How do your worst and best producing soils test comparitively on OM and water holding capacity/perculation.  Sometimes physical soil properties are not always taken into consideration when one only focus's on nutrients. 

This reminds me of a thread and discussion that MikeNESD started a while back about poor seed slot closure.  Don't just assume nutrients on a soil test or tissue test make or don't make the crop, after all they don't even track the three most neccisary ones.

Three important charicteristics of soil:
Phisical
Chemical
Biological

I'm sure most people know this, but the latter two can create differences between soil and tissue tests.