1.2 Detalhes do contato das pessoas capacitadas e instituições envolvidas na avaliação e documentação da tecnologia

Nome da(s) instituição(ões) que facilitou(ram) a documentação/ avaliação da Tecnologia (se relevante)

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH (GIZ) - Alemanha

1.3 Condições em relação ao uso da informação documentada através de WOCAT

O/a compilador/a e a(s) pessoa(s) capacitada(s) aceitam as condições relativas ao uso de dados documentados através da WOCAT:

Sim

1.4 Declaração de sustentabilidade da tecnologia descrita

A tecnologia descrita aqui é problemática em relação a degradação da terra de forma que não pode ser declarada uma tecnologia de gestão sustentável de terra?

Não

2.1 Descrição curta da tecnologia

Definição da tecnologia:

Application of biochar to soils in the tropics / sub-tropics improves their ability to store and supply nutrients and water for crop growth, thereby enhancing yields and food security. At the same time, biochar holds carbon in soils for extended time periods, which makes it an agricultural practice that contributes to climate change mitigation.

2.2 Descrição detalhada da tecnologia

Descrição:

Biochar is carbonised organic material that is produced through pyrolysis, that is thermal conversion under low or no oxygen. The biochar is used as an amendment to farmland for ameliorating soil properties. Owing to the great number of micropores and charges on biochar, its application to soil boosts water and nutrient storage, and their delivery to crops. Biochar also helps neutralise acidity in soils, replacing the need for lime. All these positive effects make it ideally suited for acid, nutrient-poor soils in tropical/ sub-tropical regions. Even at low rates of 1 or 2 tonnes per hectare, biochar significantly increases crop production. Biochar hardly decomposes in soils, causing positive effects to last for several years without repeat application. This also provides very stable carbon storage on farms which helps mitigate climate change. Its stability also allows farmers to gradually add biochar to the entire farm, thereby increasing their food self-sufficiency and incomes.
Biochar itself is not a fertilizer, but a soil rejuvenating agent. Therefore, farmers must apply essential nutrients through synthetic or organic inputs to reap the full yield potential and maintain soil fertility. Yet, when biochar is combined with fertilizers, about 40% - 70% nitrogen and phosphorus can be saved over multiple seasons while maintaining the same productivity. Biochar is a promising solution to address low response of crops to fertilizer addition in tropical soils and to alleviate the impact of input price hikes and supply disruptions.
In the study presented here, farmers produced biochar as a residue from small gasifier stoves during daily cooking. These systems are highly energy efficient and reduce the consumption of firewood while improving indoor air quality, which, alongside crop yield gains from biochar, is perceived positively by farmers. The specific design of gasifier stoves requires them to be well-packed with appropriately sized tree prunings or maize stems. For larger meals it requires a refill, which users find less convenient than their traditional open combustion fires. Life-cycle assessment shows that households significantly reduce greenhouse gas emissions with the gasifier stoves when biochar is applied to the farm. For the field trials with maize and kale in this study, farmers applied their usual rates of inorganic fertilizers, animal manure, or a combination of both. Results from this multi-locational participatory assessment showed that maize grain yield increased by 0.2 - 0.7 tonnes per hectare for every tonne of home-made biochar that was added to the field.
One household can produce 300 kg biochar per year by cooking on the gasifier stove. With this amount a biochar dosage of 1.5 t/ha can be realized on an area of 0.2 ha per year. If biochar is not spread evenly, but along seed rows, its effective dosage can be increased. As the gasifier stove can be operated for 2-3 years, it is assumed that the costs of 50 USD, which are needed to purchase one gasifier, are good to equip 1 ha of land with an amount of biochar that results in increased crop yields.

2.3 Fotos da tecnologia

2.5 País/região/locais onde a tecnologia foi aplicada e que estão cobertos nesta avaliação

2.6 Data da implementação

Indique o ano de implementação:

2016

2.7 Introdução da tecnologia

Especifique como a tecnologia foi introduzida:

• durante experiências/ pesquisa

Comentários (tipos de projeto, etc.):

IITA (International Institute of Tropical Agriculture) started a long-term field trial in 2006, in which crop and soil properties were monitored following one initial biochar application of 100 t/ha. ICRAF investigated the charcoal value chain in Kenya and, among others, promoted cooking stoves which were more efficient than the traditionally used open fires. Those stoves run on pyrolysis, which provides heat for cooking and charcoal as a residual. That charcoal can be used for cooking so that the initial biomass is used more efficiently as an energy source. Or, alternatively, the residual charcoal is used as biochar to improve the farmers' soils.
This combination of cooking and biochar production and application to soils began in 2016 as participatory research.

