community based energy solution to climate change mitigation and improved food security
The adoption of a simple household pyrolytic stove has been shown to potentially provide multiple benefits from reducing the rate of deforestation, improved soil fertility, enhanced household air qual
Improving soil fertility through Biomass fuel efficiency and promoting adaptation to Climate Change
Agricultural practices that improve land use and management, through increasing and maintaining soil carbon stocks can, if properly implemented, generate multiple benefits: climate change mitigation, increased agricultural and food production, pro-poor income generation, environmental services and improved resilience/adaptive capacity of farming systems. Alexander Mueller Assistant Director-General, Food and Agriculture Organization of the United Nations (FAO)
Arresting land degradation through improved Biomass Energy use
Biomass energy (fuel wood or charcoal) plays a central role in the lives of rural communities. Fuel wood can account for up to 90% of energy source in the rural areas, covering between 50-95% of the total energy needs at household level.
In Kenya it is estimated that 5,000 ha of closed indigenous forests are lost each year due to the demand for fuel wood and charcoal leading to serious deforestation and land degradation. Forested lands are also under threat from competing land use and especially from agriculture1.
While enhancing wood supply and emphasizing improved energy technologies are considered effective strategic solutions to correcting the imbalance between fuel wood supply and demand, the question of agricultural productivity and deteriorating nutrient conditions requires broad based solutions.
Our approach is to promote the integration of energy solutions and improved agricultural practices to small scale farmers in rural areas through a concept that integrates improved biomass use for energy and using the by products to increase the soil organic carbon thus enhancing soil fertility. By introducing pyrolytic stoves, households use less biomass for their energy needs. The stove uses any type of biomass material to produce the heat for cooking and the by product is charcoal. This first step already reduces the demand for trees as a source of fuel. The second phase involves training local farmers to integrate the crashed char into the soil. Increased soil organic carbon leads to a chain of processes that improves soil fertility thus in turn increasing food security, reduction in the loss of biodiversity by improving biomass fuel efficiency, improved household air quality and involves local communities in combating the impacts of climate change.
Producing Biomass Energy and Converting Biomass to a Soil Amendment
Soils in Africa are poor in Organic Carbon. Recent studies show that soils in Africa have approximately 166 397Tg C. This is about 9% of the global Soil Organic Carbon stock. The clearing of forests or woodlands and their conversion into farmland in the tropics reduces soil-carbon content, mainly through reduced production of detritus, increased erosion rates and decomposition of soil organic matter by oxidation. Various reviews agree that the loss amounts to 20 to 50% of the original carbon in the topsoil 2. The most common form of agriculture in the tropics is shifting cultivation using slash-and-burn techniques. The problem in these techniques is that they only increase the nutrient concentration and soil fertility for a short period. After this the tropical conditions cause a rapid mineralization of the soil organic matter. This sort of cultivation causes erosion and deforestation in many tropical countries. Soil Organic Carbon can be increased by using an old technology that was used in the Amazons centuries ago.
The Amazonians practised the slash-and-char technique already in pre-Columbian times to create their fertile Terra Preta (black earth) soil. Instead of burning they charred biomass and added the charcoal to the soil. These soils have maintained their fertility and researchers have been very interested to finding out how. Recent studies have proved that charcoal is responsible for the high organic matter contents and good fertility of these soils.
This old Indian technology is the blue-print of this project. Through the process of pyrolisis, it is possible to produce biochar (terra preta) which can then be applied to the soils. Adding charcoal to soil can significantly increase seed germination, plant growth and crop yields. Biomass production of different plants can be increased by 13–300 %. Charcoal affects soils in several ways. Coal ash and charcoal can increase the pH and decrease the aluminum saturation of acid soils, which are one of the main problems in weathered soils of the humid tropics. Charcoal increases the soil organic matter (SOM) content and thus the cation exchange capacity (CEC). CEC is important for the efficiency of applied mineral fertilizers. Unlike ash, charcoal improves the nutrient retention of the soil. It also improves water retention of coarse-textured soils, which enhances the water availability to crops and decreases erosion3.
Biomass gasification stove (anila)
The anila stove is a simple technology for converting biomass to char at household level. The stove consists of two metal barrels which can be filled with biomass and wood. For longer cooking periods, the outer barrel should contain an adequate amount of biomass to increase the time of pyrolisis.
The next step:
- Product development to make it accessible to rural communities at low-prices and acccommodate various needs.
- Scientific validation of the impact and optimum levels of adding charcoal into different soils in the project areas.
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