This thread was a response to questions about how to build soil. I look at the big picture what helps soil grow & end with a discussions about how towns & cities might be designed to help.
So there’s so much to cover in how to repair things. I’m going to do a slow thread on how the designed and built environment can be directed to soil building and climate repair.
1st thing to think about is what is soil? For brevity i’m going to say soil is the culturing of weathered rock with a food web of microorganisms that leads to making rock nutrients solvable &stores them along with organic carbon. (Soil scientists i know i’m over-simplifying)
I’m talking about aerobic souls formed with oxygen rather than anaerobic. Wetlands souls are amazing and do good. But there are reasons to focus in aerobic for now. (I’m a huge fan of wetlands and pond systems too)
Too much water and too much compaction removes oxygen. The system switches to anaerobes that live by yanking Oxygen off of soil nutrients, making them smell bad and able to leave the soil. They also produce alcohols that prevent plant roots from growing.
So this kind of soil needs: enough air, water, contact with plants (that feed it with sugars and proteins made with photosynthesis and CO2 exuded from their roots.)
Rock weathers into subsoil without a lot of big life, when plants interact with it they build living subsoil through their roots and the accumulation of organic matter on top.
Living soil is protective. So it actually protects the subsoil from some of the processes that speed up formation. Which is why in natural conditions it can settle into a very slow rate of production.
We have been running civilizations in the use of this built up soil. Turning it killing fungi and structure to get bacterial blooms that feed out Annual crops.
This leads to Erosion rates more similar to mountain systems then the low lands where the soil formed. We are burning through our soil to grow and crash quite a few civs
You have to understand. The buffering capacity of our plants souls* could have handled the CO2 from fossil fuels. Only what we used fossil fuels for was to increase erosion, change the balance of water runoff, deforest, and plow over the grasslands every April. 8/?
*Sorry about the autocorrect to soul. Lol
I have to be off-line for a spell but I’ll continue with a discussion about how we design to accelerate that soil building process. Including some references in case studies
So i want to introduce a few puzzle pieces. The first is the work of this man PA Yeomans. He was a mining geologist who retired and starting thinking about soil care from a Geomorphologist POV
When he set off to tend his land, the Australian gov provided soil conservation literature focused on contour plowing. Based on the view that soil is precious(it is) but that it’s impossible to speed its production (it’s not)
The main problems with contour based design can be seen from this image by PA. On land contours are not parallel. This slows water but it drains ridges and concentrates water in valleys. Overdrying and overwriting soil at the same time. Can even blow out.
PA developed a way of understanding topographic features to organize landscapes so that: water is infiltrated, spread, extra collected stored as high as possible to re-hydrate during dry times. He realized this could be used to organize everything on broad acre farmland
This prob is too dense for Twitter. But imagine land as big ridges between streams and they have smaller ridges and valleys. Imagine the inflection point in those smaller valleys where the land nicks in like a clavicle * in the pic 13/
PA called them keyponts and they are : the highest water concentrating point in land, where soils thicken, & any line parallel to this on the land concentrated water above but spreads water below
Now he had a way to organize features. First he placed ponds at those points. Collection drains could be set to collect overland flow and move it into those ponds. Then any roads could follow those drains with minimal impact actually helping water collection.
And bellow, the land could be plowed with a subsoiler that sharpers the subsoil without turning the soil. And he would plow down on ridges and up on valleys which means water spreads.
PAs land:
And here in red are plow lines (or how to organize and water receiving element such as tree rows to spread water along ridges)
Roads, buildings, pasture, agroforestry- whatever could be designed. Roads can also be placed along ridges, Trees get planted along ridges & in valleys and along streams with complete connectivity. And humans move out of valleys to ridges, leaving valleys for soil and wildlife.
This planning process is like adding sourdough starter to flour and sugar and adding just enough water. The subsoil can be reached by water, roots, inoculated by microbes. you can rapidly add feet of topsoil. Keyline farms are amazing. They stop flashy creeks & can repair land
And it should be viewed as appropriate for where people live and farm. Ag land not the giant ranges that could be bison prairies.
So there is more. PAs last book was on how these design methods could be applied to cities and towns. That towns could extend along ridges,roads could direct water into Catchment which could water yards then agricultural & reforested lowlands. He called it “the city forest”
The City Forest by P.A. Yeoman hosted on SoilandHealth.org
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Think about what this would mean. Human settlements designed so they are collectors of water, human labor, and even humanure, directed towards the generation and care of soils and forestry.
So let’s talk examples. Frederick Law Olmstead designed a number of Stormwater collecting parks Into towns. One of the most famous being Boston’s Emerald Necklace. /24
His son John Charles did something similar when he designed Portland Oregon’s water collecting neighborhood of Lauralhurst. Before the current Stormwater system, Laurelhurst Park was the detention basin.
