HOW TO IDENTIFY THE SYMPTOMS OF NUTRIENT DEFICIENCY IN CULTIVATION.

Hello friends of steemit in this opportunity I am going to talk to you as we can identify the symptoms of lack of nutrients in our crops. Throughout the growing season, plants may exhibit unusual coloration, growth retardation, leaf damage or defoliation. Often these visual symptoms are due to nutrient deficiencies, which reduce yields and crop quality. The recognition of visual symptoms during the growing season and the identification of production problems before harvest allows producers to plan post-harvest steps that will help prevent similar problems with the following crops. The most visible symptoms of nutrient deficiency can include a yellowish color on the leaves, and loss of leaves. Soil conditions can make nutrients less available, and in poor soils, plant roots may not be active enough to compensate for reduced availability of nutrients. In sandy soils, for example, continuous washing by rain and irrigation eventually depletes the few available nutrients. The greater or lesser richness of the soil will affect the plants according to the plant species, since some plants consume more nutrients, while others, such as cacti, grow well in poor soils.
Although the soil contains the necessary elements, other elements may block them by chemical effects called antagonisms:
• Excess Potassium reduces the availability of Magnesium.
• Excess Magnesium may induce a lack of Potassium.
• Excess Calcium can interfere in the assimilation of Magnesium.
• Excess Sodium produces deficiency of Calcium and Magnesium.

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THE EFFECT OF PH LEVEL
Another common problem is the inadequate soil pH. Both a high pH and a low pH can cause deficiencies or toxicities due to excess. The pH plays an important role in the availability of nutrients. PH affects most reactions with soil particles and other nutrients. The most affected by pH are micronutrients, but the absorption of other nutrients, such as calcium and magnesium, is also affected (absorption is reduced at a low pH).
Nutrient deficiencies are induced when the pH is higher or lower than the recommended pH range for individual plants. The blocking of nutrients is influenced by the pH of the soil. Blocking refers to the reactions of soil particles with nutrients, which render them unavailable to plants.

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IF THE SOIL IS ACID (low pH, less than 6.5), there may be deficiencies of Calcium, Magnesium, Phosphorus, Molybdenum, and Boron. A pH of 5.5 or less can cause deficiencies of Calcium, Magnesium, Phosphorus, Molybdenum and Boron or cause toxicities of Manganese, Zinc, Aluminum and Iron. To solve the lack of these elements, it is necessary to provide them with fertilizers and try to raise the pH by adding ground limestone (whitewash).

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IF THE SOIL IS NEUTRAL (pH between 6.6 and 7.5), there is an optimum availability of all the nutrients that the plants normally need in terms of pH. But even if the pH is favorable, there may be shortcomings if the soil is poor in nutrients.

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IF THE SOIL IS BASIC OR ALKALINE (pH greater than 7.5) it is very likely that there are problems, especially with acidophilic plants because in alkaline soils several essential elements are blocked for every vegetable. In basic soils, there may be deficiencies of Iron, Manganese, Zinc, Copper, Phosphorus and Boron. In these soils, they can be supplied by fertilizers in the form of chelates containing the nutrients that are lacking and, in addition, lower the pH of the soil or substrate and / or lower the pH of the irrigation water if it is being irrigated with alkaline water.

THE IRRIGATION MANAGEMENT
Excess water affects the availability of nutrients for the plant. Excessive irrigation results in a lack of oxygen in the soil and in a poor root system.
The efficiency of absorption of nutrients is reduced and nutritional deficiencies, such as iron deficiency, can be induced. In addition, excess irrigation leaches nutrients from the root zone. The lack of water can also affect the availability of nutrients for the plant. When the soil is dry, the movement of water through it is reduced. Since nutrients move in the soil along with water, their availability to the plant is greatly reduced.

