Here's a regenerative agroforestry system for semi-arid to arid climates integrating different agricultural technologies
Here's a regenerative agroforestry system for semi-arid to arid climates integrating different agricultural technologies

There are many possible configurations for this pit layout depending on where the water source for irrigation is (if irrigation is available), where the biochar feedstock is, where the Permafert ingredients are and different Permafert production tech eg. middens, pallet systems, pits. Separate Permafert pits are shown in the above diagram or possibly in-pit production used by most Zai pit farmers.  Another option could be making some or all of the pits into 'Pyramid kiln' shapes (see 'Resources' page) and making biochar in-pit. Personally, I prefer a separate Lu'au pit or Kon-Tiki kiln eg.Rolls, as these conical structures are cleaner burning than 'Pyramid' shapes and allow quality and quantity control for building the aquifers in the Zai pits and making the Permafert in separate structures.


In terms of tools, all you really need is to cut 16 short stakes eg.thin bamboo, with a saw, and make a set square and measuring stick. I'm digging 900x900x300mm pits so I made a 900mm x 900mm set square from some old PVC electrical conduit pipe and a 300mm measuring stick for measuring pit depth. A long handled hoe eg.A $65 Cyclone long handled burr hoe (Oz produced with a lifetime guarantee), for breaking the soil (need to screw into the handle at the base of the head) and a $15 square faced shovel for shifting the soil. So, after staking out the pits, 4 at a time, using the set square, the digging begins. The shifted soil can be placed around the North and South edges of the pits, similar to swales, which needs to be pounded into semicircular mounds eg. with the back of the shovel. There will then be enough space in between the pits, on the East and West sides, for walking between and managing the pits.  The mounds will increase the water catchment/collection in the pits.


The Zai pit structure shown in the diagram is based on what I was able to test in pots, the Permachar Kitchen Garden (PKG), The Permafert Swale  (TPS) and Permachar Wicking Module (PWM). Kind of looks like a multi-layered Carbon-based solar (PV) cell. The hope is the pits, like PV cells, will become 'greener' and more efficient over time. Though not purely scientific, I have tested these systems with different plants over months to years and they seem to work very well most of the time. I'm prepared to do a '3 sisters' plant guild trial using this pit structure on the Zai pits I am working on as I think with climate change, the Mediterranean climate in which I live, defined as semi-arid (500-800mm rainfall, aridity index between 0.2-0.5), due to a decreasing 'aridity index' (see the file download at the bottom of the page) will eventually transition to a more arid climate, like the RIverland, where the '3 sisters' should grow well but maybe they will grow well in the current climate? This trial may be a useful bioindicator for future trials/plantings ;)


I should mention too that while there is good rainfall around many parts of Oz, it's a good time to be digging pits, buying seeds, germinating them and growing seedlings for the Spring and making biochar in between the rain as there is less wind compared to Spring. It's also the off season for bushfires so the time is right to make biochar. Another thing is you can half-dig the pits while the soil is wet and when you get to the dry stuff underneath, stop digging and wait for more rain. After the rain, the second half of the pit is moist and easier to dig. I'm pretty stoked as I found red clay at 300mm depth which should be perfect for lining the bottom of the pits as it will buffer excess water beneath the biochar aquifer in times of heavy rainfall.  In drier periods, the biochar will hold water and wick it to the Permafert as needed. Biochar has a higher water holding capacity (WHC) than sphagnum moss!


I am using existing trees for wind protection and have good access to North,Northwest, West sunlight. If there are no trees around, I would suggest planting species of the Acacia genus around the edge of the pit matrix, maybe in every second pit to provide enough space for tree canopy. These will fix nitrogen in the Permafert (or even reused soil from the pit), provide flowers for pollinators and birds (and for aesthetics), provide wind protection for the veggies and herbs in the middle of the matrix. Some species are good for coppicing for biomass/feedstock to make more biochar (charcoal, but with a different thermal profile of the charcoal you can cook with and loads more surface area)  for more Zai pits in the future - a 'permanent agriculture'? Some species produce edible wattle seed and even edible flowers. Carbon drawdown is a plus too. Here's a good starting point for research:

I've drilled down to one species that I want to try growing which should be suitable for my location and functions: Acacia saligna (300-700mm rainfall), which is fast growing and can be coppiced for biochar production - which is a relatively new area of research.


