Copper (Cu) activates enzymes and catalyzes reactions in several plant-growth processes. Vitamin A production is closely linked to the presence of Cu as well, and it helps ensure successful protein synthesis. Classified as a micronutrient, only a small amount of this essential nutrient is needed for plant survival.
Many vegetable crops show Cu hunger, with leaves that lose turgor and develop a bluish-green shade before becoming chlorotic and curling.
Copper is necessary to chlorophyll formation in plants and catalyzes several other plant reactions.
Other metals in the soil, such as iron, manganese and aluminum, affect the availability of Cu for plant growth.
Copper (Cu) is necessary for carbohydrate and nitrogen metabolism, so inadequate Cu results in stunted plants. Copper also is required for lignin synthesis, which is needed for cell wall strength and wilt prevention. Deficiency symptoms of Cu are stem and twig dieback, leaf yellowing, stunted growth, and pale green leaves that wither easily. Symptoms generally appear on young plants.
Copper deficiencies are mainly reported on organic soils and on sandy soils that are low in organic matter. Copper uptake decreases as soil pH increases. Increased phosphorus and iron availability in soils decrease Cu uptake by plants.
Recommended Cu rates range from 3 to 10 pounds per acre as CuSO4 or finely ground CuO. Residual effects of applied Cu are very marked, with researchers noting responses up to eight years after application. Because of these residual effects, soil tests are essential to monitor possible Cu accumulations to toxic levels in soils undergoing Cu fertilization. Plant analyses also can be used to monitor Cu levels in plant tissues. When available Cu levels increase beyond the deficiency range, growers should decrease or stop applying it.Dig even deeper into Copper
Symptoms of deficiency can vary across crop species, but similarities exist for how nutrient insufficiency impacts plant tissue color and appearance. Nutrient deficiencies are commonly associated with the physical location on the plant (i.e., whether the symptoms are primarily observed on older versus newly formed plant tissue), but these symptoms can spread as the severity of the deficiency progresses.
All photos are provided courtesy of the International Plant Nutrition Institute (IPNI) and its IPNI Crop Nutrient Deficiency Image Collection. The photos above are a sample of a greater collection, which provides a comprehensive sampling of hundreds of classic cases of crop deficiency from research plots and farm fields located around the world. For access to the full collection, you can visit IPNI's website.