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SYMPTOMS OF PHOSPHORUS DEFICIENCY
Plants with phosphorus deficiency are smaller and grow more slowly than plants with adequate amounts of phosphorus. Phosphorus deficiency is normally visible in young maize plants, because the nutrient moves and moves easily in the plant.
The affected plants have a dark green color and the tips and margins of the older leaves have a reddish-purple color. The new leaves will not have this color. In addition, the number of shoots decreases, forming fine and short stems with small leaves. There is also a lower root development, less flowering and less fruit set.
The symptoms of deficiency almost always disappear when the plants grow and reach a meter or more in height.
The detection of phosphorus deficiency can sometimes be difficult, because some corn hybrids tend to show purple tones in the early stages of growth although phosphorus nutrition is adequate and other hybrids do not show color symptoms although the Inadequate amount of phosphorus severely limits yields.

THE DEFICIENCY OF PHOSPHORUS IS COMMON:
• on very humid or very dry cold soils;
• when phosphorus is applied where the roots can not absorb it;
• where the growth of the roots is restricted due to compacted soils;
• when the roots have been damaged by insects, herbicides, fertilizers, or farming practices.

SOLUTION
To solve the phosphorus deficiency, it is necessary to apply a fertilizer rich in phosphorus. For best results, bury it slightly so that it is closer to the roots. In limestone soils, apply higher than normal phosphoric fertilization to avoid retrogradations to insoluble phosphorus. The excess of this element does not seem to cause damage.

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SYMPTOMS OF DEFICIENCY OF IRON
Iron, one of the most abundant elements of the planet, is necessary for all living beings, but in small quantities. In high amounts, iron is toxic. Iron deficiency in plants can usually be detected by the chlorosis of the hours. The young leaves show the most intense chlorosis and the leaves with severe deficiency turn yellowish or completely white as they expand.

CAUSES
Normally deficiencies result from the blockage of iron in the soil due to pH. In the limestone soils, which have high pH, ​​the iron is quite insoluble and therefore, the roots can not absorb it. Irrigation with hard waters (limestone) alkalizes the substrate and blocks iron and other micronutrients.

SYMPTOM
• Iron chlorosis manifests first in young leaves, less in nerves, which remain green. Old leaves may also have yellowing symptoms. Later, the leaves crumple and fall.
• Chlorosis is not uniform: in the same plant you can see branches with quite strong chlorosis and healthy branches.
• Roots of brown color and particular smell as a result of the secretion of phenolic compounds.

SOLUTIONS
Prevent: find out the pH and limestone content of the soil. If the pH or level of limestone is high, do not plant acidophilic or calcifuge species.
Apply iron chelates through the root or foliar route, avoiding the insolubilization of iron in the soil. It is important to apply the indicated dose to avoid causing burns.
Micronutrient foliar fertilizers are efficient since the plant only needs small amounts of iron.
Trunk injections (a more professional method), although efficient, can be expensive and applicable only to trees of a certain age.
Acidify the soil to release insolubilized iron and make it available to the roots.
Acidify the irrigation water with citric acid.

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MAGNESIUM DEFICIENCY
Magnesium, the central atom of the chlorophyll molecule, gives the plant its typical green color. The deficiency of magnesium is different from others that have been discussed in this series because it affects the old leaves first, although it can also alter the young leaves if the deficiency becomes serious.

CAUSES
A high level of potassium in the soil can cause magnesium deficiency, since these are antagonistic elements. That is, if there is a lot of potassium in the soil, the amount of magnesium that the plant can absorb is limited, even if there are sufficient amounts of magnesium in the soil.
SYMPTOM
• On old leaves:
• yellowing between the nerves and the edges
• strong chlorotic lesions between the veins, sometimes violet
• a green triangle forms at the base
• the leaves below are the most affected
• Later, the same thing happens to young leaves.
• Finally, the leaves fall.

SOLUTIONS
Although treatments may take a few days to show results, there are several ways to improve or eliminate magnesium deficiency in the crop:
Use fertilizer that contains magnesium.
In severe cases, magnesium sulfate can be applied.
Apply a spray of a 2% magnesium sulfate solution to the foliage every ten days.
Use potassium fertilizers in moderation during the growing season to prevent magnesium deficiency.

