How to detect deficiencies?
Sometimes you have to deal with a reduced yield or lower quality . The plant shows peculiar characteristics. You realize: “something goes wrong with the nutrition of my crop ...”
If you intervene quickly, you can still limit the damage. But then it is important to nourish the plant with the right nutrient. To find out which one, in this article we will go deeper into causes, risk factors and symptoms of a deficiencies..
How does a deficiency of nutrients arise?
The causes of deficiencies can be:
- There are not enough nutrients in the soil. Either because of too low nutrient content in the soil itself or too low fertilization.
- Restricted soil availability of the nutrients. A number of soil characteristics sometimes reduce the availability of the nutrients such as: pH, clay content, a too high salt content, ....
- Imbalances can reduce or block the absorption of other elements that are sufficiently present in the soil. For example, if the phosphorus fertilization is too high, the plant absorbs zinc more laboriously.
- The climate also has an important influence. For example, excessive rain can wash out the highly soluble nutrients. Or vice versa, nutritional elements will become immobile because of drought. Cold weather often reduces the root activity, making it harder for the roots to absorb the nutrients.
- Plant development and condition also play a role: diseased plants or plants in recovery will absorb the available nutrients less efficiently.
- Compacted soils, nematods , asphyxiation due to poor drainage, ... these aspects influence the root development and thus reduce the efficiency of the roots.
How do you tackle a deficiency? Reacting quickly is important.
What do we do when we notice symptoms? Doing nothing is not an option. A plant with deficiencies does not have a good photosynthesis and will eventually produce less. A lack of nutrients therefore disrupts various processes and affects both the quantity as the quality of our production.
It comes down to respond as quickly as possible when we observe symptoms. But which element should we apply? That’s always the big question.
Leaf and sap analyzes naturally provide 100% certainty about the condition of the plant, but they take up valuable time. It often takes several days to weeks before the results of the laboratory are available. If you don’t intervene immediately, the condition of the plant will become worse and it will only be harder to treat the deficiency.
The worse the deficiency and the longer the plant suffers from it, the more difficult it will become to treat the plant and the more difficult it is for the plant to recover.
- Visual diagnosis
If you want to intervene quickly, a visual diagnosis is the first step in assessing which element to apply. This visual approach is not always evident. That's why we give you here a few tools to better recognize the symptoms.
The right approach for a correct diagnosis
To define a specific deficiency, you must first take into account a series of elements and observations. Only after that general check can you define which nutrient is lacking for your crop.
- What are the initial symptoms?
The first symptoms are the most typical. It is therefore important to recognize them quickly. Because as soon as the deficiencies develop further and the symptoms become more severe, the symptoms of all elements will become very similar. They will become visible on as well young as older leaves and your crop will have to deal with yellowing followed by necrosis, a general growth stop, etc.
- Answer these 6 important questions.
- On which leaves appear the first deficiency symptoms?
- What are these symptoms? Yellowing or another discoloration (e.g. red), necrosis, deformation, ...?
- What is the pattern of these symptoms? Does the yellowing cover the entire leaf or only the area between the veins? How green do the veins remain?
- Is the size and shape of the leaves normal or are they smaller and deformed?
- Furthermore, is the growth of the plant normal, are the internodes average or shorter, thicker, ...?
- Are there any symptoms on the other parts of the plant, such as deformation on the meristems, poor flowering or poor fruit set, on the fruits, ... ?
- Do you know the characteristics of your plant and its environment?
Extensive information about your crop and its growing conditions also helpfull to determine the possible deficiency. The crop sensitivities indicate for which elements your crop is extra susceptible. You’ll find the crop sensitivities on our crop pages. Also information about the soil, the weather conditions, etc. will also give indications on which elements are possibly more difficult to absorb.
- Are we dealing with specific symptoms?
Some symptoms are very typical and only occur on a specific crop. For example, a manganese deficiency leads to black spots all over the leaf in potato. This specific symptom only occurs on potato and can’t be generalized as a symptom for manganese deficiency in other crops.
- Or is it a combination of ...?
If a crop suffers from several deficiencies at the same time, this can cause confusion because the symptoms will become less specific and more difficult to recognize. Keep this in mind.
Moreover, not all symptoms on our plants are always the result of a nutritional problem. They can also be the result of diseases, infections, stress, .... This is important to always keep this in mind.
An important indicator: the mobility of the nutrients within the plant
The mobility of the nutrients within the plant will determine where the first symptoms appear.
- If an element is mobile in the plant, such as potassium, the plant will transport the nutrients from the oldest leaves to the new growth points. This way, the deficiency will not jeopardize the growth and development of these growth points. The first symptoms of the deficiency will then appear on the oldest leaves. The oldest leaves serve as a temporary storage for this element.
- If an element is not or not very mobile in the plant, such as iron, the plant can no longer move this element. The young shoots and leaves are then faced with an iron deficiency if the roots do not sufficiently absorb this nutrient.
It is useful to take this knowledge into account to determine the deficiency correctly. It will allow you to immediately include or exclude some nutrients as the possible lacking nutrient during your first visual diagnosis.
Below is a table with an indication of the mobility of the different elements in the plant. It allows you to estimate which deficiency you are facing in your crop. . Please note there are differences between different crops.
First symptoms on the oldest leaves or on the whole plant
First symptoms mainly on the oldest leaves, sometimes more general
First symptoms mainly on the youngest leaves, sometimes also on the more developed leaves
First symptoms on the youngest leaves and on the growth points
In our next blog post we will explore more the typical symptoms of deficiencies for each specific nutrient.
With these general indications in mind, you can already draw a first conclusion. In case of any doubt or ambiguity, please call in the assistance of our specialists. Our team is ready for a visit on the spot to analyze how we can optimize your harvest and eliminate deficiencies. Mail or call us at any time!