FACTS
- Copper (Cu) is an essential microelement for plants; it is important in several redox reactions.
- Both Cu deficiency and excess severely limit plant development.
- Certain crops respond differently to copper deficiency. High-response crops include wheat, alfalfa, barley, oats, tomatoes, onions, lettuce and fruits. Moderate-response crops include corn, sugar beets, sorghum and soybeans.
FUNCTION
- Copper is necessary for chlorophyll formation, playing a vital role in photosynthesis efficiency.
- Activator of several enzymes, including the catalysis of vitamin A production.
- Essential for the mitochondrial respiration processes.
- Involved in iron mobilization and phytohormone signalling.
- Role in the formation of lignin, an integral composite of cell walls.
- Contributes to seed set, stress resistance and pollen production.
AVAILABILITY
- Concentration in soil ranges from 2 to 100 parts per million (ppm), with an average value of about 30 ppm. Most of the Cu in the soil is not available to plants.
- Its concentration in plant tissue ranges from 5 to 20 ppm.
- Copper exists in soils as Cu2+, and most copper is absorbed by the plant in that form.
- Copper is the most immobile micronutrient in the soil, so symptoms generally appear in young tissues.
- Availability of copper increases in soil pH below 7.0 and decreases at a higher pH, due to fixation to soil clay minerals.
- Copper can also be adsorbed to iron and manganese oxides and can precipitate with carbonate and phosphate minerals.
Credits: Michał Słota, Ph.D., Content Farmers.
