This key element is also critical for improving crop resilience and promoting seed production. Deficiency symptoms vary between crops but can include leaf yellowing, leaf tip die back and leaf distortion. Now you can address your copper requirements with an ACO Registered Farm Input. Copper Essentials™ contains 4.9% copper organically chelated with fulvic acid and amino acids. This revolutionary mix of biological chelating agents improves plant uptake and assimilation of copper.