nitrate is a form of nitrogen. Ammonia, nitrite and nitrate (also atmospheric (gas)), but that doesn't count.

Why have it tested? This has already been done and the npk is fairly well established at 2.5-1-1. This isn't precise and certainly can vary from crop to crop, but it's a good ballpark.

justaguy-
The reason for testing is I contacted the manufacturer of this particular alfalfa meal, and he got back to me with the following numbers 5-1-2.

In just about everything I've read the nitrogen and potassium was as you state.

So, I'm more or less just curious. If I'm understanding this correctly IF the levels are as indicated, then doesn't it make the material twice as valuble (from a strictly content standpoint)? It would also be more valuable to my circumstances if the ratios were as stated, because I currently have a potassium deficiency, but a surplus in phosphorous.

So, as far as the nitrate nigrogen goes, would testing for that reveal the total nitrogen contained in the product (Total N as in NPK) or does it tell me something else I'm not necessarily interested in?

As always, thanks for your input.

I am not sure what methodology is used for such a test.

OK. Thanks for responding anyway. I'll try another call to the ag lab and see if they can explain it to me.

When you get a material tested for guaranteed analysis labeling(That's what they call the N-P-K on the bag), they will be looking at total nitrogen. If you just get nitrate done that will only give you part of the picture that you're after. So...no that won't give you the N from "NPK" You'll be missing out on your ammonium (NH4), which is also very soluble and used by plants (although to a much lesser extent than nitrate unless you're talking about rice or some other oddball) and converts quickly to nitrate. It also won't include any nitrogen that will become available over time as the alfalfa meal breaks down.

OK. Interesting. So, what kind of test would you have done to determine total nitrogen?

Or, at a minimum, if I can only get the nitrate nitrogen test done, then I'll know that in reality I have MORE nitrogen available than the tests indicate.

Any idea why a testing lab like Clemson, would only test for nitrate nitrogen? I mean, why wouldn't they just by default test for total nitrogen? Test more expensive and nitrate nitrogen gives the big picture anyway?

OK. Interesting. So, what kind of test would you have done to determine total nitrogen?

Or, at a minimum, if I can only get the nitrate nitrogen test done, then I'll know that in reality I have MORE nitrogen available than the tests indicate.

Any idea why a testing lab like Clemson, would only test for nitrate nitrogen? I mean, why wouldn't they just by default test for total nitrogen? Test more expensive and nitrate nitrogen gives the big picture anyway?

Well, I don't know the first thing about Clemson labs or who their clients are or why those clients need testing done.
But here's my guess:
To get just nitrate you only need to run one test. That test will tell you the amount of nitrogen that is immediately available in the form that is most used by the majority of plants. Since they do just nitrate by default, they must know that it's what most of their clients are interested in. In order to get total nitrogen you have to run multiple tests and the prices goes up very fast. I would bet they'd be happy to do it for you if you asked, but you would get charged for it.

OK. I'm following you. That was my guess too. I'll contact them to see if they can do the entire test.