Terra Preta - Dark Soil - Experiment

[SilverSurfer_OG]

Keeping soil healthy and fertile long term is all about building humus and the rhizosphere.

The idea behind no-dig gardens is you give the fungi network the time it needs to grow and build the symbiotic relationships with your plants roots. The best practice in beds or fields is to try and maintain 100% cover, 100% of the time or as close as possible. It is also important to build the biodiversity in the soil. Thats why its good to have 'weeds' with long tap roots like dock or dandelion to mine nutrients from the clay layer and bring them to the surface. When that plant is cut down or dies all those nutrients are in the rhizosphere.

When crops and especially green manures are ready they are allowed to break down back into the soil. This captures more carbon and keeps the soil growing. The addition of char seems to speed up this process by holding onto vital nutrients and moisture.

Its really about growing roots so the mycellium and other fungi can attach themselves and they make more nutrients available. Quite often the nutients like phosphorous are abundant but unavailable to the plants. The char is most beneficial in low moisture situations with low fertilility.

Indoors we can still build that soil fertility but if its done in pots we have to regrow the rhizosphere. No dig beds are ideal but not practical for everyone.

 

[bushdriver]

hey silver, so if i was to set up beds(which i plan to do in my attic) do u suggest cover crops when continuous cropping, or alternating beds and time for cover crops to be dug back in and break down? like jaykush has been saying the soil will always benefit from time but i dont know if i have space to double up on beds, maybe tho.... also what cover crops do u guys use, white clover, lucerne, what others would work well alongside cannabis?

 

[jaykush]

you only need to let the soil rest once!!!!!!!!!!!

after that just top dress everything, simple as that.

you only need to rest the soil again if you go adding tons of shit to the soil.

 

[MrFista]

Agreed. There is no withholding period in no till though I practised withholding twice as I didn't know better...

If you have a healthy microherd and a healthy layer of mulch in a char soil (high C is key, but that papers got a LOT of work to do before I share it) the soil doesn't need amendments all the time you just topdress. All I topdress with is mulch now, mainly browns and a few broadleaves, also compost teas, and worm rum in the water...

Some reasons... No till systems preserve free living N fixers. High carbon detritusphere correlates to increased omnivorous nematodes and subsequent increased N availability through their feeding habits. And more..., much more.

I'm quietly convinced N is a big waste of time in a system set up correctly. A layer of browns correlates to increased N in the following growing season (approx 3 months to take effect but then may be ongoing with continuous cover mulch). Run an entire grow with a good char soil and mulch you may never need ferts again.

I failed to find homogeneity in soil food webs, only comparitive roles taken by organisms not necccesarily compatible in other ecosystems (eg: mole cricket). But instead I found relative homogeneity in the hologenome. The bacterial consortiums that live in our soils are relatively similar. Specialists seem to occur in both the soil food web and the microbial community in correlation to plant species and specific types of substrate.

I think the reason I have been able to create an 'authentic' TP soil - (no need for fertiliser) is partially due to the fact the hologenome is relatively ubiquitous and so adding proponents to make similar physical and chemical properties was most of the work done. then it was up to the microbial communities to create microaggregates, and the worms, fungi ants and others to make macroaggregates and for me to light me a phat one, and examine my works, and know it is good.

I'll just leave it there for now. TP soils are the real deal.

 

[SilverSurfer_OG]

High C levels? That paper sounds intersting

I have lots of eggshells in my mix but not charred. I would love to get some kind of grinding machine for oyster shells. Some beaches here are almost 100% oyster shells right down and into the water. Have never seen crushed shells for sale here which is funny.

I had a workshop on building soil carbon with an organic gardening guru and he was basically saying the same thing about N. How the legumes and green manures would add all that was necessary plus as you say the breakdown of any brown mulch.

The guru - Tim Marshall -also said if you have any grasses growing to allow them to reach maturity and produce lignans in the roots. When this breaks down it adds much more goodness to the soil. So you leave em till the seeds are forming and either cut them down or roll/crimp them to stop the flow of sap.

