What is keyline?
P. A. Yeoman (1904 – 1984) was an Australian engineer and agronomist who lived and worked in New South Wales. He observed how water flowed over the land and developed a system for harnessing water to build soil fertility without chemicals, which he called the keyline system. A keyline plan is developed for a property using the concepts of the keyline system. His ideas are published in four books, three of which are available free online:
- Yeomans, P. A., The Keyline Plan (1954) Online version
- Yeomans, P. A., The Challenge of Landscape : the development and practice of keyline, Keyline Pub. Pty., Sydney, (1958). Online version
- Yeomans, P. A., The City Forest : The Keyline Plan for the Human Environment Revolution, Keyline Pub. Pty., Sydney, (1971). Online version
- Yeomans, P. A., Water for Every Farm: A practical irrigation plan for every Australian property, K.G. Murray Publishing Company, Pty, Ltd, Sydney, N.S.W., Australia (1973)
The Keyline Scale of Permanence
In the “The Challenge of Landscape”, Yeomans introduces “The Keyline Scale of Permanence”, which describes the hierarchy of the permanence of the factors to be considered in any land planning. He writes “Every decision made on any aspect of land planning must be based on or fit in with all others that are more permanent, or more permanent in their effect than it is.”.
The Keyline Scale of Permanence is:
2. Land Shape
This means that the first thing to be considered is climate, because it is the most difficult thing to change, apart from establishing limited micro-climates. I discussed our sub-tropical climate in a previous post. Climate includes such things as typical rainfall amounts and timing, typical minimum and maximum temperatures, sunshine hours and wind directions, and the variation in all these things. Information is usually available from government meteorology departments, as well as making personal observations for a particular property.
Land shape is the inherent contours, valleys and ridges, of the land, that are difficult to change on a large-scale, and must be understood and used carefully in the plan.
I got stuck on this point for several months, because I didn’t have a contour map of our property. You wouldn’t think that would be so difficult to get, but in the end I was just lucky that someone who could help me saw my request on facebook. Unfortunately I can’t share that source with you, but I can suggest that you approach first your state department of natural resources (QLD were no help due to staff-cuts) and then try private mapping/surveying companies. I’m not sure that the cost would have been, but in the end all they had to do was type in my property number and put the contours over an aerial photo, its not a huge job, so its probably worth asking for a quote and seeing what you can find out.
When you have a contour map of your land, it makes everything in the books easier to understand. I’m terrible at visualising these things, especially over 260 acres, so when I saw it on a map it was clearer to me. This is where Yoemans introduces one of the fundamental aspects of the Keyline System, the keyline itself. Yeoman defines the keyline as:
“…valleys of smooth, rounded shape, whether they are small, of a few acres, or large, of a few hundred acres, generally have two distinct slopes along the centre line of the valley; one, the first and steeper slope falling from the hill or ridge, and, second, a flatter slope below, which generally is constant to its junction with the watercourse below. The point of change between these two slopes--the point where the first steeper higher slope meets the flatter lower slope I named the keypoint of the valley in my earlier, book, "The Keyline Plan".” P.A. Yeomans in The Challenge of Landscape (1958)If you just read that definition and though “WHAT!!”, head over to this site, which has more explanation of these concepts, and even better, a photo of a valley, where you can clearly see the keypoint.
It took me a few attempts to figure out what the keyline was, and as I said above, when I got the contour map that really helped. When I saw the photo in the site above, I realised that part of the trouble is that we don’t have many “grassy valleys” for me to look up and see the keyline! All our valleys are full of trees on the steep slope, with grass as the valleys flatten out. Also on 260 acres we don’t actually have as many examples as you might find on a larger property.
Water supply is third in the hierarchy, it must be planned by taking into account the climate and land shape of the property, and it takes precedence over other farm infrastructure, such as roads and fencing. As Yoemans discusses, water is integral to farming, even if it not used for irrigation, it is needed for stock, and with irregular rainfall, we need to carefully plan how we can catch and store this valuable resource.
Water can be stored both in dams and in the soil. Building soil carbon will improve the water storage capacity of the soil, as well as the general fertility. We currently have five dams on our property. Yoemans discusses setting up dams so that they flow from high in the property to the lower areas. We were very lucky to have the opportunity to see how our dams worked following the very heavy rain that we received from ex-cyclone Oswald earlier this year. We have one dam up in our upper cultivation area that drains down a valley to the large dam near our stockyard. One other dam near our boundary drains into our neighbour’s dam and then back into another of our dams.
