Keyline design

Keyline plow” showing deep ripping cultivation shanks and coulter of a ‘Yeomans Keyline plow’ implement which attaches to a tractor. Photo by: Milkwood.net, CC BY-NC-SA 2. via flickr.

Keyline design is an approach to land management and the sustainable use of freshwater water resources. Primarily, keyline design aims to maximise the beneficial use of the rainwater that falls on a landscape. The method is particularly relevant for adapting to climate change, as it can help to mitigate the effects of drought and improve the resilience of ecosystems (Giambastiani et al., 2022).Keyline design strategies include:

Water Harvesting

Capturing rainwater and storing it in the landscape, often using ponds, swales, and dams, to provide a water source during dry periods.

Keyline Ploughing

A technique that involves ploughing along the contours of the land, just off the natural ‘keyline’ of the landscape, which is the pattern that water follows, due to gravity, as it moves through the terrain. This ploughing technique helps to spread water out across the landscape rather than allowing it to concentrate and cause erosion.

Soil Building

Enhancing soil fertility and structure to increase its water-holding capacity, which is achieved through practices like composting, mulching, and managed grazing.

Agroforestry

Integrating trees and shrubs into agricultural systems to create windbreaks, enhance biodiversity, and provide additional sources of food, resource, and income through products like timber, fruit, and nuts.

Perennial Planting

Using perennial plants rather than annual ones to reduce soil disturbance, improve soil structure, and provide vegetation cover to protect against erosion.

Name of NbS

Keyline design

Type of NbS

Engineered interventions (not using vegetation)

Location

  • Peri-urban
  • Rural

Keyline design was originally developed by Australian farmer and engineer Percival Alfred Yeomans in NSW, Australia in the 1940s. Although best suited to large-scale applications in rural areas, it can be used as a method of sustainable agriculture and land management on a smaller scale, such as the peri-urban edges of towns and cities common throughout Te Moananui Oceania.

Case Study

Taranaki Farm regenerative agriculture

Rancho San Ricardo, Oaxaca, México” showing agricultural plantings following keyline cultivation, parallel along contours. Photo by VillaTierradelSol, CC BY-SA 4.0. via Wikimedia commons.

Relationship to Indigenous knowledge

Although a practice based on large-scale engineering, and environmental modification and control which seems in many ways at odds with Indigenous ways of relating to the natural environment both in Australia and worldwide, keyline design does have an inspirational basis in Indigenous knowledge. The development of Keyline design was informed in some aspects by the connection and knowledge that Aboriginal Australians have with their land (Hill, 2003). Additionally, Pericval Yoemans’ son Neville Yeomans evolved Keyline design by observing and integrating aspects of Indigenous socio-healing and socio-medical practices into sustainable agricultural practices. This approach involves a local context-based design that aligns with natural systems, promoting adaption to natural landforms and respect of the design principles found in nature (Bradley, 2011; Spencer, 2005).

Climate change benefits
  • Changes in rainfall
  • Desertification
  • Drought
  • Increased temperatures
  • Loss of food production
  • Soil erosion
  • Reduced freshwater availability
  • Wildfire

Keyline design addresses climate change impacts, particularly in relation to water and shifts in weather and broader climate patterns. Keyline design also has the potential to create positive impacts for biodiversity, soil health and even agricultural productivity (Fiebrig et al., 2020). Changes in rainfall can be mitigated by storing water in the landscape in dams and ponds, and in the soil by improving infiltration, meaning the impact of dry periods is lessened (Hill, 2003). The practice of keyline ploughing spreads water through the landscape, reducing the impact of heavy rain events, and reducing overland flow and erosion (Giambastiani et al., 2022). Increasing temperatures can be mitigated through diverse, naturally resilient plantings, and by maintaining water in the landscape, which has the potential for evaporative cooling and maintenance of soil temperature (Schwarzer, 2021). Keyline design has knock on effects, where often food production is protected or increased, water availability is maintained, and wildfire risks are reduced (Hill, 2003).

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Societal / socio-cultural benefits
  • Climate change adaptation
  • Water security and quality
  • Disaster risk reduction.

