Hemm ferric chlorosis is a typical physiopathy due to defiċjenza tal-ħadid, which manifests itself with a diffuse sfurija tal-weraqwhich leads to a general deterioration of the plant. Usually, this chlorosis shows itself in the calcareous soilswhere the iron present in the soil is difficult to absorb due tosistema ta 'għeruq. To solve this problem it is possible to intervene in the first place by improving the conditions of the ground, increasing its organic substance present. If this is not enough, iron chelates can be used, prodotti permessi fil-biedja organikawhich appear as easy-to-use powder in micro granules.
In this article, therefore, we analyze this pathophysiology and how to remedy it.
What is ferric chlorosis
The lack of iron in the soil, or its poor assimilability, causes iron chlorosis, which is a physiological disorder not due to the attack of pathogens or parasites. An obvious symptom of this plant problem is leaf yellowing. Attention, as we have seen talking about the yellow lemon leavesthis symptom can also be due to other causes, such as a lack of nitrogen or lack of it protezzjoni mill-ġlata.
Isfar tal-weraq
The yellow leaves due to iron chlorosis have a peculiarity that makes the physiopathy recognizable. At the beginning, in fact, it is not the whole leaf that turns yellow, as the veins are spared. If you observe a yellow leaf, but with the veins still green, you can certainly trace the cause to ferric chlorosis. Over time, then, if no action is taken, the entire leaf surface turns yellow, until it becomes whitish.
The importance of assimilating iron for plants
Iron (Fe) is a metal that plays a decisive role in regulating several biochemical processes of plant life. It is an element that falls within the processes of biosynthesis of chlorophylland is also an important cofactor for the activity of enzymes involved in processes such as the metabolism of carbohydrates, cellular respiration, the reduction of nitrites and nitrates.
The presence of iron helps the fixation of atmospheric nitrogen gas in the soilanother important element for the regular growth of plants and trees.
Consequences of ferric chlorosis
The symptoms of iron chlorosis can occur on the new vegetation of previously healthy plants, bringing out a disorder linked to the low mobility of iron in the soil / plant ratio. The lack of this element causes a slowing down of the vegetative activity, which is associated with an anomalous accumulation of nitrates. The photosynthetic process is altered, due to the inability of the iron-deficient plant to synthesize chlorophyll and assimilate nitrates. Hence, leaf yellowing.
The plants most prone to iron chlorosis
Not all plants have the same sensitivity to iron chlorosis. Among the most susceptible we have: ħajja, frawli, legumi, tela, tadamcitrus fruits (lumi, klementini, larinġ, grejpfrutmandarins), ħawħ, Madankollu, Kiwihydrangea, isfarġel, azaleawisteria.
The plants less susceptible to iron deficiencies, on the other hand, are generally grasses (barley, qamħwheat, wheat, oats, etc.), rice, patata, Siġra tat-tuffieħ, pitraviqoton u ħjar.
How iron behaves in calcareous soils
In addition to a greater or lesser sensitivity inherent in the botanical species, it is the plants cultivated in calcareous soils that are most at risk of ferric chlorosis.
The element iron (Fe) is contained in the soil in very high percentages, about 25% of the weight of the soil. In reality, the soluble fraction that can be absorbed by plants is far less than their needs, especially in calcareous soils, characterized by high pH levels. A high pH makes iron solubility and therefore its absorption even more difficult.
In calcareous soils, which have a percentage of total limestone higher than 15-18% and above all active limestone higher than 5%, the pH fluctuates between 7.5-8.5, therefore it is very alkaline. The soil therefore tends to perform a very chlorinating action, with the iron minerals present very stable. The stability results in a very low concentration of soluble iron (and available for crops).
What are iron chelates
Iron in the soil can be easily absorbed by plants thanks to the presence of soluble compounds, or soluble chelates. These protect the metal from precipitation processes that make it unavailable. The substances that act in this way can be of natural origin (humic and fulvic acids, leonardite) or of synthetic origin, i.e. the chelates allowed by the legislation (Legislative Decree 29 April 2006 n. 217) and indicated with abbreviations: Edta, Dtpa, Eddha, Heedta, Edcha, Eddhsa.
Sustanzi umiċi
Humic and fulvic acids are increasingly used as organic fertilizers. The humified organic matter content of the soil is a factor that can have a great influence on the availability of iron. Humic acids and fulvic acids limit the precipitation of metals, activating chelation reactions between iron and the numerous electron-donor functional groups that constitute them (-CO-OH, -OH, -C = O, -NH2).
The root systems of plants and microorganisms present in the soil are then able to produce other chelating substances (organic acids, amino acids, peptides, etc.). These, although not very effective in attacking iron-containing minerals in a short time, are instead able to tear the metals from the humified fraction of the organic substance, forming chelates that are easy to absorb for the roots. Fertilizers based on humic and fulvic acids are completely natural and can be found in specialized stores.
Chelated iron
Even more effective against ferric chlorosis are the synthetic iron chelates, which appear as a red powder in microgranules. They can be dissolved in water through the system irrigation, or give as it is by amending the dust to the ground. These chelates solve the problem of chlorosis rather quickly, as they are readily available and absorbable by the roots. The advice is to use them periodically, to improve the use of iron. In orchards, for example in a citrus grove, they can be given in early spring, with the resumption of vegetative activity. In horticulture and in very deficient soils, chelated iron can be given at the beginning of the cycle (even in the middle, if needed). If you are going to buy them, you can find them here. For dosages and for a safe result, the instructions on the label must be followed precisely.
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