Green Manure Crops

So, I have 7 acres of land I acquired. Its in pretty poor condition. Was tilled by multiple groups in the past trying to get something out of it, but always with no luck.

The forested areas where ravaged by miners, and clear cut, there is no old growth and just densely packed small trees and the occasional moderate sized one.

the hillsides where the forest is, has a about a half inch of pine needles on it, and below that is just gravel, lots and lots of gravel.

the field is just dry dirt with rocks in it that nothing really wants to grow on it seems.

I'm doing different hugelkulture mounds in the field, and possibly some small ones on the hill.

I'm trying to figure out good manure crops that I can spread around to start working up a humus layer.

I'm pretty sure I can get things going in the field... but the hills are basically rocks and gravel, likely from all the roads and mining done up there, but maybe its natural.

I might just be mostly talking out loud at this point, but maybe someone has a good idea of how to get something going on these gravely locations.

I remember Joel Salatin talked about his farm when he was a kid had similar conditions to yours. Very rocky, without much hummus layer and poor soil health. As I remember (I can't think of what book  he wrote about this in - someone help me!) he ran animals on that land in paddocks made of poles sunk into tires and buckets filled with concrete to keep the fencing up and basically built the soil year to year running a steady stream of cows, then rabbits and chickens in tractors, then green cover crop - lather, rinse repeat.

I'm probably butchering this. It may have been his dad that started the animals rotating on the land.

I have successfully used dutch clover in areas of our farm that are more gravelly with poor drainage, including a build site that I convinced the county to let me spread clover vs grass. In areas that are really hard up, I have spread rabbit poop, then straw, then rye grass and let it go bananas for a couple years, then ran chickens in the area and put down buckwheat after them (I like the flowers) and then just let it be. I figure in another year or two, I'll throw more rabbit poop in those areas and then seed some clover and then just let it go wild again. I like the clover and buckwheat combination, but clover is a bit of bully and can take out whatever it doesn't like around it.

I tend to seed in the fall and let our rains do the watering for me. In more sloping areas, (of which we only have a couple small ones) I threw down rye grass and covered in straw mulch in the fall and let it just go. Had a good showing of rye grass the next summer. Then I chop and drop the rye after it seeds and let it build over time. Thank goodness for scythes!!

I'm so glad that site has you looking over it. In time, without our interventions it'll rewild, but how nice to have you concerned about the health of it and giving it a leg up.

By far I'm no expert on this. But having posted my disclaimer, I'll venture some suggestions.

Most grass type crops grow without much pampering. Plus if seeded thick enough, most will grow by broadcasting the seed. Thus I'd be looking into things like rye, wheat, oats, or barley.

Maybe Travis will see this post and make better suggestions.