Pete and I drew the dams on our contour map (dark blue blobs) and marked the flows from one dam to another and from the valleys (light blue lines). We also marked divined bore sites (yellow dots) and the highest point, where we want to put a tank (red dot). This exercise was useful in thinking about where else we could put dams. I’m still not sure about the shapes of dams that Yoemans describes and how to use them. The concept of having dams high in the landscape and using them for stock water is also used by Joel Salatin, and we can see the merits in developing such a system. However, Yoemans also suggests using these dams to irrigate the lower country. I think that in our sub-tropical climate, with fairly regular rainfall, it may not be necessary to consider irrigation, although during dry periods it would be useful. I would rather try to build soil carbon and store the water directly where its needed.
I was reminded at a recent erosion management workshop to be careful about following strategies that have been successful in other climates, including the southern states of Australia, as they do not necessarily have the same extremes of climate that we experience in sub-tropical Queensland. As I discussed recently, our climate here in the South Burnett is sub-tropical with no distinct dry season, although we can have prolonged periods without rain at any time of the year. When we do get rain, it is often in storms or the result of cyclones off the coast, so it is usually relatively short bursts of heavy rain. We need to be very careful to plan appropriate overflows for our dams. Our largest dam currently overflows through our stockyard, which is not ideal!
Water planning at our property is broader than just development of dams, as we also have several potential bore sites, which we would like to use as extra water-security. This will have to be a subject for another post or I will never get through the rest of the keyline heirachy.
Roads and Trees
Yoemans lists roads next in his hierarchy, but I think that trees should be next. I can see why he did this when I had a look at an aerial view of the property he was working with at the time. It currently has few trees, and I assume it had even fewer when he started. We are starting from many trees. Anyone who has tried to establish trees will know that its much easier to start with many trees than to try to establish new trees, that’s why we chose our property. I’m not saying that all the trees are in the right places, but I think that having considered climate, land shape and water, we should then consider the location and type of trees on our property, before we design the roads.
Yoemans writes about establishing trees on contour lines, but again, he is starting from few trees. We have the luxury of many trees, and government legislation that prevents us from clearing most of them, so we will be keeping more than rows of trees on contours. Within the bounds of what we are legally allowed to clear, we have decided to leave trees on all steep slopes and all south-facing slopes. We are going to open up a few of our lower valley areas by removing undergrowth, but not the tall trees, as these provide shade for the cattle. We are going to maintain fire-breaks around the house and sheds, and keep fence-lines clear of trees.
As for roads, I think we are going to have to move some roads to accommodate our water plans, as some of the roads currently run down the valleys.
Buildings and Fences
Buildings and fences are the next level of permanence and having considered all the other factors it makes sense that these come next.
Soil is the last level, not because it is the least important, but because it is the least permanent. Top soil blows away in the wind if there's no crop cover, but with the right strategies it can also be improved over a short time frame. This was quite a radical concept at the time of these books being published.
The other thing that I found a little confusing is that we don’t actually plough all these valleys, as they are steep, they are more suited to trees. The areas that we do plough are virtually flat, North facing slopes. On the contour map most of the areas is within one 10 m contour band. The areas are already divided by “contour banks”, which are built on the contour to prevent soil erosion in heavy rain events, this means we have to plough along the contour. The ideas about leaving trees in bands along the contour is quite different to the structure of our property, where we have decided to leave trees on all steep and south-facing slopes. We want trees for firewood and fence posts, so it seems like if they have to grow somewhere, these are the most appropriate places where we couldn’t grown good pasture anyway.
How does this apply to a small farm?
It is difficult to apply the keyline concept to 260 acres, let alone eight acres, as you will be lucky to have even one complete valley on that area of land! Our eight acres is on the side of a hill, we have a dam in the creek at the bottom of the hill. Ideally we would have water storage further up the hill. We don't do any ploughing or cropping on this land. The most useful concept is the hierarchy of permanence, which works on all scales, even if some of the details are more suited to larger properties.
Have you read the books? Have you applied the concepts? What do you think?
Each month in 2013 I reviewed a principle from David Holmgren's Permaculture: Principles and Pathways beyond Sustainability:
Catch and Store Energy
Obtain a Yield
Apply Self-Regulation and Accept Feedback
Use and Value Renewable Resources
Produce no Waste
Design from Patterns to Details
Integrate, Rather than Segregate
Use Small and Slow Solutions
Use and Value Diversity
Use edges and value the marginal