If you have a rake for your tractor, you can use that to scrape the cut grass to one side, then into a pile and let it compost down. If you have a tedder you could turn the grass every dry day until it dries and shrinks then let it rot. You could just let it all rot down where it is and the new season grass will grow through. Because it was topped and not mown, the bits of grass will be small not the full length as when growing.
Someone else will be along to tell you which is best for your meadow (we have done all in the past, with no obvious long term difference in outcome)
With a bit more equipment you could mow the field and make your own hay (Mower or scythe, tedder, baler or an army of friends with pitchforks and string to make stooks)