3.1 Principal/principais finalidade(s) da tecnologia

• Melhora a produção
• Adaptar a mudanças climáticas/extremos e seus impactos
• Atenuar a mudanças climáticas e seus impactos
• Criar impacto econômico benéfico
• Cria impacto social benéfico

3.2 Tipo(s) atualizado(s) de uso da terra onde a tecnologia foi aplicada

Uso do solo misturado dentro da mesma unidade de terra:

Não

3.3 O uso do solo mudou devido à implementação da Tecnologia?

O uso do solo mudou devido à implementação da Tecnologia?

• Não (Continuar com a pergunta 3.4)

3.4 Abastecimento de água

Abastecimento de água para a terra na qual a tecnologia é aplicada:

• Precipitação natural

3.5 Grupo de GST ao qual pertence a tecnologia

• Gestão integrada de fertilidade do solo

3.6 Medidas de GST contendo a tecnologia

3.7 Principais tipos de degradação da terra abordados pela tecnologia

Comentários:

Biochar increases the cation exchange capacity of soils and enhances the plant availability of phosphorus so that it contributes to soil fertility. Biochar increases the soil pH so that it treats acidification of soils. In the field of soil physical properties, biochar decreases the bulk density of soils and adds pore space to soils so that the infiltration into the soil and the usable field capacity of soils are increased. In this specific case, soil sealing and compaction do not play a role, but biochar can address those soil degradation issues.

3.8 Redução, prevenção ou recuperação da degradação do solo

Especifique o objetivo da tecnologia em relação a degradação da terra:

• Reduzir a degradação do solo
• Recuperar/reabilitar solo severamente degradado

4.2 Informação geral em relação ao cálculo de entradas e custos

Especifique como custos e entradas foram calculados:

• Por unidade de tecnologia

Especifique a moeda utilizada para os cálculos de custo:

• USD

4.3 Atividades de implantação

	Atividade	Periodicidade (estação do ano)
1.	Biochar production	Year-round while using the gasifier cooking stove.
2.	Mixing biochar into the soil	During the normal time of field preparation for and planting of the next crop
3.	Proceed with normal cropping activities

Comentários:

This SLM technique adds biochar to the ongoing cropping activities. So, the choice of crops, soil preparation, planting, inputs, and harvest do not change after biochar application. The biochar is sourced from so-called gasifier cooking stoves, which are stoves that perform through pyrolysis. The excess energy of that pyrolysis is used for cooking, while the residual char is applied as biochar to the farmers' field. Char (biochar) is produced during every cooking activity, collected, and finally applied. Most household in the project regions use open three-stone fires for cooking followed by charcoal. Adoption of the gasifier stoves is a shift away from the open fires and charcoal.

4.4 Custos e entradas necessárias para a implantação

	Especifique a entrada	Unidade	Quantidade	Custos por unidade	Custos totais por entrada	% dos custos arcados pelos usuários da terra
Mão-de-obra	gasifier cooking stove		1,0	50,0	50,0
Custos totais para a implantação da tecnologia					50,0
Custos totais para o estabelecimento da Tecnologia em USD					50,0

Comentários:

As costs we only listed the 50 USD per gasifier cooking stove. As the other farm operations do not change, no further costs for plant materials or fertilizers or other were listed, because those inputs do not change solely due to the use of biochar from the gasifier stoves.
One household can produce 300 kg biochar per year by cooking on the gasifier stove. With this amount a biochar dosage of 1.5 t/ha can be realized on an area of 0.2 ha per year. If biochar is not spread evenly, but along seed rows, its effective dosage can be increased. As the gasifier stove can be operated for 2-3 years, it is assumed that the costs of 50 USD are good to equip 1 ha of land with an amount of biochar that results in increased crop yields.

4.5 Atividades recorrentes/manutenção

	Atividade	Periodicidade/frequência
1.	Replace the gasifier cooking stove	every three years

Comentários:

Once biochar has been applied into a given soil, it sits there in the soil and does not require further maintenance. The farming activities and their associated labor remain unchanged compared to the the time before biochar application.

4.6 Custos e entradas necessárias pata a manutenção/atividades recorrentes (por ano)

	Especifique a entrada	Unidade	Quantidade	Custos por unidade	Custos totais por entrada	% dos custos arcados pelos usuários da terra
Equipamento	gasifier cooking stove	1	0,33	50,0	16,5	100,0
Custos totais para a manutenção da tecnologia					16,5
Custos totais de manutenção da Tecnologia em USD					16,5

Comentários:

The depreciation of the gasifier cooking stove and the need to replace it every three years is included here unde rrecurrent costs.

