Does anyone know what large commercial farms use?
As far as I know, the most widely used fertilizers within "Conventional" (non-Organic) Agriculture are chemical fertilizers derived from petroleum.
Within certified "Organic" Agriculture, the most widely used fertilizers are slaughterhouse byproducts such as blood, bone, and feather meal.
I really grimaced when I found this out.
Also I don't see any financial advantage in having animals on your farm unless you kill them and/or sell them because it's more efficient and effective to just grow a cover crop and till it back into the soil as a green manure..
So I haven't read that book but I'm pretty sure I disagree with the Nieman Ranch guy.