Keyline Design

Overview | Water Savings | Applications | Additional Benefits | Resources | Case Studies | Page Credit

Overview

Keyline design was originally developed by P.A. Yeomans in the 1950s to address dwindling water supplies and soil erosion on Australian rangeland. He worked out a system of ‘amplified contour ripping’ that maximizes productive use of rainfall and facilitates the uniform irrigation of land. Keyline is a comprehensive whole farm water management plan that uses natural landscape contours and cultivation techniques to harvest rainwater and build soil fertility. The central idea behind keyline design from a water perspective is to capture water at the highest possible elevation and comb it outward toward the ridges using gravitational forces, reversing the natural concentration of water in valleys. Maximizing the flow of water to the drier ridges using precise plow lines falling slightly off-contour slows the movement of water and spreads it more uniformly, infiltrating it across the broadest possible area.

Keyline design involves a landscape-scale understanding of the relationship of topography and water movement. A keypoint is the point on a slope cross-section where the slope transitions from convex to concave, where the convex ridge characterized by high erosion gives way to the depositional concave slope. Keypoints are often characterized by the beginning of a discernable channel, where subsurface flow from higher in the slope surfaces, in effect like the end of a pipe, and can be effectively captured and redistributed. A keyline is the contour line that intersects with the keypoint. As opposed to contour lines which often vary in distance along their length, keylines fall off contour at the same elevation along the length of the line such that keylines are always parallel to each other, making the creation of keyline cuts particularly amenable to mechanical management using a tractor and plow.

The Yeomans plow, sometimes called a keyline plow or subsoiler plow, is an effective technology for helping realize the keyline concept: it is a special chisel plow that loosens the sub-soil without inverting the soil. The small ridges created by the plow on the soil surface facilitate the movement of water downwards through the soil profile and direct the movement of water across the land. The plow also facilitates the transport of organic matter deeper into the soil horizon.

Keyline plans typically employs water storages (usually ponds) as a component of the overall plan. Small ponds of surplus runoff water can be placed at the natural intersection of a ridge and a valley, or convex and concave slopes, known as a key point. This stored water can provide gravity-fed irrigation later in the season for pastureland or crops. The spillway or primary outlet channel from ponds is managed in a way to maximize the distribution of water to irrigate the land below.

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Water Savings

By effectively capturing and distributing rainwater and enhancing soils, keyline design allows the grower or rancher to begin to irrigate from off-farm sources later in the season, and may lead to the need for fewer applications in the dry season. Keyline systems capture significant quantities of water that would otherwise run off, and store it in the soil. Keyline systems also build soil fertility, which further improves moisture-holding capacity. Ultimately, while no research has quantified the reductions in applied water associated with this system, it is clear that the benefits are substantial. For instance, we know that for each 1% increase in soil organic matter, which can increase water storage by 16,000 gallons per acre-foot of applied water.

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Applications

Keyline applications in California are new and not currently widely explored. The techniques and principles have been employed extensively in Australia, where keyline was first developed. While keyline systems were originally developed for rangeland and are widely applied in that context, they are increasingly being used in the development of reforestation projects, vineyards, and crop production. Keyline and the use of the Yeomans plow can benefit all agriculture, from upland pasture to low-gradient bottomland. It has been successfully applied to land with a 1-foot rise for a 5,000-foot distance. The Yeomans plow is especially useful on highly compacted soils of any grade, where it substantially increases infiltration and soil fertility, and reduces erosion and runoff.

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Additional Benefits

Soil Enhancement and Carbon Sequestration

Along with improved water management, enhancement of soil fertility is a key goal of keyline. P.A. Yeomans fundamentally believed that “…soil can be improved beyond its best natural or original fertility and the process is simple, rapid and economical.” The Yeomans plow effectively moves organic matter down through the soil horizon. The Marin Carbon Project is one effort in California working to document the potential of the Yeomans plow to sequester carbon in rangeland soils. The plow works by employing sharp blades on the forward face of the tynes to break up compacted soil. Each tyne has a foot on its base that combs lower layers of the soil, cracking open and aerating the soil, and allowing organic matter to travel downwards.

Erosion and Sediment Control

Keyline systems contribute significantly to erosion control by greatly reducing or eliminating the overland flow that transports topsoil. Keyline systems slow the transport of water, spread it out across a larger area, and sink more of it into the soil, minimizing water erosion and controlling salinity. As a result, the output of sediment-laden water to streams is reduced, which also benefits the aquatic environment in California’s streams and rivers. Keyline also builds healthier soils that are less prone to erosion. The cultivation pattern helps to spread water evenly, stabilizing valleys and further preventing erosion.