4.7 Fatores mais importantes que afetam os custos

Descreva os fatores mais determinantes que afetam os custos:

Purchase price of the gasifier stove. Opportunity cost for collection and pre-processing of tree prunings and crop residues for the stove.

5.1 Clima

5.2 Topografia

Indique se a tecnologia é aplicada especificamente em:

• Não relevante

Comentários e outras especificações sobre a topografia:

Kwale: 328 m a.s.l.
Embu: 1350 m a.s.l.

5.3 Solos

Caso disponível anexe a descrição completa do solo ou especifique as informações disponíveis, p. ex. tipo de solo, PH/acidez do solo, nitrogênio, capacidade de troca catiônica, salinidade, etc.

The following information are available for two field plots out of the three counties:
Embu County: pH(H2O) - 5.01, SOC - 2.01%, sand - 21%, clay - 43.5%
Siaya County: pH(H2O) - 5.25, SOC - 1.56%, sand - 22.4%, clay - 60.1%

5.4 Disponibilidade e qualidade de água

5.6 Características dos usuários da terra que utilizam a tecnologia

Indique outras características relevantes dos usuários da terra:

Women and children operate the gasifier stove and therefore produce the biochar. In the field it is mainly men who mix the biochar into the soil and perform other farm operations.

5.7 Área média de terrenos utilizados pelos usuários de terrenos que aplicam a Tecnologia

5.8 Propriedade de terra, direitos de uso da terra e de uso da água

Propriedade da terra:

• Indivíduo, não intitulado
• Indivíduo, intitulado

Direitos do uso da terra:

• Indivíduo

Direitos do uso da água:

• Acesso livre (não organizado)

Os direitos de uso da terra são baseados em um sistema jurídico tradicional?

Sim

5.9 Acesso a serviços e infraestrutura

6.1 Impactos no local mostrados pela tecnologia

Impactos socioeconômicos

Produção

Renda e custos

Impactos ecológicos

Clima e redução de riscos de desastre

6.2 Impactos externos mostrados pela tecnologia

6.4 Análise do custo-benefício

Como os benefícios se comparam aos custos de implantação (do ponto de vista dos usuários da terra)?

Como os benefícios se comparam aos custos recorrentes/de manutenção(do ponto de vista dos usuários da terra)?

Comentários:

The main benefits from this SLM technology from the land users' perspective are increased crop yields, reduced need to collect fuel wood, and improved indoor ambient air quality. The latter two benefits materialize immediately, onec the gasifier is used. The crop yields increase during the season that follows the biochar application, which is a short-term benefit. These benefits justify the establishment costs, which in fact are the costs to purchase the gasifier.
On a long-term perspective, the effect to improve the soil, which leads to crop yield increases, remains, because biochar is stable in soils ove rlong time periods. Particularly positive is that there are no maintenence costs to keep the biochar in the soil.

6.5 Adoção da tecnologia

• casos isolados/experimental

De todos aqueles que adotaram a Tecnologia, quantos o fizeram espontaneamente, ou seja, sem receber nenhum incentivo/ pagamento material?

• 0-10%

6.6 Adaptação

A tecnologia foi recentemente modificada para adaptar-se as condições variáveis?

Não

6.7 Pontos fortes/vantagens/oportunidades da tecnologia

Pontos fortes/vantagens/oportunidades na visão do usuário da terra
Most land users stated to have observed positive impacts on soil health and improvement of soil fertility. Additionally, about 25% of the land users specifically mentioned that the moisture retention in the soil improved after biochar application. Some land users experienced lower costs for fertilizers.
Most land users found the small top-lit updraft cooking stoves are easy to use, though being more suitable for food with short cooking time. All land users stated that the gasifier cooking stoves were cleaner than the traditional open fires and charcoal stoves, since the gasifiers produced less smoke, less soot, and fewer ashes. Some land users responded even that the gasifiers were less harmful to cooking utensils and food tasted better (less smoky). The gasifier stove was preferred by land users because it takes less fuel and therefore saves time to collect fire wood and household expenditures. This was particularly viewed positively by women. The residual char also can be used as an energy source. Some land users saw sales of charcoal as potential additional income.
In total, the package of using gasifier stoves for cooking and applying the residual biochar to soils was seen as beneficial by most land users, because it saved costs and efforts on the side of cooking and increased crop yields and income.

