First you'll need to log in as root via SSH. Once logged in I suggest choosing your favorite editor. For me it's nano, so for me I would run:
Next you need to open crontabs to make a quick change by doing this:
Once the crontab file is open, you need to add this to the first line of the file.
Then save the file and exit. You will no longer get emails from cronjobs sent to root directly from the server. This is mostly done on cPanel servers because cPanel already emails you if there is an issue.