Most eficient silage

[Smisteryo]

Hello!

I am wondering which of corn or grass produce more silage. I was searching but I didn't undersand exactly.
I am playing season and i will use silage for cows, not for sale directly.

I found on that grass produce around 35k of silage and corn around 55k, but playing seasons it will be 3 harvest of grass and only 1 corn.

It would be more efficent corn somehow? It is worth to buy the harvester for corn?