Best clover for long term soil improvement?

So last summer I cleared about an acre of aspens, white pine and mixed hardwoods from our property for a large garden. We are doing it almost exclusively no till, in raised beds made of logs from the felled trees. We didn't have nearly enough compost to fill the entire area with beds, so we are just going to build and fill them over the course of the next several years. So that leaves about 50% of the area empty and last year I planted various types of clover and alfalfa in hopes of improving the sandy soil over this time.

My question is what types of clover or other cover crops are going to be my best bet. As of now nearly the entire area is growing either alfalfa, crimson, landino, and medium red clover(with some flax mixed in here and there). I have been reading about how many types of clover will succumb to disease in the second year and I am worried about this happening. In some of the areas and especially pathways I would like to have these covers a permanent fixture, but still have the option of using the space down the road and hopefully having better soil there to work with.

Any advice or links to information about using clover as a long term soil improver would be greatly appreciated. Or any advice/resources about any sort of long term soil improvement scheme for sandy former forest areas.

How much of that acre do you plan to have in garden?
In NZ clover is used as a long-term plant in all sorts of contexts. I've never heard of it being prone to disease, but maybe that's a climate difference.
I have a lot of 'white Dutch' around the place, it's low enough to walk on easily. I've got red clover and hairy vetch in amongst the perennials. It's too tall and tangly to walk on, but the bees love it.
trefoils are other legumes to look at.
For next winter, how about growing rye and other cereals to add carbon/organic matter?
Also fava beans are a great source of human and animal food, carbon/biomass, nitrogen-fixation and they sustain the first bumblebee in the spring. We grow it over the winter here.

It sounds like you've got a nice mix growing there already...you seeded and established that after the clearing? Were you thinking of seeding other stuff over that mix or turning it under and starting again?

Does anyone use sweet clover in your area? Where I live it seems to do well on drier sites and poorer soils. It is not widely used as it can have some toxicity issues for grazing although there are lower coumarin varieties out there now. In its second year it can produce an awful lot of growth in a hurry, so depending on what your methods or equipment are you may need to stay on top of it or the residue may get difficult to manage. If you let it set seed it seems to be pretty darn persistent and tough...perhaps too persistent and tough...it's biennial so if you terminate it in year one you would avoid any seed set and not have it take over your world.

An excellent book on cover crops (248 pages) is a free PDF download here:

"Managing Cover Crops Profitably", 3rd Ed.

Clover is great! I would spread a few types as well as some complementary plants that might self seed (for my area that's radish, buvkwheat, sunflower, and kale which might work for you too?) Even if they just produce abundant seeds for broadcast the next year that isn't so hard..

The point is, try 5-6 good candidates and in 3 years you will probably have strong growth of the best 2. Like the TV show, the strongest vote the weakest off the island...

I probably have about a quarter of the area filled with annuals, mostly in raised beds. Another quarter in different sorts of berries, but the clover is interspersed there anyway. The rest we may fill with more beds as time goes on, or maybe plant some grain for our chickens and ducks. Probably less than 2/3s of the area gets full sun, so I am somewhat limited with the options.

I put most of the clovers in late last summer after it was cleared, some of them early this spring as soon as the snow melted. I'm still not sure about tilling in, I have just been mowing it by hand with a long razor and using it for mulch so far this year. Some of it is starting to go to seed, so I'm hopefully going to be able to hand harvest a certain amount of seed for later use.

I'm not sure about the sweet clover. Our feed store doesn't have it as far as I know, but I will ask them next time I'm out that way.

Thanks for the replies and the link in particular, that is a great resource!