I have sited the pits close to my Kon-Tiki 'Rolls' kiln (with nearby feedstock for biochar and a biochar heap between the kiln and the pits), 2 point water sources and nearby Permafert middens, which I may abandon and try Permafert pits instead for the trial/case study. I'll germinate the maize, beans and squash in August and plant in September. I'm also going to plant some pumpkins and zucchini too Acacia saligna in smaller pits around the edge of the pits.


I imagine that the Zai pits will have their greatest benefit in semi-arid to arid climate zones but should not be discounted in more favourable and wetter climate zones - they should still work though water-saving may not be their obvious benefit/feature. In very wet soils the pits probably won't be as effective and could even prevent successful growing of some plants due to 'wet feet'.


Could this be a solar, Carbon, Zai pit, permaculture, regen agroforestry and hybrid software revolution? In the future, it may be possible to integrate software and Carbon offsets and removal using the Zai pit/biochar regen agroforestry system. This could significantly increase the income for farmers and help the planet decarbonise/recarbonise!! For eg., you could work out how much Carbon is sequestered/stored in one Zai pit and multiply that number by the number of similarly built pits for accounting purposes...voila...'geometrical replication' of pits for Carbon drawdown and a growing population on a rapidly desertifying planet with a green Covid-19 recovery. But, would this be yet another form of Colonialism? Only if farmers were involuntarily made 'Carbon slaves' (as opposed to 'energy slaves') with a new paradigm of control.  Ultimately, it should be a choice to buy/sell CORCs, CRCs, Carbon credits etc and even use software (desktop/mobile/cloud) to do it. There's also that question of converting these financial 'entities' into cash or cryptocurrency or both?  Does Gaia care how it's done (possibly, as we are a part of her)? In one scenario, transparent 'blockchained' pit auditing with reflectometers and scales would be a bitch but would create many regional jobs in the process.  National wireless/copper/fibre networks or global networks such as Starlink or even Oneweb  etc could be used to upload/download information onto laptops/smartphones into hybrid software via the internet just about anywhere in the world but the internet service would need to be affordable and reliable.


Pioneering is speculation but before you drink the coolade perhaps initially or permanently, community level/involved/engaged projects with community crowdsourcing for RAS is the best combination, suggested by the lead software designer at The problem I can see there is crowdsourcing (spare) funds probably don't exist in large amounts in communities on most of the planet...unless it was internet-based crowdsourcing but most sites like 'Indiegogo' provide punters with something material...maybe some 'fair trade' coffee, for eg? Sounds fair but any exports have a Carbon footprint however platforms like 'Vaayu' are looking at tracking Carbon footprints for product supply chains at the retail 'point of sale'. Maybe this will help decarbonise the world economy? I imagine that at some point not-for-profit and corporate philanthropy has a role and some, but not all Governments, would cough up the cash for their farmers offsetting and reducing Carbon as well as growing cash crops, food and medicine. Who knows, maybe the next great cash crop will be 'Regen agroforestry' (as opposed to 'Carbon farming') and farmers won't even bother growing a monoculture of palm oil trees (cash crops) anymore or growing a monoculture of switchgrass (Carbon farming but love those phytoliths)?  Ecosystems are biodiverse as should agroforestry polycultures be - the difference being 'economic' purpose. The plants grown in a regen agroforestry system need to have multiple 'economic' purposes or functions that include providing ecological services, promoting biodiversity and Carbon sequestration for the planet - and besides, biochar has multiple functions too. Holarchies within holarchies.


