The "Potager du Laesseux" in the Dordogne

Agriculture and soil. Pollution control, soil remediation, humus and new agricultural techniques.
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Did67
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Re: The "Potager du Laesseux" in the Dordogne




by Did67 » 17/05/17, 22:15

Lachanette wrote:
I had the impression that the special mulching tarpaulins, which let water pass, would also let air pass?


No doubt, indeed. I had zapped that it was woven tarpaulins ...
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Re: The "Potager du Laesseux" in the Dordogne




by sicetaitsimple » 17/05/17, 22:42

Lachanette wrote:For did67 and sicétaitsimple

Or I take ground at 20 cm deep, mix it with rainwater and plunge the probe into it? I will also measure the pH of the well water.

.......

In any case the kitchen garden has relatively well given the previous years, so I do not worry too much!



I will repeat myself, but in my opinion the best is that for the moment you put your Chinese pH meter in the back of a cupboard, that you are doing your season without worrying too much about it, maybe it will bring talking points, and that you do some analyzes at various depths towards the end of the summer with a Neudorff type chemical kit. And nothing prevents you once again from loading 2 or 3 m2 with wood ash to compare, in case there is actually a real pH bp.

But if it has worked well previously, we should perhaps not worry too much about the display of this famous pH meter .....

Indeed if you have a well with which you water, it may be interesting to know the pH of the water, there may be an explanation there on this pH gradient in the soil if it is real.
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Re: The "Potager du Laesseux" in the Dordogne




by Did67 » 17/05/17, 22:52

Lachanette wrote:
I planned a soil analysis this spring (in lab) Maybe it will give an idea ... But if I mix the different depths, it may not be speaking.

Or I take ground at 20 cm deep, mix it with rainwater and plunge the probe into it? I will also measure the pH of the well water.

The causes I mentioned did not seem to speak to you, in any case, the acidification of old meadows and the role of fungi due to the presence of old poplars ...

In any case the kitchen garden has relatively well given the previous years, so I do not worry too much!

To be continued...


If you do a soil test, you will indeed have to take an average sample, for cost reasons.

But if the average result is 7,5, it cannot be 5 to 25 cm !!!

To the Neudorff kit I prefer pH strips bought 3 sous on the internet and a bottle of distilled water bought in a DIY store. Take the soil, mix with twice the amount of distilled water, shake for a long time, filter and soak the strip.

In the well, you put the direct strip.

No, I am not convinced that a soil "goes wrong" by itself, even if indeed fungal activity will "pull" a little towards acidity. But the presence of poplars is not an intense coniferous forest!

I do not see, apart from the use of acidifying fertilizers, why a meadow would acidify ???
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Re: The "Potager du Laesseux" in the Dordogne




by jpbord » 18/05/17, 02:45

Lachanette wrote:thank you jpbord
You agree to give me a place in this connection that you created, it does not bother you? As you gave a pretty open as I launched myself without hesitation, it was after that I wondered if I had done ...


No problem cordially
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Re: The "Potager du Laesseux" in the Dordogne




by Ahmed » 18/05/17, 08:44

The approximate side of PH kits is one thing, but the presence of limestone does not give a clear indication either: indeed, limestone is said to be active or not; in the second case, the soil may very well be fairly acidic ...
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Re: The "Potager du Laesseux" in the Dordogne




by Did67 » 18/05/17, 08:53

Yes, soil chemistry is a bit complex. The pH is the more or less important presence, in the soil solution, of H30 + ions [the more there are, the more the solution is acid, the lower the pH]

It is not the limestone, but the Ca ++ ions which can "drive out" the H3O + ions ...

But in general, in calcareous soils, the solution recharges with Ca ++ ions ...

Here, in Alsace, we know the case of limestone aerial loess, which, on pebble substrates in the Alsace plain, decalcify on the surface (with formation of concretions in depth, called "loess dolls").

There, I am still surprised by the values, which are already "clearly acidic" ...
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Re: The "Potager du Laesseux" in the Dordogne




by sicetaitsimple » 18/05/17, 18:19

Ahmed wrote:The rough side of PH kits is one thing


Admittedly, this is approximate, but in my opinion it is quite reliable in terms of indicating the location where you are located (neutral, slightly acidic, or slightly basic, or other ...), which seems to me sufficient to judge the advisability or the risk of bringing in ashes. The principles of aqueous pH analysis by colored indicators have existed for ages, including in areas such as health, it works.

Next, knowing the pH of your soil to the nearest 0,1 point, for a gardener I recognize that it is of little interest.

There remains the question of the representativeness of the sample analyzed, of course, that is another problem!
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Re: The "Potager du Laesseux" in the Dordogne




by Did67 » 19/05/17, 12:06

sicetaitsimple wrote:
Admittedly, this is approximate, but in my opinion it is quite reliable in terms of indicating the location where you are located (neutral, slightly acidic, or slightly basic, or other ...), which seems to me sufficient to judge the advisability or the risk of bringing in ashes. The principles of aqueous pH analysis by colored indicators have existed for ages, including in areas such as health, it works.

Next, knowing the pH of your soil to the nearest 0,1 point, for a gardener I recognize that it is of little interest.

There remains the question of the representativeness of the sample analyzed, of course, that is another problem!


I think Ahmed was talking about the "multifunction" device which is not a real pH meter. I think it analyzes a certain conductivity, and deduces an estimate of pH from it. Which must depend on the humidity. The drier it is, the more, in my opinion, the device indicates .... a number close to 7 (which is the "empty" measurement, in air ...).

The strips are quite precise, if we take those with two "colored spots" [without advertising, for information: https://french.alibaba.com/p-detail/spe ... 89196.html]. There, it is clearly the sampling and the dilution which will influence the result as much as the reading uncertainty.

The pH-water of a soil is never strictly speaking the "pH of the soil". It is the pH of a solution extracted from the ground and in balance with it. Soils have buffering powers, depending on their richness in clays, humic substances, etc.
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Re: The "Potager du Laesseux" in the Dordogne




by sicetaitsimple » 19/05/17, 12:44

Did67 wrote:
I think Ahmed was talking about the "multifunction" device which is not a real pH meter.


I don't think so, but it's not very important. I just wanted to say that it is better to have a measurement which is certainly approximate (+/- 0,5 point) but in which we have a certain confidence (the colored tests) than in something which displays a value which is certainly very precise (at 0,1 , XNUMX point) without having the slightest conviction that he is not saying anything. I have tried to find an independent "test" of this type of device, without success.
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Re: The "Potager du Laesseux" in the Dordogne




by Ahmed » 19/05/17, 12:57

My introductory formula was purely rhetorical and served to underline the importance of the nature of limestone, depending on whether it is active or not ... I did not especially question the reliability of the PH meters, but on the contrary the fact that the result may surprise compared to what we expected and which is however perhaps correct.
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