isn't the decaying organic matter producing humic and fulvic acids that tend to dissolve mineral nutrients in soil?
thnx
thnx
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Balancing Soil Minerals
- Thread starter m_astera
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Actually member Humpry Davy has done a lot of work on tcec and weight vs volume. Logan labs was one of his resources...so full credit and props to him for the thinking. I have ask him to join the discussion. Hopefully he will...he has mucho to bring to the table
Preaching to the choir
Such testing of full spectrum from an accredited (legit) lab in my neck of the woods is over $100
Edit; Does Logan labs use this equipment? & HPLC?
Sounds good. I will wait and see if/what input HD has before contacting Logan.
The microbes and fungi feeding on the organic matter produce many different acids, e.g. malic, citric, carbonic, as do plant roots. These acids are what can etch minerals from rocks. My understanding is that both plant roots and microbes take up mineral elements from the soil in this order of preference:
ions from the soil/water solution> ions held on exchange sites> mineral elements etched from rocks.
I don't think humic "acids" have much if any role in etching minerals from rocks.
C
Cep
Years ago I mistakenly thought it was just fulvic/humic acids exuded from plant roots that assisted in uptake. I have a cavity thats been developing for a year or so and man, every time I eat an apple I get reminded of how good malic acid is at etching.
Logan uses ICP testing, not HPLC (high pressure liquid chromatography). They charge ~$25 to test for 11 elements + pH, estimated CEC, and soil organic matter.
From your linked post (#11 in this thread):
"Suppose I do get the Albrecht-Reams testing and follow the saturation advice by purchasing and applying minerals? Probably no harm done right? So long as the nutrients ARE actually sequestered only to be exchanged for organic acids. (You can't believe how many different ones there are) No harm done and possible benefits and I feel like I've done my best."
The "Reams" test is a Morgan test, pH 4.8, which has been around since the late 1930s. It is useful for determining which minerals are readily available at normal root zone pH. It is useless for determining exchange capacity and worse than useless for balancing base cations and minerals in general.
At present the best testing method for determining potential mineral availability is the Mehlich 3, introduced in 1984. It is a combination of very strong acids and EDTA, with a pH of 2.5. Any minerals that are not extracted by the Mehlich 3 solution are not likely to be available to either the crops or soil biota.
Good to know. That alters my opinion a little.
Too bad.
Humphry Davy
Member
In regards to soil density and lab results.
Michael was right on point when he mentioned that soil density must be taken into account when applying minerals and his math/method are correct.
As for lab results, they are skewed due to them only taking a volume scoop rather than measuring density, as milky and mike pointed out.
I could go into the conversions and I would be happy to if anyone would like that, but ultimately you measure your soil density just as Michael pointed out, we will call that number "X".
You divide 'standard soil density' which is 1.47 gr / ml and divide that by your soil density, "X".
The factor you multiply all your lab results is 1.47/X, except for EC, C:N, C%, pH, OM%, and all the saturation %'s and if you get saturated paste test do not multiply those number by this factor.
Michael was right on point when he mentioned that soil density must be taken into account when applying minerals and his math/method are correct.
As for lab results, they are skewed due to them only taking a volume scoop rather than measuring density, as milky and mike pointed out.
I could go into the conversions and I would be happy to if anyone would like that, but ultimately you measure your soil density just as Michael pointed out, we will call that number "X".
You divide 'standard soil density' which is 1.47 gr / ml and divide that by your soil density, "X".
The factor you multiply all your lab results is 1.47/X, except for EC, C:N, C%, pH, OM%, and all the saturation %'s and if you get saturated paste test do not multiply those number by this factor.
Unless I'm trying to displace another cation, such as excess Mg, K, or Na, I go with the calculated amount. If I am trying to displace another cation I may go higher, but 6000 lbs/acre of Ca is a pretty heavy dose already.
Humphry Davy
Member
Michael, I did want to ask your opinion on application limits, Steve mentions 800 lbs / acre on nitrogen, even if using a slow release N source such as feather meal.. the problem is, if we have a C:N of about say 45:1, it would take years and years to achieve a ratio of 24:1, also the plants would most likely consume that amount and then some before the next test, i fell like you would be constantly depleting the N overtime.
