Green manuring – the growing and turning under of cover crops to fertilize and improve your soil – is one of the best things you can do for your garden. This practice eliminates the need for chemical fertilizers and nitrogen, helps unlock nutrients in the soil, cuts down on weeds, increases the number of beneficial organisms in your soil, and improves your soil’s ability to hold water. The result is that you spend less time, energy, and money while enjoying a healthier, more productive, and more attractive garden. This concise guide introduces you to the primary methods of green manuring and shows you how to select your cover crops, how to plant them, and when and how to turn them under.
Good general knowledge book
I'd like a bit more geographically specific info, but it was a good overall book.