Keyline design is a method of water and landscape management that enables and promotes climate change adaptation. In particular water security and quality are improved by spreading and sinking water into the landscape, therefore increasing water stored in the landscape in groundwater and in dams, and reducing overland flow that moves sediment and pollutants into water sources, alongside increasing erosion by avoiding concentrations of water into a singular flow (Giambastiani et al., 2022). Slowing and storing water in the landscape can have numerous disaster risk-reducing effects including reducing the risk of wildfire by keeping the landscape irrigated, and by providing water sources in the landscape for fighting fires (Hill, 2003).

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Ecological and biodiversity benefits
  • Disturbance prevention
  • Food production (for humans)
  • Fresh water
  • Soil building.

The ecological and biodiversity benefits of keyline design come from increasing water storage in the landscape. Water throughout the landscape becomes habitat for plants and animals, in particular insects, birds, and amphibians – all of which are important in a healthy ecosystem. Food production is improved in a diverse way through more permanent plantings including tree crops, and water for irrigation is ensured and distributed in a way that employs gravity to move water around (Collins & Doherty, n.d.). Physical alteration of soil structure through keyline subsoil ploughing, increased vegetation and specific grazing patterns in the landscape allow topsoil to begin to build up quickly (Hill, 2003).

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Yobarnie, Kurmond, NSW” from the book ‘Water for every farm by P. A. Yeomans. Image shows Yobarnie farm after 17 years of keyline irrigation development, including multiple keyline irrigation dams. Photo by Douglass Bagline, upload by Milkwood.net, CC BY-NC-SA 2. via flickr.
Keyline Irrigation Taranaki farm” showing the opening of the lock pipe of a dam, allowing water to flood into a keyline irrigation ditch that runs along the contour. Students observe. Photo by Deepbiosoil, CC BY-SA 4.0. via Wikimedia commons.

Technical requirements

Keyline design requires a detailed understanding of the landscape and utilises plans (especially topographic and contour information) of the landscape to identify patterns as a basis for design decisions. Understanding geology and ecology are also important and inform the design process (Collins & Doherty, n.d.). The development and implementation of keyline systems themselves often require heavy machinery, and the keyline plough is a specialised cultivation tool for loosening topsoil and subsoil layers, usually parallel or slightly skewed to contour. Some farms may require additional inputs, particularly amendments to improve soil quality (Fiebrig et al., 2020).

Like any changes, keyline design must integrate with existing infrastructure and conditions on a site. Consideration of these is required at the planning phase to produce appropriate and beneficial outcomes. Keyline design was originally developed for the Australian continent, so modifications will likely be required to adapt the strategy to local climate conditions in Te Moananui Oceania.

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Issues and Barriers

In Te Moananui Oceania there are several barriers to the implementation of keyline design on farms or urban landscapes. Environmental challenges relate to the diverse topography, soil types, and climate variability in the region, compared to the origin region of Keyline in Australia where hot, dry climates prevail.

Many farmers in small island Te Moananui Oceania operate on a smaller scale (Sherzad, 2018) and therefore, there are socio-economic challenges relating to the upfront cost of the development of keyline features in the landscape, and acquiring the equipment required. This may pose barriers to implementation. Equally, keyline is a methodology that requires specific knowledge or oversight, and so there is also a need for skilled labour in specific areas – like planning, earthworks, and water management. Like other alternative land management methods, implementation of keyline methods might likely rely on external aid to develop projects on larger scales. Despite local environmental knowledge, there may be a lack of specific knowledge and technical expertise in engineered solutions like keyline design in Te Moananui Oceania.

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Opportunities

Throughout Te Moananui Oceania there is a growing need for approaches that address climate change mitigation and adaption, disaster risk adaption and water and food security (Kiddle et al., 2021). There is a growing understanding that improving and maintaining soil fertility in the region is key to food security (World Heritage Centre, 2014). Keyline design is a practice that moves toward these outcomes. Keyline design is complementary to other forms of sustainable agriculture and can be implemented in unison with other practices or techniques (such as agroforestry and urban agriculture).

Keyline design has proved adaptable as a method possible in various conditions and climates (Giambastiani et al., 2022). Keyline design practice has the potential to generate community engagement and skill building in new methodologies, understandings about soil, water, and whole system health, and to improve food and water security, while allowing local stewardship of land and resources.

