>>60What on earth do you imagine you would need math for? Maybe it's different in the U.K. (I think not) but we barely do any math. It's mostly software packages that take care the calculations. At most I would imagine using spread sheets. As for on the spot math, people get fired for just calculating on the spot. Most calculations are carefully pre-determined, maybe 30/40 years ago you would be expected to work with pen and paper but even the best make mistakes which is why it's all software based now. Really if that's the only thing worrying you then you'll be fine. All the science and latin will come with time.
Also Tex A&M is one of the few I have heard of, very good breeding department if I recall. Get a degree son.
Diving straight into soil chemistry may not be the best idea as a first step. Not sure about the level you are at but a soil scientist I know gave me a book recommendation that really helped give me a broad base of knowledge to get started.
"Principles of Horticulture", Adams, Bamford & Early. The later book deal primarily with gardening techniques and such but this book has a basic level of knowledge that applies both to Hort and Ag.
I also have "An Introduction to Agricultural Biochemistry" Chesworth, Stuchbury & Scaife. It's a very simple bio book dealing with mostly animals. Animals might not appeal to you but people who manage pasture still need agronomists and if you work with them you will need a basic understanding of the animals' relationship with the land.
No joke, you should start growing plants at home, on a window sill or under lights. Start trying different things with the soil and trying to apply knowledge. It really helps get a grasp of a plants relationship with it's growing medium and gives good instincts for understanding plants. I currently have 23 different plants around my desk.