Hmm, afaik up to 10% biochar is considered beneficial in any soil and will keep nutrients fixated in the soil, more than that is mainly good since it removes co2 from the environment.

Why ship it? you just burn brush and waste where you have it and put the fire out before charcoal turns to ash and then innoculate it with compost and you are done..

New Delhi and other cities are suffering from farms burning off dry wheat stalks. Will a charcoal process offer an incentive to farmers to burn hay cleanly?

I'm curious, why it doesn't work in temperate climates? Also, I think it heavily depends on how "rich" / volcanic the soil is in the first place, perhaps?

https://iopscience.iop.org/article/10.1088/1748-9326/aa67bd : here

[..]Here we use a global-scale meta-analysis to show that biochar has, on average, no effect on crop yield in temperate latitudes, yet elicits a 25% average increase in yield in the tropics. In the tropics, biochar increased yield through liming and fertilization, consistent with the low soil pH, low fertility, and low fertilizer inputs typical of arable tropical soils. We also found that, in tropical soils, high-nutrient biochar inputs stimulated yield substantially more than low-nutrient biochar, further supporting the role of nutrient fertilization in the observed yield stimulation. In contrast, arable soils in temperate regions are moderate in pH, higher in fertility, and generally receive higher fertilizer inputs, leaving little room for additional benefits from biochar. Our findings demonstrate that the yield-stimulating effects of biochar are not universal, but may especially benefit agriculture in low-nutrient, acidic soils in the tropics. Biochar management in temperate zones should focus on potential non-yield benefits such as lime and fertilizer cost savings, greenhouse gas emissions control, and other ecosystem services.[..]

That appears to be a limited meta-analysis that itself postulated the reason temperate yield didn't improve because temperate soils were more fertilized on average than the tropical soil studies.

We're talking in the context of soil depletion in this thread, so I don't think their limited conclusion applies.

Possibly. I haven’t done any studies. I find good soil management with rotation and maintaining soil biome is sufficient in my Ca 8a/8b soil. My fields have soils that can be categorized as yolo loam and adobe can’t.

One thing not mentioned often about rainforrests is that their soil is actually pretty damn terrible. Which is also why you see things like carnivorous plants there.

So what if rainforest soil is terrible...their main function is to sequester carbon and act as a carbon sink supporting habitat and balance terrestrial ecology.

That is more for "why it helps there in the first place" than any disparagement of the rainforests. That the soil is terrible is more reason to leave them there - especially when they provide steady rain.

It isn't like temperate climates where you can rotate between farms, fields, and forrests over time easier.

right. i hear you.

may i ask what you mean by 'terrible'...nutritionally deficient or acidic..etc etc?