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Follansbee, Wv

In an effort to better understand soil sample test results, and thereby be able to make informed decisions about my soil, without having to bug other people, I would like to start a conversation on the analysis of test results. I am doing this for several reasons, first and foremost, so I can better understand what is going on at the root level, and secondly, to maybe enlighten others. I know many people have differing theories as to the ideal soil for growing AG’s, so if possible, detail your theory, and explain why you think it’s appropriate for your conditions. I personally believe that no absolute values exist across the board for all growing conditions. In other words, while the desired levels of various nutrients may be similar, I don’t believe the exact same levels of said nutrients would be appropriate for all soil and growing conditions. While that statement is a point of argument, and differing opinions are very welcome, it’s not the primary mission of this thread. Expanding the knowledge base of all growers in the area of interpreting soil test analysis results is my primary goal.

1/19/2005 10:10:19 AM

Follansbee, Wv

I would like to start off with CEC and Base Saturation levels. I will use some of my own test results for illustration purposes.
I understand that CEC is the Cation Exchange Capacity of the soil, the basic cations being CA, MG, K, and NA, and the acid cations being H and AL. The higher the CEC, the more of these cations the soil can hold. Correct so far? This leads me to my first question. With a pH of 6.6, CEC of 10 and %Sat levels of K=3, CA=64, MG=34, and H=0, which totals 101%, there is no exchangeable acidity in the soil. Is this a good, or bad thing? It is my understanding that low pH levels will create an environment in which excess AL will be made soluble, due to the acids in the soil, and may become toxic to plants, especially in pH ranges below 5.0, but should all of the CEC sites be taken up by the basic elements, leaving nothing for the acidic? Or am I misinterpreting what I have read?

Now, taking another test result, pH=4.9, CEC=13, and %Sat levels of K=2, CA=20, MG=4, and H=74. The levels total 100%, however only 26% of the CEC sites are occupied by basic cations, while 74% are acidic. Obviously, the acidic nature of this soil should produce nearly toxic levels of soluble AL. The application of lime will neutralize the acidic cations of H, and reduce the amount of soluble AL to below toxic levels, making more sites available for the basic cations. So the question still stands, is the elimination of all acidic cation base saturation desirable, or is it the natural result of a near neutral pH?

If anything I have said here is wrong or misleading, please correct me. I am trying to learn about this, and am expressing my opinions to see if they are valid.

1/19/2005 10:10:41 AM

Garden State Pumpkins

Yo ...g1t...5 years I still don't have this!!!..Monty you're already way ahead of me...I read and I read and I read but to no avail...when I think I have it...Nope!!!!
I post my soil results here and listen to what everybody tells me to do...something about CAT ION exchange I'll never get!..Grow em Big! Chuck

1/19/2005 6:50:13 PM

Follansbee, Wv

Just keep reading Chuck! Hopefully those with more knowledge than I will chime in. The whole point of this thread is to stimulate conversation that we all can learn from. That way we can all make better decisions as pertains to soil prep, on our own, and according to our individual locations needs.

1/19/2005 10:14:52 PM

Ctpumpkin@optonline.net

When I get back Monty.

1/20/2005 5:49:48 AM

Www.extremepumpkinstore.com

Monty, I want to learn this as much as you, but then I look at the soil results of some of the HH and notice that no two are the same, most levels are high, but no two are the same, more confusing then ever!

1/20/2005 8:10:29 AM

Utah

LOL @ Chuck !
:)

1/20/2005 8:49:29 AM

Follansbee, Wv

I wouldn't expect two samples to be the same. Like I said earlier, I don't think there are exact levels across the board that will work in all types of soils. I'm not trying to determine that. I am just trying to understand the test results themselves so I can make my own decisions when it comes to making ammendments. Once I understand what I am looking at more clearly, I will be able to decide what to do, and what to expect from year to year.

1/20/2005 9:25:35 AM

Menomonie, WI (mail@gr8pumpkin.net)

The local AG Extension agent compared a soil test, to tasting something with a eye dropper. Then only after a few tests are done to be able to get a good understanding of the soil.

1/20/2005 10:19:07 AM

Utah

A few links for those who would like to read up on CEC.
the first 3 are from the hort.net archive- ie- pumpkin growers talking about the subject.
The last one is a paper on CEC for a college class.

http://www.hort.net/lists/highlight.cgi?bits=3&search=cation+AND+exchange&URL=pumpkins/dec99/msg00120.html#marker

http://www.hort.net/lists/highlight.cgi?bits=3&search=cation+AND+exchange&URL=pumpkins/dec99/msg00170.html#marker

http://www.hort.net/lists/highlight.cgi?bits=3&search=cation+AND+exchange&URL=pumpkins/apr03/msg00306.html#marker

http://syllabus.syr.edu/esf/rdbriggs/for345/cation.htm

Chuch I hope these help ! lol !
gordon

1/20/2005 12:25:57 PM

Utah

opps Chuck ! not Chuch

1/20/2005 12:26:20 PM

Garden State Pumpkins

Yo Geetwotee,,,,...errrr Gordon...LOL...Alright I'll start reading this stuff again...but I just think people from the Garden State just can't do this...Just like directions...you tell us make a left or a right not head north or south at the light!!! LOL

1/20/2005 6:34:12 PM

Www.extremepumpkinstore.com

lol

1/21/2005 8:34:48 AM

Garden State Pumpkins

Yikes! This poor dog will never...I repeat Never....

