Category: Aridity: Dry sub-humid

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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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Fencing

Fencing around eroded soils, rills and gullies is a cheap and low-maintenance form of sediment catchment, soil and water runoff prevention on gentle, moderate and steep slopes. Three types of fencing are detailed in this intervention about their prevention of different types of soil erosion at varying topographies.

  1. Silt Fences → Softer intervention for sediment catchment, preventing runoff and wind displacement on rills, arid fields or gentle hillsides. 
  2. Woven Fences → Harder intervention for slope stabilisation and sediment build-up in gullies and rocky mountainous landscapes.
  3. Biotrampas → Harder intervention for rock catchment, landslides and slope stabilisation in gullies and heavily eroded, steep mountainous landscapes.
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Kitchen Gardens

Similar names: Community Gardens, Permagardens, Permaculture Gardens, Vegetable Gardens, Urban Gardens

Kitchen Gardens consist of pieces of land close to households in which plants such as vegetables, herbs and fruits for use in the kitchen are cultivated. These gardens can include space for livestock, (fruit & nut) trees and hedges cultivated for fodder. Kitchen Gardens have long been practised to provide subsistence and a variety of food for small households, whilst also providing an additional source of income when surpluses are generated and sold at the market. With a few adjustments, this practice can be adapted to most kinds of ecosystems, and even in highly urbanised areas, with the aid of pots and containers. This intervention is most suitable for flat or gently sloped terrains (0-5%), however, to obtain a lower slope in hillside conditions, it can be combined with Eyebrow Terraces. Gardens can also be created in schools and other public facilities, involving the entire community.

Kitchen Gardens offer socio-economic benefits by diversifying income streams, reducing food expenses, and empowering women and youth through their involvement in establishment and maintenance. They enhance food security by providing diverse, nutritious crops locally and serve as social hubs for education on food production and healthy soils, positively impacting mental health. Ecologically, they promote biodiversity, improve soil health through organic practices, and conserve water resources through efficient irrigation systems. In summary, Kitchen Gardens contribute to increased household income, reduced food expenses, improved dietary diversity, and enhanced ecological sustainability, making them valuable assets for communities.

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Alley Cropping

Similar names: Alley Farming, Nalaad, Intercropping, Farming with Shade Trees

Alley Cropping is a farming method whereby trees and shrubs are planted in rows, and crops are grown in the spaces between these rows. This technique helps reduce soil erosion by slowing down water runoff and increasing water absorption capacity of the soil. The trees protect crops from strong winds, provide habitats for wildlife, and attract pollinators such as bees. Planting different species of trees or shrubs can bring additional benefits as they may be harvested to provide fodder for animals, food, firewood, or materials for mulching.

Farmers can start Alley Cropping on a small scale by planting hedgerows around their fields or farms. On larger farms, the distance between the rows can be increased to enable the use of machinery. Common crops used for Alley Cropping include corn, soybeans, wheat, and potatoes. Often, these crops are combined with trees that produce valuable products like hardwood timber or nuts. This technique is flexible and can be adapted to meet the specific needs of any farm, making it a practical way to improve productivity and sustainability.

NOTE: This method works particularly well in humid and semi-humid regions, but has also been successful in dry areas when undertaken with careful planning. In drier regions, it is important to ensure that hedgerows do not compete with crops for soil moisture.

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Miyawaki Forest

Similar names: Tiny Forests, Fast Growing Forests, Urban Forests, Potential Natural Vegetation

The Miyawaki method is a reforestation technique that entails the growing of a forest within a few decades – instead of centuries – by taking into account the succession of plants and plant diversity that naturally occurs in forests. This method was first conceptualised in Japan by Dr. Akira Miyawaki and has been successfully implemented in areas with relatively high rainfall rates such as India, Malaysia, and South America. However, it has also been successfully practised in other/locations/, such as the Mediterranean; the steppe zone of Jordan; and the Persian Gulf region.

This technique is particularly effective as it imitates the structure of a mature forest. It aims at recreating all the different levels of vegetation and combinations of species that would naturally occur in a native forest without human intervention – defined as “potential natural vegetation”. Practitioners must carefully select the right indigenous vegetation best adapted to local conditions, and they need to commit to watering and mulching the seedlings during the first years of implementation of the intervention. One of the advantages of using this technique is that it allows for the quick regrowth of a dense forest rich in biodiversity which can retain rainfall and create a cooling microclimate effect. Furthermore, the maintenance is comparatively low, as the forest becomes self-sufficient after 3 years.

