OhmyGosh! My third graders are singing this for a thanksgiving program, and I had no idea about all the above contexts! In elementary texts it appears thusly:

TZENA

Tzena Tzena Tzena Tzena
Come into the fields and we'll begin to work the land.
Hoeing, sowing, new things growing,
Pioneering all together, come and lend a hand.

Tzena Tzena building a new nation
Toiling busily all day----
Soon we'll dance, and have a celebration,
But first we'll work and then we'll play!

[not play first, as suggested above!!] But at least, I got 'em saying Tzeh na, instead of the southern variant Tzayyy na!

This could very well be too much information! But thanks anyway!