Category: Goal: Prevent erosion

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Eyebrow Terraces

Similar names: Banquettes, Boomerangs, Terraces, Stone Bunds, Eyebrow Systems, Eyebrow Basins.

Eyebrow Terraces are a form of microcatchment water harvesting system. They are handmade micro basins, in the shape of an eyebrow, and are often made from soil and stones. Their main goal is to facilitate vegetation growth on steep slopes by collecting runoff water from a small catchment area and having it infiltrate the soil. This way, it is stored in the root zone and will be available for crops. They are usually situated on hillsides and can be used on up to 50% of slopes. The steeper the slope, the more the bunds have to be reinforced with stones. Eyebrow Terraces work well in areas characterised by 200-600 mm of annual rainfall. Reinforcing Eyebrow Terraces with stones on steep slopes makes them more resistant to the increased water speed caused by the slope. Instead, they can be some metres apart. After completion, the pit uphill from the eyebrow may fill with sediments and soil, thereby giving rise to terraces.

Some of the main advantages of Eyebrow Terraces are that they reduce the risk of flooding, while simultaneously increasing the on-site conversion of water through the facilitation of filtration. Furthermore, the intervention improves the yields in the area, by increasing the soil organic content, as sediments are trapped in the terraces.

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Exclosures & Enclosures

Enclosures are fencing structures that restrict animal and human access to land with the goal of supporting the regeneration or protection of said land. Enclosures also refer to the practice of fencing-off an area in order to protect it from human use and animal intrusion. The main goal of Enclosures through fencing is to allow natural regeneration and rehabilitation of degraded lands within the enclosed space. This intervention fosters natural regeneration and helps to restore organic matter and a healthy soil structure. Enclosures can also be used to change the cover of the land to allow time for new land coverage (vegetation) to be established. Enclosures can be applied in a variety of different landscapes and environmental conditions. This technique is a relatively cheap intervention if the materials are available on site but can be somewhat more expensive where materials need to be acquired or where more sophisticated Enclosures are built. Fencing could be done for a permanent or temporary use, and this is defined by the goal of the project. 

Some of the major features of Exclosures and Enclosures are the economic benefits linked to the environmental benefits coming as a result of their implementation. Firstly, the increased vegetation that comes as a result of fencing increases vegetation which in return enhances water-retention capacity of soil. This helps to both replenish the nutrients in the soil and to restore the ability of the soil to retain water.  Furthermore, the enhanced water retention capacity of the soil reduces the exposure to flood damage. When it comes to agriculture, Enclosures and Exclosures improve long-term returns from crop production and pastureland, as the long-term productivity of the land is improved by improved and regenerated soils. This helps to increase crop yields quality. Exclosures and Enclosures can increase security of land tenure and make property rights clearer due to clear demarcations of the boundaries of your land. This can, in turn result in a higher willingness to invest in the land. Finally, Enclosures and Exclosures provide an opportunity for complimentary economic activities to be realised, such as harvesting grass (‘cut and carry’), extraction of wood, or growing of fruits and vegetables. Growing additional crops can also increase and diversify income streams and contribute to enhanced food security.

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Grazing Management

Sustainable Grazing Management is about managing pasture and livestock in a way that prioritizes the long-term capability of a landscape. Its goal is to maintain healthy and productive pasturelands and provide economic benefits, and can be applied to range, pasture, and grasslands in all types of topographies and climates. The way grasslands are managed both directly and indirectly impacts the ecological health of the surrounding ecosystem, including the local water and mineral cycles as well as biological succession, in turn also creating socioeconomic effects for farmers and herders.

As opposed to more traditional and unsustainable practices such as extensive or continuous grazing where livestock graze on one large, open pastureland, there are several methods of more sustainable Grazing Management. Two examples of this are Rotational Grazing Management and Integrated crop-livestock grazing.

