For my grow next year. I will dig out the 3-4 inches of topsoil/compost which has a ph of about 7.0-8.5 and lime the solid clay subsoil underneath which has a ph of 3.5. I will do this at the end of this years harvest when all stalks and roots have been dug out and discarded. Once the limes sprinkled in i will dig it in with a fork so the lime breaks into the clay and has time to bring the ph up to approx 6.0.
I left it too late this year as i had a lot going on so to counter my tobacco roots hitting the acidic clay i made mounds approx 6-7 inches high for all my plants.
But i really want to break the solid clay pan for next year.
As for nitrogen. Tobacco doesnt need a huge amount of it, 2 x standard applications of dried blood (npk 12/13 - 0 -0) should be enough for the entire season. If you look at my grow blog this year, i gave my 3 sungrown criollo 98 1.5 teaspoons of dried blood per plant and watered in. The leaves are a healthy green.
Too much nitrogen will make it difficult to cure leaves after harvest and can also give a bitter taste. Also never giving any more N once you start to see the flower bud forming.
You do however want to make sure there is enough potash in your soil. Tobacco not just loves but also needs ALOT of potash, Especially after topping. This helps the cell walls thicken, produce more oils and drastically improves burning/combustibility properties of the leaves. (Something i learned after my 1st years grow, which failed to stay alight at all)
When using manure of any kind, you want to make sure its well rotted.
Finally remember any soil amendments you make will need time to start working, hence why i'm starting mine at the end of this years harvest. Gives the lime, volcanic rock dust, sand etc. Approx 6ish months to break down and work their magic.
Im still kinda new/experimenting with tobacco myself. This is only my 3rd year growing so i still also have a lot to learn.
I maybe wrong or my opinion on certain things maybe different to others but the best way to find out what/how much you need of something is to either do a full soil test via a soil lab or grow a few times and see what happens with your plants.
Oh and i almost forgot, Stay away from chloride! Wether thats in any fertilizer or your water. Its probably the worst thing for tobacco plants.