The process or act of adding nutrients to soil or combining reproductive cells; currently doing or habitually doing this action.
Present participle of fertilise, formed by adding '-ing' to the verb stem. This creates both a gerund (noun form of a verb) and a present participle (verb form showing ongoing action).
The '-ing' form is magical in English because it works as both a noun and adjective—'fertilising soil' shows it as a verb, but 'fertilising agents' uses it as an adjective, letting one word do double duty.
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