Pontos fortes/vantagens/oportunidades na visão do/a compilador/a ou de outra pessoa capacitada

Biochar improves soil properties which intensifies crop production. Even a small amount of biochar added to the soil has a long-lasting positive effect on yields. The effect of a one-time biochar application lasts for decades. Therefore, if soils are enriched with biochar by repeatedly adding low quantities, its benefits to land users accumulate over time. Biochar increases the cation exchange capacity, pH, and phosphorus availability of soils, which are key constraints to in many farming systems across tropical Africa. Non-responsive soils are turned into soils that respond to fertilizer application.

6.8 Pontos fracos, desvantagens/riscos da tecnologia e formas de superá-los

Pontos fracos/desvantagens/riscos na visão do usuário da terra	Como eles podem ser superados?
Half of the respondents stated the production of biochar was time consuming due to the process of cutting the feedstock in suitable sizes, as needed for the gasifier stove.	Chopped firewood for the gasifier could become a source of income for youth.

Pontos fracos/vantagens/riscos na visão do/a compilador/a ou de outra pessoa capacitada	Como eles podem ser superados?
Gasifiers may emit more methane than technologically more advanced pyrolysis units.	Improve the gasifier utility with a shift to the latest mobile or decentralized technologies that produce syngas, green hydrogen or electricity that can be used for cooking.
Deploying gasifier and biochar at large scale without regulations poses a risk of unsustainable rates of tree clearing and residue removal.	Follow rules such as EBC and only use on-farm or residual biomass.

7.1 Métodos/fontes de informação

7.2 Referências às publicações disponíveis

Título, autor, ano, ISBN:

Biochar from cooking stoves reduces greenhouse gas emissions from smallholder farms in Africa; Sundberg et al., 2020

Disponível de onde? Custos?

https://link.springer.com/article/10.1007/s11027-020-09920-7, open access

Título, autor, ano, ISBN:

Use of Biochar-Producing Gasifier Cookstove Improves Energy Use Efficiency and Indoor Air Quality in Rural Households; Gitau et al., 2019

Disponível de onde? Custos?

https://www.mdpi.com/1996-1073/12/22/4285, open access

Título, autor, ano, ISBN:

Implications on Livelihoods and the Environment of Uptake of Gasifier Cook Stoves among Kenya’s Rural Households; Gitau et al., 2019

Disponível de onde? Custos?

https://www.mdpi.com/2076-3417/9/6/1205/pdf, open access

Título, autor, ano, ISBN:

Factors influencing the adoption of biochar-producing gasifier cookstoves by households in rural Kenya; Gitau et al., 2019

Disponível de onde? Custos?

https://www.sciencedirect.com/science/article/pii/S0973082618308913, open access

Título, autor, ano, ISBN:

Soils, sinks, and smallholder farmers: Examining the benefits of biochar energy transitions in Kenya; Mahmood et al., 2021

Disponível de onde? Custos?

https://reader.elsevier.com/reader/sd/pii/S2214629621001262?token=D446F30FC8FDAEC80F73AE31BBFEA69E754E2F9EB21A9605CC6D04A2FE0FCD39182848F88AC6D17BF7D12B8EEED7BD9E&originRegion=eu-west-1&originCreation=20210415190025, open access

Título, autor, ano, ISBN:

Gasifier as a cleaner cooking system in rural Kenya; Njenga et al., 2016

Disponível de onde? Custos?

https://www.sciencedirect.com/science/article/abs/pii/S0959652616000743?via%3Dihub, access at no costs through limited number of institutions

Título, autor, ano, ISBN:

Biochar addition persistently increased soil fertility and yields in maizesoybean rotations over 10 years in sub-humid regions of Kenya; Kätterer et al., 2019

Disponível de onde? Custos?

https://www.sciencedirect.com/science/article/pii/S0378429018318938?via%3Dihub, open access

Título, autor, ano, ISBN:

sMaize grain yield responses to realistic biochar application rates on smallholder farms in Kenya, Kätterer et al., 2022

Disponível de onde? Custos?

https://link.springer.com/article/10.1007/s13593-022-00793-5, open access

7.3 Links para informações on-line relevantes

Título/ descrição:

Biochar stoves for socio-ecological resilience: Lessons from small-scale farms in rural Kenya / Report by ICRAF

URL:

http://apps.worldagroforestry.org/downloads/Publications/PDFS/PB20040.pdf