Recently i have been adding however much feather meal it takes to achieve 24:1 for the top 6", and i till that in by hand. I then apply mycogenesis, as i apply it anytime i disturbed the soil surface. However i have noticed ammonia smell which is a sign of N loss, I'm thinking the reason the high carbon is not capturing all the N is the lack of O2 in the heavy amount of feather meal : soil in the top 6". Im considering using 10:1 feather meal : peat moss mix to amend into the soil to help aerate the mix I add, and with a 10:1 (weight:weight) the amendment should still have a 15:1 C:N. Any thoughts on this and application limits for other elements?
Was also curious on your thoughts of using biomin chelated products for amending? I use them only when I see there could be an antagonism associated with using the elements sulfate form. For instance, if i have very high P, i will use biomin Fe over iron sulfate. I'm just curious as to how long the element stays chelated in the soil solution. If it was to stay chelated for long periods, i would fear the concentration of that element in the soil solution would be very high. Im willing to bet with a biologically active soil, the chelate is short lived as I believe they use those organic acids as a food source considering its N content. However ill be the first to acknowledge biology is not my field of expertise, so i leave those questions to whomever feels qualified to answer them.
Ive been recently using saturated paste tests along with the standard soil test and have found some interesting things.
Before i dive into those findings, I have been using Logan Lab's agronomist's recommendations for saturated tests, i was finding that my results far exceeded his recommendations but the standard test did not show any significant excesses. Upon discussing this with the agronomist, he stated that those numbers should be considered minimums and that they may not even be adequate to support large plants. Ultimately I'm current working on determining targets for saturated tests with tissue testing and what little sap analysis meters i have (pH,EC,K,Brix).
I originally was following your Ideal Soil recommendations but found certain elements were testing at very low levels on the paste test when they showed they were adequate on the adjusted soil density lab results according to your recommendations.
Zinc is one, I've seen the 10:1 ratio mentioned a lot for P:Zn, however at this ratio I'm not getting adequate Zn showing up on the saturated tests. Hugh Lovel mentions the 10:1 ratio but he also is referencing a total soil test and from my understanding, the P levels are the only element that show a large difference between M3 and total testing with total testing showing more P. Therefore i believe a lower ratio of P:Zn needs to be targeted when using M3. I will share my targets at the end of this post.
I also stopped using the ppm limits on micro's. I have simply been using ratios of elements to elements for targets. Reason being is when using a high CEC, i was constantly hitting the limit on micros and found them short in the soluble tests.
I dismissed Steve Solomans K recommendations, because with our high CEC, he would have K around 1%. However he recommended P=K, and I still use his formula which involves a log function of CEC to determine my P target. For my soils it generally ends up being around 600-700 ppm elemental P (remember that is with soil density factored, not the labs initial results). The equation is, (LN(TCEC)*159.3)-39.25.
Also I'm finding that in the paste tests, when comparing the Ca:Mg:K:Na, the Mg is always testing too high, even when the sat % is as low as 10%, these are recent findings, so with more data that supports this, I might be lowing my target for Mg.
Iron is the one element that I have had the most trouble with getting adequate amounts to show up on the paste test. Perhaps this is due to tie-ups? Either way, I've increased my iron targets on my most recent soils to see what happens on the next soluble test.
Heres my targets:
C:N=24:1
P: (LN(TCEC)*159.3)-39.25 ppm
Ca= 68%
Mg=12% (might drop this to 10 and increase the K and/or Ca %'s depending on what sap testing tells me along w paste tests)
K=4%
Na 0.25%
S 300 ppm (generally Im way over this, and have been considering using a C:S ratio of 55:1 as hugh loves recommends, as i would think a standard test vs a total test would not show a large difference in S levels as its sulfate form is very soluble)
Fe: 2.5 * target P (yes you read that right lol)
Mn: 1/10 * target P
Cu: 1/12 * target P
B: 1/1000 * target Ca
Zn: 1/2 * target P
Mo:1.5 ppm
Co: 4 ppm
Se: 1.2 ppm (i can not find a source for Se)
Si: 100 ppm
I have created an excel program that takes your data from logan labs and converts the data for your soil density, shows where your at as far as ppm's before and after amendments, analyzes the saturated tests and standard test and choosing amendments based on factors such as pH, possible antagonisms, ect. It also allows you to adjust your ratios to change your targets and it also tells you what minerals most likely will need to be foliar fed. I'm still making tweaks here and there but plan to offer it to all in the future, ultimately i made the program because i got sick of all the pencil work considering I'm doing about 5 soil tests a week for myself and other clients.
Edit: I also irrigate K throughout the entire grow, that way I don't have to load the soil so much with K up front, as I believe cannabis is a K accumulator.
