crab meal vs. oyster shell

Pattahabi said:

You and I aren't going to get along. Do me a favor, why don't you change the wiki page on liming if anyone can change the info? It's not quite that easy. If that's the best argument you can come up with for your position on liming, I rest my case.

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hyroot said:

I never once said anything about liming. I said crab meal had n,p,cal, mag and chitin and not a ph buffer / regulator. Then you argued about it having cal. I never said it didn't. You don't know how to read.

with wiki. You click on the source tab.then the code page opens up and you can rewrite anything. Some pages require you to make a wiki account. Alot don't..

why don't you make a nutrient tea with crab meal (Neptune brand) periodically check ph.. Grow some plants for once.

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Pattahabi said:

You're amusing. Here's some reading for you. I'm still waiting for any resources to back up your crab meal claim.

Soil pH and Liming - Iowa State University

And a couple of picts.

View attachment 3177820
View attachment 3177821

Peace,
P-

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Schwagstock said:

I think what he is meaning is that crab meal although not necessarily a buffer, does contain calcium which, calcium does help to buffer, though not a buffer itself it does help in the process.

(I too have noticed from personal experience if I add the crab meal to my teas the ph tends to go upward to 6.7 from 5.9)
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.1984.tb01428.x/abstract

Abstract. Calcium is the soluble cation that occurs in largest amount in most soils. It does not take part directly in the proton transfer reactions involved in pH-buffering, but it provides the cation charge balance for these reactions. It is also the complementary cation in formulations of chemical potential for many other ions in soils. The presence of free calcium carbonate in calcareous soils. The presence of free calcium carbonate in calcareous soils ensures a very high soil buffer capacity; dAB/dpH ≃ 1000 Eq. m−3.

In acid mineral soils, dissolution and precipitation of aluminium ions contribute to the buffering processes, but most of the buffering in non-calcareous soils is caused by specific ion adsorption at variable-charge sites, in particular those associated with the dissociation of humus acids. Typical buffer capacity values of non-calcareous soils vary from 10 Eq. m−3 for sandy soils to 100 Eq. m−3 for peats. The pH changes associated with buffering are produced by leaching of calcium from soil, or by adding calcium to soil in liming materials.

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The main straight liming agents, Limestone, Calcite (aka Agricultural Lime), Oyster shell powder and Crab meal are sources for Calcium Carbonate (CaCO3). All are pure Calcium Carbonate with the exception of Limestone which can have a Mg level between 2 – 3% depending on the specific mine, country of origin, etc.

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Pattahabi said:

Thanks schwag! I appreciate the information. While the article does say that calcium does not take part in the buffering, it does say calcium carbonate ensures a very high soil buffering capacity. If I am not mistaken, crab meal is a source of calcium carbonate:



Certainly love to discuss things like this with people that are willing to site sources and have an intellegent conversation.

Much respect,
P-

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Pattahabi said:

Thanks schwag! I appreciate the information. While the article does say that calcium does not take part in the buffering, it does say calcium carbonate ensures a very high soil buffering capacity. If I am not mistaken, crab meal is a source of calcium carbonate:



Certainly love to discuss things like this with people that are willing to site sources and have an intellegent conversation.

Much respect,
P-

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hyroot said:

I'm surprised you didn't attack him for something he didn't say.. And it seems you were in the wrong twice hmmmm.

again I never once said anything about liming yet you kept on going back to it. And yet were wrong.

@Schwagstock. Thank for clearing that up. Some people have to argue for the sake of arguing.

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Nullis said:

Oyster shell flour is predominately calcium carbonate, just like egg shells, and it cotains virtually no magnesium. Dolomitic limestone has something like 6-12% magnesium.

Ca, Mg and K are 'base cations', simply put they are the most prevalent and exchangable cations in the soil. Good base cation saturation will counteract acidity and these cations tend to associate with oxides and carbonates, which increase alkalinity. Crab meal sources tend to contain from 15-25% calcium, and K is also a base cation.

I would use both crab meal and dolomitic limestone.

With teas, especially the bacterially dominated type, the pH is always going to raise over time no matter what you put in it. Most bacteria produce an alkaline bio-slime.

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NyQuilkush318 said:

Bro would it be best to break the lime stone up to rock dust or just leve it hold as a stone in ur soil

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Patraise ph faster with a flush bro tahabi said:

Definitely more surface area is going to make it easier to break down. While crab meal will act as a pH buffer, a powdered oyster shell would do a better job. I agree with Nullis, I use both crab shell and oyster shell in all of my mixes. Plain dolomite lime can work, but the amount of Mg is out of balance. If I were to use lime, it would be calcitic or agriculteral lime, and really I would use oyster shell and crab meal over lime anyday.

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Pattahabi said:

Definitely more surface area is going to make it easier to break down. While crab meal will act as a pH buffer, a powdered oyster shell would do a better job. I agree with Nullis, I use both crab shell and oyster shell in all of my mixes. Plain dolomite lime can work, but the amount of Mg is out of balance. If I were to use lime, it would be calcitic or agriculteral lime, and really I would use oyster shell and crab meal over lime anyday.