His main advice i noted down was as follows:

Aim for 100% cover, 100% of the time
Grow white and yellow flowers to attract beneficial insects, especially native wasps
Allow grasses to reach maturity and form lignans
Have some kind of deep rooted 'weeds' to mine nutrients
Remove all weeds/herbs from crown root of plants
Use a high scilica rock dust to unlock phosphorous
If tilling soil never turn over. Use a tool with a stabbing motion to go down and let air into soil. There was a machine that did break that rule and turned over but it was with a gentle action which was important...

He didnt mention bio-char unfortunately though i did mention i was tinkering with it.

Indoors the flowers would be of less/no importance but i imagine a mix of plants would be good. The clay layer and other natural features you wouldnt incorporate indoors or would you...

How would the N fixing legumes go indoors do ya reckon Fista?

Do you think its do-able to have the same biological functions indoors as in the field? We wouldnt want winged beasties all over our lights but what about in the dirt?

To answer your question bushdriver i am not sure what would compliment cannabis the best. I imagine the ones you mention would be good. I have always fancied Yarrow i think it is as its sposed to increase the amount of essential oils in neighbouring plants.

I want to build a round, no-till bed indoors to use with my vert setup.

 

[bushdriver]

how are you going to use a bed in a vert set up?

 

[MrFista]

I'm indoors now so this is working indoors. Clay - I added a lot of clay at the beginning, and there's some bones, some old pottery. Peat, compost, worm castings, sheep shit, zoo doo with rhino elephant llama etc etc shit... This soil got loaded with OM before it became what it is today - no ferts required. It is important to get OM right up and then let the microherd do their thing.

I had little success indoor cover cropping. I let other plants grow if they don't harbor pests had a tomato growing in with the buds last time wild seeded just let it run. Couple of unidentified weeds in the subcanopy now...

Cover crops are great! They just don't suit my indoor.

It's about building soil. Plants and N fixers are the bees knees for building soil. Free organic compounds from the atmosphere to build your soil. That's the business end right there.

Got so much reading to do, don't want to go further as I'll end up eating my words. Plenty to learn yet.

 

[MrFista]

SS - Humic substances are characterised by 50% or more of their carbon within aromatic structures. The structure of lignin (many phenolic structures) aligns with lignicolous material being a principle component of humic substances. So the advice you are getting is correct as far as I can deduce.

I again emphasise clay as a crucial player in the development of these soils.

Wang. S.C., Kao, M. and Huang, P.M. (1980) The effect of pH on the catalytic synthesis of humic substances by illite. Soil Science, 129, 333-8.

 

[SilverSurfer_OG]

Yeah cool so you have the clay on the bottom layer as in nature or is it all mixed through?

I guess indoors keeping all forms of mould away from surface is a top priority. So yeah the cover crops couldnt just be cut or allowed to die off. I guess you could let them grow and then cover with a thick layer of dry mulch or soil but that kind of defeats the simplicity.

Thats what else the guru said. 95% of a plants nutrition comes from the sun, water and the atmosphere. So we only have to account for 5% in the actual medium!

With that in mind even a fast growing annual which is very hungry is actually self sufficient in this system. As the plant grows the roots pushing through the earth are scraping away organic matter from themselves. This returns to the food web and keeps recycling.

The trick is to keep roots growing. Only fresh roots are actually feeding and making more OM and plant mass. So a large bed is ideal.

My plan for a vert setup is have a cool tube in the middle of two semicircular beds so there is a channel in the middle for me to walk along and inspect the plants/lights. I could do it with two rectangluar beds also. Just need enough head space to grow plants nice and tall.

 

[descivii]

SSOG, Fista and Kush;
How deep would you say an indoor bed would need to be for it to be self-sufficient?

What if there were a thin bed and pots were sat on the soil surface and roots were allowed to wander down into the bed. Would say a 1gallon nursery pot sat on the surface be able to send roots down into soil and make the network connections in the time frame necessary?

J.

 

[MrFista]

@ SS

"Yeah cool so you have the clay on the bottom layer as in nature or is it all mixed through?"

