Terra Preta raised garden beds (海地)

Terra Preta raised garden beds are a combination of techniques from permaculture and the production of Terra Preta, an anthrosol. These garden beds, which were created with local resources, are highly fertile and enable the production of much higher yields than traditional techniques, while diminishing soil erosion.

One of the major problems in the mountainous rural zones of the municipality of Léogâne in Haiti is the severe degradation and erosion of soils. The soil loss aggravates the vulnerable situation of the local population, mainly farmers. The Terra Preta raised garden beds were introduced in this region after the earthquake of 2010, and were replicated by several organisations and also by members of the communities. They are based on two main techniques:
1) Terra Preta is a technique to create soils based on a lacto-acidic fermentation of organic matter with charcoal powder. This technique was used by indigenous people in Amazonia, and rediscovered and replicated recently by scientists. The technique is characterised by the use of local resources and a high fertility. With this technique, a soil layer of several decimeters can be produced in a few years, whereas this takes normally around 100 years per centimeter. Soil analyses show that the formation of humic acids can be demonstrated after 4 months.
2) Raised garden beds (Hugelculture) are a technique from permaculture. Permaculture is a science of agricultural and social systems which uses the principles of ecology and the knowledge of traditional societies to simulate the diversity, stability and the resilience of natural ecosystems. Raised garden beds consist of an interior of ligneous material, covered by a layer of earth. The elevated construction facilitates the work in the garden and the decomposition of wood inside the beds. Due to their spongy structure, the raised garden beds function as a water reservoir during dry periods.
The garden beds are placed perpendicularly to the slope direction as much as possible, and are arranged alternately, with an extension to redirect the surface runoff towards the structures. This arrangement prevents the water from draining directly. This promotes the infiltration of water into the soil, where it is captured by the ligneous material, which prevents erosion (see the photograph).
The following inputs to the garden beds can be found locally:
- Organic matter: ligneous material, dry straw, fresh straw, harvest residues, organic residues rich in NPK (kitchen waste, animal waste, etc.),
- Charcoal powder (biochar),
- Possibly ashes or other fertile materials.
With these materials, which are generally without cost and locally available, a raised garden bed can be set up in less than an hour. Even without additional fertilisation after the set up, the technique offers the possibility to have several cycles of vegetable production. Experiments showed good results during 4 years of continuous plantation in Thozin (Grand Goâve). In order to secure soil fertility for many years, organic matter can be added after the period of plantation. It can be easily incorporated below the first layer of soil, and the decomposition takes place automatically. When put in place on sloping terrain, the garden beds slow down erosion strongly, and can serve to protect houses.
The technique is valued because of its cost-effectiveness and its sustainability compared to known techniques. The complexity of the implementation can be a limiting factor for an autonomous replication by the beneficiaries. That is when they see the set-up of the structures and think they know how to replicate it without taking account of all the details which are essential for the good functioning of the structures. This is why generally a certain level of support by technicians is required.

地点: Municipality of Léogâne, West department, 海地

分析的技术场所数量: 10-100个场所

技术传播: 适用于特定场所/集中在较小区域

在永久保护区？:

实施日期: 不到10年前（最近）

• 通过土地使用者的创新
• 作为传统系统的一部分（> 50 年）
• 在实验/研究期间
• 通过项目/外部干预