This youtube video put up by NCATATTRA demonstrates many of the benefits of cover crops on large scale farms:
It’s long and a little technical. Bottom line, well managed cover crops increase soil health by adding organic matter, retaining water, strengthening soil structure, supporting soil micro organism diversity, providing nutrients for cash crops and attracting a diverse array of wild pollinators and birds.
The more diverse the array of cover crops you use the better, it seems like 7 different species at a minimum are needed to get complementary beneficial interaction between plants in the mix.
I’m looking forward to watching another one of NCATATTRA’s cover crop videos geared toward smaller farms:
Here’s a great PDF the USDA put together with a lot of information on the individual plant species as well. It’s where the Cover Crop Chart from the top of this post came from: