Is sulfurous acid acceptable as a soil amendment in organic crop production?

By Jennifer Schomp

Sulfurous acid is a gaseous compound made up of sulfite and bisulfite (hydrogen sulfite) anions that are an effective pH adjuster when suspended in an aqueous solution. It was considered by the NOSB in 2009 for addition to the National List, and in July 2010 the National Organic Program (NOP) added sulfurous acid to the National List as an allowed synthetic for use as a plant or soil amendment, where it remains, having...