We had a second verse:

Hoe, hoe, hoe your row
Through the summer heat
Corn and tomatoes and rice and potatoes
Are might good to eat

Also had a different Kookaburra;

Kookaburra sits in the old gum tree
Eating all the gumdrops he can see
Laugh, kookaburra, laugh kookaburra
Save some gum for me.

Suspect the third grade teacher took some liberties with both. Folk process, no?