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Nullis said:

Dolomitic lime isn't out of balance or anything, although magnesium contents will vary. Dolomite lime is a limestone with roughly equal parts, or something like 54% calcium carbonate to 46% magnesium carbonate (~22% Ca : 11% Mg). Pure dolomite is relatively rare, though.

For example, this stuff that we use on the garden is labeled "Calcitic\Dolomitic". View attachment 3180387So, according to the label there is minimum 30% Ca, and 3% Mg or 10:1. Even if that were higher, I am not sure the ratio of Ca\Mg in applied materials or even ultimately in the soil matters substantially as long as they are both present.
Check this out: http://www.spectrumanalytic.com/support/library/ff/Ca_Mg_ratio.htm

Note the CaCO3 equivalency or CCE is 95%. The provided Ca\Mg carbonate values apparently account for 87% of that, perhaps a tad more, while the remainder must be from oxides or potentially other mineral carbonates/oxides. The other "impurities" could be other mineral substances with no liming effect, or even hydration.

CCE is basically a standard for the purpose of comparing liming materials, to aid in determining the amout of a particular material to apply. The CCE of a material compares it to pure (100%) calcium carbonate (CaCO3). Different liming materials are more/less able to neutralize acids, e.g. pure magnesium carbonate is a tad more effective at 118% CCE.

I don't use crab meal directly, although it is in soil\compost that I sometimes buy. But, I did a little research and I was able to find a CCE for a pure crab shell meal (43.9%), then I found a paper on a method for processing the shells for chitin and other materials that confirmed ~41% CaCO3 is typical for crab shell.

So yes, ground crab shell could be up to about 44% as effective as the same amount of a (near) pure CaCO3. The only other thing I can think of you would have to consider is the partical size of the crab meal, which might not be as finely ground as lime and thus really not quite as effective.

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Here’s the deal on liming agents.

Calcium Carbonate Amendments

These are the 3 major forms of Calcium Carbonate (CaCO3)


Limestone – (this is what chemical reps refer to as Agricultural Lime) and will usually have a Calcium Carbonate level between 83 – 95% depending on which specific mine the product is coming out of. Limestone (Agricultural Lime) will also have a small amount of Magnesium (Mg) – about 3 – 5% depending again on which mine is the source

Calcitic Lime – this is pure Calcium Carbonate – usually around 95% and contains no traceable amount of Magnesium

Oyster Shell Powder – another pure form of Calcium Carbonate. This product is NOT from oyster shells from Happy Hour at Red Lobster. This is a specific product that is mined in the San Francisco Bay and has been since the 1920′s. This is the product most often used by poultry producers, worm operations, etc. It carries a label showing 96% Calcium Carbonate
When figuring the amount of actual Calcium (Ca) when using the carbonate limes, take the total amount and multiply by 38.5% and that will (approximately) give you the actual Calcium levels.

Dolomite Lime – Calcium Magnesium Carbonate contains elemental Calcium (not Calcium Carbonate) so the numbers on the product will reflect the actual Calcium levels. The Magnesium Carbonate component is tightly bound to the elemental Calcium resulting in a much longer time period required for the Calcium to become available.

Gypsum – Calcium Sulfate Dihydrate contains both Sulfur Oxide and elemental Calcium. When broken down by microbes the sulfur releases Hydrogen (H) which will lower the pH (if necessary) and also contains Calcium which can raise the pH (again if necessary) – see Base Saturation and CeC

A typical liming agent used by organic farmers is something like this:
2x Calcium Carbonate
1x Dolomite Lime
1x Gypsum

Mix and add at the same rate if you were using a single agent.

At HomeDepot last night I looked at their products in the nursery section.
Soil Sweet – Dolomite Lime and it was less than $6.00 for 25 lbs.

Super Sweet – Limestone at around the same price

Gypsum – $8.95 for 50 lbs.

Choose your poison.

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In the mid-1980's the University of Wisconsin conducted research into the effect of Ca/Mg ratio on alfalfa growth. They found that while the Ca/Mg ratio in the plant tended to reflect the soil Ca/Mg ratio, the plant content of these nutrients was affected much less and in no case did the soil or plant ratio affect yield. In this work the plant Ca and Mg contents were never below the respective critical levels for each nutrient, even though the soil Ca/Mg ratios ranged from 2.28/1 to 8.44/1. They concluded that, assuming there are adequate levels of Ca and Mg present in the soil, variations in the Ca/Mg ratio over the range 2 to 8 have no effect on yield.

In 1999 the University of Missouri, Delta Research Center published the results of an investigation into the effects of soil Ca/Mg ratio on cotton. They amended plots with gypsum or epsom salts to create soil Ca/Mg ratios between 3.8/1 and 11.7/1. They found that cotton yields were not significantly different between treatments.

McLean, et al in Ohio, could find no specific cation ratios that predicted sufficiency or shortages of K, Mg, or Ca in several crops (Table 1). Notice that for all crops the Ca/Mg ratios of both the high and low yielding groups have essentially the same ranges. There is no trend or bias in the relationships between the Ca/Mg ratio and the relative yields of any crop. This indicates that the soil Ca/Mg ratio had little or no effect on yield and the researchers concluded the same.

