Register free!
Search
 
     

Click for Weather
Reply
 
Thread Tools Display Modes
  #41  
Old 07-04-2009, 10:01 AM
muddstopper's Avatar
muddstopper muddstopper is offline
LawnSite Silver Member
 
Join Date: Dec 2002
Location: transition zone
Posts: 2,343
Quote:
Originally Posted by Smallaxe View Post
Cation Exchange Capacity. Simply put it is where a nutrient molecule latches onto a particle and the root is able to extract it for use. How many places for a molecule to latch onto defines its capacity.
Not just any molecule. CEC is a measure of the "Positive" (cations) molecule, and how they are Adsorbed and not Absorbed by the "Negative" (anion) nutrient molecules. Adsorbed being that the molecules are attached on the outside of the negative molecules where thay can be easily detached, rather than being absorded, where s they are surrounded by negative molecules and rather hard to dislodged for plant uptake. To many negative results in a absorbsion of Cations, rather than adsorbsion and to many Cations, will result in absorbsion of Anions, whereas a correct balance of Cations and Anions will result in more readily availability of both types of nutrient molecules.

Hydrogen being the major acid causeing Cation where the positive charge of the hydrogen molecule is used to dislodge the other positive charged molecules from the negative molecules. Further, as hydrogen is found in abundance in water solutions, this same hydrogen molecule is used to exchange negative nutrient molecules with the plants. Ph being one measure of how much hydrogen is in the soil.
Reply With Quote
  #42  
Old 07-04-2009, 11:04 AM
Kiril Kiril is offline
LawnSite Fanatic
 
Join Date: Jun 2007
Location: District 9 CA
Posts: 18,309
CEC = measure of electrical charge per unit mass of soil, typically expressed as meq/cmol or cmolc/kg.

Soils adsorb

Plants absorb


A short review

http://www.soils1.cses.vt.edu/MJE/sh...n1.1/cec.shtml

Last edited by Kiril; 07-04-2009 at 11:11 AM. Reason: added a link
Reply With Quote
  #43  
Old 07-05-2009, 09:56 AM
Smallaxe Smallaxe is offline
LawnSite Fanatic
 
Join Date: May 2007
Location: Central Wisconsin
Posts: 9,903
Quote:
Originally Posted by muddstopper View Post
Not just any molecule. CEC is a measure of the "Positive" (cations) molecule, and how they are Adsorbed and not Absorbed by the "Negative" (anion) nutrient molecules. Adsorbed being that the molecules are attached on the outside of the negative molecules where thay can be easily detached, rather than being absorded, where s they are surrounded by negative molecules and rather hard to dislodged for plant uptake. To many negative results in a absorbsion of Cations, rather than adsorbsion and to many Cations, will result in absorbsion of Anions, whereas a correct balance of Cations and Anions will result in more readily availability of both types of nutrient molecules.

Hydrogen being the major acid causeing Cation where the positive charge of the hydrogen molecule is used to dislodge the other positive charged molecules from the negative molecules. Further, as hydrogen is found in abundance in water solutions, this same hydrogen molecule is used to exchange negative nutrient molecules with the plants. Ph being one measure of how much hydrogen is in the soil.
Great additional comments - A little more detailled than my 'simply put' context.
2 followups.

Are all nutrients anion molecules?
Is compost mainly positively charged Cations, due to it high Carbon content?
__________________
*
Now that I know that clay's texture(platelets) has nothing to do with water infiltration, percolation, or drainage
,,, I wonder what does...
*
Reply With Quote
  #44  
Old 07-05-2009, 10:12 AM
Kiril Kiril is offline
LawnSite Fanatic
 
Join Date: Jun 2007
Location: District 9 CA
Posts: 18,309
Quote:
Originally Posted by Smallaxe View Post
Are all nutrients anion molecules?
No

Quote:
Originally Posted by Smallaxe View Post
Is compost mainly positively charged Cations, due to it high Carbon content?
No, and I am not even sure where you are going with this.
Reply With Quote
  #45  
Old 07-05-2009, 10:31 AM
Smallaxe Smallaxe is offline
LawnSite Fanatic
 
Join Date: May 2007
Location: Central Wisconsin
Posts: 9,903
Kiril,

What are the exceptions?
Why does compost have a lot more CEC than regular topsoil?

There are too many factors - to be sure... One example - simply put - is useful.
__________________
*
Now that I know that clay's texture(platelets) has nothing to do with water infiltration, percolation, or drainage
,,, I wonder what does...
*
Reply With Quote
  #46  
Old 07-05-2009, 03:53 PM
growingdeeprootsorganicly growingdeeprootsorganicly is offline
LawnSite Senior Member
 
Join Date: Jan 2008
Location: obamaland
Posts: 770
kiril, thanks for the new link, great info...!


smallaxe, if you read kiril's link and link to the other links/pages there it explains why some clay's have more CEC then others, if you look at OM, and it's humic fraction it becomes sort of more
obvious why humus has more CEC then clays, it's not just the carbon, think oxygen and hydrogen too for that matter
Reply With Quote
  #47  
Old 07-05-2009, 07:12 PM
growingdeeprootsorganicly growingdeeprootsorganicly is offline
LawnSite Senior Member
 
Join Date: Jan 2008
Location: obamaland
Posts: 770
i find interesting how pH is such a major factor on what type of phosphate is in majority in solution and how water soluble some phosphates can be at different pH
Reply With Quote
  #48  
Old 07-05-2009, 09:05 PM
Kiril Kiril is offline
LawnSite Fanatic
 
Join Date: Jun 2007
Location: District 9 CA
Posts: 18,309
Quote:
Originally Posted by Smallaxe View Post
What are the exceptions?
Exceptions to what???

Quote:
Originally Posted by Smallaxe View Post
Why does compost have a lot more CEC than regular topsoil?
It doesn't necessarily have more. Remember OM has pH dependent charge/CEC, and it increases at a faster rate than clay as pH moves towards neutral.
Reply With Quote
  #49  
Old 07-06-2009, 02:01 AM
JDUtah's Avatar
JDUtah JDUtah is offline
LawnSite Silver Member
 
Join Date: Nov 2007
Location: UT
Posts: 2,671
Quote:
Originally Posted by Smallaxe View Post
Great additional comments - A little more detailled than my 'simply put' context.
2 followups.

Are all nutrients anion molecules?
Is compost mainly positively charged Cations, due to it high Carbon content?

What are the exceptions?
Why does compost have a lot more CEC than regular topsoil?

There are too many factors - to be sure... One example - simply put - is useful
I think I know what you are looking for, and think I have some good and bad news. I am working on a reply, but it might take a few days to get it all together.
Reply With Quote
  #50  
Old 07-06-2009, 07:58 AM
Smallaxe Smallaxe is offline
LawnSite Fanatic
 
Join Date: May 2007
Location: Central Wisconsin
Posts: 9,903
Quote:
Originally Posted by Kiril View Post
Exceptions to what??? ....
The train has derailed.
__________________
*
Now that I know that clay's texture(platelets) has nothing to do with water infiltration, percolation, or drainage
,,, I wonder what does...
*
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump





Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 01:52 PM.

Page generated in 0.10132 seconds with 10 queries