Iron is an essential micro nutrient that plays an important role in metabolic processes such as proteins and DNA synthesis, respiration and photosynthesis.
Iron plays a significant role in various physiological and biochemical pathways in plants. It serves as a component of many vital enzymes such as cytochromes of the electron transport chain, and is thus required for a wide range of bio chemical functions including energy transfer. It is an important component in the nitrogenase enzyme reduction system that aids in nitrogen fixation, reduction and lignin formation.
Iron is a photosynthetic nutrient that is involved in the synthesis of chlorophyll. It is essential for the maintenance of chloroplast structure and function and it acts as an oxygen carrier in respiration and photosynthesis.
Reduced iron Fe2+ the ferrous form of iron is biologically available to plants.
Iron is quickly oxidize into Fe3+ in aerobic Soils, Soil’s above a pH of 5.5 and in the presence of water, making it difficult to remain in a reduced biologically available form. Amino, humic/fulvic chelation and the introduction of siderophore producing micro organisms such as Trichoderma can greatly increase the bioavailability of iron.
Factors that can reduce iron availability include high soil pH, poor soil aeration, low organic matter, poorly drained and or compacted soils. Alkaline soils PH<7.0 or acidic sandy soils which also reduce iron availability due to leaching and oxidation. Deficiency symptoms may also be exacerbated by excess amounts of copper, manganese, phosphorus, sodium, zinc or by a shortage of potassium.
Deficiency symptoms of iron include interventional homogenous chlorosis of foliage, veins remain green, areas in between become pale or yellowish white, and stunted growth. Symptoms show up in terminal leaves (top leaves) because iron is a mobile necrosis of the tips and leaf margins will occur as deficiency symptoms progress.