Why not use the buffer test for calcium/pH?
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Why not use the buffer test for calcium/pH?
My understanding is that Logan does not do a buffer pH test to determine how much lime is needed to affect the pH. It would seem that this is important to know, but it does not seem to be a concern to those that provide expert recommendations, like morpheus. I'm not saying they need to start using buffer information, I'm more interested in why it doesn't seem to be really necessary. I understand that morpheus says he does not look at pH, only calcium, but if you have a test that tells you how much calcium to add in order to target a particular pH, why wouldn't that be good information to use? I mean, can't you get low pH from high aluminum content so that while your calcium content is good, your pH may still be very low? A buffer test would help sort that out, no? I know it is complicated, which is why I ask the question.
- andy10917
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Re: Why not use the buffer test for calcium/pH?
If you look at the early postings in the Soils Forum, you'll see the Buffer pH data. I think there were a couple of reasons for it falling into disuse -- (1) it has value mostly if you are tilling in your Lime, where you want to know how much Lime is going to be needed, and (2) it didn't turn out to be a very good predictor of how quickly the soil would respond to surface-applications. 90%+ of our applications are with grass in-place on the soil, and even our renovations don't typically involve tilling. We do smaller, more-frequent applications to not shock the lawn, the soil chemistry or the microherd. We also tend to use Limes that are not the bulk agricultural limes, but limes that involve humates and other products/technologies. Bottom line: Buffer pH was a so-so performer in a situation that didn't directly apply to what we were trying to do.
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Re: Why not use the buffer test for calcium/pH?
Thanks. So is the limit of approximately 50 lb lime/ksf based on tilled lime or for surface applications in an existing lawn? I'd imagine it would have to be considerably lower if it is a surface application.
Also, do you find in the majority of the cases that when you have the calcium at a targeted value that the pH falls in line as well?
Also, do you find in the majority of the cases that when you have the calcium at a targeted value that the pH falls in line as well?
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Re: Why not use the buffer test for calcium/pH?
50 lb/K is the recommended maximum application rate on existing turf for standard, cheap dolomitic lime that runs ~$4 a bag. Fast-acting calcitic limes are applied at substantially lower rates and run ~$15 a bag.
- andy10917
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Re: Why not use the buffer test for calcium/pH?
It gets more complicated then that. We can't account for all of the differences in lime qualities and quantities - things can vary from 9 lbs/K with the humate products (and effective in 5-8 weeks) to 50 lbs/K for the powder and some of the prilled products (and effective in 12-14 months). We specify the expectations that match our recommendations (humate products, every 90 days). For other products, we say to follow bag instructions. All of our recommendations assume surface applications.So is the limit of approximately 50 lb lime/ksf based on tilled lime or for surface applications in an existing lawn? I'd imagine it would have to be considerably lower if it is a surface application.
I recommend Calcitic lime most of the time and specify the addition of Epsom Salts (Magnesium Sulfate) in varying amounts to be mixed in, and I try to dial-in a 68% Calcium, 12% Magnesium, 4% Potassium cation ratio. I can get it close as long as I don't have an unsolvable problem (like starting with Magnesium at 25%).Also, do you find in the majority of the cases that when you have the calcium at a targeted value that the pH falls in line as well?
I don't see Calcium as "falling in" behind pH. I see pH as the end-result of all of the cation and Exchangeable Hydrogen numbers. The trick is getting all of the numbers to stall where you want them at the same time. If you get all of the other numbers right, then pH is a simple calculation. In other words, pH is the result, and not the cause.
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Re: Why not use the buffer test for calcium/pH?
Yep, as previously said a little differently - my main reason I don't think they make sense for everyone all the time is that they aren't good predictors of what will need surface applied on a home lawn with limited control of other factors, particularly when you factor in that the shortage is often more than can be applied in a single year anyways.
Ergo, it's more accurate to make a practical observation of how a particular field reacts to a program year over year to see what will really help a soil and scenario. Once you start getting really close, I can see the case for getting precise numbers, but as was previously mentioned - it's much easier to observe over time and use that as a more accurate indicator.
There are just too many moving factors you can't control in the real world - amendments aren't done in a lab after all - but in the field.
So, better to spend the additional $$ on that bag of lime or urea
Ergo, it's more accurate to make a practical observation of how a particular field reacts to a program year over year to see what will really help a soil and scenario. Once you start getting really close, I can see the case for getting precise numbers, but as was previously mentioned - it's much easier to observe over time and use that as a more accurate indicator.
There are just too many moving factors you can't control in the real world - amendments aren't done in a lab after all - but in the field.
So, better to spend the additional $$ on that bag of lime or urea
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Re: Why not use the buffer test for calcium/pH?
I had a follow-up thought about this - I had decided that it wasn't directly a response to NJDan's original question and didn't add it, but I think it's important in the overall picture.
Many people represent that liming is simple - that all you need is a CCE (Calcium Carbonate Equivalent) number, a Buffer pH and a pH number and the math is simple to calculate. These people tend to be complete academics who either don't apply Lime themselves, or apply Lime and don't scratch their heads and question things when the results don't match the math. Also, it gets repeated again and again by Internet writers that do not test what they read in books by the same academics.
Remember how we have a problem with soil tests when there is "Free Calcium" in the soil that is not in solution ("calcareous soil")? It happens because acidic extractants are used that are much better at dissolving the Calcium than your soil is. We have to retest and use an alkaline Ammonium Acetate extractant, or the soil test results will estimate the TEC of the soil as high as 100+ in some cases, and regularly in the 40's and 50's. What is happening is that the calculations are wrong because the extractants don't match the real-world behavior of your soil's use of the Calcium.
