A baler is a machine that helps farmers pick up hay or straw and turn them into big bundles, almost like giant bricks. This is done so that the hay or straw can be stored more easily and taken to other places, like a barn or a market.
The baler has big arms that scoop up the hay as it's being cut and packs it tightly together. Then, it ties the bundle up tightly with string or wire so that it doesn't fall apart.
It's kind of like when you play with Play-Doh and shape it into a ball, except the baler shapes the hay into a giant brick.
So, instead of having loose hay or straw that can take up a lot of space and be hard to move around, the baler helps farmers bundle everything up neatly and efficiently.