The phrase "rich harvest" means a plentiful or abundant gathering of crops or rewards. It indicates a successful result or outcome after hard work, often related to farming or achieving goals. Full definition
Baseball, it seems, is about to enjoy its third straight rich harvest of rookies, and Texas may reap the biggest prize in switch - hitting Second Baseman Bump Wills (si.com)
Lands that have, in past years, yielded rich harvests are now sown with a new and terrifying seed (darkestdungeon.com)
But she believed that God provided opportunities for the faithful, even in the most unfavorable circumstances: «When so rich a harvest is before us why do we not gather it? (firstthings.com)