THURSDAY, JAN 26, 2023: NOTE TO FILE
Module 3-18
Vetiver and biochar
Vetiver grass, Chrysopogon zizanioides, is a unique grass with a long hairy root that anchors the soil and is planted on swales to mitigate soil erosion. Vetiver grass is not an invasive plant and is found in the tropics and subtropical areas, although it also grows fairly well in the temperate zones. Its roots can yield a valued oil. It can be used to create very basic latrines (Vetiver Latrines). The Vetiver System is used extensively for erosion control by the Vetiver Network International.
Vetiver grass has a wide range of applications, namely;
- Soil and water conservation (on-farm and off-farm)
- The stabilisation of soil related infrastructure, and the containment of sediment from such structures
- Rehabilitation of wasted and ecologically damaged sites and the containment of such sites against future disasters
- Water-pollution and waste management
In addition, Vetiver grass leaves and roots can be used:
- As a source of feed for livestock and wildlife
- For pest control (intercropping, bio-pesticide)
- For handicraft (baskets, hats)
- In building construction (bricks, roofing)
- For water purification and medicinal purposes
- As an ingredient for cosmetics
Some special attributes of Vetiver grass include:
- A deep, penetrating and extensive root system that binds the soil, and reinforces the structure.
- Erect and stiff stems and leaves forming a dense hedge that is very effective in reducing the erosive power of strong water flows
- Vetiver is tolerant to a wide range of climatic conditions, temperature ranges from –minus 14 degrees Centigrade to 55 degrees Centigrade.
- Vetiver is tolerant to drought, saline, sodic and acidic soil conditions.
- Vetiver survives under prolonged and complete submergence and it resumes growth after the water recedes.
- Vetiver regenerates quickly after a fire
View the short video below (7:40mins) on how the Vertiver System can be used to stop erosion in high rainfall tropical location whilst the collage illustrates some of these points. It also stresses the beneficial effects it has on soil quality and the improvement of water quality. It is an exceptional plant for the use of bio-mitigation and bio-remediation and will play an important role in large scale ecosystems restoration as we will see more and more large scale restoration projects during the coming decades.
https://www.vetivergrassuk.com/
Floating raft for waste water treatment
Collage of Vetiver Grass System
4.10. Biochar
Figure 4.10: The benefits of Biochar, (source) |
One of the techniques that scores highest for its greenhouse gas abatement rate is the application of biochar (World Bank, 2012). Biochar can be obtained on farms from the carbonization of biomass through pyrolysis or gasification. The International Biochar Initiative maintains that – applied correctly – “the carbon in biochar resists degradation and can hold carbon in soils for hundreds to thousands of years”. It needs to be applied in combination with organic nutrients (e.g. liquid compost) to have a positive effect on yields. “Biochar and bio-energy co-production can help combat global climate change by displacing fossil fuel used and by sequestering carbon in stable carbon pools” (Biochar International, 2015). There is increasing evidence that indigenous cultures of Amazonia, Asia and possibly even Europe practice the burial of organically activated biochar (see Terra Preta).
Module 3, lesson 19