- The original mix of mine the clay was all mixed through. There is clay soil beneath the grow, but what is happening at the soil/clay interface I have no idea. In the TP soil pictures we are familiar with the clay layer is to my understanding where the TP stops and the natural soil begins. I imagine centuries ago the TP was a thinner layer, and through accelerating it's own mulch production, and with the help of worms, termites etc, spread it's influence further into the clay subsoil.

"I guess indoors keeping all forms of mould away from surface is a top priority. So yeah the cover crops couldnt just be cut or allowed to die off. I guess you could let them grow and then cover with a thick layer of dry mulch or soil but that kind of defeats the simplicity."

- I was concerned with moldy mulch at first but now realise it is not a problem. There is no issues with the plants and as the mulch layer gets thicker the base of it stays damp far longer there must be decomposition as it dissapears over time but it's all good and so far not a problem at all. Just throw it on there.

"Thats what else the guru said. 95% of a plants nutrition comes from the sun, water and the atmosphere. So we only have to account for 5% in the actual medium!"

- Yes! And it can be even better than that. Adding the mulch back replenishes much of the micronutrients, worm casting teas and rum in the water adding more, I doubt I'll ever have problems, and there's always adding seaweed to the mulch...

The link below shows what happens in that N cycling I told you about - adding carbonaceous material is said to draw on N at first as microbial biomass goes up but then the nematodes kick in and lots of N becomes available. What I'm saying is, keep the applications of mulch going, don't worry about the N once it kicks in your plants are green green green and the N problems are over. This is very similar to what happens to char addition - the microbes boom and draw the N pool for a while, then boom, fertility.

http://faculty.plattsburgh.edu/robert.fuller/370%20Files/Week8Organic%20Matter/CN.htm

If you wanted to be a clever bugger you could probably time it to draw N off as you are finishing on the first run hehe.

"With that in mind even a fast growing annual which is very hungry is actually self sufficient in this system. As the plant grows the roots pushing through the earth are scraping away organic matter from themselves. This returns to the food web and keeps recycling."

- A fast growing annual 'seems' self sufficient in this system. I think the worms are almost as big a players as the plants roots when it comes to soil building though, along with the mulch. All parts of the larger picture.

When it comes to sustainable - I am importing mulch and castings to the grow via mulch and teas. Not 100% self sufficient then, just getting there...

I think a large outdoor plot of TP type soil would need no imports once established with good support plants like comfrey/nettles/leguminous species including leguminous trees etc. Adding animals to this system would be simply amazing.


@ descivii - 12 inches works, 18 would be better. If you have room for a thin bed with pots on top you have room for a bed. The 'network connections' will not establish with your plant very well at all in the manner you propose - there may be some benefit compared to not having the extra leg room for roots.

 

[SilverSurfer_OG]

I cant wait to build a big bed indoors. Have to excavate a bit first. I think i will do a layered approach in real big pots made out of landscape, breathable fabric next. Make sure i get em ready at least a month before planting.

I have put char through 4 beds outdoors now. Probably about 5-10% char at mo. They were heavily dug out because of a heap of stones. Will be interesting to see how fast i can fill them up again. Must have taken at least half the total volume of what was there in rock. Got right down to the clay layer. The soil that was there looks real rich and dark. I have found deposits of char from various fires around the place. A stone house burnt down on the old block i am next too and it is slowly being turned from rock foundations to rasied bed with solid rock walls. The rocks here go deep into the clay layer in parts. The soil on top is black and rich. Surrounded by eucalypts and wattle which are both highly flammable. So probably got the remains of a forest fire from hundred or thousands of years ago which would have added natures char in there. Cant wait to crank out some serious produce. Its always just been drips and drabs food wise so be nice to get a soild harvest. The weed plots all got some char mixed in too.

Completely self sufficient will take a while, yes. Teas and mulch are no worries but when you have saved so much time in prep, cleaning pots, measuring ferts and tidying up stray roots and soil.

I should have worded that bit about the roots a bit better. They are recycling into the system but arent the major source of carbon. Like you say its the whole system working in harmony. When you harvest it must be a nice boost with all the root dieoff but.

