Copper (Cu)

Copper is included in the Standard Soil Test. Copper deficiency is not a common occurrence on South Carolina soils. However, copper deficiency is likely to occur on organic soils, mineral soils high in organic matter content (>5 %), and on very sandy soils that have been over-limed and thus have a high soil pH (>6.0 or 6.5, depending on soil type). Copper is retained in available forms in clay soils. Copper can be leached from very sandy soils low in organic matter content. Correcting a copper deficiency from occurring in organic soils requires application rates of 20 to 50 pounds copper sulfate (CuSO4.5H2O) per acre or a foliar application at the rate of 1 to 2 pounds CuSO4.5H2O per acre. There is a very narrow range between deficiency and toxicity for copper, and either soil or foliar-applied recommendations should be based on a deficiency verified by a plant tissue analysis. Copper exists in the soil solution as the cupric (Cu2+) cation.

List of Copper-containing Commercial Fertilizers: