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Problems with Acid Sulfate Soils

 

Andrey Vungtau (andrey.vungtau@yandex.ru): Dear Listers, my last two Penaeus vannamei crops failed.  The problem: acid sulfate soils—and I’m completely lost.

 

Whenever I direct more oxygen to the soil on the bottom of my ponds, sulfuric acid is formed, but if I don’t provide oxygen to the bottom, the shrimp will suffocate and die.

 

I’ve tried applications of EDTA, lime and Thiobacillus (a gram-negative bacteria), but they did not help.

 

Is there a way to deal with acid-sulfate pond bottoms?

 

I know that pond liners would resolve my problem, but that would be quite expensive.

 

David W. Smith (david@focussafety.com): Dear Andrey, losing your shrimp crop is a lot more expensive than installing pond liners.  If you install pond liners now, you’ll save time and money over the long term.

 

Eric Pinon (list@serviceaqua.com): Andrey, line your ponds.  Liners will resolve your acid problem, reduce seepage and reduce your pond turnover time.

 

John Birkett (jbirkett42@yahoo.com): Andrey, anaerobic bacteria that breakdown organic matter are what usually cause iron build-up on pond bottoms.  Have you tested the organic matter content of the soil on your pond bottoms?

 

Andrey Vungtau (andrey.vungtau@yandex.ru): Thank you David, Eric and John for your advice.  John, I guess there is always a lot of organic matter on the pond bottom, but my problem began from the very start, when there were no organics, just a week after stocking and aeration.

 

Now, the iron content in our water rises whenever we aerate.

 

Nelson Gerundo (nelsongerundo@yahoo.com): In the long run, lining your ponds will save on operating and maintenance costs.  You should also see less iron accumulation in your pond water.

 

I understand that your pond banks are lined and that the pond bottoms are not covered.  You could lay HDPE liner on the bottom of your pond or cover it with marine limestone that’s been crushed and compacted.

 

Ramon Macaraig (monmac52@yahoo.com): Andrey, you seem to be paying a lot of attention to water quality parameters.

 

What are your shrimp telling you?

Are they still there?

Do you see any quality defects?

When do the defects emerge?

At what body weight are the shrimp affected?

What algae, zooplankton changes do you notice with acid sulfate soils?

 

Nelson Gerundo (nelsongerundo@yahoo.com): Hi Andrey, if you choose to line your entire pond with HDPE liners or lay crushed marine limestone, try to culture your shrimp at higher salinity.

 

Sources: 1. The Shrimp List (a mailing list for shrimp farmers).  Subject: Problems with Acid Sulphate Soils.  January 24-25, 2018.  2. Bob Rosenberry, Shrimp News International, January 25, 2018.

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