1/25/2005 11:10:34 AM

Chico, Ca

Wash your hands and sanitize your computer after going on the mallorn site( hort.net). I have never been to a site so contaminated with computer viruses in my life. we had to drop being on the list because we had so many emails sent to us that were virus generated.We even found things posted on the pumpkin list by US that we never sent...I'm not kidding,we were getting emails through them from people not even on the list. All were around 1k with attatchments.we got hunderds of them. All just waiting for some poor sob to open them an infect their computer.

1/25/2005 7:35:16 PM

Follansbee, Wv

I read those links g1t, as well as some others. This statement from your first link almost answers the question of acidic cations:

"Typically it is not economical to saturate your soil to a 100% saturation level. Agronomist recommend a balanced saturation rate 65-75% calcium,10-15% magnesium and from 2-5%potassium."

From what I understand, the CEC will ALWAYS be saturated to 100%, however not always with basic cations, as is evedenced by soil sample 2 above.

This quote from your fourth link may have some bearing:

"The CEC's of whole soils and the contributions of clay and organic matter at different pH's are shown in slide 14. The change in CEC of the clay increased 1.7 times in the pH range from 2.5 to 8.0, while that of the organic matter increased nearly 6 fold. As a consequence, organic matter which contributed only 19% to the CEC of the whole soils at pH 2.5 contributed 45% to the total pH 8.0."

That makes the importance of OM pretty obvious! However, at the more neutral pH levels, with high OM, it appears that 100% saturation with basic cations is inevitable. There almost appears to be a mathematical correlation between OM and CEC. In other words, if one knew their CEC figures, they could calculate OM content, but there is one thing missing from the equation; the exact clay content of the soil. Not only the amount of clay, but also the type of clay would need to be known. HMMM, getting off track here...sorry

cont...

1/26/2005 8:51:53 AM

Follansbee, Wv

Anyway, it appears that there is some differing of opinion between the two links mentioned above. On the one hand, 100% saturation is not recommended, but on the other hand it's nearly impossible to stop. I wonder if there is a "window of opportunity" so to speak, in which a certain OM level in a given soil would allow saturation levels close to those listed in link one, without total saturation, and still be within the desired pH range of say, 6.5 to 7.5. Talk about a soil balancing act! I guess that's more food for thought, back to the research...

1/26/2005 8:52:03 AM

Contact me at the end of the school year. I just started taking "Intro to Soil Science" he he he Watch out in '06!!!

1/26/2005 9:44:51 AM

Follansbee, Wv

I can see your Masters Thesis now Brigitte:

Critical Analsys Of Balanced Soil And Its Effect On Fruit Weights Of The Atlantic Giant Pumpkin

LOL, maybe you can write off growing pumpkins as an educational expense...

1/26/2005 2:36:16 PM

Follansbee, Wv

Well, it's been several days, and no input. The original question still stands. Is the elimination of all acidic cation saturation desirable or not?
I am no soil engineer, and don't pretend to be one. I am a gardener however, and I strive to learn as much about my hobby as I can. Perhaps if more people took an interest in what happens below the visible soil surface, they could grow bigger pumpkins? Come on people, this discussion is intended to stimulate thought.
If you are not willing to put forth the effort to understand your own soil, then breeding AG's isn't the only "crap shoot" game in town. Your own growing season is on the next table over.

2/3/2005 10:51:32 PM

Ctpumpkin@optonline.net

If limestone materials are needed to correct the pH then they should be applied. Once the pH is correct the H usually is zero. Whether it is or not isn't the goal & makes no difference.

Most of the time, H will be zero & this is good.

2/3/2005 11:19:43 PM

Utah

Monty ...
I'm no soil guru either ... I don't think any of us are.
Personally at some point I had to put aside a lot of trying to figure out all the theory and go to ... what do i need to do to my soil. What should I add to my soil. 2 years ago I started a new patch at my new house... which had a fairly heavy clay based soil... and the answer for me was lots of OM (horse manure), some 16-16-16, some 34-0-0-16 amonium sulphate, a trace mineral suppliment (azomite), and some chelated calcium.
in the fall of 2002 my pH was 7.8 in Nov 2004 it is 6.7
OM was 7.1 now 9.2
CEC was 29.3 now 22.9 - so adding OM not not always raise CEC ... Clays based soil have higher CEC's.
My N, P and K are all a lot higher now ...
my Ca and Mg are both lower but I think still fine
My Salts are up ... slightly above the normal range...From all the fresh manure ... so next year i'll cut way back on that ... and look for other OM sourse ... like leaves, or composted manure.
So far I've been happy with my results...

2/4/2005 10:01:42 AM