I guess it is just a regional difference.  In this neck of the woods most landowners ... well, there are a few ... would not have the audacity to even consider asking such a thing. Here, if you lose the lease the last thing you do is pull the combine out of the field. If the owner or next tenant want to till it, that is their problem.  And you can prevent them from doing that until the end of the lease unless a written lease specifies otherwise

Having said all that, in the situation you described I would probably offer to do the work for the landowner at prevailing custom rates as published by the University Extension Service. That is the fairest compromise.

Actually, there may be another problem for him to consider.  If you are the tenant of record at the FSA office he may be required by the FSA to give you the tenant's portion of the income from the CRP.  I lost the lease on a farm with a small field in some CRP ... I forget exactly which program it was ... but the FSA told me since I signed the contract I had the right and option to keep that for the length of the contract and the landowner could do nothing about it.

The FSA used to make a big deal out of a tenant not being terminated just so ground could go into a program.