Category: Goal: Reduce runoff

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Semi-Circular Bunds

Similar names: Demi-Lunes, Banquettes, Boomerangs, Water Bunds, Earth Bunds, Earthworks, Micro Basins, Half-Moons, Earth Smiles

The technique of creating Semi-Circular Bunds belongs to the overall category of water harvesting interventions and consists of half-moon-shaped basins dug in earth. The main goal of water harvesting, as the name suggests, is to collect water, and to make moisture available for vegetation for a longer time. This type of micro-catchment water harvesting technique is suitable for slopes up to 15%, however Bunds made of earth are seldom used in areas with slopes greater than 5% with a precipitation rate higher than 300 mm/y. At lesser slopes, Semi-Circular Bunds are also used in areas with higher rain falls.

Semi-Circular Bunds are a low cost intervention, where the time requirements of bund construction are very low as they can be implemented very fast, especially when the raw materials (plant residues) are available. The intervention also allows for the cultivation of plants and species that would not grow in previously dry conditions. Overall, the direct benefits of Semi-Circular Bunds can be realised in the short term and often after one year of implementation.

Watch this bunds instruction video for step-by-step guidance on how to implement them effectively.

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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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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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Farmer Managed Natural Regeneration

Similar names: treecovery, natural regeneration, tree-based regeneration, Kisiki Hai

Natural regeneration is a biological process that can be assisted and managed by farmers and landowners to increase the recovery of native ecosystems and their functions. Usually practised on wooded agricultural land, Farmer Managed Natural Regeneration (FMNR) is an approach that aims to increase the number of trees by protecting, managing and pruning existing tree and shrub stumps and roots to create the optimal conditions for them to flourish and germinate seeds again. 

An advantage of FMNR is the freedom that farmers have in implementing and adapting this technique to their specific landscape. Farmers can make decisions based on their knowledge and experience and choose which tree species they want to target, for example, fruit trees. Farmers can also select which species they want to save or remove during the pruning process, as well as when and what preferred tree density they want.

Learn the four steps of FMNR in the below instruction video:

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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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Tilling

Similair names: ploughing

Tilling is one of the most important and widely used agricultural techniques in the world. It dates back to ancient times. Tilling involves physically manipulating the soil to achieve optimal conditions for seed sowing and crop planting. Different tools and techniques for tilling agricultural land exist. Put simply, tilling consists of breaking, cutting, or turning over the first layer of soil (usually between 15 and 25 cm) before planting crops. This helps to achieve a range of potential benefits such as increased aeration of the soil, increased water infiltration capacity, improved nutrient availability, burying of leftovers of previous crops, and weed control. These effects provide good conditions for plant growth and root establishment. Although tilling aims to improve soil structure for planting crops, excessive tilling can have the opposite effect and create a detrimental impact on the soil by leading to a depletion of soil microorganisms and fertility. By loosening the soil, tilling also increases the vulnerability of land and soil to erosion.

Tilling offers several ecological and socioeconomic benefits. Ecologically, it improves soil aeration and drainage by breaking up compacted soil, facilitating better root growth and nutrient uptake, and aids in weed control by disrupting weed roots, reducing competition for resources. Socioeconomically, tilling enhances soil structure, creating a favourable seedbed for planting, which can boost crop yields and contribute to food security. It also accelerates nutrient cycling by decomposing organic matter and releasing nutrients back into the soil, reducing the need for chemical fertilizers. However, excessive tilling can lead to soil degradation and nutrient loss.

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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.