Category: Land use: Forest

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Riparian Buffer Zones

Similar names: Conservation buffers, Stream corridor bank enhancement, Riparian buffer strips and hedges, Terrestrial buffers, Riparian buffer systems

Riparian buffer zones are the interface between land and a river, stream or creek often characterised by riparian woodlands, forests and riparian strips. The plant habitats and natural communities along the river banks are better known as riparian vegetation and they are characterised by hydrophilic plants, bushy vegetation and forest systems. The presence of riparian buffer zones is crucial due to their role as natural biofilters and their protection of aquatic environments from excessive sedimentation, polluted surface runoff and erosion. Furthermore, they provide shelter, shade and food for many aquatic species.

Often the riparian zones are damaged by various anthropogenic activities such as agriculture, construction and silviculture. In this case, biological restoration can take place, with the most common practices being erosion control and revegetation. Furthermore, in some places riparian zones are fully lacking and reintroducing them could bring plenty of benefits to the local ecosystems. Because of the great biological function these systems have in supporting a diversity of species and landscapes, they are in some places subject to national protection mechanisms.

Initiating and restoring riparian buffers is crucial for the healthy functioning of riparian ecosystems. The vegetation around the banks of the river slows the flow of water which controls the power of the river and the destruction that could occur downstream. When near agricultural land, the riparian buffers filter various pollutants from agricultural runoffs, enhancing water quality via biofiltration. 

Disclaimer: Check whether Riparian Buffer Zones are subject to national protection in your area, as this could help with their protection and restoration.

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Muvuca Direct Seeding

Similar names: Seed-based land restoration, Direct sowing

Muvuca direct seeding is a nature restoration method, where a mix of seeds from dozens of native species at different successional stages are planted simultaneously into the ground. The method mimics natural regeneration mechanisms such as seed soil banks and seed rain. Better known conventional practice is direct seeding’s popular counterpart – transplanting, which is a technique of moving plants from one location to another, usually to preserve the optimal condition of the seedlings. Despite providing more control over the plant’s growth, transplanting doesn’t allow for a high variety of plant seeds to grow simultaneously.

The Muvuca system uses a high diversity of species and ensures longer-term operational efficiency, which in return enables mechanised restoration with reduced planting, low maintenance in terms of time and reduced costs. Planting can be done either manually or mechanised (using machinery such as tractors), which enables the scalability of the intervention. Furthermore, the grown plants through Muvuca become more robust and resistant to various weather conditions, which results in stronger root systems and overall healthier vegetation. Overall, Muvuca direct seeding can contribute to the scaling up of restoration efforts, while reducing costs and increasing the species diversity. Meanwhile, the demand for native species enables the promotion of conservation and well-being.

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Composting

Similar names: Organic Amendments

Composting is an effective method of organic waste management, involving the controlled aerobic decomposition of organic matter, such as plant and animal waste. This process results in Compost, a stable, humus-like material that can be directly applied to soil. The primary goal of Composting is to reduce the amount of organic waste sent to landfills while providing economic, environmental, and social benefits. When used in soil, Compost enriches it, reducing the need for chemical fertilizers and lowering potential methane emissions from landfills.

The Composting process (Source)

Due to its recycling nature, Composting is a cost-effective tool for managing organic waste, utilizing leftover materials from land-based processes. It offers a range of co-benefits that enhance land and soil regeneration practices. Agronomically, Composting supports crop yields, improves soil moisture content and workability, enhances crop nutritional quality, and suppresses weeds, pests, and diseases. Additionally, Composting provides broader environmental benefits by supplying essential nutrients (such as mineralized nitrogen, phosphorus, and potassium), reducing soil erosion, sequestering carbon, and improving soil biological properties and biodiversity.

Furthermore, Compost can be used as a mulching material in landscaping, garden management, and the restoration of abandoned quarries, among other applications.

Agricultural benefits of Composting (Source)

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Assisted Natural Regeneration

Similar names: Pruning, Kisiki Hai, Managed Regrowth

Assisted Natural Regeneration (ANR) is a simple, low-cost forest restoration method that can effectively convert deforested and degraded lands into productive forests and rangelands. The method uses a blend of active planting and passive restoration techniques, which help vegetation to naturally recover by eliminating barriers and threats to their growth. ANR is similar to Farmer-Managed Natural Regeneration (FMNR), with the difference that ANR applies to degraded forest lands and rangelands while FMNR is usually practised on croplands. Overall, ANR mimics the natural systems and habitats by supporting the land processes through ANR. 

ANR is a flexible restoration approach and could be adapted to various contexts and objectives. A set of ecosystem restoration techniques are being facilitated, to eliminate obstacles to plant growth and survival. Those could vary depending on a range of factors, such as location, land type, restoration goal, etc. Hence, local community engagement is crucial for successfully implementing and managing ANR. Their knowledge of the land and ancestral traditions offers the best indication of what techniques and practices would be most beneficial. The most common ANR techniques are visualized in the figure below.

(source)

In comparison to other regeneration techniques such as tree-planting campaigns, ANR has comparatively low implementation and maintenance costs. The method could be applied on a local and larger scale level, with some areas and contexts being more favorable than others when it comes to implementation (see Requirements). However, where implemented, ANR can create jobs and bring income to local communities, as the implementations would require establishment and maintenance.

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Stone Lines

Similar names: Cordons pierreux, stone bunds.

