Sag: I agree with your statement about the buffer pH being a value rather than a true pH. The measured pH is the true soil pH. We agree on the recommendations for Fldeerman (although they are not what I'm used to seeing).

But you had to throw another curve into this:
My charts show a different lime rate for the scenaro that you gave. For a buffer pH (value) of 6.4, an initial pH of 5.5, and using lime with an agricultural index of 75 the recommended lime addition to reach a target soil pH of 6.5 is 4 tonne/hectare. That's roughly equivalent to 2 ton/acre. I'd like to know where the difference is because most soil tests are in line with the OMFRA chart.

For comparison, please check figures from your chart:
Target pH 6.5, initial pH 5.5

Buffer pH Lime req (tonne/ha)
7.0 2.0
6.5 3.0
6.0 9.0
5.5 17.0


Dan O.