Copper (Cu) is essential for normal plant growth and development. It activates enzymes in a number of plant growth processes including chlorophyll formation and protein synthesis. Copper is important for plant immune system functions, creating disease resistance. It is necessary to form lignin, an essential component of cell walls. It’s also been tied to vitamin A production.
However, there is a fine line between optimum Cu and toxic Cu levels in soil and plant tissue. This metal nutrient can affect most of the major biochemical reactions in plants either by bioavailability or as an excess.
Wheat and other small grains such as rice, barley, and oats are especially affected by Cu deficiencies. Too little Cu available for plant uptake in the soil compromises crop fertility and reduces grain yield.
Many crops may suffer from a condition named “hidden hunger.” Many micronutrient deficiencies aren’t immediately evident. The micronutrient Cu may be adequate but not optimal. It’s like having a snack when your body tells you it needs a meal. Over time, this affects the ability of a plant to activate immune system responses to fight off pathogens. Unusual lodging conditions, among other problems, are symptoms of a Cu deficiency.
Soil conditions affect the bioavailability of Cu for plants. The two biggest factors affecting plant copper uptake are soil pH and soil organic matter. Soils with a pH higher than 7.5 tend to have Cu deficiencies.
Organic soils are high in Cu but that doesn’t mean it’s available to plants. Cu binds strongly to organic matter. It also bonds to nitrogen, oxygen, and sulfur.(1)
Soil and plant tissue testing can determine if the soil has a copper deficiency. On organic farms, copper sulfate can be used as a foliar spray. For a mixed-use organic farm with livestock, there’s good news: manured fields are unlikely to ever have a Cu deficiency.
Getting the Right Amount of Copper on Your Fields
Foliar sprays are more effective than in-furrow because of the strong bonding actions of iron, aluminum, and manganese in the soil. That bonding makes soil Cu unavailable for plants. By the way, Cu bonding also makes other micronutrients deficient. Everything’s connected: soil, plant, and human health.
How do you go about getting the right amount of Cu in your fields and available to plants? It starts with a soil test to determine if you need to add Cu or not. If Cu is tied up with other micronutrients, you’ll have multiple deficiencies. Haney and PFLA tests will determine micronutrient and microbiology levels. Soil nutrients and biology are interconnected.
Copper sulfate is often the preferred source of Cu on organic farms because of its cost. However, liquid fertilizers are more effective for uniform distribution and ease of application. Our team of certified crop consultants has researched many Cu formulations, and we recommend Attest-O for organic growers.
The formulation of Attest-O helps transport Cu throughout the vascular tissue of the plant. It’s a liquid that works well for foliar applications. The chelated Cu formula transports nutrients across the leaf cuticle layer. It deposits the right amount of Cu at the right time in the right place.
The magic of micronutrients lies not just in their individual roles but in their synergies with other nutrients and how they contribute to the overall health of the plant. The right amount of Cu affects the flavor, storage ability, and sugar content of fruits and vegetables. It also affects the protein content of small grains. But Cu doesn’t work alone.
Healthy soil is a balancing act. For more information on how to balance micronutrients and macronutrients on your organic farm contact our team at ST Biologicals. We’re here to help you succeed. Soil speaks, we listen.