Whats the rum for?

How much char have you used also?

 

[MrFista]

Char - only up to around 5% char still. Made more soil added more char so the percentage is the same. Would have liked more but didn't have it. New char is going outside as I don't seem to need it. this can be my 5% long term test.

The worm rum is because it's fantastic to add to water for near any plant (some epiphytes and carnivorous plants don't appreciate it) it's probably rich in substances from worm exudates and nutrients whatever it is plants love it. I have just put a corrugated sheet on a wee slope under my bigass worm farm with a gutter going to a collection vessel - sweet. So I got plenty of worm rum to supplement water, and castings for teas.

Roots yeah, outdoors they take on a whole new light. Deep broadleaf tap roots will help the soil a great deal they'll bring subsoil nutrients up and open up the hard clay for further penetration of water and some of that black carbon and the life it encourages so deep in the TP soils of the Amazon in places.

Raised bed with solid rock walls - you could go for species from warmer climates in those. Keep other winter species in with them to shelter them as well should be sweet unless you get hard frosts. An idea.

Your beds might be in an area of extreme fertility. Darwin says rocks dissapeared where he stayed at the rate of about 1 cm a year due to worm activity. They don't sink, the soil comes up. Your conditions however, may have been very different to England. At any rate, if the foundations are down a bit in the soil, chances are the whole of the topsoil right down to the level of the original cleared site will be worm castings/mulch/dust/dung made soil. Gold.

 

[SilverSurfer_OG]

Sweet. 5% of how much dya reckon?

Ahh you dont mean like capn morgans... worm rum. I get it

Well i have started up some melons that aint sposed to do so well down here. I have some popcorn, pumpkin and beans for the walled garden. I have a watermelon, rock melon and pineapple melon. Reckon i can find room for at least 1.

Extreme fertility sounds good! Just gotta rebuild that rhizosphere.

 

[bushdriver]

mista fista ur the man with the info!
in your indoor beds are there worms?? does anybody use worms indoors other than manual cast application?

 

[MrFista]

Thanks bush - the info is there for anyone but it takes a long time to accumulate, Jaykush is the man really.

Yes the worms are there. A lot of the teas have cocoons in them and I pick them out before straining and add to the grow. Tiger worms and another unidentified species live in the topsoil/mulch layer, not a lot, but enough to make me very happy knowing they are there. I imagine the larger earthworm species will be visiting from underneath if they are not there already as the bottom of my bed touches ground in many places between insulative materials at the base.

 

[descivii]

Was looking for some activated carbon (scrubber) and noticed something farther down....BioChar?

http://www.buyactivatedcharcoal.com/granular_activated_carbon

same company but a bit of reading on terra preta, nothing new but thought I'd add it here.

http://www.buyactivatedcharcoal.com/terra_preta

J.

 

[bushdriver]

ur beds sound amazing fista!
ok this is something i need to clear up.. say if u were to char bones, does the phosphorus stay bound with the carbon in the charcoal or does that leach out at a faster rate? i guess what i'm getting at is it only the carbon that stays about or do the original elements of the biomass stay too? so ur nutrient profile cud be dictated by what u turn to char..

 

[MrFista]

That is a very good question of which I'm unqualified to answer. Do not think of char as a nutrient source, ignore my earlier writing on this. Whatever nutrients are in char are bound up so as to be an extremely minimal nutritional input to the soil, if any.

The phosphates you require will be present in the ash which comes with the char. Char is important for many other reasons, it creates an atmosphere for increased mocribial activity leading to improved plant nutrient assimilation and reduced fert needs. The nutrients in char however, if not off gassed in pyrolisation will be locked up in aromatic structures and extremely hard to get at.

I have a strong suspicion many of the chemical structures at the char/soil interface are catalytic. Couple more years chemistry they might let me have a decent attempt at finding out.

 

[jaykush]

i was thinking about that question to and your answer is my best answer.

That is a very good question of which I'm unqualified to answer. Do not think of char as a nutrient source

that is until the char has been soaked, mixes with soil and cooked, or added to the compost pile. because then its FULL of goodies.