It's hard to imagine in Oz getting money from the Government for making biochar and putting it into pits while we are still developing coal and natural gas 'assets' (read 'climate liability'/cognitive dissonance)...

In Oz, it's sort of like on one hand, we've got most of the world telling the Government to stop burning fossil fuels and make a pledge for 'Carbon neutrality' in 2050. I believe this target, although scientifically fuzzy, at least galvanises international action.  Maybe the planet will be Carbon-negative by then and addressing the volumes of CO2 already in the atmosphere and to come before 2050 'neutrality' (According to NASA, once CO2 is added to the atmosphere, it hangs around, for a long time: between 300 to 1,000 years).  Don't forget the other greenhouses gases too! On the other hand the Government is in bed with the fossil mates riding the back of decades of climate misinformation leading to public confusion and investment so they can get away with it for a little while longer but not for long.  According to the IEA, renewables are on the rise and non-renewables on the decline around the world. It's important to note that the world energy supply is just one source/sector of Carbon emissions - there are many others, so it's not contradictory to say that although renewables are increasing, Carbon emissions are steadily increasing too even with Covid-19. As I've previously blogged, the world's largest climate survey to date in January this year by the UNDP determined that 72% of Australians believe there is a 'climate emergency'.  Borrowed time.


It seems we are going down two main paths - one of 'ecocide' and the other of 'ecosystem regeneration'.  The 'ecocide system' is built into the state system architecture, according to Bill Boyer (1984) - this may be difficult to generalise now by today's standards given the efforts by some countries to decarbonise eg.UK. Digging Zai pits for 'ecosystem regeneration' isn't a waste of time or done in isolation as it's local and global action (glocalisation) and are even more critical to build due to their potential for 'geometrical replication' and are probably one of the 'safest' (safe climate) and most affordable and accessible options for biogeochemical Carbon sequestration. On a positive note, it seems everyday there are announcements of greentech breakthroughs that will get us to a Carbon-negative planet faster, hopefully by 2040 or earlier (fuzzy).  Some of these breakthroughs are then monetised and deployed. The latest 'Western green energy hub' proposal for WA is the world's largest Green Hydrogen proposal to date  :) It's another great example of 'geometrical replication' aka individual solar PV cells->PV panels and single wind turbines (a limited 'polyculture') multiplied to thousands.  It's no wonder why so much R&D goes into producing the perfect solar cell due to the 'geometrical replication' effect - hence the need for 'Green chemistry' with a focus on C-based PV cells. By the time the project gets built (beyond 2028), the chemistry will be 'greener', efficiencies of these technologies will be presumably much higher than now and the green hydrogen production capacity will be even higher than currently stated - assuming the proposal is flexible for technology choice.  Imagine if Hydrogen Systems Australia plasma arc electrolysers were used, which are 3 times more efficient than most electrolysers around the world...


From preliminary research, the pits are water saving, yield increasing, fertility increasing and more resilient to disease compared to some traditional methods of growing.  The addition of biochar to the pits will further increase these gains as well as Carbon offsetting and reduction. I believe there are many possibilities and opportunities to replicate/scale up regen agroforestry systems but there's still a lot more research to do on this, especially regarding biochar systems integration. If you're interested in doing research in this area, please get in touch on the 'Contact' form and we can swap notes.



Try doing a google search for 'biochar Zai pit' - it seems this is a new field of research!!

Also, try doing a google search for 'semi-arid agroforestry'

Boyer, William H., 'America's future: Transition to the 21st Century' (1984), New Politics Publisher, Oregon, USA

A Climate Atlas of the Barossa Valley, SA, Australia
Adobe Acrobat Document 6.7 MB
A compost heap (foreground) with 'Geometrical replication' of Zai pits (background) in the Sahel- there are many possibilities of designs
A compost heap (foreground) with 'Geometrical replication' of Zai pits (background) in the Sahel- there are many possibilities of designs
Fractal squares...could inspire a planting topography for the RAS. Kind of looks like a QR code.
Fractal squares...could inspire a planting topography for the RAS. Kind of looks like a QR code.

