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Eugene,OR

I just got my soil test back and my CEC (which I think is the Cation Exchange Ratio) is much lower than it has ever been. In this test it is 7.4 and in the past it has been in the high 20's to mid 30's. Any insight to what this means and what I should do???
Thanks

2/18/2011 1:03:36 AM

Bethlehem CT

I am not a soil scientist but If you have a low cation exchange capacity it means that nutrients will wash quickly from your soils. Sandy soils tend to have low c.e.c.s and clay soils will have high c.e.c's. You can boost your C.E.C. by the addition of organic matter.
I would be willing to bet your C.E.C has dropped over the years as Organic matter has decreased in your soil.
There is some pretty major chemistry involved in understanding soils, most of which is way over my head. But I think most of us can use our soil test data and understand and treat the soil with a practical understanding of it.

2/18/2011 8:22:58 AM

Upa Creek, Mo

I remembered this post from a while back. See Mr. Wallace's response, Big Moon is on the right track.

http://www.bigpumpkins.com/MsgBoard/ViewThread.asp?b=14&p=368301

2/18/2011 10:42:58 AM

Eugene,OR

My organic matter is "very high" 19.9%.

2/18/2011 11:16:35 AM

Mill Bay, British Columbia

Russ, my organic matter is high too (sandy loam with high OM) and to combat falling CEC in fall soil tests, I have been adding granular humic acid at the recommendation of my soil expert/mentor.

I add 25 lbs in spring and fall and that keeps my CEC in the higher range that we are looking for. Worked for me.

2/18/2011 11:21:17 AM

South East

russ, retest

2/18/2011 6:05:35 PM

Eugene,OR

I like the idea of re-testing. I think that this is a strange reading. It is very different from anything I've seen in past years...and I haven't changed anything.

2/18/2011 8:18:51 PM

Central Ca

Having worked in labs. I agree with The Cooks. More mistakes happen in Labs than they are willing to admit. Perhaps a different lab or talk with the lab you originally tested at and tell them there's something out of whack and the mistake was on their end. That should get you a free re-test. -Kevin

2/18/2011 9:13:34 PM

Picton,ON (j.vincent@xplornet.ca)

C.E.C is not tested it is calculated. I would phone the lab and question them, Its likely a mistake. Don't waste your money on a retest. It has to be higher than that based one your O.M.

If you are concerned about the C.E.C level, add Humic Acid.

2/18/2011 10:08:14 PM

Germany/Bavaria

Just curious vineman.....which lab did you send the sample to?

2/19/2011 2:43:57 AM

Willamette Valley, Oregon

I'm with CountyKid...probably a typo or miscalculation. I'd start by asking the lab to double check before you get too worried.

2/19/2011 3:12:48 PM

Santa Rosa, CA.

20% organic mater, what are you growing in? compost. I think you should take a year off and rest your patch. Re-test in 2012 :)

2/19/2011 9:09:58 PM

Colorado

When I changed labs from local to western my CEC dropped from 25 to 11.The 25 was a mathematical formula based on base saturation and was not accurate.Western uses a appropriate technique for alkaline soils.Their 11 # was a much more accurate representation of my soil.If your soil is in the acidic range I believe the #'s would be close.

4/14/2011 1:02:15 PM