No good soil test lab will test for Nitrogen anymore because the availability of N is too dependant on soil temperature to give a reliable result. A test for organic matter is real simple and you can do that your self, what you are really interested in knowing is your soil pH, and why it is where it is (the CEC helps here), and the macro as well as many micro nutrients as possible since the micro nutrients affect a plants ability to uptake the macro nutrients. Michigan State University CES now charges $12.00 per sample for about the same test. This test is an indicator, not the end result. A soil test now is the base from which you begin and if you amend your soil and retest in 5 years you should see where you are going. There is no good reason to test the same plot every year, or more often, but you can test different beds, different years, to see what is going one in them.

>>No one can help you since the link gores to a downloadable music file. Feeling a bit 'gored' this morning? LOL While you're fixing the link coraloski, a cover crop (or 'green manure') is not essential to next year's harvest and there are other ways. You could buy compost, make compost and add it, make compost in place by layering materials starting right now and plant through it in the spring, or maybe some other ideas that aren't coming to me right now. Although 2 acres is a lot of ground to do any of those...hope you have some equipment.

If you have reason to believe the back is significantly different from the front then you should test them separately. Yes, you would have to pay for both. Ideally you would pull multiple cores from each area you want tested and that would get you an "average" across the area. This is to avoid a situation where - and this is a crazy example - you dumped a bunch of lime in one spot and your test comes back with a high pH but the rest of your yard is actually acidic.

Tricky? Not really. Place one or two squares of nylon window screening in the bottom of the inverted top. I use such in regular pots without issue. For stability, rocks can be placed in the bottom section. Furthermore, if this is just to test the media, the weighted bottle could sit in a terra cotta pot or a shallow hole in the ground, or braced with bricks, or any number of other cheap, down and dirty solutions.