More commonly known as (P)HCA, it is simple acid/molecule formed by the group hydroxide and oxygen (acid) attached to a C atom, leaving the free bond to a radical.

It is very common both in nature and as a synthesis product, found for example in fulvic and humic acids.

The (P)HCA, from an agricultural point of view, due to its molecular structure offers important properties:

• Complexing effect: it has a high affinity with macro and microelements. It can “capture” Na atoms that are part of the CEC and reduce the undesirable salinity caused by this element. An example of a chelating (P)HCA is gluconic acid.
• Rooting effect: it induces the growth of root hairs which improve assimilation of nutrients. Water absorption in cotton plants has been increased through the application of (P)HCA.
• Other: induction of an increase in the synthesis of lignin and the phytoalexin gossypol.