Category: Aridity: Semi-arid

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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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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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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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Contour Bunds

Similar names: Level Bunds, Contour Stone Bunds, Earthen Bunds, Contour Bunding

Contour Bunds are a form of micro-catchment technique and are a very simple and cheap form of water control. The bunds are created along the contour lines. There are also small earth ties, perpendicular to the bunds, that subdivide the system into micro-catchments. Contour Bunds are very similar to Negarim in that they aim to slow down runoff and improve water infiltration in the soil. For this reason, Contour Bunds are often associated with the cultivation of crops, fodder or trees which are grown between the bunds. Contour Bunds also help to control soil erosion. Contour Bunds for tree planting is suitable in arid and semi-arid areas with rainfall rates between 200 and 750 mm. They can be applied on slopes of up to 5% but they require even terrains, without the presence of gullies or rills. The soil should preferably be 1.5 to 2 m deep in order to ensure proper root development and water storage.

Contour Bunds are also a cost-effective nature-based solution, which is relatively cheap, especially on a larger scale and on even lands because less earth is moved. The intervention could be combined with machinery, which additionally enables the technique to be scaled up to larger areas. Finally, fodder crops can be grown before the trees become productive, which as a result could lead to a reduction in the amount of runoff that can reach the trees.

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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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Gabions

Similar names: Riprap, Gabion Baskets

Gabions are metal baskets filled with stones. Gabions act as retaining walls and will mitigate the effects of heavy rainfall, which is accelerating due to climate change. They can be placed in streams and gullies to slow the flow of water and prevent flooding. If the water is not slowed down, the topsoil is washed away and erosion worsens. With the topsoil gone, there are no nutrients left, making the soil unsuitable for vegetation and water absorption. Gabions will hold this and prevent erosion and further degradation. Moreover, the Gabion allows water to pass through while trapping soil particles. Where possible, the community should be involved as Gabions play a role in protecting their communities and land. Gabions can also be used for coastal protection and slope stability. Sometimes they are also used for aesthetic purposes.

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Grass Seed Banks

Similar names: Community Seed Banks (also for other seeds)

Grass Seed Banks are a conservation and restoration strategy aimed at revitalizing degraded landscapes, particularly in arid and semi-arid regions. Communities can decide where they are suitable and establish them in degraded areas of about ten hectares. Grass Seed Banks are sowed with grass seedlings and should be naturally fenced using shrubs to protect the grasses against grazing livestock and wildlife. These seed banks serve as repositories of native grass seeds, which are essential for restoring vegetation cover in areas affected by desertification, land degradation, and biodiversity loss. They are a community-based initiative that restores degraded landscapes and provides economic opportunities for local communities, especially women. Grass Seed Banks can be managed and maintained by local women’s groups, who sow and harvest the grand grass seeds. Once the grasses are fully grown, they produce grass seeds, which the women can sell at local markets (for example to other restoration projects) or as fodder for livestock.

By selling the grass seeds, women can earn additional income. When grass seed bank projects are successful, the status of the women in the community can be improved. Selling the grass seeds can also help other restoration projects and thereby help to regreen other areas as well. Moreover, they can help to attract insects and small animals, which boosts local biodiversity and the growth of vegetation in the area around the seed banks.