How it works ?
It's a mask effect. The grass is basically a Noise Gradient. The bent grass is the same Noise Gradient, with a Rotate Layer added. The canvas with grass and Rotate Layer encapsulated is blended onto a BLine Region.
The first thing to do is prettier grass.
1 - We draw the floor with a BLine Region.
2 - Noise Gradient is added above. It's done with transparency.
3 - Noise Distort will create the fine lines of the grass.
4 - For a less uniform color, we add a Noise Gradient with a Blend Method on COLOR. It's just a slight color effect, so the Amount is very low.