Super-char?

My understanding is that biochar, charged charcoal powder, is activated with any variety of nutrient-dense material, generally in or with the aid of water or liquid form. I hear people charging with things like urine, coffee, fish emulsion, etc. But my question is, since biochar theoretically takes on the nutritional makeup of whatever it's soaked in, doesn't it make sense to soak it in a mixture that contains the widest range of nutritional components for the garden? For example, one would think that any combination of compost, castings, manure, urine, emulsion, compost teas, molasses, eggshells, seawater etc, would provide the maximum benefit and potentially alleviate any imbalance in the nutritional makeup?

Or does it matter all that much?

Additionally, have others toyed with crop-specific biochar? Like if your plants are heavy potassium feeders, soaking it in ash, etc?

That seems to make sense to me Priscilla.  

In nature biochar forms during wild fires and lays on the surface.  As plants die or drop leaves over it the biochar absorbs nutrients as this litter layer breaks down.  So that's what I do with all my biochar....put it in places where things are breaking down and releasing freed nutrients.  Generally for me that means putting it in my compost pile, putting it down before sheet mulching, or spreading it in the forest and forest garden where the fall leaves will cover it and where it quickly becomes part of the leaf litter.  Studies have shown that trees will grow up to at least 10% faster with a half gallon of biochar applied per square foot, thus fixing lots more carbon and creating much more goodness!

One would think that if it was charged with a range of nutrients, the plants would choose what they need.  I'm thinking that it might be wise to have some idea what you're adding, so you won't be overloading it with too much of any particular ingredient, but if your usual range of materials is diverse, I can't see it doing anything but good.

Whatever benefits you get from "charging" your biochar with nutrients (nitrogen, others) will be a one-time benefit.  As soon as you put that biochar into the soil, those nutrients will be cycled into the soil.

The long-term benefits of biochar are as a home for microbial life.  

Think of it as a reef.  If you take an old school bus (or battleship or pile of concrete lampposts . . .) and sink it out into the tropical ocean, in no time there will a community of things that attach themselves to said school bus.  In 25 years, you'll barely be able to know that it was a school bus --- it'll be a wonderful mess of corral and critters, teaming with life.  The lifeless hunk of matter becomes a reef that attracts all manor of other sea life.

Biochar is a reef.  It attracts and holds life.  Tiny critters being eaten by bigger critters being eaten by even bigger ones.  

Marco Banks wrote:Whatever benefits you get from "charging" your biochar with nutrients (nitrogen, others) will be a one-time benefit.  As soon as you put that biochar into the soil, those nutrients will be cycled into the soil.

The long-term benefits of biochar are as a home for microbial life.  

Think of it as a reef.  If you take an old school bus (or battleship or pile of concrete lampposts . . .) and sink it out into the tropical ocean, in no time there will a community of things that attach themselves to said school bus.  In 25 years, you'll barely be able to know that it was a school bus --- it'll be a wonderful mess of corral and critters, teaming with life.  The lifeless hunk of matter becomes a reef that attracts all manor of other sea life.

Biochar is a reef.  It attracts and holds life.  Tiny critters being eaten by bigger critters being eaten by even bigger ones.  

I don't understand that. If the nutrients are immediately released into the soil, what's the point of charging the biochar at all?

If you don't charge the biochar it will adsorb available liquid and soluble  nutrients.
Here's my understanding of it.
It's like putting croutons into soup.
If it's already a thin shallow gruel,  the dry bread will soak up everything.
If you soak the croutons in a rich broth and add that to the gruel,  you make the gruel richer.

If you put "bare", unactivated biochar into the soil and then plant veggies (for instance), the biochar will draw the nutrients out of the soil for a couple of years to activate itself, leaving the veggies without much nutrition for growing, and the crop will be poor.

By activating the biochar for a while, and then adding it to the soil, you get a two-year head start on the soil improvement.

I think MB exaggerated how much the plants will draw nutrients from the biochar -- it's not an all-or-nothing situation.  That's the whole point of using biochar.  The biochar holds the nutrients and the microbes dole them out to the plants as needed, retaining some.  

Biochar is capable of holding nutrients through periods of heavy rain and melting snow, while soil does very poorly in nutrient retention, and let's them wash beyond the reach of the roots, or down the rivers to the ocean.

Sue Monroe wrote:If you put "bare", unactivated biochar into the soil and then plant veggies (for instance), the biochar will draw the nutrients out of the soil for a couple of years to activate itself, leaving the veggies without much nutrition for growing, and the crop will be poor.

By activating the biochar for a while, and then adding it to the soil, you get a two-year head start on the soil improvement.

I think the previous poster exaggerated how much the plants will draw nutrients from the biochar -- it's not an all-or-nothing situation.  That's the whole point of using biochar.

Exactly. If uncharged biochar (charcoal) can take 2 years to stabilize by absorbing nutrients, it should also take around the same amount of time to release the nutrients it's absorbed, and at the same time it should be replenishing it's supply of nutrients as additional nutrients are added to the soil around it.

