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Fish Fertilizer acid / base reactions

Question asked by Daniel Hodges on Sep 27, 2020
Latest reply on Oct 13, 2020 by Karen Wisniewski

Hi Everyone new to chemistry and learning lots but I had a question that I am having trouble working out.

I work for a vegetable grower and we make our own fertilizer.


My question is around the fish fertilizer. The brief description of the process is we use fish meal and mix it with phosphoric acid and enough water to make a paste. Let it sit a week then add, depending on volume a good amount of KOH. We also add a some skim milk and a small amount of molasses. This process among other things converts the protein in the fish to plant available nitrogen and gives us phosphorus and potassium.


I would love to understand all the chemical processes that are happening here! but at the moment I would really like to understand how we are converting the protein's in the fish meal to nitrogen. Is it phosphoric acid or KOH that is doing the work and how does the amount of these acids effect the process. Why such a small amount of acid but a large amount of base.


I have done my own research but coming up short in understanding what is going on and what the acid and base are doing.