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Conservation Agriculture

Similar names: No-Tillage Agriculture, No-Till Farming, Zero Tillage, Zlimate-Smart Agriculture

The Conservation Agriculture approach is a system of managing agricultural lands based on certain farming practices. It aims to achieve sustainable production through minimizing soil disruption, while preserving soil quality and improving its biodiversity. Indeed, the main goal of Conservation Agriculture is to tackle land degradation and increase efficiency in the use of water and nutrients. For this reason, this technique works well with degraded agro-ecosystems as it helps in the restoration of resources, and to increase profits and food security. Beside the conservation of soil structure and fertility, this practice plays an important role in preventing soil erosion caused by machineries, especially in hilly and mountainous areas.

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Mulching

Similar names: Covering, Groundcover, Topping, Blanket Mulching

Mulching involves applying a layer of material to the soil surface mainly in order to improve soil health and enhance plant growth. Either organic or inorganic materials can be used as mulch. Mulching simulates a natural forest environment. In a natural forest, soil is covered by leaves and organic material, and it is rich in living organisms that recycle nutrients. Mulch can be composed of a wide variety of materials (see method of application) and has a number of potential uses. It is an especially helpful technique in climactic zones with high evaporation rates. 

The physical and ecological benefits of Miyawaki are numerous. Firstly, the layer of mulch helps retain soil moisture by reducing the soil’s exposure to direct sunlight and preventing evaporation. Mulching is also effective at stifling weed growth by physically impeding their growth and stopping their access to sunlight needed for photosynthesis (amongst other mechanisms of weed prevention such as allelopathy with certain Mulching materials). Other benefits of Mulching include that it helps prevent soil erosion, is an effective means of regulating soil temperature by acting as insulation and improves the fertility and structure of soil (especially organic Mulching). Please refer to the conditions section for information on potential problems with Mulching so as to ensure the best chances of successful implementation.

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Water Spreading Bunds

Similar names: diversion embankments, diversion bunds, low lying crescent embankments, spate irrigation (general term).

Water spreading bunds is a technique in the category of floodwater farming (also called spate irrigation) which consists of the use of earthen bunds, usually applied where trapezoidal (regular) bunds are not suitable. Regular bunds may not be suited for area where runoff rates are high and they would be damaged, or where the crops may suffer from flooding.

The goal of the water spreading bunds is, as the name suggests, to spread water and not to confine it, like trapezoidal bunds do. They are intended to spread floodwater that has been either diverted from a watercourse or has reached the floodplain. The technique of water spreading bunds is very site-specific, as it can only be used on lands close to a watercourse, usually on alluvial fans or floodplains, and is characterized by almost flat slopes (up to 1%). Water spreading bunds are usually applied on even lands with deep and fertile soil, with a precipitation rate within 150-300 mm. Therefore, hyper-arid or arid areas where floodwater farming is often the only possibility to achieve fodder or crop production.

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Gully Rehabilitation Stem Cuttings

Similar names: Gully Plugging with Stem Cuttings, Check Dams from Stem Cuttings, Brushwood Check Dams, Live Check Dams

Gully Rehabilitation Stem Cuttings is an intervention that “plugs” particularly active gullies and streams by building Check Dams made of Stem Cuttings to control erosion and runoff. These living barriers are efficient in slowing down runoff water and stopping sediment buildup in the gullies. Field research has proven that they work well in soils of sandy/loamy texture, where the performances of these dams are greater than ones made of stone dams due to rooted poles and the stabilised root system of the living barrier.

Stem Cuttings involve taking sections of woody stems from suitable plants and inserting them into the soil in a gully or erosion-prone area. These stems will develop roots and grow into new plants, helping to stabilize the soil and prevent further erosion. Stem Cuttings are cost-effective and environmentally friendly, promoting natural vegetation growth, and enhancing biodiversity, and ecosystem health. They also provide erosion control once established, preventing further degradation of the gully.

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Multi-storey Cropping

Multi-storey cropping, or multi-tier cropping, is a production system characterized by an extremely efficient utilization of space by focusing on both vertical space and ground arrangement. Crops of different heights, stages of maturation, sunlight requirements, and root systems are grown in tandem. By selecting crops of different heights, canopy patterns, and root systems, multiple layers of canopy (2 to 5 layers) can be grown on a farm. This farming system seeks to maximize farm productivity and income and usually involves cultivating entirely cash crops. It is best suited to smallholder farms in tropical zones that receive high levels of sunlight. 