NOTE: The implementation of this technique can be expensive as it requires a lot of seedlings for a relatively small area. However, it allows to obtain a fully functional forest in a short time, with minimal maintenance needed.

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Improved Fallows

Similar names: Mixed Improved Fallows, Mixed Intercropping, Shade Trees, Relay Intercropping

Cultivating Mixed and Improved Fallows is a technique that aims at keeping yields high while maintaining the soil’s fertility and moisture. This can be achieved by growing two or more species in succession, sown at different times of the year on the same piece of land which positively influences each other while providing beneficial soil nutrients. This newly replenished soil should therefore never be left exposed but always covered by crops and mulch. Traditionally, farmers used to leave a section of their land to “rest” (= the fallow) for one year or more after a period of intense cultivation. This allows the soil to be covered by natural vegetation which restores nutrients, organic matter, and soil microbial activity necessary to make the soil fertile. However, with the increasing demand for resources, this practice is rarely used. To ensure long-term soil fertility, some farmers have come up with the solution of planting fallow plants, which can either be a tree, a shrub or a herbaceous cover crop – often a leguminous species, during the fallow phase. Fallow plants can then be used to: provide fodder, break cycles of pests (as some species are natural pest-repellents), attract honeybees, keep weeds away, shade crops, increase soil activity, and increase biodiversity. 

Mixed Improved Fallows can perform even better than having one fallow species on rotation. This is when two or more fallow species are combined with one traditional crop. Usually, one of the two fallow species grows to a tall height providing shade, while the other is usually a “nitrogen fixing” plant which restores nutrients in the soil. 

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Silvopasture

Similar names: silvopastoral system, mixed pastures.

Silvopasture is a technique that integrates trees and shrubs with the keeping of grazing livestock on the same piece of land. Silvopasture interventions aim to realise the benefits of combining two systems: grazing animals help to keep weeds away from trees and fertilise the soil with manure, while trees (often fruit trees) provide additional fodder for the livestock through their extra leaves/biomass. Silvopastoral systems are used as an alternative to conventional cattle farming systems to combat deforestation problems.

This intervention is traditionally applied in tropical and temperate zones but also in subhumid, semiarid, and arid regions. Some other variations are agro-silver-pastures, which combine trees or shrubs, wish crops and cattle. A more complex system should be well planned but that can bring a variety of benefits. Also called the crop-livestock-forest system (CIF). Another alternative is silver fishery, which combines woody perennials and fish resources.

Silvopasture offers numerous ecological benefits, including improved water management by reducing runoff and increasing retention, which prevents soil erosion and landslides. It enhances soil quality and nutrient content, supports carbon sequestration through tree planting, and boosts biodiversity by introducing trees that provide habitats for various species. Additionally, it reduces the risk of fire by controlling understory vegetation and improves livestock conditions by providing shade, which can increase their lifespan and milk yield. Economically, silvopasture lowers costs by using livestock for weed control, diversifies income sources through harvesting trees and livestock products, and enhances food security and sustainability for farming communities. It also supports indigenous livelihoods by preserving traditional knowledge and culture.

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Charco Dams

Charco Dams are a traditional means of water harvesting in arid and semi-arid landscapes of Eastern Africa, especially in Tanzania. This type of dam has a deep reservoir and limited surface area which helps to reduce water-loss from evaporation. Charco Dams are built to collect rainwater and runoff water from flat surfaces. As a result, they are suitable for livestock watering and crop irrigation, but less suitable for domestic use (unless the water is treated). Typically, trees and shrubs are planted around the edges of the dam to act as windbreaks to further reduce evaporation. Small earth dams may vary significantly in size based on the water storage capacity needed. Storage of up to 1000m3 is possible, beyond which a pond is considered large and will require different building protocols. Dams need to be thoroughly planned in order to ensure their feasibility, longevity, and safety. Please make sure to consult the additional supporting resources provided for more specific details on how to plan and build a Charco Dam, or talk to a local extension officer for help on planning and implementing a Charco Dam in your landscape.

Picture by: Rikolto (Vredeseilanden)