Category: Aridity: Arid

Posted on

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.

Posted on

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.

Posted on

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.

Posted on

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.

Posted on

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.

Posted on

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.

Posted on

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.

Posted on

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.
Posted on

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.

Posted on

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.