Multi-storey cropping can be implemented in an intercrop or mixed-crop arrangement. Crops may also be planted in a more random arrangement where practitioners/farmers have specific knowledge of the local environmental and ecological system and which crops may be optimal for their context. Multi-storey cropping enables the diversification of crops produced and often brings higher yields per unit area than mono-crop settings. This type of crop-growing system leverages the synergies between plants to enhance productivity (foliage size, shade formed, nutrients used, etc.). Multi-storey cropping systems also place a strong emphasis on nutrient recycling;  these systems allow organic matter to re-enter the soil, thus improving the structure and fertility of soils (this can be aided further by actively implementing Mulching). Finally, a multi-storey cropping system reduces soil erosion by increasing the soil cover and water retention of an area.

Some of the main advantages of multi-storey cropping are the increased long-term productivity of farms due to improved soil health and the survival of different crop varieties thanks to the provision of shade by taller plants. The provision of shade and multiple crop types can increase soil fertility and restore the nutrient content of the soil. As a result, this can lead to long-term productivity of the soil which can contribute to long-term food security and quality due to improved soil health. Furthermore, what is also observed is a reduced exposure of farmers/implementors to market volatility due to diversified sources of income from planting multiple crops. This on its own can result in a potential increase in farm income (once the system is complete) due to diversification of income screams through the planting of multiple crops, and reduction in crop vulnerability (for crops which prefer shade). Finally, when the intervention is applied is can result in a decreased flood risk/flood damage due to the increased soil cover and dense vegetation preventing excessive water runoff downstream.

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Tree Islands

Similar Names: applied nucleation, cluster planting, Assisted Natural Regeneration, Tree Island Planting

Tree islands, also known as “applied nucleation” or “cluster planting”, are a forest restoration technique that combines tree planting and natural regeneration. The primary goal of tree islands is to restore degraded landscapes by accelerating natural forest regeneration. It involves the strategic planting of small clusters of trees (“tree islands”), creating focal points for ecosystem restoration and accelerating natural regeneration in between the islands. They enhance natural forest recovery, rely on animal species for the dispersal of native tree seeds, and promote high levels of native biodiversity. 

The tree islands act as biodiversity hotspots, improving soil fertility, water retention, and microclimate, creating resilient ecosystems. They increase the availability of tree seeds and attract seed dispersers. They also provide shade, suppressing sun-loving plants that can overgrow in the area,  leaving no space for trees to establish. By creating tree islands, a base is offered from which the forest can re-establish itself and grow back much faster than conventional natural regeneration approaches.

Overall, tree islands represent an innovative and promising approach to forest restoration, offering a sustainable method for accelerating the recovery of temperate, tropical, and subtropical forests. It is a cost-effective forest restoration technique that uses only about 20% of the trees that would be needed for a whole forest plantation of the same area. This makes it more accessible and the structure more natural.

When implementing this intervention in a certain area, it is best to involve the community. It can even become a community-driven initiative, with community members working on the implementation, monitoring, and maintenance of the tree islands. This enables them to play an active role in local forest regeneration.

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Swales

A swale is an intervention designed to retain water run-off on a slope. It is a long, small ditch on the contour lines, i.e. at the same elevation. Several swales can be constructed next to each other to increase their effect. Swales have a small berm on the downslope side, which often contains vegetation and acts as a retaining wall.

Swales are cost-effective and relatively easy to implement, preventing soil erosion, nutrient run-off, and flooding. They capture water which runs down the hill and let it infiltrate into the soil. Growing vegetation on the berm will strengthen the berm and the soil and will hold water and nutrients better. Trees, in particular, work well for strengthening berms and are watered by the water held by the swales. If possible, it is also an option to add stones to a berm to make it even stronger. In the Perma Atlas Initiative, swales have been a great success in preventing flooding. Swales are similar to Contour Bunds and Fanya Chini and they can be used on a small or large scale. The greatest reduction observed when swales are introduced are in water runoff, soil loss, phosphorus runoff and nitrate-nitrogen runoff.