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Little River, TX | Curt:
It has to be reasonably simple for me to understand.
Just as with a soil test the results will come back listing the values they found. Nitrogen is the one element that seems to change the most and fastest.
If sampled at around 3½ or so weeks after the first cutting and in late bud stage, Maybe a bloom or two in the field.
The Lab may report 3.85% N That will be within the desired range of 3.12% & 4.15% N,
Get a little anxious and sample at 3 weeks, and maybe mid bud stage the Lab may report 4.75% N ( as they have done with me) but not to worry.
With the other elements. say the phosphate results were 0.34% P that is not bad and within the desired range mg is 0.35% again that is ok as it is within desired range. both on the high end but ok.
It is possible all the remainder elements will be reasonably good also. It is also possible one of the other elements is too low. Add fertilizer with that element and things improve.
But, in my case, Potash is 2.20% K and calcium is 2.60% Ca now these are both out of the desired range. Nothing drastic, but stand persistence will suffer. Winter and drought tolerance can be a problem.
This is where things become challenging. Is the potassium too low because there is too little available soil K or because there is too much available soil calcium? This is what I usually see, here. I can not lower the calcium levels so must add potash.
The soil test tell me I have excessively high calcium and high potassium. In my case the naturally high calcium levels block the Ca. This is even with the soil test being high, 350 ppm K, in potash.
If I fertilize to bring the soil test up to 425 ppm K the plant calcium will drop. The plant analysis may then be 2.50% K & 2.00% Ca. both a little out of desired but close for now.
If I dump potash on the soil and bring the soil test up into the 500 ppm K range then both K and Ca will be in the desired ranges. Costly to be sure. It would be a lot less costly is my soil was short of calcium and the plant being short of calcium and in the luxury range for potassium. Even applied by the ton lime is cheaper than potash!
Again in my case bringing up the plant K levels, which in turn can reduce the Ca levels also will bring the magnesium (Mg%) levels to mid range. If, as is in my case the Mg% wants to drop down the lower end of it's desired range. In this case I use some K-Mag in my fertility program.
Again in my case, once my soil test and tissue test are in a desired range they stay there for 3 to 6 years. If you have mostly sandy soils, things are much less complicated. Then a little dab will due the job, but you may have to apply smaller amounts potash fertilizers both in the spring and the fall.
Clear as mud?
What is scary is, I consider myself on the ragged edge of total ignorance. In fact a little knowledge can be dangerous. 
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Plant Tissue testing questions............