It would be possible to live in the centre of the fractal, if there is a centre? If there was a central water source eg.a bore or a well, or even large water tanks, it could make sense to build out around it if irrigation was needed but it would need to be protected from disease. Alternately, 'Measured Irrigation' produces large water bladders that could be decentralised throughout the pattern. Lu'au pits could be located in the 8 second largest black squares. Permafert pits could be located in the 64 third largest black squares. Zai pits could be located in the white squares. Keyholes/access points could be made connecting all of the Zai pits to the Permafert pits and Lu'au pits and 'centre'.

A RAS could be designed around this Greek textile pattern
A RAS could be designed around this Greek textile pattern

I came across a similar pattern to this 20 years ago when looking at some Incan textiles, in Cuzco, Peru. I like the Greek version as each spiral could be multi-layered canopy with taller trees on the outside gradating down to lower storey and more vulnerable plants in the centre, plus there's alleys for access that pass between the spirals.

Why not build a RAS mapped out like a Peruvian Nazca line monkey's tail?
Why not build a RAS mapped out like a Peruvian Nazca line monkey's tail?
Even the Milky Way galaxy is a spiral - Zai pits in space?
Even the Milky Way galaxy is a spiral - Zai pits in space?

There are repeating geometries/patterns found all through nature eg.spirals. Maybe it would be more Zen to live in a spiral design, square or circular, than fractal squares?

I think access to land, access to water, access to sustainable feedstock, efficiency of pit production, access to all the different pits and aesthetics should ultimately determine the topography of a RAS design...

Here's a possible accounting program for a RAS that could be coded in 'Python':
#average of 3 Zai pits
How much biochar in pit aquifer (kg)?
How much Permafert in pit (kg)?
#average of 3 Permafert pits
How much biochar (kg) in 1 kg Permafert?
#overall number of Zai pits in RAS 
How many Zai pits?
#kg of biochar in RAS
biochar per pit (kg) X number of pits
#tonnes of biochar in RAS
Kg of biochar in RAS/1000
#tonnes of C in RAS
fraction of C per kg biochar eg.0.7  X total kg of biochar in RAS/1000 
Machine Learning could be used with the following inputs:
What is the feedstock type for the biochar?
What is the biochar production technology used?
What is the average highest treatment temperature (HTT) of pyrolysis?
#tonnes of CO2 in RAS
Tonnes C X 3.67
#number of CORCs
total metric tonnes CO2 'removed' in RAS = number of CORCs
#CORC value
Current market value of CORCs?
#Choose currency
Choose preferred currency type
-tonnes of biochar in RAS
-tonnes of C in RAS
-tonnes of CO2 in RAS
-Number of CORCs
-Overall current value of Carbon 'removal' in the RAS in preferred currency
Learning Issues (LI)
  1. How do you work out the amount of C per kg biochar?
There maybe research on this that lists/tables the Carbon fraction/percentage of C per kg of biochar for a given feedstock (and possibly for a given production method eg.Kon-Tiki, Lu'au pit etc.) - or - even better:
According to the above article abstract, biomass/feedstock choice and pyrolysis conditions, such as highest treatment temperature (HTT) (eg. measured with a $40 Benetech GM900 laser thermometer) are the main drivers of yield and C content of biochar. To simplify the above program, an average of 70% C content of biochar could be used too for starters.
The above study (with a free pdf download) provides some tables including C content of biochar for different pyrolysis temperatures and feedstock types. Though the list is not exhaustive, I would argue that this is a great foundation for future Carbon accounting of biochar
The biochar, placed in a 20 litre stainless steel bucket (expensive but awesome),  could be weighed with an analog/digital hanging hook scale (100kg max is probably good enough).
The Carbon Dioxide Removal Certificates (CORCs) are one example, from, for exchanging Carbon removal (reduction) for money. Their accounting method is presumably different to the one here proposed for this specific RAS configuration/design. The above accounting program that I have proposed for the RAS does not account for:
-C offsetting of the plants over time in the system, which could be calculated as an additional revenue stream but presumably enters a new world of accounting complexity and room for inaccuracy due to loads of physical measurement and documentation of plant growth. Maybe machine learning could be applied here as well.
-additional soil organic Carbon (SOC) increases as a result of biochar addition, which could be measured with a reflectometer eg. ''
-release of C from the biochar over time as it very slowly breaks down/degrades over Millennia to 65 million + years, which could be determined by a separate proggy that calculates phytoliths per kg/tonne of biochar such as the following idea (previously blogged):
#OK. here's another accounting program idea for a RAS, that could be integrated with the previous program:
scan sample of biochar (?with a reflectometer (C + PhytOC)/reflectometer(C) and fluorescent microscopy (PhytOC) from a larger quantity of biochar produced)
output~) input into a cloud database:
C content/percentage
PhytOC content/percentage/type
input:how many tonnes of biochar have been produced?
plant name?
#machine learning algorithms are applied
output: a graph with Carbon sequestered over 10,000 years~)
C credits (tonne.year(s)) earned over 10,000 years~) multiplied by current market cost of tonne.year~)print ('money earned for biochar produced')

