Micronutrients
Megan Blauwet
- Identify functions of micronutrients in the plant
- Match soil properties with potential deficiencies
Micronutrients make up a small percentage of the overall plant, but are critical for growth. Most are used in enzymes rather than structural components of the plant.
Extreme cases, like extreme pH values, peat soils, or otherwise unusual conditions makes deficiencies more likely. Since deficiencies are resolved by small quantities per area, they may be added to other mixes or strategy that allows more effective spreading. Materials such as manure or composts may be used, depending upon analysis.
There are eight micronutrients that are essential for plant growth. These include boron, zinc, manganese, molybdenum, iron, copper, chlorine, and nickel. All micronutrients are needed in small amounts so when soils contain too much of them, toxicity can occur.
Boron (B)
Boron is used in plants for germination, pollination, sugar transport, cell wall development, protein formation, and carbohydrate metabolism. Boron is one of the most common micronutrient deficiencies. Boron is most often limited in alkaline soils and oppositely can have toxic amounts in acidic soils. A deficiency in boron will affect the vegetative and reproductive growth of the plant. Deficiency symptoms include chlorosis, death of buds/flowers, and death of new growth. A fertilizer most often used to add boron to the soil is sodium borate which contains around 10-20% boron.
Zinc (Zn)
Zinc is a part of many enzymes in the plant that are used for metabolic functions. A lack of zinc will create problems with protein, carbohydrate, and chlorophyll formation. Deficiencies are most likely to occur in calcareous soils with low organic matter and high pH. Zinc has a relationship with phosphorus in the soil where too much phosphorus can result in Zn deficiency. Deficiency symptoms include striping of corn leaves or yellowing of leaves. Zinc sulfate is the most common fertilizer used to add Zn to soils.
Manganese (Mn)
Manganese is an important micronutrient involved in critical functions in the plant such as photosynthesis, nitrogen assimilation, and respiration. Deficiency is most likely to occur in high pH soils and toxicity can occur in low pH soils. Manganese competes with iron in the soil so it is important to keep them balanced. The symptoms of Mn deficiency includes yellowing of leaves with wide green areas on the veins. Manganese sulfate is a common fertilizer added to soils that are deficient.
Molybdenum (Mo)
Molybdenum is a part of enzymes that are used in nitrogen fixation, nitrate reductase (converting nitrate into proteins), and the conversion of inorganic phosphate to organic. Unlike most other micronutrients, molybdenum deficiencies occur in acidic soils. Toxic amounts of molybdenum in plants used to feed animals can be quite harmful. Since molybdenum is related to nitrogen functions in plants, deficiencies can look similar and result in yellowing of