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02-07-2002, 07:13 PM
#3
Nontypical Buck
Join Date: Feb 2003
Location: Ontario Canada
Posts: 2,059
RE: Soil Test Results are In
Didn't you receive results for Nitrogen, Phosphate, and Potash? Normally you should get numerical readings which you can compare to requirements for different crops.
I can try to offer some answers to your questions.
buffer pH is a pH reading which takes into consideration the buffering effect of your soil. Sands have little buffering capacity vs clays that have larger ones. It takes more lime to raise the pH of clay soils because of this. The buffer pH takes this into account for your soil.
Cation Exchange capacity: Clay particles have ion exchange sites with negative charges that attract cations. Such cations are exchangeable if they can be replaced with other cations dissolved in water. The cation exchange capacity shows the fertility or potential fertility of the soil. (more exchange sites)
Cation Saturation: is a measure of how much of this exchange capacity is being utilized to store nutrients. It is the percentage of cation-exchange capacity occupied by basic cations ( Ca++, Mg++, K+, and Na+).
K:Mg ratio is the Potassium to Magnesium ratio. High levels of Potassium can make Magnesium deficiencies worse. So if the ratio is too great you must add Mg if you add K.
Your agricultural rep. should be able to convert your soil test into fertilizer and lime addition rates if you tell him/her what crop you wish to grow.
Dan O.
Edited by - dan o. on 02/08/2002 13:20:52
I can try to offer some answers to your questions.
buffer pH is a pH reading which takes into consideration the buffering effect of your soil. Sands have little buffering capacity vs clays that have larger ones. It takes more lime to raise the pH of clay soils because of this. The buffer pH takes this into account for your soil.
Cation Exchange capacity: Clay particles have ion exchange sites with negative charges that attract cations. Such cations are exchangeable if they can be replaced with other cations dissolved in water. The cation exchange capacity shows the fertility or potential fertility of the soil. (more exchange sites)
Cation Saturation: is a measure of how much of this exchange capacity is being utilized to store nutrients. It is the percentage of cation-exchange capacity occupied by basic cations ( Ca++, Mg++, K+, and Na+).
K:Mg ratio is the Potassium to Magnesium ratio. High levels of Potassium can make Magnesium deficiencies worse. So if the ratio is too great you must add Mg if you add K.
Your agricultural rep. should be able to convert your soil test into fertilizer and lime addition rates if you tell him/her what crop you wish to grow.
Dan O.
Edited by - dan o. on 02/08/2002 13:20:52
02-07-2002, 10:09 PM
#5
Nontypical Buck
Join Date: Feb 2003
Location: cazenovia, NY USA
Posts: 2,973
RE: Soil Test Results are In
Good post - The results can be confusing - and I suspect that sometimes the lab doesn't always explain the results so we can understand.
Dan O is on the money about the Buffer. I'll give you an example (how it was explained to me): Lets say your soil test result was 5.5 ph and so was mine. We both want to plant clover and your lime (calcium) requirement is 3000 lb per acre. Yet my Ca requirement is 5000 lb per acre. The reason for the difference is the BUFFER ph. Basically, in this case - my soil is heavier (more clay like) and holds more acid in reserve. In other words - I have to add more lime than you to acheive the same ph (7.0 is usually the goal). The lime added must first neutralize the buffer, before it can reduce the ph of the soil. The buffer ph they list is a measure of this, though I cannot recall the exact relationship.
Whats important for you is the Calcium (Ca) recommendation - and it should be listed in tons/acre
As far as the ppm results you got - there should also be an indication of whats required for the crop you indicated you were planting. My results always show a little graph, and the recommendation at the bottom lists the lbs/acre required for the crop I want to plant.