RAS case study structure

There are 8 main components:
1-Seedling production
Heirloom non-GMO seeds -
10% BC (with biochar & liquid sea kelp from KTR) in standard potting mix
Grown during August
Planted in September
2-biochar production, for aquifer and Permafert
 -pine waste
 -forestry waste
  Kon-Tiki 'Rolls' kiln (Lu'au pits for another trial)
-bentonite clay (Roseworthy, SA) added to each layer of feedstock during pyrolysis
-quenched with liquid sea kelp + H2O
3-Permafert production in pits
  Biochar - KTR
  Bentonite - KTR
  Liquid sea kelp (KTR) - Microtek Organics, SA
  Richgro 'Blood & Bone' - Bunnings
  Clayey brown loam - truck load, Eco Waste & Compost Solutions, SA
  ?Aged chicken manure from a certified organic poultry farm/
bags of cow manure (standard 25L, available in most hardware stores but dubious/?absent microbiology)
+ 3 big Zai pits
4-Zai pit building
How many Zai pits?
900*900*300 pits for food+medicine
  Biochar aquifer
  Permafert layer
  Mulch layer
16 for 3 sisters (1 control/3 biochar aquifer+Permafert * 4)
2 zucchini (1/1)
2 pumpkin (1/1)
Total: 20
Acacia saligna  pits, 3 control (mixed red clay+top soil/brown sandy loam), 13 (mixed red clay+top soil/brown sandy loam+BC (+sea kelp))
Total: 16
3*Permafert pits - big ones eg. 2000*900*300 - for Zai pits
5-growing the guilds
 Sunflowers + 3 sisters
  Sunflowers + Zucchini 
  Sunflowers + Pumpkin
  Acacia saligna
20 litre buckets from IBC*2
I can then calculate how much water I add to each pit
I can use a plastic container to monitor water level to guide timing of irrigation, as with the MI container
?rain gauge - weekly measurements
7-Produce a yield
Weigh all the yields
Weigh root ball
?monthly plant height measurements
8-Carbon accounting
'Proggies for RAS'
Weigh all the biochar with electronic hanging scales, 20 litres at a time in a 20L ss bucket, calculate amounts used in aquifers, Permafert and clay/loam mix for Acacia saligna. Can create a conversion table between litres of biochar and kg of biochar for both the pine waste feedstock and forestry waste feedstock
Control pits have no biochar or Permafert, just the in situ brown sandy loam/red clay mixed together and placed back into the Zai pits