Well, it does prevent algae in a higher lighting setup, but it's more than that. Mineralizing the soil makes a LOT more of the nutrients in the soil bioavailable to the plant's roots. It should last a lot longer than just soil by itself and can still work just fine in a low-tech setup.Hi Stepheus and Aaron, thank you for your reply.
Regarding soil mineralization, I did think of trying it when I first read the thread a while ago. However, my understanding was that it was mainly for preventing algae. But algae was not an issue for me (probably due to the low light setup combined with plenty of floating plants).
I guess what really stopped me from trying it was that I did not fully understand how the mineralization process would affect the soil's life span. For example, I remember reading in Ms. Walstad's writing that adding CO2 will use up the soil's nutrient at a rate much faster than it is being replenished through feeding the fish (if I have mis-understood her writing, please correct me).
May be I should ask: When people maintain their tanks using Ms. Walstad's way, will the mineralization process affect the soil's life span?
The soil becomes mineralized when it is exposed to oxygen. Plants release oxygen into the soil via their roots when they are healthy and growing, however, it is much much faster to simply expose the wet soil to air as the oxygen needed for the process to take place is much more abundant.Thanks Aaron. I have two questions in mind.
When the soil is not mineralized, will the same nutrient be available at a later time?
Does the mineralization speed up the release of nutrients that would otherwise be available at a much slower pace?
Hmm...that's not quite right.Aaron, if I understand your explanation correctly, preparing the soil through mineralization will thoroughly expose the soil to oxygen. That will result in a massive release of nutrient within a relatively short period of time. Without the mineralization preparation, much of the soil nutrients remain trapped due to the lack of oxygen. Later when plant roots release oxygen, those trapped nutrients will then be released, albeit at a much slower pace than through the mineralization preparation
However, given the limited amount of nutrients in a fixed volume of soil, the mineralization preparation will cause the soil nutrient to run out much sooner than otherwise, unless we replenish the nutrients through massive dosing. Have I missed or mis-understood something?
That's closer. I didn't mention this in the article, but the initial release of nutrients is actually pretty slow. It takes 3-4 weeks for the bacteria to establish in the substrate that help the plant's roots to unlock the nutrients from the soil. Once these microbes are in place then the plants will have a virtually unlimited supply of nutrients.Sorry Aaron, your first explanation came across ok. Just that I was not expressing myself well. Let me try again. Hope this time will be better.
Nutrient release is a multi-step process. One of the steps depends on the availability of oxygen. Mineralization preparation speeds up (or even completed) that oxygen-dependent step by making sure that soil has been exposed to plenty of oxygen before being used in a tank.
Soil that has not been through the mineralization preparation will be constrained by the limited amount of oxygen generated by plant roots. Thus, the amount of initial nutrient release and the continued rate of nutrient release will be much less than those of the soil that had been through the mineralization preparation.
Mineralized soil does not have oxygen constraint. It can therefore release a massive amount of nutrient in a newly set-up tank and its continued rate of nutrient release high.
The nutrients are never released anywhere, rather they are unlocked and use by the plant's roots as needed. For example, if I were to measure the nitrate and phosphate levels in my tanks they would be nearly zero almost all of the time because the nutrients stay in the substrate.But for a given quantity of nutrient, the more rapid it is being released, the sooner the nutrient will be completely depleted.
One way of replenishing nutrient is through fish food. But if the soil nutrient release is at a much faster rate than that of the replenishment from fish food, soil nutrient will run out. And that is my concern with the impact of mineralization preparation.