Recently i have been adding however much feather meal it takes to achieve 24:1 for the top 6", and i till that in by hand. I then apply mycogenesis, as i apply it anytime i disturbed the soil surface. However i have noticed ammonia smell which is a sign of N loss, I'm thinking the reason the high carbon is not capturing all the N is the lack of O2 in the heavy amount of feather meal : soil in the top 6". Im considering using 10:1 feather meal : peat moss mix to amend into the soil to help aerate the mix I add, and with a 10:1 (weight:weight) the amendment should still have a 15:1 C:N. Any thoughts on this and application limits for other elements?
Was also curious on your thoughts of using biomin chelated products for amending? I use them only when I see there could be an antagonism associated with using the elements sulfate form. For instance, if i have very high P, i will use biomin Fe over iron sulfate. I'm just curious as to how long the element stays chelated in the soil solution. If it was to stay chelated for long periods, i would fear the concentration of that element in the soil solution would be very high. Im willing to bet with a biologically active soil, the chelate is short lived as I believe they use those organic acids as a food source considering its N content. However ill be the first to acknowledge biology is not my field of expertise, so i leave those questions to whomever feels qualified to answer them.
Ive been recently using saturated paste tests along with the standard soil test and have found some interesting things.
Before i dive into those findings, I have been using Logan Lab's agronomist's recommendations for saturated tests, i was finding that my results far exceeded his recommendations but the standard test did not show any significant excesses. Upon discussing this with the agronomist, he stated that those numbers should be considered minimums and that they may not even be adequate to support large plants. Ultimately I'm current working on determining targets for saturated tests with tissue testing and what little sap analysis meters i have (pH,EC,K,Brix).
I originally was following your Ideal Soil recommendations but found certain elements were testing at very low levels on the paste test when they showed they were adequate on the adjusted soil density lab results according to your recommendations.
Zinc is one, I've seen the 10:1 ratio mentioned a lot for P:Zn, however at this ratio I'm not getting adequate Zn showing up on the saturated tests. Hugh Lovel mentions the 10:1 ratio but he also is referencing a total soil test and from my understanding, the P levels are the only element that show a large difference between M3 and total testing with total testing showing more P. Therefore i believe a lower ratio of P:Zn needs to be targeted when using M3. I will share my targets at the end of this post.
I also stopped using the ppm limits on micro's. I have simply been using ratios of elements to elements for targets. Reason being is when using a high CEC, i was constantly hitting the limit on micros and found them short in the soluble tests.
I dismissed Steve Solomans K recommendations, because with our high CEC, he would have K around 1%. However he recommended P=K, and I still use his formula which involves a log function of CEC to determine my P target. For my soils it generally ends up being around 600-700 ppm elemental P (remember that is with soil density factored, not the labs initial results). The equation is, (LN(TCEC)*159.3)-39.25.
Also I'm finding that in the paste tests, when comparing the Ca:Mg:K:Na, the Mg is always testing too high, even when the sat % is as low as 10%, these are recent findings, so with more data that supports this, I might be lowing my target for Mg.
Iron is the one element that I have had the most trouble with getting adequate amounts to show up on the paste test. Perhaps this is due to tie-ups? Either way, I've increased my iron targets on my most recent soils to see what happens on the next soluble test.
Heres my targets:
C:N=24:1
P: (LN(TCEC)*159.3)-39.25 ppm
Ca= 68%
Mg=12% (might drop this to 10 and increase the K and/or Ca %'s depending on what sap testing tells me along w paste tests)
K=4%
Na 0.25%
S 300 ppm (generally Im way over this, and have been considering using a C:S ratio of 55:1 as hugh loves recommends, as i would think a standard test vs a total test would not show a large difference in S levels as its sulfate form is very soluble)
Fe: 2.5 * target P (yes you read that right lol)
Mn: 1/10 * target P
Cu: 1/12 * target P
B: 1/1000 * target Ca
Zn: 1/2 * target P
Mo:1.5 ppm
Co: 4 ppm
Se: 1.2 ppm (i can not find a source for Se)
Si: 100 ppm
I have created an excel program that takes your data from logan labs and converts the data for your soil density, shows where your at as far as ppm's before and after amendments, analyzes the saturated tests and standard test and choosing amendments based on factors such as pH, possible antagonisms, ect. It also allows you to adjust your ratios to change your targets and it also tells you what minerals most likely will need to be foliar fed. I'm still making tweaks here and there but plan to offer it to all in the future, ultimately i made the program because i got sick of all the pencil work considering I'm doing about 5 soil tests a week for myself and other clients.
