I hope I came across to another free resource for my garden. It is a common practice to use zeolite sand as an underlayer for caged birds. It has highly absorbant. It gets mixed with bird droppings and seed husks and then thrown away. What might be the pros and cons of adding pure zeolite to potting mix? Or adding this dropping mixed zeolite to compost pile? Does it add any nutrients similar to rock dust? Has anyone ever used it in garden?
Zeolites are microporous, aluminosilicate minerals most commonly used as commercial adsorbents and catalysts.
The silicon building block in Zeolite is electrically neutral, but the aluminum building block carries a negative charge.
Several people are making the claim that Zeolite is valuable because the negative charge of the Al creates charged sites throughout the entire crystal structure.
These same people claim this is a naturally found compound located in volcanic rock, this is indeed where the stilbite compounds are found.
However, the term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating the material, stilbite, produced large amounts of steam from water that had been adsorbed by the material.
For our soil health the first thing to look at when assessing all amendments is the chemical makeup of that material.
Aluminum is indeed a trace element most life forms need in nano quantities, more than that and you can have a poisonous situation arise fairly quickly.
While it is possible that many of the "detoxifying" properties are documented, it seems that most of these studies are by people who are marketing the material as a detox product.
For me, that sends up a giant red flag.
I personally would do a small space, trial run and take lots of samples and run lots of tests to make sure that any negative side effects of this material were not going to do any harm to my microbiome organisms, my plants, my animals and myself.
It is not a rock dust, however, it could be possible that it would bond to minerals our plants need and if our bacteria can't break those minerals free then we have done more harm than good.
Many of the mineral ions we love to have in our soil carry a positive charge, in the zeolite the silicon is neutral and the aluminum is negatively charged which means the aluminum will attract positively charged minerals to form aluminum salts.
I would make a test oriented compost heap and trial the material with a fungal rich compost.
Thanks Redhawk. I was hoping you would comment and I am really glad you did. After reading your massage, I dived into our academic data base and searched for zeolite and agriculture. Frankly, especially about soil, when I search for an answer; I end up having 15 new questions and one sort of answer. I came across two articles that helped me to understand more on the subject. I have more questions though.
If there is any soul in permaculture that uses zeolite in their sites, please chime in and share your experiences. What I am going to summarize is not sourced from practice, but academic research.
Those two articles are: "Zeolite-amended cattle manure effects on sunflower yield, seed quality, water use efficiency and nutrient leach" (Gholamhoseini et al, 2012) and "Zeolites and their potential uses in agriculture" (Ramesh ad Reddy, 2011). The first article is focused on a solution on a particular problem while the second one is more of a review (It has more than 6 page long reference). Things on my cheat sheet:
-There are more than 40 naturally occurring zeolites. Clinoptilolite is one of them. They have an open three dimensional structure, with a lot of voids (similar to biochar?)
-There have been some initial research on zeolites in Japan, but both articles lack reference on the subject. The main goal was to discover their potential as both carriers of nutrients and medium to free nutrients.
-Si/Al ratio is important for classifying zeolites. Higher the Si/Al ratio, the matter becomes more hyrophonic and will be more thermally stable. Cation content will be less.
-There is a table given for zeolite chemical composition given in (2) article. For Turkish Clinoptilolite the numbers are roughly
SiO2 (75%) CaO (3%) K2O (3.5%) Al2O3 (11%) Na2O (varies 0.1-0.6%) Fe2O3 (1.4%) MgO(1%).
For Oregon clin.
SiO2 (60%) CaO (5%) K2O (0.15%) Al2O3 (12%) Na2O (0.11%) Fe2O3 (0.9%) MgO(0.1%).
-Zeolites are used for nitrogen retention in soils. Most for research are focused on sandy soils. They have high cationic interchange capacity and a great affinity for NH4 and K ions. Decreases nitrate leaching up to 11%.
-Increase of tomato yield but no positive effect on sweet corn is reported. Increase of sunflower yield, protein content and such.
-Has a potential to be used as carrier of slow release fertilizers, cides and as a trap for heavy metals.
-20-25% mixture by final weight with manure compost is ideal. (14-25% range has very positive results depending on irrigation)
-Experiments showed zeolite incorporated with poultry manure served as effective fertilizer and soil conditioner (Leggo 2000)
-Reduces the plant availability of heavy metals (Cd, Pb, Cr, Zn, Cu)
-None of the articles mention problems related to aluminum toxicity.
There are some videos on youtube about its detox properties. I don't buy their claims. I didn't come across any article on their claims in ac. literature.
So long story short, I think it has a potential to look into. Maybe an alternative to biochar? It is best to do some experiments as you have already described.
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