I think there was definitely some exaggeration to say the least. Ha.

One of the fantastic things about biochar is how many services it does well in the soil.  Beyond housing microbes, holding on to nutrients and retaining water there is another key soil service it performs.  Biochar makes life easier for soil microbes by reducing the cost of their metabolism.  The carbon walls of biochar are actually rich in oxygen groups.  At the atomic level these oxygens are arranged on stacks of graphene oxide to help space these carbon sheets out and get them to adsorb great quantities of nutrients, but they also form electron donor and receiver groups hooked to each other through a semiconductor bridge.  This is perfect for helping the microbes with their redox reactions.  This shows up in the fact that mature biochar soils have higher soil microbe populations, yet lower "per capita" metabolic activity.  This is very important for the plants that are running the show because they then don't have to exude as much carbohydrate to support the microbes that support them...and therefore they can grow faster and/or set a heavier crop.

Priscilla Stilwell wrote:
I don't understand that. If the nutrients are immediately released into the soil, what's the point of charging the biochar at all?

You're not charging it with nutrients.  You're charging it with microbial life.  Charcoal is tremendously porous.  It's been said (and I don't remember where, or if this is even true . . . but) that a 1" square chunk of charcoal has about an acre of surface area.  All those microscopic holes and crevices are microbial condos.  They eat, poop, kill each other, break down complex substances into bite-sized nutrients that plants can absorb . . . and on Saturday nights when the moon is just right they do the microbe boogie.

Microbes are the fundamental building block of the soil food web.  A handful of healthy compost has 10's of billions of microbes in it.  When you put compost in your soil, all that microbial life works in concert with the plant roots to find and up-take nutrients.

Everything you can do to feed and house the microbial community will benefit your plants.  Because biochar does not decompose, it's long-term housing for your microbes.  It'll be just as effective in 1000 years as it is next year.

The "charging" of biochar is with microbes not NPK nutrients. It's primary role is add housing and feed sick for microbial/fungal communities, which leads to increased water retention and nutrient availability. If you want less leaching of skill nutrients I think you are looking for clay colloids.

If you're already composting then mixing ground charcoal into the compost is going to be the easiest way to charge and apply biochar. If you aren't composting then probably the easiest way to charge it is to stick it in among an aerated compost tea. Then spread it where you want it and spray the tea

Why can't you charge the biochar with microbes AND nutrients?

It only seems polite if you're giving them a new home, that you should have dinner delivered, too.  It's really tiring to move into a new place just to find that you left all the food in the storage unit that closed half an hour ago.

Sue Monroe wrote:Why can't you charge the biochar with microbes AND nutrients?

Agreed Sue, that's the reason I don't compost without biochar....holds more nutrients from being lost from the compost process while being surrounded by soil microbes that can move right in.  I really like it in sheet mulching because I think it's a closer mimic to what nature does with biochar...more of a leaf litter mimic.  But laying in on the ground under trees seems to me to be the best mimic of all....everything but the forest fire.

That sounds fine as long as the wind doesn't blow it away.  Do you lay something on top of it to prevent that?

Sue Monroe wrote:Why can't you charge the biochar with microbes AND nutrients?

It only seems polite if you're giving them a new home, that you should have dinner delivered, too.  It's really tiring to move into a new place just to find that you left all the food in the storage unit that closed half an hour ago.

Certainly -- both happen when charge your biochar.  Nutrients tend to wash through the soil unless you have carbon to capture it.  A certain amount of N, K & P (as well as other nutrients) are captured in the charcoal.  The goal in permaculture is to mimic natural ecosystems.  In nature, you have naturally occurring fires that drop charcoal to the ground where it's stepped on by animals and ground into dust and down into the soil profile.  In nature, leaves and grasses, as well as manure, are dropped constantly onto the soil surface as mulch.  It feeds the microbial community which feeds the plant roots.

However, nowhere in the natural cycle do you see charcoal artificially charged in nutrient dense buckets of stuff.  How are microbes fed in nature?  The most effective way microbes are fed are through the sugars and starches secreted by plant roots.  These sugars and starches are called "root exudates".  Every plant pumps these goodies into the soil to feed the microbes in the area around the plant roots.  

Microbes don't eat N, K, and P.  They eat C.  Carbon is the fuel for the entire soil food web.  Microbes (and fungi in particular) will make N, K & P available to roots, but they don't eat them.  Plants need them but microbes don't.

Here's some articles on the soil food web.

https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053868

https://www.holganix.com/blog/soil-food-web

Sue Monroe wrote:That sounds fine as long as the wind doesn't blow it away.  Do you lay something on top of it to prevent that?

For the sheet mulching I put a layer of biochar on the ground then cover it with the sheet mulch ingredients.  Concerning spreading it under tress...I don't crush it (I just about never crush it as for my methods it's a waste of time).  There's still lots of very fine biochar, but I don't have bare soil so the fine stuff ends up falling into the breaking down organic layer.