What are the earthly pleasures of land that the speaker describes in "The Seafarer"?
"The Seafarer" is an Anglo-Saxon poem in which the speaker, a man of the sea, at first outlines all the reasons why he has to be miserable at sea: it is cold, it is exhausting, and it is isolated. The biggest criticism of all is that the sea cannot provide the "earthly pleasures" you mention in your question.
The speaker is certain that those who have always lived their lives on dry land could never understand his misery because the only thing they have known is life on land.
And who could believe, knowing but
The passion of cities, swelled proud with wine
And no taste of misfortune, how often, how wearily
I put myself back on the paths of the sea.
The pleasures of living on the land, then, according to the seafarer are passions, wine, and good fortune. He also mentions these things he misses about living on land:
All of these things are beautiful and have value, but the sea calls to him and it is the sea which allows him to be content. For the man of the sea,
Orchards blossom, the towns bloom,
Fields grow lovely as the world springs fresh.
No harps ring in his heart, no rewards, No passion for women, no worldly pleasures, Nothing, only the ocean's heave; But longing wraps itself around him.