I've just started doing test strips this year. I have low soil levels(.4ppm) and am showing deficient tissue tests(5-8ppm...normal is 11). I put 1 lb of boron in sidedress band with 32% @ V4. As of yet my weekly tissue test did not show any difference between treated and untreated, but the corn is just getting big enough root systems to reach the sidedress band now, so I'll know more in a few more weeks if 1# at sidedress makes a difference in the tissue test. But obviously won't know about yield until harvest. I'm gonna be watching it at tasseling the most to see if I notice any difference.

I do see what you are saying about the tissue test "standards" and it got me thinking. I've looked up the boron removal rates for corn and soybeans and in corn 90% of the boron is in the grain...in soybeans 83% is in the leaves. So if only 10% of corn's boron is in the leaves....maybe it doesn't even WANT boron early on and you won't see any response via tissue sampling on treated soil.

Here is a sheet of my weekly tissue tests that I've been sending in. The top two and bottom two results are corn, the middle is soybeans. 

So as you can see my corn levels are betwen 5 and 8ppm....but my tiny little soybeans with that tiny little root system are 32ppm?  What?  How does a tiny little root system of a soybean plant extract that much more boron than corn?  The soils are similar...almost identical since its just a field across the road.  5ppm vs 32ppm?  I just think that corn doesn't WANT boron now(not in the leaves anyhow).  Even with high soil tests I suspect that early season testing of corn leaves for tissue testing won't show any response to SOIL APPLIED boron....I suppose it might in foliar, but a typical "foliar" application gets only a tiny amount of boron on the actual leaves....most hits the soil. 

Maybe the corn plant is sending all the boron it extracts from the soil to the ear that is forming down within the plant...and there is nothing left to go to the leaves...or maybe only EXCESS boron goes to the leaves.

Just to reiterate my point....only 10% of corn's boron is in the stover(leaves)...heck maybe most of that is in the stalk...IDK.  Perhaps tissue testing for boron is not an effective way of knowing if your corn plants want more boron, or if its a yield limiting factor....maybe we should be testing the grain?  Or the ear itself during pollination or milk, or dough?  that is where the boron is needed. Maybe someone should send a memo to Midwest Labs.

Just some ideas............