Recently, I compiled soil test data that came through MFA's West Central AGRIServices office in Adrian from 2000 to present. The first set of tests were from 2000 through 2006. The second were from 2007 through 2009. When I looked at soil tests in the "low" to "very low" range, the results in the older data group showed 52 percent were low on phosphorous and 18 percent were low on potassium.

The later group showed that 51 percent were low on phosphorous and 27 were low on potassium. As for soil pH, the older set of samples showed 29 below a pH level 6. In the more recent collection, some 38 percent of samples were below a pH level of 6. Our MFA home-office agronomy staff agrees that this is not just a local trend in our area, they are seeing this all across the MFA trade territory.

I'm sure that by now you are thinking that this is a fertilizer sales pitch, but that is not my goal. My goal is to develop a fertilizer recommendation based on all information available to us. The only true way to do this is based on current sampling, taken in an unbiased and random pattern and combined with yield data from each field.

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Sometimes you see the thin stand, or an area that is always wet. Or, you may be on the thin ground from which you borrowed to fill a ditch or build terraces. Often times, though, you are in the good dirt—maybe where the beans used to be 5 or 10 bushel better, or the corn is the same as it was years ago. You think about the cause, and consider insects or a disease. You know you are fertilizing the same as always, and you are using the best genetics. Still your yields just barely improve.

We all know that most fields have inconsistent soil types and yield capabilities. So could it be that most areas of the field have shown a slight yield increase as you bring a better genetic package with your seed purchase. Meanwhile, it could be that the very best soil yields the same because the fertility has fallen off. In an attempt to increase yields we put on more fertilizer, and as we would expect, slowly the yields increase. But, if you identify the low-soil-test areas, especially the ones that happen to be the best ground and fertilize it to its highest potential, you'll be giving those seed genetics the means to perform as expected.

Now, just like the effect of a few drowned-out spots that drag your average yield, you can see it the other way around with your best soil boosting yield to its potential. I illustrate this to point out that as we continue to plant better genetics and expect more yield from every acre, the fact is our soil fertility is not keeping up with demand. All of the new technology you put in a tractor cab (yield monitors, auto steer and even Internet on your smartphone) may or may not make you money, but my read on the data is that we are neglecting the proven technology available to put each fertilizer dollar in the most needed spot.

We don't always need to crank up the fertilizer rate to get the best return; we just need to apply it wisely. I would like to suggest that you soil test your fields in a grid-sample method and use variable-rate application to apply your fertilizer and lime.

Doing this will place the right amount of fertilizer where it is needed most and not waste fertilizer in places that don't need it.

Dale Guss is the branch manager of MFA-owned West Central AGRIServices in Adrian, Mo.