Guess what? Hydrochloric Acid is what is used to determine CCE numbers. Same damned problem! We don't measure what the real-world behavior will be over 4 months after application or 12 months after application - we measure what happens in a test tube in a few seconds. We assume one will equal the other, but it doesn't!
The bottom line is that Buffer pH and CCE numbers are no match for looking at how a couple of years worth of test results telling us how Lime (or other nutrients!) will behave IN YOUR YARD, IN YOUR SPECIFIC CONDITIONS. Believe me, what the CCE numbers calculate and what REALLY happens are very different animals and after having read thousands of soil tests and seen the end-results, I don't even bother doing the calculations any more.
Many people represent that liming is simple - that all you need is a CCE (Calcium Carbonate Equivalent) number, a Buffer pH and a pH number and the math is simple to calculate. These people tend to be complete academics who either don't apply Lime themselves, or apply Lime and don't scratch their heads and question things when the results don't match the math. Also, it gets repeated again and again by Internet writers that do not test what they read in books by the same academics.
Remember how we have a problem with soil tests when there is "Free Calcium" in the soil that is not in solution ("calcareous soil")? It happens because acidic extractants are used that are much better at dissolving the Calcium than your soil is. We have to retest and use an alkaline Ammonium Acetate extractant, or the soil test results will estimate the TEC of the soil as high as 100+ in some cases, and regularly in the 40's and 50's. What is happening is that the calculations are wrong because the extractants don't match the real-world behavior of your soil's use of the Calcium.
Guess what? Hydrochloric Acid is what is used to determine CCE numbers. Same damned problem! We don't measure what the real-world behavior will be over 4 months after application or 12 months after application - we measure what happens in a test tube in a few seconds. We assume one will equal the other, but it doesn't!
The bottom line is that Buffer pH and CCE numbers are no match for looking at how a couple of years worth of test results telling us how Lime (or other nutrients!) will behave IN YOUR YARD, IN YOUR SPECIFIC CONDITIONS. Believe me, what the CCE numbers calculate and what REALLY happens are very different animals and after having read thousands of soil tests and seen the end-results, I don't even bother doing the calculations any more.
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Re: Why not use the buffer test for calcium/pH?
It sounds like maybe the main thing is your idea that buffer pH and the resulting CCE recommendation is more based on crops where the soil is tilled. If the recommendations do not match reality for a lawn, then it simply sounds like a bad application of the test method. Stick to crops I guess.
What kind of humates are used to incrrease calcium? I understand about humates in terms of peat, leaves, sawdust, etc. but humates to improve calcium levels?
What kind of humates are used to incrrease calcium? I understand about humates in terms of peat, leaves, sawdust, etc. but humates to improve calcium levels?
- andy10917
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Re: Why not use the buffer test for calcium/pH?
Not at all. The main premise is that you cannot predict the behavior of a Lime product in real-world soil by using strong acids in a test tube. It has nothing to do with tilling.It sounds like maybe the main thing is your idea that buffer pH and the resulting CCE recommendation is more based on crops where the soil is tilled. If the recommendations do not match reality for a lawn, then it simply sounds like a bad application of the test method. Stick to crops I guess.
Processing Humic Acid with Lime is the basis of the all of the new processes to manufacture "fast-acting limes". It allows the Lime to affect the soil pH in 4-8 weeks instead of 12-14 months, and at much lower application rates.What kind of humates are used to increase calcium? I understand about humates in terms of peat, leaves, sawdust, etc. but humates to improve calcium levels?
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Re: Why not use the buffer test for calcium/pH?
andy10917 wrote: ↑November 21st, 2017, 6:21 pmNot at all. The main premise is that you cannot predict the behavior of a Lime product in real-world soil by using strong acids in a test tube. It has nothing to do with tilling.It sounds like maybe the main thing is your idea that buffer pH and the resulting CCE recommendation is more based on crops where the soil is tilled. If the recommendations do not match reality for a lawn, then it simply sounds like a bad application of the test method. Stick to crops I guess.
I was responding to your first reply in which you said, "(1) it has value mostly if you are tilling in your Lime, where you want to know how much Lime is going to be needed." Aren't you saying that the buffer recommendation works better for tilled applications (like maybe crops) vs using it for lawn care in which it may really be a misapplication?
- andy10917
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Re: Why not use the buffer test for calcium/pH?
I see your point. I was trying to get to the fact in the first reply that the application limitation is tight enough that the Buffer pH is sort of meaningless - the true amount that will be needed is always going to be higher than the limitation. For a new member getting their first soil test, the chance is 75%-80% that you are either alkaline or more than the maximum application amount.
In tilled situations, you "could" apply much higher amounts, but I still maintain that the amounts predicted by Buffer pH calculations are almost always wrong (and typically to the low side since CCE is overestimated).
In tilled situations, you "could" apply much higher amounts, but I still maintain that the amounts predicted by Buffer pH calculations are almost always wrong (and typically to the low side since CCE is overestimated).
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Re: Why not use the buffer test for calcium/pH?
Well that all sounds reasonable. The bottom line is whether it works in the real world, as you say. If you've done 1000's of recommendations both using buffer pH and not using it, then that is the real "acid test." Thanks for the info!
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