Ideal Soil Element Ratios

There’s no such thing as ideal. Or is there?

While calculating the ratios of soil elements I made an interesting observation about carbon. Both plant and soil.

We know from previous studies that about 8% soil organic carbon (SOC) is optimum for yield. It turns out that’s about the same amount of carbon in most plants. Coincidence? I think not.

Optimum soil carbon for yield likely correlates with actual plant carbon.

If I take that and assume an 8% SOC 10cm topsoil and a linear decline over 60cm depth, I get 15.75% Total SOC. You see these levels in some forests and Terra Preta.

I wonder what percentage of fungi and bacteria is carbon?… Just checked… and it turns out fungi are about 8%!

*Mind Blown*

Spirulina, a cyanobacteria? 3.12%. If you divide 8% by 3.12% you get a Fungal to Bacteria ratio of 2.56:1.

Meaning you’d need 2.56 fungi to 1 bacteria to get the equivalent of 8% carbon.

What did David Johnson say was ideal Fungi:Bacteria ratio? Well, will you look at that, 2.56 is pretty darn close to the productivity maxima.

So, depending on what you are growing, it could well dictate the ideal soil organic carbon and the bacteria:fungi ratio.

FWIW, if you’re growing a human, then we’re 18.5% carbon… and a vegetarian would need to consume something like 2.3x the amount of food as a carnivore. This is below the bifurcation growth rate of chaos theory at 3.0.
Fungi:Bacteria Ratio.png

15.875% Total SOC.png

8-soc

1280px-Logistic_Bifurcation_map_High_Resolution.png