From: http://www.spectrumanalytic.com/support/library/ff/Ca_Mg_ratio.htm

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Dolomite Lime – Calcium Magnesium Carbonate contains elemental Calcium (not Calcium Carbonate) so the numbers on the product will reflect the actual Calcium levels. The Magnesium Carbonate component is tightly bound to the elemental Calcium resulting in a much longer time period required for the Calcium to become available.

Gypsum – Calcium Sulfate Dihydrate contains both Sulfur Oxide and elemental Calcium. When broken down by microbes the sulfur releases Hydrogen (H) which will lower the pH (if necessary) and also contains Calcium which can raise the pH (again if necessary)

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Nullis said:

AFAIK there are few pure sources of dolomite lime on the market. Agricultural or garden lime is virtually all calcitic or dolomitic. Dolomitic is distinguished from dolomite, it does not contain as much Magnesium and the analysis I presented is typical of a dolomitic lime: not out of balance at all, 12% MgCO3, 3% Mg (10:1 Ca:Mg).

But that begs the question, what would the 'correct' ratio be? And what about the total ratio of Ca to Mg in the soil itself? Since we'd have to consider everything else in the mix. According to my resarch, though, it really doesn't matter so much.


The information in the following quote isn't strictly correct. Most notably, the descriptor "elemental" is used incorrectly.

Dolomite lime does not contain "elemental" Calcium, neither does Gypsum (which is hydrated calcium sulfate or CaSO4·2H2O, period.) That is not how gypsum works, and in fact gypsum itself is not a good liming agent (it is typically used to add Ca to soils that already have a high pH).

In chemistry when something is "elemental" that means it is in its most basic, most naturally stable form. Elemental oxygen is diatomic O2 (an oxygen double bonded to an oxygen) while Ozone is another (triatomic) elemental allotrope of Oxygen (O3). Elemental Chlorine is most typically diatomic Chlorine gas Cl2, elemental Hydrogen is H2 (Hydrogen gas) while elemental Sulfur is more typically octatomic S8 (8 atoms of Sulfur each single-bonded in cyclic conformation). S2 is very rare, since S=S [double] bonds aren't strong like O=O bonds are. The most stable elemental S8 occurs as orthorhombic crystals.

Dolomite as a mineral is usually expressed CaMg(CO3)2, or (CaMg)(CO3)2 and referred to as calcium magnesium carbonate. It does not contain elemental Calcium 'tightly bound' to anything. As a matter of fact, elemental Calcium does not exist in the natural world. Dolomite is actually referred to as a double carbonate salt. The crystal lattice structure is trigonal-rhombohedral, just like calcite, except that the Calcium and Magnesium ions are alternating in the lattice. Sometimes instead of a magneisum ion there is an iron or magnanese here or there, giving the material a different color.

Coot was wrong, unfortunately, and that wouldn't have been the first time.

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Nullis said:

AFAIK there are few pure sources of dolomite lime on the market. Agricultural or garden lime is virtually all calcitic or dolomitic. Dolomitic is distinguished from dolomite, it does not contain as much Magnesium and the analysis I presented is typical of a dolomitic lime: not out of balance at all, 12% MgCO3, 3% Mg (10:1 Ca:Mg).

But that begs the question, what would the 'correct' ratio be? And what about the total ratio of Ca to Mg in the soil itself? Since we'd have to consider everything else in the mix. According to my resarch, though, it really doesn't matter so much.


The information in the following quote isn't strictly correct. Most notably, the descriptor "elemental" is used incorrectly.

Dolomite lime does not contain "elemental" Calcium, neither does Gypsum (which is hydrated calcium sulfate or CaSO4·2H2O, period.) That is not how gypsum works, and in fact gypsum itself is not a good liming agent (it is typically used to add Ca to soils that already have a high pH).

In chemistry when something is "elemental" that means it is in its most basic, most naturally stable form. Elemental oxygen is diatomic O2 (an oxygen double bonded to an oxygen) while Ozone is another (triatomic) elemental allotrope of Oxygen (O3). Elemental Chlorine is most typically diatomic Chlorine gas Cl2, elemental Hydrogen is H2 (Hydrogen gas) while elemental Sulfur is more typically octatomic S8 (8 atoms of Sulfur each single-bonded in cyclic conformation). S2 is very rare, since S=S [double] bonds aren't strong like O=O bonds are. The most stable elemental S8 occurs as orthorhombic crystals.

Dolomite as a mineral is usually expressed CaMg(CO3)2, or (CaMg)(CO3)2 and referred to as calcium magnesium carbonate. It does not contain elemental Calcium 'tightly bound' to anything. As a matter of fact, elemental Calcium does not exist in the natural world. Dolomite is actually referred to as a double carbonate salt. The crystal lattice structure is trigonal-rhombohedral, just like calcite, except that the Calcium and Magnesium ions are alternating in the lattice. Sometimes instead of a magneisum ion there is an iron or magnanese here or there, giving the material a different color.

Coot was wrong, unfortunately, and that wouldn't have been the first time.

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