Kim Audette

About voles...in my experience, the pounding of machinery drives the voles to quieter places, which for you is the swales.  

You could repel the voles with a spray of castor oil.  Don't spray the trees, but around the trees.  Voles can't wash it off and it causes them intestinal discomfort without killing them.. so they'll go somewhere else.

Many farmers love the no till concept but also admit that there are times one or two tillings per year is best for your soil.  Taking the alfalfa above ground for silage might make your effort to change.crops profitable, and turning those massive alfalfa roots into tilth by a plow would help your field retain water.

Since the Dark Ages, rabbitry in Europe relied on man-made islands planted with rabbit food, and with man-made warrens, to keep the nobles rich.  Its a tried and true practice.  

That being said, you realize by now, you have to provide shelter from predators.  Roosters and trained dogs  have the attitude to provide most protection.. Alas, cant mix in a garden.