Fertile land grows things without much persuasion. Black soil on a river plain, a valley thick with wheat, a garden bed where you push the seeds in and they come up.
Fertile also describes living things able to produce young or seed — a fertile mare, a fertile plant, and the human questions of fertility, fertile years and fertility treatment. The figurative use is everywhere: a fertile imagination, a fertile period in a painter's career, and the set phrase fertile ground for something, as in the town was fertile ground for the new party. You spread fertiliser to fertilise the soil and make it fertile. The opposites split by subject: barren land, infertile soil, an infertile couple. Watch the picture, though — fertile says what could grow, not what is growing, so a bare field in February can be the most fertile land in the county.
1adjectivefertileRich enough to produce plenty of crops or plants.
“The valley has the most fertile soil in the region.”
synonyms: rich, productive
2adjectiveableAble to produce young, seed or fruit.
“The clinic tests whether both partners are fertile.”
3adjectiveproducingProducing a great many ideas or results.
“Boredom turned out to be fertile ground for the whole project.”
Fertile came through French from Latin fertilis, 'fruitful', which is built on the verb ferō, 'to bear, to carry'. Fertile ground is ground that carries a crop. The metaphor was already sitting there in Latin, and English simply kept it.
Latin
fertilis — fruitful, fertile
Old French
fertile
Middle French
fertile
English, today
fertile
Built from
From Middle English -, from Middle French fertile, from Old French fertile, from Latin fertilis (“fruitful, fertile”), from ferō (“to bear, carry”).
Etymology from Wiktionary, CC BY-SA