Antonyms usually refer to a single word, but the opposite of "dry farming" would essentially be an unfarmable swamp. However, "wet farming" is essentially irrigated farming. Pick the one you like best.
dry
One antonym could be "dry" or "dehydrate"
Dehydrate, dry
dry
Dehydrate, dry
Rough. Dry. Unslippery
Wet or moist.
a dry river bed
Wet, moist, damp
They are antonyms.
a synonym of "arid" would be desert, dry, serean antonym would be humid, moist, rainy
An antonym is a word opposite in meaning to another, e.g. light - dark, wet - dry. There is no antonym for the word donkey.