This Act, consisting of 31 sections divided into three Parts, establishes the following: "fertilizer" means: (a) any substance likely to increase plant growth which supplies nutrients to plants or conditions soil for that purpose, other than farmyard or stable manure, humus, seaweed, crude night-soil, crude offal, crude refuse or crude waste which is untreated or undried; and (b) any substance prescribed as a fertilizer for the purposes of this Act. A person must not sell any fertilizer (except