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How to Read Your Arkansas Soil Test Results - Part 2

So you've done your due diligence and requested a soil test. Now you have a piece of paper from the University of Arkansas Division of Agriculture containing a wealth of knowledge about your soil. Now what? What do these numbers mean and how do I use this to improve my produce?

Understanding the Numbers

Frankly, I'm not sure anyone out there has all the answers about creating the very best soil, and I'm certainly still learning the basics of what these numbers mean. Before we get into the details, I want to point out a few things:
  • Perhaps it's counter-intuitive, but it is actually better to have nutrient levels that are too low than too high. Too much nitrogen, for example, will grow big, bushy plants, with weak root systems and little fruit production. Another reason to amend slowly according to soil tests is because it's far easier to ADD elements than to REMOVE them. Once you add a particular soil amendment, you can't take it back out. 
  • Add your amendments a little at a time, and request a new soil test anytime to see how things improve. Tests are free, so there's no reason not to use this valuable resource as often as needed.
  • The fertilization recommendations given by the UofA are automatically generated and do not specifically address your soil needs. You'll need to amend your soil based on the numbers. 
Part 1 of your soil test: Nutrient Availability Index
To understand the Nutrient Availability section of our soil test, we must visit the periodic table and learn what all those nutrient abbreviations mean. If you're serious about learning about your soil, I HIGHLY recommend taking Calvin Bey's classes in NWA. We are comparing the "desired level" number below with the "lb/acre" number on our Arkansas soil test. Disregard the "ppm" column altogether.

Once you get your soil test back, refer to this free pamphlet from the University of Arkansas Extension service (requires the ability to read PDFs).  Print it out and read it carefully. It contains valuable information, but it is written by scientists, so it can be a little difficult to understand. Please feel free to email me if you have questions.

Adding Micronutrients

If you notice, there are a lot more than just three elements on a soil test. That means that commercial fertilizers that contain Nitrogen - Phosphorus - Potassium only (which reads like 10-10-10 on the bag) are doing nothing to add the rest of these minerals to your soil. This is very similar to looking at the nutrients on a multi-vitamin bottle, we need all these and many more. That's why a general fertilizer simply isn't enough.

This is why compost is so very important. It is fertilizer made by nature, possessing the many different trace minerals we need, well beyond this list. Compost contains no unbalanced levels of one nutrient, meaning you cannot over-fertilize on any one element, which prevents an imbalance. The best practice is to add a 1/8-1/2" layer of compost to the top of your beds and work it into the top several inches of soil.

Is all this clear as mud? I know, it's confusing. And you'll get different info from different sources, so do what seems the most prudent for your situation and remember this, even if you remember nothing else from this post: Do not over fertilize. You can always add more amendments slowly. Nature is forgiving, but it takes awhile to recover when we overwhelm her.

Be honest, have you gotten a soil test or are all those numbers too overwhelming to bother?


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