I should say right at the beginning that I’m not a highly educated man.  I’m just a guy who’s been involved with a narrow slice of agriculture for a number of years and soil testing has been a primary source of information which I can react to in order to offer my customers the best choice to be successful growers.

The most common test is a PH test which does exactly that – measures PH. It’s an easy and usually free test which indicates the acidity or alkalinity of the soil being tested.  It provides good information for checking out potting soils and garden soils in small areas for the leisure time grower. Local nurseries will have suggested materials to help with your situation in that area.

For the larger scale yards, sports fields and finally farm fields, the main type of test (for $10 or so) is a basic mineral test.  From each area to be tested, 1inch “plugs” of the same depth (usually 3-5” or the “root” depth) are pulled with a special tool and are bagged accordingly to represent each separate area you are testing.

This “mineral” test is very basic and has been around for many years. It will tell you approximately how much (in lbs per acre or in parts per million- PPM) of the most important minerals you have in each designated area.  Then, if the lab knows what you are growing in that area, they’ll figure out how many lbs per acre or PPM it takes to grow a viable crop for you and compare the two figures.  This comparison will give positive or negative figures and thus the recommendation for what soil amendments (i.e.  NPK+ _?_) will come from this information.  PH of course is figured and noted.

Another commonly used test is the one using “Base Saturation” methodology.  Samples are taken in the same manner as before.  This test is based on analysis of the smallest particle of soil which can be measured in the lab.  This test measures the % of the major soil nutrients which are attached to this piece of soil.  This measurement gives a very accurate picture of WHY the PH is where it is by making it very obvious as to which major minerals are out of their normal range.  When given the range parameters, it’s easy to pinpoint current and potential problems.

This type of test is more of a chemistry test and allows insight into why the soil is doing what it does in each situation.  Further, this test has a measure of “soil tightness” – usually misunderstood and related to as a measure of compaction, although that’s probably OK – which allows the grower to further understand why his crops are reacting as they are to each different soil.  The Base Saturation “basic” test measures Phosphorus availability using a light soil acid (P1) and a strong soil acid (P2) which further allows the grower to access the strength of his soil microbiology by understanding what’s available easily compared to what it could be with the levels he has in his soil.  The “basic” test also includes trace minerals and organic matter which help further to define each situation.  This is really a terrific test, but it does require a little bit of study to understand the numbers and what they’re saying.

There is a third test available, but is less known, which uses water to extract and measure the available nutrients as compared to the other tests which normally use a acid extraction.  Water extraction is deemed to be most accurate since it almost duplicates the soil situation.  It gives very precise information, but I’ve found it to tell generally same story as the Base Saturation test at a lesser cost !

I’ll admit that I prefer the Base Saturation tests.  They are easy to understand and are very accurate even though the story they tell may not be the one the grower was looking for !  A word to the wise here is necessary.  When ordering these tests be sure to find out what will be included in your information – always ask for sodium to be measured and for trace mineral information and Organic Matter.  You’ll probably pay $20 -- $25 for each sample which you have done (the lab will provide the bags and labels and necessary submittal information and sheets if you ask). Just work out your own deal. 

Some fertilizer dealers may provide soil samples for nothing as part of doing business with them.  Some dealers are even doing the base saturation tests and you need to make sure they will include the sodium, trace minerals and P1 and P2 measurements.  I mention this because they work with the labs on contract and get a deal ($$$$) for samples.  Their deal may be just for the nuts and bolts and not for all of the needed information which generally they don’t understand fully.  Just be sure to ask because otherwise this freebee may not live up to expectations!

Base Saturation testing is usually done by independent labs which are all over the USA.  Some universities use this type of testing, but not many.  More are going to it so you just need to ask.  Just start calling around to find a lab in your area or use the internet search to get direction as it’s full of information.

Base Saturation testing forces the grower to recognize the understated value of the biology of the soil without which NOTHING would grow.  Then it brings up the question(s) as to what to do with which materials to treat the soil microbiology efforts equal to what the grower does with granular amendments.

Which materials am I talking about to work with the soil biology ?  Just drop me a note or call! 

Whichever you do, get started now and learn what’s going on.