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Financial case

Yeomans (1954) claims keyline design lowers the need for costly agricultural inputs (fertilisers and water), increases soil health and productivity to produce better economic outcomes, and provides reliable long-term ecological health and resilience on a landscape scale. Despite this, there are limited case studies available detailing the costs of implementation of keyline design. Influences on the total cost of implementation might include the size of the landscape, the current condition of the landscape, the cost of skilled labour and equipment, and the cost of materials (Collins & Doherty, n.d.; Giambastiani et al., 2022; Hill, 2003; Yeomans, 1954). Additionally, ongoing costs related to the maintenance of engineered soil structures, like dams, and agricultural plantings like tree rows must be considered. Overall, despite potentially significant upfront costs, the benefits of keyline design can lead to reduced costs over time and potentially increased profitability (Fiebrig et al., 2020).

Environmental and regulatory improvements might make keyline design more easily implementable in the future – particularly in economic terms, and there is a financial case for the value of increasing biodiversity and reducing erosion in landscapes where keyline practices are used (Giambastiani et al., 2022). The financial case for keyline design will be greatly influenced by local conditions related to rainfall.

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References
  • Bradley, K. (2011). The Yeomans Project: Where Art & Farming Meet. https://www.milkwood.net/2011/08/01/yeomans-and-the-art-affair/
  • Campbell, J. (2009). Islandness: Vulnerability and resilience in Oceania. Shima: The International Journal of Research into Island Cultures, 3, 85–97. https://hdl.handle.net/10289/2898
  • Collins, A., & Doherty, D. J. (n.d.). Soil, water and carbon for every farm: Building soils, harvesting rainwater, storing carbon. Retrieved February 29, 2024, from http://agwaterstewards.org/wp-content/uploads/2016/08/KeylineArticle.pdf
  • Fiebrig, I., Zikeli, S., Bach, S., & Gruber, S. (2020). Perspectives on permaculture for commercial farming: Aspirations and realities. Organic Agriculture, 10(3), 379–394. https://doi.org/10.1007/s13165-020-00281-8
  • Giambastiani, Y., Biancofiore, G., Mancini, M., Di Giorgio, A., Giusti, R., Cecchi, S., Gardin, L., & Errico, A. (2022). Modelling the effect of keyline practice on soil erosion control. Land, 12(1), 100. https://doi.org/10.3390/land12010100
  • Hill, S. B. (2003). Yeomans’ keyline design for sustainable soil, water, agroecosystem and biodiversity conservation: A personal social ecology analysis. In B. P. Wilson & A. Curtis (Eds.), Agriculture for the Australian Environment. Proceedings of the 2002 Fenner Conference (pp. 34–48). https://www.researchgate.net/publication/237240838
  • Kiddle, G. L., Pedersen Zari, M., Blaschke, P., Chanse, V., & Kiddle, R. (2021). An Oceania urban design agenda linking ecosystem services, nature-based solutions, traditional ecological knowledge and wellbeing. Sustainability, 13(22), 12660. https://doi.org/10.3390/su132212660
  • Schwarzer, S. (2021). Working with plants, soils and water to cool the climate and rehydrate Earth’s landscapes. In Foresight Brief: Early Warning, Emerging Issues and Futures (Vol. 025). UNEP. https://www.unep.org/resources/emerging-issues/working-plants-soils-and-water-cool-climate-and-rehydrate-earths
  • Sherzad, S. (2018). Family farming in the Pacific islands countries. FAO. http://www.fao.org/3/ca0305en/CA0305EN.pdf
  • Spencer, L. (2005). Cultural keyline: The life work of Dr. Neville Yeomans [James Cook University]. https://doi.org/10.25903/x9jm-0t92
  • World Heritage Centre. (2014). Safeguarding precious resources for island communities. In World Heritage Papers (Vol. 38). UNESCO. https://unesdoc.unesco.org/ark:/48223/pf0000228833.locale=enYeomans, P. A. (1954). The keyline plan. https://www.soilandhealth.org/wp-content/uploads/GoodBooks/The%20Keyline%20Plan.pdf

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