Flood Control, Stream Enhancement, Groundwater Recharge, and Watershed Health

By capturing and retaining water, keyline systems help control flooding. The net effect of keyline is to flatten hydrograph peaks, reducing flooding during storm events by storing more water in the soil and in storages, and allowing stored water to seep back into waterways over a much longer period of time. The implementation of keyline plans on multiple farms and ranches in a given watershed can significantly benefit the health of the watershed as a whole, as well as local fisheries and other water-dependent industries such as tourism. Keyline can lengthen the run of seasonal creeks, augmenting supply in drier summer months and improving the quality of water that is returned from farms to waterways. Keyline can also contribute to groundwater recharge, improving the health of wells and in particular increasing water security in alluvial valleys.

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Resources

Water for Every Farm – Yeomans Keyline Plan. P.A. and K.B. Yeomans
Seminal work on keyline systems. Covers core principles, keyline pattern of cultivation, farm dams, ponds, fencing, water harvesting and many other practical aspects of keyline design.

The Keyline Plan. P.A. Yeomans.
Available online. The principles of keyline design and planning.

The Challenge of Landscape: The Development and Practice of Keyline. By P.A. Yeomans.
Available online. The fundamentals of keyline planning and design.

Yeomans Plow Company
Information and specs on the Yeomans plow and related implements. Distributor information is also available at this site.

Rainwater Harvesting for Drylands and Beyond. By Brad Lancaster.
An excellent and thorough 3-volume practical guide for creating an integrated, multi-functional, and water-sustainable water-harvesting plan.
Volume 1: Guiding Principles to Welcome Rain into Your Life and Landscape
Volume 2: Water-Harvesting Earthworks
Volume 3: Roof Catchment and Cistern Systems

Keyline Design Mark IV By Abe Collins and Darren J. Doherty
An article providing a good basic introduction to keyline.

Permaculture.biz
The website of Australian keyline designer Darren Doherty. The company provides keyline and permaculture design, education and consulting services around the world. Information on keyline courses in the U.S. listed.

Rx for the biosphere.
A lecture by Darren Doherty delivered in Santa Barbara and posted on YouTube. Covers elements of keyline design in Australian context.

What are Keylines and How Do They Work? By Liza Cowper.
A concise article explaining the ideas behind keyline.

Keyline Designs
A consulting service providing assessments and plans for the sustainable development of land and water resources in agricultural and suburban areas. Lots of great information about keyline is available on this website.

The Yeomans plow in action.
A short video showing the use of a Yeoman’s Keyline Plow

Harvesting Water the Permaculture Way. A DVD presented by Geoff Lawton.
“The complete introduction course to constructing a dam and swale on a small acreage farm using the principles of permaculture to harvest water passively.”

Contour Farming: NRCS Conservation Practice Standard.
Specs and support for keyline-related practices.

NRCS Technical Guide
NRCS provides a set of key technical resources to guide on-farm water (and other resource) management practices. These include information and recommendations about specific practices related to keyline design as they pertain to local areas. Visit the online Field Office Technical Guide (eFOTG) and click through to the map to your county for details. Once there, you can search through practices listed in Section IV of the pull-down menu in the left-hand column of the page. Here, you may also find information about financial support that may be available for implementing these practices. In addition to practice-specific assistance, the eFOTG provides key data to help growers in resource management decision-making, including natural resource information (Section II in the pull-down menu) about local soil (e.g. web soil survey), water, air, plant and animal resources; planning tools for developing resource management systems (Section III); and other useful tools and information.

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Case Studies

Nicasio Native Grass Ranch
Through their experiments in preserving native grass species, John Wick and Peggy Rathmann discovered keyline design principles of soil conservation and water harvesting. From the California Institute for Rural Studies report California Water Stewards: Innovative On-Farm Water Management Practices

Markegard Family Grass-Fed
This video is part of the Water Stewardship video series produced by the Ecological Farming Association. Markegard Family Grass-Fed uses keyline strategies to build soil, increase forage production, save electricity, and reduce runoff on their ranch.

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Page Credit

Content for this page was originally developed by Brock Dolman, Occidental Arts and Ecology Center WATER Institute. Various others have since contributed content.

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