By using the 'Embedded Scripts' feature and the 'Application Scheduler' feature you can create a script that will write the disk defrag information to your local event logs on a regular basis.
1). Create the following embedded script:
defrag.exe %Systemdrive% -a -v
(The file name should have a .cmd or .bat extension so it is run with the command interpreter).
2). Use the 'Application Scheduler' feature to run your embedded script on a regular basis to write the results of your script to the event log.
3). Optionally create an event log filter that will email the results of the application scheduler script.
Further information on both of these features can be found at the following URLs: