I'm with Joe on this one. I think at some time someone has conflated the two titles, and it's been passed down this way. The song makes no mention of "Wheat in the ear" although it's a phrase that comes down to us from the Bible.
The original verse (or chorus?) doesn't appear to fit with the other verses given in any way.

For context, a longer quote from Kipling's "Captains Courageous":

Then Manuel touched the jangling, jarring little nachette to a
queer tune, and sang something in Portuguese about "Nina,
innocente!" ending with a full-handed sweep that brought the song
up with a jerk. Then Disko obliged with his second song, to an
old-fashioned creaky tune, and all joined in the chorus. This is
one stanza:

"Now Aprile is over and melted the snow,
And outer Noo Bedford we shortly must tow;
Yes, out o' Noo Bedford we shortly must clear,
We're the whalers that never see wheat in the ear."

Here the fiddle went very softly for a while by itself, and then:

"Wheat-in-the-ear, my true-love's posy blowin';
Wheat-in-the-ear, we're goin' off to sea;
Wheat-in-the-ear, I left you fit for sowin';
When I come back a loaf o' bread you'll be!"

That made Harvey almost weep, though he could not tell why. But it
was much worse when the cook dropped the potatoes and held out his
hands for the fiddle. Still leaning against the locker door, he
struck into a tune that was like something very bad but sure to
happen whatever you did. After a little he sang in an unknown
tongue, his big chin down on the fiddle-tail, his white eyeballs
glaring in the lamplight. Harvey swung out of his bunk to hear
better; and amid the straining of the timbers and the wash of the
waters the tune crooned and moaned on, like lee surf in a blind
fog, till it ended with a wail.

"Jimmy Christmas! Thet gives me the blue creevles," said Dan.
"What in thunder is it?"
"The song of Fin McCoul," said the cook, "when he wass going to
Norway."


Cheers
Nigel