Stone lines are stones grouped in the shape of a line and placed along contours. The stones can be of different sizes. The goal of these lines is to conserve the soil and reduce runoff, as they are used to slow down water runoff and break its velocity. Hence, they increase infiltration and retain sediment and seeds to make water and nutrients available for crops. Stone lines are most suitable for water harvesting on slightly sloping plains (up to 5%) in semi-arid regions. For slopes starting from 5%, stone bunds can be used (see eyebrow terraces).

Stone lines are an easy and cheap intervention if stones are available in the immediate surroundings. This intervention is widely used in Africa, both in dry and humid areas. Moreover, stone lines are often used in combination with Zai Pits intervention for the rehabilitation of degraded and crusted lands. It is applied in semi-arid areas, on sandy and loamy soils where the slope is lower than 5%. A great example can be seen in Niger, where the combination of the two techniques is applied to capture runoff, making infiltration more efficient and improving nutrient availability. The pits have a diameter of 20-30 cm, and a depth of 20-25 cm and are spaced about 1 m apart in each direction. Stone lines are spaced 20-25 m apart on slopes of 2-5%. With this layout stone lines are quite small, usually, three stones wide and only one stone high and they are placed, along the contour lines, by hand. Very often grass grows between the stones leading to a greater infiltration and helping the accumulation of fertile sediments. Maintenance-wise, stone lines need to be repaired annually, in particular after heavy precipitation events.

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Vegetative Lines

Vegetative lines involve the planting of lines of vetiver grass following the contour lines, along stream banks and roadsides, to create a hedge. These hedges act like semi-permeable barriers, aimed to hinder surface erosion as they slow down run-off and retain sediments picked up by excess rainwater. This setup improves water infiltration and helps to increase the ground moisture level. Their root systems also help stabilise the soil and prevent further soil erosion. Thus this provides increased stabilisation of embankments, gully erosion, roads and slopes. Furthermore, water runoff and soil runoff reductions are observed, at around 57% and 80% respectively.

Vetiver grass can grow on slopes of > 50% and can be planted on a high variety of soils (red latosols, black cracking vertisols, roadside rubble, C-horizon gravels, laterites, sodic, and saline soils). Furthermore, vetiver grass is resistant to different types of climatic conditions: rainfall from 600mm to 6000 mm /year and extreme temperatures of -14°C to 55°C, and could survive several months submerged in water. Vetiver grass can support high levels of toxicity by manganese, aluminium and other metals and high levels of soil acidity, salinity, alkalinity, and acid sulphate conditions. All in all, they provide great solutions as they are non-invasive, fire resistant, and regrow quickly and be used as mulch, fuel (vetiver energy value is 55% the energy value of coal), and as fodder. Finally, vetiver grass is very efficient in stabilising Semi-Circular Bunds, Eyebrow Terraces or Negarim.

Very similar to the intervention described above is the so-called “Vegetative lines with cactus”. This intervention is based on the same principle as the Vegetative lines with vetiver grass, but it is suitable for drier environmental conditions (0 – 600mm). Like some other interventions, over time, this type of intervention can lead to the formation of terraces due to tillage and water erosion between the hedges.

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Negarim

Similar names: diamond-shaped micro catchment, V-shaped micro catchment, V-shaped bunds, Triangular bunds, small run-off basins

Negarim is an intervention that consists of small runoff micro basins characterised by a diamond shape, bound by low earth bundles. This water harvesting technique is mainly used for growing trees and bushes in arid and semi-arid areas but, as a side effect, it also preserves soil from erosion. It works great with rainfall rates starting from 150 mm/y and can be applied on slopes of up to 15%. This technique is more suitable for small-scale tree-planted areas and is pretty easy to create. Since Negarim mostly targets tree- and bush-planting, the area in which this technique is performed should be characterised by a soil depth of at least 1.5 metres, but preferably 2m. This is to ensure enough space for the roots to develop and for adequate storage of the water harvested.

The technique was originally developed in the Negev desert in Israel; in fact, the word Negarim comes from “Neger”, the Hebrew word for runoff. Nonetheless, the first report of this water harvesting technique comes from the south of Tunisia. This microcatchment system is widely spread in Israel, especially among research farms in the Negev desert where the yearly amount of rainfall reaches 100-150 mm. However, Negarim and its variations are well known, and used also, in other arid and semi-arid areas like in North- and Sub-Saharan Africa.

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Zai Pits

Similar names: Chololo pits (Tanzania), Zaï pits (Burkina Faso), tassa (Niger), agun pits (Sudan), kofyarpits (Nigeria), yamka (Kyrgyzstan), planting pits.

Zai Pits are small basins in which the seeds of annual or perennial crops are planted. The pits are then filled with Mulch, manure, compost or good soils to increase soil fertility and the capacity of the soils to retain water. Zai Pits can be beneficial for soil conditions and they are a very successful method which can allow for the growth of vegetation in dry areas. They are also very efficient in protecting seeds and soil organic matter from being washed away from water runoff. One of the major advantages of Zai Pits is that it increases water filtration, through the collection and concentration of water for the plants due to increasing termite activity. What is more, Zai Pits can collect more than 25% or more of run-off water. This as a result decreases water run-offs and evaporation. When looking at the bigger picture, Zai Pits can improve soil fertility and agricultural productivity of several crops and can increase production by up to 500% if well executed.

Zai Pits are an efficient method to increase yield productivity due to more water and nutrients available. This intervention is most suitable for flat or gently sloped terrains (0-5%) with a precipitation range of 350-600 mm/y.  Zai Pits can also work with other techniques such as stone contours and hand-dug trenches.

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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.

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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.