The Essentials

Nickel is now recognized as the 17th essential nutrient of crops. When I first studied essential nutrients, 15 were recognized and a mnemonic device was used to remember them:

C HOPKNS CaFe Mg (managed) B (by) Mn (my) CuZn Mo.

This has been updated to:

C HOPKNS CaFe Mg (managed) B (by) Mn (my) CuZn’s Mo, Cl yde & Ni ck

to account for Cl and Ni.