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NITROGEN DEFICIENCY
Nitrogen gives vigor to plants and plays an important role in the abundance of leaves. It is an element that moves as well on the ground as on the ground. Since nitrogen deficiency is a frequent occurrence in nature, some plants change because of it. Some alter the regulation of their hormones in order to increase radical growth. Others close the pores of water movement, resulting in water stress and decreased growth.

SYMPTOM
• As with magnesium deficiency, chlorosis begins in old leaves, although it can affect the whole plant.
• Early senescence of old leaves
• The old leaves turn pale green and then yellow.
• The lower leaves fall if the deficiency is serious and continued.
• The plant does not grow.
• Scarce foliage
• Rhaetic and yellowish appearance of the plant
• Sometimes it blooms with a certain abundance.
Be careful not to confuse this deficiency with other problems (such as nematodes, root asphyxiation, among others) that may produce some of the same symptoms.

SOLUTIONS
• Apply nitrogen fertilizers, such as complete fertilizers N-P-K.
• Use nitrogen in the form of nitrates for a faster solution.
• Use organic fertilizers such as mulch, guano, earthworm humus, etc. to take advantage of the nitrogen they provide during decomposition.

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ZINC DEFICIENCY
Zinc deficiency (Zn) in corn produces light interveinal slats or a whitish ribbon from the base of the leaf that extends toward the tip. The edges of the leaf, the area of ​​the central vein and the tip of the leaf usually remain green. The plants suffer a growth retardation during the first weeks because the internodes shorten. The deficiency appears later in the beans when the flower buds fall or in the cotton, when the growth and fruit set are delayed. Therefore, most crops need a supply of Zn immediately available both for growth at the beginning and end of the season and for the development of yield. Zinc deficiency worsens if the pH of the soil is high, if the soil has low organic content, and if the soil is cold and humid. Often only a few kilos of zinc are needed per hectare and it is important to distribute it evenly.

VISUAL SYMPTOMS OF ZINC DEFICIENCY
• Interventional necrosis
• Yellowing of new leaves
• Development of pitted surfaces on mature leaves
• Gutation
• The leaves become small

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CALCIUM DEFICIENCY
The symptoms of calcium deficiency appear first in the leaves and young tissues. This deficiency inhibits the growth of the plant and makes the plant look more like a bush. The younger leaves are usually small and deformed, with brown chlorotic spots that develop in the margin of the leaf. These spots spread and finally reach the center of the leaves. The ribs turn brown as well. A typical characteristic of calcium-deficient plants is dark veins in completely necrotic leaves. The leaves may look faded and broken. In addition, the growth of the root meristems stops due to lack of calcium.

IMPORTANT PROCESSES
• Calcium is extremely immobile in the plant and therefore especially affects new tissue, especially meristems.
• Calcium deficiency is difficult to handle and is often a problem in the production of tomato and pepper, as it results in the rotting of the fruit apex.
• Calcium deficiency can be a problem in acid soils. The technique of liming improves the pH, but only on the surface soil (10-30cm). When the roots extend beyond the surface soil, they suffer from the lack of calcium in the deeper layers, which results in a root growth arrested.

VISUAL SYMPTOMS OF CALCIUM DEFICIENCY
• Curled leaves
• Deformation and death of the tips (meristems), which results in the production of many branches
• Death of the apexes of the root
• Chlorosis inside the margins of the leaf
• Dark colored ribs

IN CONCLUSION
There are many factors that could affect the nutritional status of the crop, some of them are described in this article. In many cases it is more practical to treat the cause of the deficiency. The visual identification of nutrient deficiencies can be used as a practical and quick diagnostic tool. However, it has a great disadvantage: once symptoms of deficiency appear, there is already a greater effect on the performance, growth and development of the plant.

SOURCE:
https://www.smart-fertilizer.com/articles/nutrient-deficiencies
https://www.hortalizas.com/miscelaneos/deficiencias-de-zinc-y-calcio/
https://www.hortalizas.com/nutricion-vegetal/sintomas-de-deficiencia-de-hierro/
https://www.hortalizas.com/nutricion-vegetal/symptoms-national-deficiencies-nutrients-magnesium-and-nitrogen/

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