I'm wondering how much of the keyline concepts (developed in semi-arid or arid Australia) apply to relatively humid areas. I'm looking at making some design changes on a property that gets around 50 inches of rain a year. The hill has about 100 feet of relief, and there is already a natural saddle at the base of the hill that is filled with wetlands (not going to change that). The soil type on the hills is rather heavy. I have visions of mudslides if too much water is retained and sent through the soil, but like the permaculture idea of having a keyline for gravity irrigation.
To my understanding, increasing the mass of roots in the hillside will help prevent mudslides in several ways. Every source I've read emphasizes that plants are an important part of such a system.
(They will mechanically hold soil, transpire water out of it, and build up tilth to the point that crumbs of soil are stronger, more permeable, and more absorptive.)
Similar systems I've read about for high-precipitation areas tend to start with trenches full of organic matter that foster deep-rooted species, and often evolve into terraces with a careful mix of deep, medium, and shallow-rooted species. But they are all careful to limit the extent of such a system, fostering large forested areas, especially in the upper half of a slope and anywhere that is particularly steep.
Done right, the upper part of your system might not involve any earth shaping, just careful management of vegetation to favor springs emerging downhill.
Branches and trunks can be staked along keylines, covered in deep mulch and/or green manure, and planted with a well-chosen mix of vegetation. With so much water, it won't be too long before they're topsoil; as long as roots have replaced the stakes before decomposition is too far along, things should stay stable the whole time. This would disturb the soil structure less than digging.
Canals and ponds have to be planned very carefully. I have no experience, but what I've read suggests that experience and education can save a lot of trouble in that regard.
"the qualities of these bacteria, like the heat of the sun, electricity, or the qualities of metals, are part of the storehouse of knowledge of all men. They are manifestations of the laws of nature, free to all men and reserved exclusively to none." SCOTUS, Funk Bros. Seed Co. v. Kale Inoculant Co.
No doubt that vegetation (especially trees) will help anchor the hillside. I'm just wondering to what degree the ponds on the hillside are universal to permaculture, or whether there are soils and climates where they become more a liability ... am definitely taking my time, considering as many angles as possible before committing to a plan or taking action.
our area is very wet for a good part of the year with drought in July quite often..when we needed fill around our new home...we took the topsoil and mulch and good stuff..muck and such..from the lowest spot closest to our house..and used it for fill around our home..it was so thick and rich..the properties were all graded to slope toward the newly made "pond" and it filled with water..we have always had a drainage ditch on our property ..through our woods..toward a river on the north..we have one area along the drainage ditch..in the woods..that is swamp..the deer love it and a lot of wild plants grow there..and when we have our wet season ..our woods are very wet..as are some of the field..
as for keyholes..we really don't have actual keyholes but we do have very fertile wet mucky wonderful soil ditches that run into wet spots..and then drain from over flows to new ditches..and more wet spots..
most of them are natural..but the little pond(150 x 75) as been there for 7 years now and has become a wildlife center for our property as well as producing wonderful planting edges (it is far from round)..it will go somewhat dryish during the drought but always has some water in it..all year around.
Bloom where you are planted.
The area that has an orange cross is the area I am talking about. The blue hatching is the wetland saddle. The hillside faces due south. It is a 80 foot rise over 800 feet going up the one orange line, about 1600' across the hillside along the other orange line. I'm thinking about putting grapes, hardy kiwis, hazelnuts, linden, apples and pears on the slope as the over story, with clover, herbs, sheep and geese under, still early in the planning. This image is from late winter, but the hill is quite grassy and green in the spring. Just bought the land, haven't been on it long enough to know how dry it gets.
I'll take a stab at it. Took part of my PDC from Darren Doherty! But this is strictly from memory ... I'll have to dig out my notes to verify, so correct me if I'm wrong. I'm looking at this as a "pop quiz"!!
The keypoint is located in the folded, "drainage" area of a hillside (i.e., where a creek might flow) and occurs at that point where the slope of the hill transitions from convex to concave. The keyline is the contour line that runs through this keypoint (it's on-contour).
Keylines are "plowed" using the chisel plow (Yeoman's plow) parallel to the keyline. As the slope flattens out in the concave portion, these plowed lines are not on contour but instead slope downward to the vertical ridgelines. Keyline plowing is a method to distribute water from the drainage areas of a hillside to the dryer vertical ridges which are typically dry. The chisel plow lifts and uncompacts the soil allowing free water movement without disturbing soil's surface which would cause erosion. These keylines would allow you to plant your trees and shrubs across the entire hillside and ensure they get sufficient water even out on the ridges. Without them you might be limited to the drainage area only. (see Water for Every Farm - Yeoman's Keyline Plan)
Swales are by definition always on contour, and as such are not necessarily parallel to each other. Swales are for slowing water flow down a hillside and infiltrating it into the soil high in the landscape. Swale and keyline have similar purposes but different methods.
Permaculture is a gestalt ... a study of the whole. Not just how to produce more and better food, but how human life on the planet affects and is affected by the surrounding environment.
Bill Kearns http://columbiabasinpermaculture.com
It's all grassy - the picture was taken shortly after the spring snow melt. The texture differences might reflect different types or densities of grass, but no bare soil anywhere. The dark spots are conifers - 30 to 50 feet, mostly. On the soil map, the entire hill is the same soil series, although there are surely differences from place to place. I haven't done any sampling yet - the property is some distance from where I currently live ... walked it a few times before buying it. The grassy areas showed evidence of being cut over decades ago.
I would like to know if if would be feasable to use the contour terraces used to stop soil erosion and drain water from pastures and farm ground in the typical fields here in eastren Kansas. These terrace systems are generally already in place and and would greatly decrease the money involved in implimenting building soil/keylining. In the book,'The Biochar solution' it says that two years of biochar/compost tea slurry injection can completely replace chemical fertilizers giving financial reasons for transforming industrial ag into something healthy for the Earth. I also have heard in my broad acrePermacultureclass that a man in Austrailia not only has a biochar/compost tea injection system on his keyline plow, he has tree planting device that can plant up to 10,000 trees a day. Does anyone have the design for these attachments? Since the USDA recently declaired silvaculture with row crops or pasture systems increase production by 22% in both of these systems; I see great potential in plant food forest on Hundreas of millions of acres of currently terraced farmland. Please respond with any contact information/information Thankyou for your time and consideratiion. Gary.