[buffett]

This seems like a pretty sound valuation methodology. If I may be so crass as to offer a couple of unsolicited opinions on some of your inputs....

The cost of equity (8.3%) seems low, but then I never use CAPM. When I do a DCF
....[which I don't always like to do, because a DCF can be like using a telescope to look into space {if you move the telescope half an inch to the left, you end up looking in another galaxy (if you increase your discount to 11%, your IV goes from $124 to $100 (not a galactic shift, but significant))}...I prefer more of a Private Market Value type of valuation based on M&A activity (but of course that's impossible for a company like Monsanto)]....
I base my discount rate on a rough "opportunity cost" comparison to the 10 or 30 year govt note (I've been using 10% for the last few years, though I suspect I'll have to bump it up if they keep raising rates).

Your ebit margins pre-06 are ~13-14%, but you have 17% going forward. I didn't find a readily apparent reason for the discrepancy, but it's a pretty big issue. If you ratchet EBIT margins down to '05 levels and project that forward, your margin of safety goes from 39% down to 25%. (Plus, I couldn't replicate your pre-06 ebit #s....in 2005, e.g., 6294-3316-1338-601=1039 not 888 (also, the 10K says to me that the #s should be 6294-3290-1334-67-588-7=1008).)

The tax rate between now and 2015 seems low, but maybe they have some NOLs or tax credits that I don't know about, and it doesn't change the IV much anyway.

The big issue is the growth rate. I mean, I know this market is going to be huge one day. But good freakin' gracious, is it really reasonable to expect that this company will double its revenue over the next 4 years, and then double again in the 4 after that, after its only grown ~4% over the last 4? I mean, wow. That's really fast.