Micro-keyline for urban settings?

Is there anyone doing keyline design in an urban setting and using a compact tractor for plowing? I've done a little bit of research into this and there doesn't seem to be much out there on urban keyline. Would it be possible to adapt a plow to be able to access urban lots, perhaps attached to a lawnmower?

I imagine such a development could have huge positive impacts on the success of community orchards and gardens and could help in the rapid transformation of degraded, sloping urban lands in parks and private lots into carbon-sequestering, water-storing, regenerative ecosystems.

G'day,

Have a look at the reply I gave to the topic: 'property to small,steep and rocky for Yomans plow' in this forum as it in part answers your query.

Otherwise the applications of Keyline in urban landscapes is described in P.A. Yeomans last book 'The City Forest'. However I am not aware of any urban developments that have followed the brilliant development template he set forward in that book. I've done a few consultancies and concepts around doing so but they've not been done as far as I know and I indeed hope that in my life this will change as I know that an urban landscape that follows this template would be something else as you've suggested.

Thanks,

Darren

I asked the same question in a different forum previously and really did not get a response. I will have to look at the reply that you mention. I will pull some of the questions that I asked in a different forum into this post to see what Darren thinks and can suggest.

On my property, there is a layer from 7-17 inches that is what they call glacial till/loam with a decent amount of structure that has a little size to it (definitely not sandy and somewhat rocky). Under that is something that they call fragipan. What is happening in my area is that the water table tends to be quite high (in spring and fall wet season they say from 6-18 inches below the surface) and it sort of sits on top of the fragipan in the wetter times of year. The fragipan layer makes it very difficult for the water to percolate through.

I am trying to figure out if keylining would make sense in an urban setting (and if it is even possible) and would it be of any benefit to break up the tough fragipan layer and allow the roots of trees like fruit trees to better permeate it. From what I have read so far, it appears that the roots of trees tend to take a sideways path once they get to the fragipan layer unless they find a crack in it that they can grow down through. My only concern about keylining is that some people have said that the ground will eventully revert back to what it started as. I guess I wonder if keylining would work long enough to get fruit trees well established in the fragipan (dense/brittle/non-permeable) layer and, if they do become well established, if they would then help the overall drainage of the site since that layer would be "broken open", so to speak. One of the early on challenges would be to make sure that the fruit trees have enough initial drainage when planted so as to not rot the root system when the weather is wet.

Thanks Jen, without knowing these conditions specifically I will apply some general principles to this case. I would first up suggest that if this (or any pan) is at 17"+ then busting through it would require a progression of passes with the Keyline plow (I'm assuming that's what you mean by 'Keylining' - to me that term includes all matter of elements within the Keyline system though I understand the venacularisation) over successive years, with each pass going 2" lower than the existing root depth. No point going any deeper than that as the rhizosphere's gotta develop along with the roots along with the above-ground parts of the plant. This is very much a process. When you are now at the depth of the pan then it will depend how thick it is as to whether you'll be able to get through it straight away or whether it will also take a couple of goes. The plow model we use bottoms out at 26" and we only use it to this depth when we are 'ripping' for tree establishment (which is one of your intentions) or laying poly pipe. For pasture work we don't go any deeper than 15-16" as that it usually sufficient to establish the perennial and annual 'biological subsoilers' who go deeper than any plow would ever go. With your fruit trees you can establish these subsoilers and then hack them off at the onset of flowering which results in what we call 'subterranean composting' of their roots and increasing the amount of short-chain carbon down there. While they are growing and thriving then a whole lot of longer-chain carbons are exuded from the roots in what is called the 'liquid pathway'. These compounds (mostly polysaccharides) are cycled into humus very quickly and with little emission back into the atmosphere and are accordingly very stable and efficient. Maintaining an ever-deepening, active and dynamic rhizosphere is the key to doing everything from curing climate change to keeping pans from reforming. Not many problems that cant be solved by deepening top soil!

Hope that this helps,

Darren

Darren,

Thanks for the response. It does give me a lot to think about. It gives me encouragement too that the pan layer can be improved on. Hopefully if I can get the pan layer loosened, it will not only allow fruit/nut trees to get established, but will also help with drainage. I understand the concept behind loosening the soil at the depth of the roots as they grow, allowing them to penetrate deeper into the earth. Would it make sense, since big equipment would not necessarily work, to do a modified double digging method in which you dig out the top layer to a depth and then use one of the broadforks (they looked pretty manageable) to loosen the pan layer? Then put the top layer back in as you are planting the trees and top it with mulch to help protect from direct rainwater so as to slow the mineral and nutrient leaching?

While I want to make sure that the soil drains better than what it does now (generally get 1-2 inches of standing water over areas that takes a week or two to drain away when it first starts to dry out), I also want to be sure that, in time, I am able to build the soil enough that it will retain water for the drier parts of the year (with mulching help). I want to start building multilayer vegetation layers at the boundaries of the property and work my way in. I am thinking that by starting with the larger, longer mature time items and then working inward, I can start to develop a more favorable microclimate on the interior portion of the lot so that I can experiment with native plants and (the part that I am most curious about) seeing what I can encourage to grow and thrive that is not typical for my zone (5A).

I don't know that big equipment would work on my lot. I live in an urban setting. My lot is "L" shaped. The main portion is 50 x 285 and the "L" shape at the back is 50 x 85. .42 acres in total. The lot is very flat. The back yard, where the work is to be done has a maple and pine along with a few rose of sharon shrubs (7-8 foot if I were guessing) along part of the eastern border which is closest to the house. Directly across from them on the western side is a crab apple tree. There are a few pines along the southernmost portion of the property line. Alll in all, much of the back yard has very good southern exposure with a lot of open sunny areas. Winds tend to come from the SW in the summer and NW in the winter.