Does this kill the next grow

Hey everyone I work at State park that has roughly 500 acres of hay fields.  Things are changing and the cutting is now falling on me to do.  I am trying to figure out a few things:

 

If I cut tall grass with a sickle bar or a disc mower but do not go back to rake or bale will the grass underneath die off?  Is there a disc mower or sickle bar that can move like a ditch bank mower?  I'm trying to figure out if I can more ditches and steep banks, leave the long non-shredded grass and not kill the grass below it?  Is this why I would be better off with a Flail or rotary mower, it cuts the grass smaller so it doesn't mold and kill the next grow?  Can anyone recommend a good cutting attachment and mower?

 

 

Thank you!

Does this kill the next grow