4. The Microbes Role in Soil Carbon Sequestration

Building on Part 3, Dr David Johnson elaborates on the effect of the fungi to bacteria ratio on carbon sequestration.

[@CraigOverend]

I love this talk. I've seen these exact numbers in papers regarding biochar input and dissolved organic carbon rates. That there was a reduction of DOC at 3% and increase over 8%. A lot of the studies also indicated that highest yields were at 8% SOC.

[@giuseppeguit]

Craig Overend can you share with me the papers about carbon input please? I am working in Universidad Nacional de La Plata Argentina.

[@mroakarm]

These charts are fine and dandy but where is all the hands on info of how to integrate this biology into the soil. The charts which show how to deal with the different soil types and how to use this on a small setting. The different problems that may arise of using too little or too much? Are there any other videos of exactly how to use this biology from the reactor other than his using pictures?

[@vickib4063]

The part of this that I don't quite understand is where the nitrogen in the soil decreases at 3% organic matter concentration. If you need nitrogen to grow plants how is this decrease in nitrogen (after this 3% point) affecting the plant growth? What am I missing here in this talk?

[@derekpierce2280]

the nitrogen in the 3% Organic Matter soil gets lower and lower because the plant is consuming it instead of feeding it to soil organisms.

[@raurkegoose5233]

At 3.68 F:B ratio and 9.12 SOM, is that a net loss of N in the soil?

[@vickib4063]

Another part does not make sense to me either. The part where you say in poor soil there is 96% carbon captured in the soil - this does not make sense to me. Surely if you are capturing 96% of carbon in poor soil - why would you bother to try and improve the soil only to capture less carbon. Of course improving the soil helps your plants but now you are not capturing the same amount of carbon. Or did you meant that you are loosing 96% of carbon capturing capabilities. I am confused. Your explanation seems back to front to me.

[@derekpierce2280]

This is an issue of the way he measured. He told us the portion of carbon captured by the plant and fed to soil organisms. He did not tell us the amount, only what portion of the total carbon is being sent into the soil. The total amount of carbon the plant captures increases through every set of diagrams because the plant is growing. Seeing that the soil is being allotted less carbon only means that the plant is using a greater percentage to grow larger. The specific usage of carbon is detailed in later diagrams, but never the total amount of carbon. The amount of carbon captured could be grams or kilograms depending on the size and type of plant. The rate the plant uses its carbon and nitrogen has to do with the abundance and balance of soil bacteria and fungi. Until there is a healthy balance of fungi and bacteria, the plant will 'choose' to use its resources to feed the soil instead of growing as much as it could. If plants didn't do this and grew as much as they could in unhealthy soil, they would have to compete with bacteria and fungi for resources, killing the plant before it could seed, the fungus before it could spore, leaving only the toughest anorexic bacteria enough time to divide and spread. This is why grasses are great footholds if you're trying to revitalize a desert- they don't need many resources to grow and seed, meaning they'll share excess resources with soil organisms. Fungal and bacterial networks in soil also do a great job of spreading nutrients from abundant zones to deficient ones, making more soil viable before the grass has time to grow.

[@realfoodman]

This is blowing my mind!