Agricultural chemicals

A flow object says what a substance is: its formula, its registry numbers, the class of chemical it belongs to. None of that says what the substance is for, and a use class is most of what an agricultural inventory is about. Until this axis existed the only way the list could express “this is a herbicide” was to stop publishing the substance and publish a group in its place — so identity was spent to carry a classification, and seventy named pesticides had no record of their own.

The statement is has role, the relation ChEBI’s own distribution uses, pointing at classes ChEBI curates. Nothing here is invented: the relation we assert and the relation we read are one relation, and every class below is one ChEBI publishes, with ChEBI’s own definition.

A substance bears many roles. Sulfluramid is an insecticide and an acaricide; chlorfenapyr is both and a proinsecticide as well. That is why this is a role and not a type, and why the counts below do not add up to the total — an object under herbicide is counted under pesticide too, because a row naming the narrow class publishes the broad one alongside it. A published table that leaves out what it entails answers wrongly.

Both halves are here because ChEBI answers for about half of the substances that matter and is silent for the rest — no role edge for the sulfonylurea herbicides, for spinetoram, for sodium fluorosilicate, for kaolin. That is a gap in ChEBI’s curation and not a claim that those substances have no use class, so the gap is filled one substance at a time, each row quoting the published record it was read from. Every substance’s own page says which half each of its roles came from.

A forest rather than a single tree, and deliberately so: plant growth regulator hangs under neither pesticide nor agrochemical, because ChEBI does not place it there and this project publishes no edge an authority declines to assert. The count is substances in this list, not flows. Select one to filter the table.

• pesticide 707 CHEBI:25944

  Strictly, a substance intended to kill pests. In common usage, any substance used for controlling, preventing, or destroying animal, microbiological or plant pests.

  • insecticide 240 CHEBI:24852

    Strictly, a substance intended to kill members of the class Insecta. In common usage, any substance used for preventing, destroying, repelling or controlling insects.

  • herbicide 225 CHEBI:24527

    A substance used to destroy plant pests.

  • fungicide 208 CHEBI:24127

    A substance used to destroy fungal pests.

  • acaricide 107 CHEBI:22153

    A substance used to destroy pests of the subclass Acari (mites and ticks).

  • nematicide 33 CHEBI:25491

    A substance used to destroy pests of the phylum Nematoda (roundworms).

  • rodenticide 9 CHEBI:33288

    A substance used to destroy rodent pests.

  • antifeedant 8 CHEBI:22583

    A substance that prevents pests from feeding.

  • molluscicide 8 CHEBI:33904

    A substance used to destroy pests of the phylum Mollusca.

• agrochemical 429 CHEBI:33286

  An agrochemical is a substance that is used in agriculture or horticulture.

  • fertilizer 24 CHEBI:33287

    A fertilizer is any substance that is added to soil or water to assist the growth of plants.

• plant growth regulator 50 CHEBI:26155

  A chemical, natural or artificial, that can affect the rate of growth of a plant.

ChEBI’s role tree is mostly biomedical — metabolite, inhibitor, drug — and publishing all of it would bury the classes that group something an inventory asks about. Only classes that do are published, and a class that would look authoritative while being incomplete is deliberately excluded: ChEBI gives greenhouse gas to carbon dioxide, methane and sulfur hexafluoride and to no HFC or PFC in this list, so grouping on it would return a greenhouse gas set missing the entire fluorinated basket.

Two more classes are published under a separate family, because they say what happens to a substance after it is applied rather than what it was applied for, and they are asserted of substances that were never agricultural: environmental contaminant (243), persistent organic pollutant (34). They are on the substances that carry them, and every substance’s own page lists them; they are not on this page because a list of agricultural chemicals that included the dioxins would be answering a different question.