You probably already know but:
N = Nitrogen
P2O5 = Phosphorus
K20 = Potassium
Mg = Magnesium
Ca = Calcium (lime)
The labs recommendation of 10:10:10 fertilizer puzzles me a bit though. You didn't give your actual results, but keep this in mind; 100 lb of 10:10:10 only has 10 lbs of N:P:K each (the 70lb left is filler - thats why its cheaper than 20:20:20, etc) If the recommendation for K (for example) was 100 lb/acre - you would need to apply 1000 lb/acre of 10:10:10 to
acheive this result ( or 500 lb of 20:20:20 - you get the picture) It would be rare to want to apply equal portions of N, P, K for most crops, Especailly for a legume where of course you want 0 N.
Post your actual results, and maybe we can help you interpret them. We all learn a little every time we interpret results too.
Dan O is on the money about the Buffer. I'll give you an example (how it was explained to me): Lets say your soil test result was 5.5 ph and so was mine. We both want to plant clover and your lime (calcium) requirement is 3000 lb per acre. Yet my Ca requirement is 5000 lb per acre. The reason for the difference is the BUFFER ph. Basically, in this case - my soil is heavier (more clay like) and holds more acid in reserve. In other words - I have to add more lime than you to acheive the same ph (7.0 is usually the goal). The lime added must first neutralize the buffer, before it can reduce the ph of the soil. The buffer ph they list is a measure of this, though I cannot recall the exact relationship.
Whats important for you is the Calcium (Ca) recommendation - and it should be listed in tons/acre
As far as the ppm results you got - there should also be an indication of whats required for the crop you indicated you were planting. My results always show a little graph, and the recommendation at the bottom lists the lbs/acre required for the crop I want to plant.
You probably already know but:
N = Nitrogen
P2O5 = Phosphorus
K20 = Potassium
Mg = Magnesium
Ca = Calcium (lime)
The labs recommendation of 10:10:10 fertilizer puzzles me a bit though. You didn't give your actual results, but keep this in mind; 100 lb of 10:10:10 only has 10 lbs of N:P:K each (the 70lb left is filler - thats why its cheaper than 20:20:20, etc) If the recommendation for K (for example) was 100 lb/acre - you would need to apply 1000 lb/acre of 10:10:10 to
acheive this result ( or 500 lb of 20:20:20 - you get the picture) It would be rare to want to apply equal portions of N, P, K for most crops, Especailly for a legume where of course you want 0 N.
Post your actual results, and maybe we can help you interpret them. We all learn a little every time we interpret results too.
02-07-2002, 10:30 PM
#6
Nontypical Buck
Join Date: Feb 2003
Location: cazenovia, NY USA
Posts: 2,973
RE: Soil Test Results are In
I forgot to talk about cation exchange - oops!
Don O, posted the meaning of this and I interpret this as follows:
A more nuetral PH increases Cation exchange, thus making nutrients more available to plants.
To increase cation exchange, we lime the soil, to lower the Ph. If for instance, you decided to put down the N, P and K recommended and forego the lime - you would not get very good results - even though the nutrients were available. Basically, acidity in the soil lowers cation exchange. As a result, plants are unable to take in the nutrients even though they might be present. When the Ph is increased with Lime (Ca) - it makes these nutrients available to the plant (crop)through increased cation exchange. Lime requirements are often the most important result of the soil test. The lime increases the Ph of the soil, and allows for more cation exchange - now the plant can access the the N,P,K you apply, or that is already available in the soil, sometimes, just liming is all thats required - if N,P,and K are already present in sufficient quantities.
In really acidic soil, you can apply fertilzer to your hearts content, and the crop plants will not be able to access any of it - its like throwing money out the window! Generally, what happens in this case is that acidic loving plants (many weeds) do well and the crop fails.
Hope this helps a little
Edited by - farm hunter on 02/08/2002 19:33:47
Don O, posted the meaning of this and I interpret this as follows:
A more nuetral PH increases Cation exchange, thus making nutrients more available to plants.
