minimum of 200-300 g. The sample packed in a plastic bag should be signed and taken to the nearest diagnostic station as soon as possible. The time from sampling to delivery should be as short as possible. For full reliability, samples cannot be taken after foliar fertilization or heavy rains. Samples taken from such plants may give inadequate results.

What micro and macro elements should be determined?

Due to the Liebig barrel principle, the best solution is to determine all elements as well as chlorides that can cause a lot of damage to crops.

Where to perform plant analysis?

Chemical analysis of plants can be performed in an accredited chemical laboratory. You can find a list of US accredited chemical laboratories here.


We are not always able to 100% determine what is happening with the plant. Biochemical analysis of plant material comes to the rescue. Biochemical diagnostics is an increasingly common method used to determine the current nutrition of plants. This method helps to determine the precise doses of fertilization, including foliar fertilization, fertigation or top dressing.

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