Next step in the journey Is Davis California in the 80s where Mike Corbett designed village homes a neighborhood designed to handle Stormwater by soaking it in Swales and orchards rather then management systems
https://en.wikipedia.org/wiki/Village_Homes
Here’s a video of Mollison touring the place in the 1990s. https://youtu.be/v_05oRQxssQ I’ve heated that they have managed several very large storm events that flooded their neighbors. All while building the soil and restoring the water table.
Village Homes with Bill Mollison (improved audio)
So:,remember this and this question: what if we really looked for a city that took this approach?
Well, here's Siena Italy which started as a number of little settlements and converged in the hills of Tuscany: that big public square is the Piaza Del Campo- built in the key point of the landscape, The roads collect water into drains and reservoirs under the piazzas.
Link to tweet with 3 Images here
28/ if you look at the landscape you see how this hilltown stayed on the uplands and collected water to irrigate the lowlands.
Link to tweet with 4 Images here
Underground passages for water, the 'fountain of the earth' sits at the keypoint, and the lowland valleys are irrigated and saved for soil...
When water falls we seek ways to shed it. We build roofs to shed it from our heads, we build gutters to shed it from our home's edges. We slant our streets and install sewers to shed it from our neighborhoods. We dump it into creeks and send it on it's merry way. "Leave" we tell it, "go, we do not want you!". ...and goes it does.
We rip up our forests and our prairies, which slow water's movement and sink it deeper into the soil. We all too often farm or graze our livestock right to riparian edges, grossly destabilizing it. Nothing to slow the water as it obeys. We say "leave us, what could we do with you?" ...and into the creeks it goes... it takes our soil and our work and washes it away.
How many decades worth of soil creation have been lost to these recent floods alone, one day, one storm system. Where is our Texas pride as our state's top soil, silts in our dams and enters into the sea?
Then comes the drought, from whence we came. "Rain!" we will say, "Poor!" and the sun will beat down and the temperature will rise. There shall be no rain, creeks will run dry, lake levels will fall and we will plead for water to make our lawns green and the sky shall not hear, year after year. We know this it is what happens here.
We can not farm this year for it is too wet, but neither was last year that great for it was too dry. Too wet, too dry, too dry, too dry. Oh Texas, what will we do? Will watch our state turn to desert and it's soil wash away? Will we watch our state increase its population by tens of millions and not change our water use patterns? Drought, Drought, Drought, Flood.https://www.flickr.com/photos/twri/6355509153/
Fear not there is another way, but you must dare to vision and work. It will be long and is not easy, but prosperity and abundance are its rewards.
1) Change how we manage livestock to mimic natural grassland ecosystems (holistic planned grazing), this is our best hope of vegetating west Texas again, grasses will hold water much better than bare dirt! Rotation and Timing, will bring back our grasslands and halt the advancement of feral juniper and mesquite from taking over our state in the center and desert in the west. Rain will absorb and life will follow. And steaks will abound!
2) Breed perennial crops for Texas (http://soilandhealth.org/01aglibrary/010175.tree%20crops.pdf)! Fields too wet to plant corn or cotton this spring? Rains came too late one year? Too early? Too little? Too much? Humidity too high and the wheat seeds might sprout? Darn, for I have here a tree which was planted once, a long time ago and does not need to be planted this year. A tree which will take water whenever it falls, leaf out (and be in near full photosynthetic production) as soon as temperatures warm, and will bear (although less) even in mild drought years. Trees! Which like thick mats of grass shelter the soil keeping it humid and in place, while slowing water as it moves through the landscape. Supplement our livestock with, white oak acorns, honey locust and mesquite pods, one of those at least, will grow from El Paso to Texarkana. Pigs fattened on acorns, mulberries and persimmons. Yum! ...and we do not have to sacrifice our soil or our ecologies to do so. Plant our fields (after decades of additional breeding work in some cases) to pecans, walnuts, pine nuts and dwarf chestnuts may we feast on their delights. http://www.badgersett.com/info/woodyag1.html
3) Contour farming has been practiced by some for centuries, recognized by USDA and soil conservation service for decades as a way to reduce soil erosion and water run off. Plant those trees on contour!http://en.wikipedia.org/wiki/Contour_plowing
4) Key Line Design, engineering the landscape to slow, spread and hold water. It tells us where to place our lakes and ponds to maximize our intended goals. Where to apply swales or bermes to hold water on contour and when to guide water down hill slightly off contour. We can hold the water that falls on our state in our chosen locations, creating recreation sites and increasing habitat, rather than sending water out to sea in times of plenty.
http://www.yeomansplow.com.au/yeomans-keyline-system.htm
Do these things and the floods that we have seen this week, will still be floods, just not nearly as destructive. Do these things and design them based on 100 year flood events.... and we will have created a hydrated, healthy and productive state of Texas.