To increase cation exchange, we lime the soil, to lower the Ph. If for instance, you decided to put down the N, P and K recommended and forego the lime - you would not get very good results - even though the nutrients were available. Basically, acidity in the soil lowers cation exchange. As a result, plants are unable to take in the nutrients even though they might be present. When the Ph is increased with Lime (Ca) - it makes these nutrients available to the plant (crop)through increased cation exchange. Lime requirements are often the most important result of the soil test. The lime increases the Ph of the soil, and allows for more cation exchange - now the plant can access the the N,P,K you apply, or that is already available in the soil, sometimes, just liming is all thats required - if N,P,and K are already present in sufficient quantities.
In really acidic soil, you can apply fertilzer to your hearts content, and the crop plants will not be able to access any of it - its like throwing money out the window! Generally, what happens in this case is that acidic loving plants (many weeds) do well and the crop fails.
Hope this helps a little
Edited by - farm hunter on 02/08/2002 19:33:47
02-08-2002, 07:14 PM
#9
Nontypical Buck
Join Date: Feb 2003
Location: cazenovia, NY USA
Posts: 2,973
RE: Soil Test Results are In
Thanks for catching my mis-statement regarding lime and Ph. Lime INCREASES Ph and I corrected my statement above.
Here is a couple links on Cation exchange and such:
http://hubcap.clemson.edu/~blpprt/bobweb/BOBWEB23.HTM
http://turf.mdsharris.com/CommonGrou...city%20CEC.htm
http://ohioline.osu.edu/hyg-fact/4000/4028.html
PH Buffer: http://hubcap.clemson.edu/~blpprt/bobweb/BOBWEB8.HTM
http://www.ianr.unl.edu/pubs/soil/g1096.htm
You can search Google and get more results if you wish.
Interpreting your results - in both plots - you are lucky - the Ph is very good already and P&K levels are decent - You will need to add very little if any lime - good for you. Now you can concentrate on the N,P, & K to add.
If your planting a legume (I assume clover or alfalfa) you will need to concentrate on P & K. Some analyists reccommend a small amount of N to jumpstart growth of the crop. It is not desireable to add much if any N, as it will favor weed growth - Clover and other legumes fix N from the air and soil.
You will get some good N,P,& K information from this link - it gives reccommendations for ppm of each required for different crops. http://www.agcom.purdue.edu/AgCom/Pubs/AY/AY-9-32.html - go down to the section
about 1/2 way through the document. Again, you can do searches on GOOGLE and come up with some simpler guidelines too, this link is a bit wordy, but gives alot if info - and key words to do further searches with.
Here's a good link if you are planting alfalfa http://www.agr.okstate.edu/alfalfa/d...ter/sfdata.htm
Good luck -
Here is a couple links on Cation exchange and such:
http://hubcap.clemson.edu/~blpprt/bobweb/BOBWEB23.HTM
http://turf.mdsharris.com/CommonGrou...city%20CEC.htm
http://ohioline.osu.edu/hyg-fact/4000/4028.html
PH Buffer: http://hubcap.clemson.edu/~blpprt/bobweb/BOBWEB8.HTM
http://www.ianr.unl.edu/pubs/soil/g1096.htm
You can search Google and get more results if you wish.
Interpreting your results - in both plots - you are lucky - the Ph is very good already and P&K levels are decent - You will need to add very little if any lime - good for you. Now you can concentrate on the N,P, & K to add.
If your planting a legume (I assume clover or alfalfa) you will need to concentrate on P & K. Some analyists reccommend a small amount of N to jumpstart growth of the crop. It is not desireable to add much if any N, as it will favor weed growth - Clover and other legumes fix N from the air and soil.
You will get some good N,P,& K information from this link - it gives reccommendations for ppm of each required for different crops. http://www.agcom.purdue.edu/AgCom/Pubs/AY/AY-9-32.html - go down to the section
about 1/2 way through the document. Again, you can do searches on GOOGLE and come up with some simpler guidelines too, this link is a bit wordy, but gives alot if info - and key words to do further searches with.
Here's a good link if you are planting alfalfa http://www.agr.okstate.edu/alfalfa/d...ter/sfdata.htm
Good luck -