godan verb (-ku), transitive verb
cultivate land; clear land
Rare transitive godan verb used specifically for opening up or clearing land for cultivation. In modern Japanese, 開く (ひらく) sense 9 covers this meaning, and 墾く is an uncommon kanji variant.
See also: 開く
昔、人々は山を墾いて田んぼを作った。
Long ago, people cleared the mountains to make rice paddies.
Clearing this land for cultivation requires a great deal of labor.