A Thanksgiving poem beginning “For the hay and the corn and the wheat that is reaped…” has been cited in print since at least 1884, when it was credited to Harper’s Weekly.
     
   
21 January 1884, Daily Evening Tribune (San Luis Obisoo, CA), pg. 1, col. 4:
THANKSGIVING.
For the hay and the corn and the wheat that is reaped,
For the labor well done, and the barns that are heaped,
For the sun and the dew and the sweet honeycomb,
For the rose and the song and the harvest brought home—
Thanksgiving! thanksgiving!
 
For the trade and the skill and the wealth in our land,
For the cunning and strength of the workingman’s hand,
For the good that our artists and poets have taught,
For the friendship that hope and affection have brought—
Thanksgiving! thanksgiving!
 
For the homes that with purest affection are blest,
For the season of plenty and well-deserved rest,
For our country extending from sea unto sea;
The land that is known as the “Land of the Free”—
Thanksgiving! thanksgiving!
—Harper’s Weekly.
 
Google Books
Pieces for Every Day the Schools Celebrate
By Norma Helen Deming
New York, NY: Noble and Noble
1921
Pg. 311:
Giving Thanks
Anonymous
For the hay and the corn and the wheat that is reaped,
For the labor well done, and the barns that are heaped,
For the sun and the dew and the sweet honeycomb,
For the rose and the song and the harvest brought home—
Thanksgiving! Thanksgiving!
 
For the trade and the skill and the wealth in our land,
For the cunning and strength of the workingman’s hand,
For the good that our artists and poets have taught,
For the friendship that hope and affection have brought—
Thanksgiving! Thanksgiving!
 
For the homes that with purest affection are blest,
For the season of plenty and well-deserved rest,
For our country extending from sea unto sea;
The land that is known as the “Land of the Free”—
Thanksgiving! Thanksgiving!
 
Google Books
The Book of Thanksgiving:
Stories, Poems, and Recipes for Sharing One of America’s Greatest Holidays
By Jessica Faust and Jacky Sach
New York, NY: Citadel Press
2002
Pg. 23:
Giving Thanks
(Author Unknown)
For the hay and the corn and the wheat that is reaped,
For the labor well done, and the barns that are heaped,
For the sun and the dew and the sweet honeycomb,
For the rose and the song and the harvest brought home—
Thanksgiving! Thanksgiving!
 
For the trade and the skill and the wealth in our land,
For the cunning and strength of the workingman’s hand,
For the good that our artists and poets have taught,
For the friendship that hope and affection have brought—
Thanksgiving! Thanksgiving!
 
For the homes that with purest affection are blest,
For the season of plenty and well-deserved rest,
For our country extending from sea unto sea;
The land that is known as the “Land of the Free”—
Thanksgiving! Thanksgiving!
 
Brownielocks—Thanksgiving Riddles and Jokes, etc. (November 17, 2006)
Giving Thanks
For the hay and the corn and the wheat that is reaped,
For the labor well done, and the barns that are heaped,
For the sun and the dew and the sweet honeycomb,
For the rose and the song and the harvest brought home—
Thanksgiving! Thanksgiving!
 
For the trade and the skill and the wealth in our land,
For the cunning and strength of the workingman’s hand,
For the good that our artists and poets have taught,
For the friendship that hope and affection have brought—
Thanksgiving! Thanksgiving!
 
For the homes that with purest affection are blest,
For the season of plenty and well-deserved rest,
For our country extending from sea unto sea;
The land that is known as the “Land of the Free”—
Thanksgiving! Thanksgiving!
Author Unknown