Edit: I also irrigate K throughout the entire grow, that way I don't have to load the soil so much with K up front, as I believe cannabis is a K accumulator.
Last edited:
Humphry Davy
Member
Are you asking can you ignore the soil density because if you don't factor it into the test results you will not have to factor it into the amendments?
Well if you don't factor it in the test, then your ppms will be off, they will be lower than what they are on the test. So if you follow a ppm recommendation, like say 25 ppm Cu, then you will may be adding Cu when you actually don't need it.
Now if you are focusing on BCS%, those numbers are not effected by the density factor, however when you amend one of those cations, the factor does come into play. That is because you are assuming your soil is much heavier than what it really is, therefore you are adding more of the cations than what you need to.
lb/acre is simply a weight vs weight calculation in the end because we assume a furrow slice of an acre weighs 2million lbs, so essentially lb/acre is 1 lb/ 2 millions lbs.
So if you're trying to add 1000 lb acre of Ca, thats essentially 500ppm with standard soil, however with our soil that same 1000 lb per acre might mean up to 5000 lb per acre when looking at lb / acre as a weight / weight.
You see the lb/acre can be interpreted just as that, weight / area, for field soil because its the same when converted using field soil density. However when lb / acre, in a weight / area sense, can not be used with lighter peat based soils because it is not the same as its weight / weight. Adding 2 lbs to an acre of our soil is not the same as adding 1 ppm to that same soil.
I may have confused you as i repeated myself a little bit
Well if you don't factor it in the test, then your ppms will be off, they will be lower than what they are on the test. So if you follow a ppm recommendation, like say 25 ppm Cu, then you will may be adding Cu when you actually don't need it.
Now if you are focusing on BCS%, those numbers are not effected by the density factor, however when you amend one of those cations, the factor does come into play. That is because you are assuming your soil is much heavier than what it really is, therefore you are adding more of the cations than what you need to.
lb/acre is simply a weight vs weight calculation in the end because we assume a furrow slice of an acre weighs 2million lbs, so essentially lb/acre is 1 lb/ 2 millions lbs.
So if you're trying to add 1000 lb acre of Ca, thats essentially 500ppm with standard soil, however with our soil that same 1000 lb per acre might mean up to 5000 lb per acre when looking at lb / acre as a weight / weight.
You see the lb/acre can be interpreted just as that, weight / area, for field soil because its the same when converted using field soil density. However when lb / acre, in a weight / area sense, can not be used with lighter peat based soils because it is not the same as its weight / weight. Adding 2 lbs to an acre of our soil is not the same as adding 1 ppm to that same soil.
I may have confused you as i repeated myself a little bit
The amount of soil organic matter measured in a sample of virgin forest or prairie soil in a given location is probably the ideal. This will vary with climate, from 1 or 2% by weight in the tropics to 7 or 8 percent in north temperate zones. If the SOM content of a soil is below the virgin soil average, likely the soil has been abused or there is a mineral imbalance that does not allow the soil to grow plants well. Trying to raise the SOM % above what is normal and natural for a given climate is generally a never-ending struggle with doubtful payoff.
If it is a sandy, low CEC soil it may be worthwhile to increase the organic matter to a level that will hold sufficient moisture and nutrients. On a small scale adding high CEC clays or zeolites will add permanent exchange capacity.
For production agriculture, 4% SOM has long been considered optimum.
Humphry Davy
Member
Well i recently got a test that showed:
Ca 71.24%
Mg 11.5%
K 3.09%
The paste test %:
Ca 45.03%
Mg 16.11%
K 7.72%
For paste test you want the ratio of each % to be,
60/20/15 for Ca/Mg/K.
So thats Ca:K of 4, Mg:K of 1.33 ideally,
this test showed Ca:K of 5.8 and Mg:K of 2.09
So the K is actually showing up low in the paste test in comparison to the other major cations.
I think once the K sap meter comes via CHN shortly, ill be able to tell a lot more. Thats just one soil test, so i won't put much into that, just an example from my end that is showing low K when its saturation is at 3%
In top soil with no compost added I am getting a 3-4% organic matter increase grow over grow. Someone told me today hemp is the king of dumping carbon in soil
I honestly do not see the use in these light weight mixes at all. Give me topsoil, maybe a touch of peat and sime pumice and I am happy.
Building real humus has to be better than importing carbon
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