Class: Nutritional Disorders
Iron(Fe) deficiency and lime-induced chlorosis
Description and Symptoms
Iron is an important micronutrient needed in small quantities by all plants. Many vital processes such as the production of chlorophyll and nitrogen fixation depends on iron. Iron deficiency is among the most widespread nutritional deficiencies.
Iron is largely sufficient in most soil; however, its availability varies with soil conditions throughout the year and on the plants themselves. Moreover, iron becomes unabsorbable when the soil is not acidic enough.
Because iron chlorosis appears mainly in crops grown on calcareous soil, it is often called lime-induced chlorosis.
Iron is considered as an immobile micro-element, meaning that signs of iron deficiency first manifest during the stage of new growth. The main symptom will be Inter-venial chlorosis of new leaves, which means that the tissue between the veins turns yellow in color, while the veins remain green.
Adding Iron: An effective iron fertilizer for correcting iron chlorosis is FeEDDHA (ethylenediamine-di-o-hydroxy-pheny lacetic acid), known as Sequestrene 138 and works best when applied to the roots via an irrigation system. Sequestered iron is available to plants without adjusting the soil's pH, which is not the case with iron sulfate - another compound that is used to treat iron deficiency.
Avoid over watering since it washes out nutrients more quickly.
Lowering pH: Besides adding iron, it is possible to acidify the soil. Sulfur, urea and organic matter, such as manure and compost, are known to help reduce soil pH.
Acidification using elemental sulfur is the quickest way to lower soil pH and is more effective when implemented into the soil than deposited on the ground surface. Beware that sulfur can also reduce soil pH to a dangerous level. While some plants function well in slightly acidic soil (pH 6.0-6.5), levels below 6 may cause damage to plants.
Caution and careful notice should be taken when using any plant protection products (insecticides, fungicides and Herbicides). It is the grower’s sole responsibility to keep track after the legal uses and permissions with respect to the laws in their country and destination markets. Always read the Instructions written on the label and in any case of contradiction work with accordance to the product label. Keep in mind that information written on the label usually apply only to local markets. Pests control products intended for organic farming are generally considered to be less effective in comparison to conventional product. One must keep in mind when dealing with organic, biologic, and to some extent a small number of conventional chemical products, that a complete eradication of a pest or a disease will often require several iterations of a specific treatment or combination of treatments.