Questions on soil analysis (OM %)

16 years ago

Organic Lawn Care folks -

last week I got the results of a soil analysis (testing done at Iowa State University.) The ISU report did not recommend that I do anything, but I thought I might ask for a second opinion from you folks. (I have been having some fungus and thatch problems with my East-Central Iowa KBG yard.)

My pH was 7.2, which apparently is about right, maybe just a bit high from what I read on the internet. So that seems O.K. Don't need to spread any lime.

My %O.M. (organic matter) was 3.8% in the back yard and 4.4% in the front yard. This one was a bit more confusing to me, as ISU did not provide a range over which 'normal' was. What should I have here? Am I low, high or just right for OM %? I have not seen this discussed much on the internet.

The rest of the test showed very high values of P (96 ppm, where 50 is considered high) and K (192-290 ppm, where 175 is considered high.) Must be the result of years of overuse of synthetic fertilization (by the home's previous owners, I guess.) I am guessing this is not a real problem, I guess better to be high than low for P and K.

Any comments, especially on the OM, I would appreciate it. Thanks.

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Comments (3)

deerslayer
16 years ago
It appears that you have great soil! Normally, OM that is 3% or more is considered high.

Here's a short article about soil tests. It contains more detail on OM%.

Soil Tests

-Deerslayer
morpheuspa (6B/7A, E. PA)
16 years ago
+1 Deerslayer.

I wish I had that soil. My OM is far lower (but still capable of good growth), and I'm working slowly toward a level more like yours!
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billhill
16 years ago
Mtgavin - Your OM level is great. Since you are posting here, I assume you are using organic lawn maintenance. And if that the case, then soil testing is of less importance after the initial base line test. OM will buffer the PH of your soil and move it towards neutral. The P and the K will take of themselves. Be aware that OM is consumed by the many various soil microbes and needs to be replenished. Mulch mow all your fall leaves and spread some compost on any week areas of your lawn. Take a look at my profile for my take on compost, which is OM refered to in the title of this post.