First question is does your tenant farmer have a long term lease or is it year by year. If long term you might have to negotiate your way out of it if he'll turn it loose. If year by year then you need to let him know ASAP that you don't plan to rent it to him anymore.
Second, if it's been in row crops then 99% chance it's been in the farm program and earning payments. You'll have to let FSA know that you're the new operator and sign up for the program so that you can recieve the payments (and/or the landowner depending on shares/arrangements) and then you'll have to certify it as fallow or zero-planted to row crops. Under the current farm program you can draw the base and countercyclical payments automatically without planting the first crop seed; in fact that's what we've done the past few years to let Uncle Sam pay for the fencing and grass seeding our 60 acre former cottonfields here on the home place into pasture. The only requirements are that you keep the weeds down (some rice farm landowners have taken the farms away from the tenants because they could make more money on the program payments than the land rents and all they've had to do is bush-hog it once or twice a year to stay eligible) but if you're running cows on it they should keep it fairly decent on that count, and you must sign up for the farm program each year and then certify it as fallow or zero-planted (to row crops). The nice thing about this option is that you get the payments automatically based on the historical crop bases and there are no strings attached (other than the three I mentioned) so you can do whatever you want however you want on whatever timetable you want.
Now you can sign up for the EQIP program through the NRCS. I signed up for it but then backed out when I found out how many requirements are put on you. They have everything from a cross-fencing cost share program to water line/trough cost share programs to paying 50% of the pasture seeding or sprigging, and even brush control cost share programs. Not all programs are offered in all areas though, so you'll have to check with your local office to find out what's available. Our office doesn't offer cost share on ponds and windmills because we have too many 'city farmers' coming in buying 5 acres and turning it into a 'horse ranch' and they would overwhelm the system requesting (and legally entitled to) funding for fish ponds and windmills, more for decoration and recreation than any real use. But they couldn't be turned down because of it so they just don't offer it at all here. Anyway, it's something to check into and if you can live with the requirements, it might be an excellent resource for you. What I didn't like about it is that I tend to do things with and eye to cost (on the cheap some might say) and when they printed out 32 pages of requirements for cross fence construction under the 50% cost share program I rapidly realized that I would end up spending 3 times what I had available on doing it their way, so even with them reimbursing half it was going to cost me more out of pocket than I planned to spend to begin with. Additionally I didn't like the 'maintain and inspected by NRCS for the next ten years' part. I just opted out and did it myself the way I wanted it done and according to what I could afford. No since in buying a Cadillac if a Yugo will get you there...
As for the specific forages for your area, that is so dependent on local climate and weather patterns, soils, topography, livestock types, stocking rates, goals, and methods that any advice you get on here unless it's from a neighbor up the road will be pretty meaningless. The NRCS guys here were really nice and very helpful though, and discussed my options with me at length and made suggestions and printed me off a bunch of their information on various grasses and legumes and research and stuff like that. They can give you planting rates, dates, seed sources, and stuff like that depending on what you're trying to accomplish. Your local Extension should have a lot of information and research pertinent to your area as well. They should be glad to help.
Hope this helps you out, and good luck! OL JR
