Biochar in small-scale agriculture can improve crop yields with climate benefits due to carbon storage in the soil. This project aims to measure biochar's contribution to climate change mitigation, better food security and farm profitability. We will study the overall environmental effect of biochar using life cycle analyses. Such an approach takes into account all primary and secondary environmental effects of different scenarios. Here it is important to use a systems perspective to assess both direct climate measures, but also emissions and greenhouse gases and toxic compounds during biochar production.
Use of biochar will depend on profitability at farm level. We will therefore evaluate the income from biochar implementation and the effects on product quantity and quality. Value chains must be established around biochar in African agriculture.
The two most important effects of biochar in sub-Saharan Africa are water retention and nutrient retention. Interaction between biochar and the nitrogen cycle will be studied to evaluate nitrogen use efficiency. We will also study the importance of biochar-soil-water-crop interactions for improved tolerance of food systems to drought. We will measure the moisture level in the soil continuously throughout several growing seasons.
We interact with local farming communities in Kenya and South Africa and test biochar in on-farm trials. Three workshops around "ParTriDes", which is Participatory Trial Design, have been conducted in Kenya and South Africa.
In two locations in Kenya (Kwale in the warm coastal region, Embu in the highlands) and one location in South Africa (Okhahlamba), we have chosen the optimal location for the field trials. To choose the right farm, we used a multicriteria decision analysis, where the project team scored the potential farms on 9 criteria. This provided a useful and quantitative basis for choosing the right farm.
ParTriDes workshops were held at all three locations, with 56 (Kwale), 65 (Embu) and 25 (Okhahlamba) participating farmers. Here, the trials were planned in precise collaboration with the farmers so that they are best adapted to the local context. During the workshops, 200-500 kg of biochar was made together with the farmers. The technique followed was the flame curtain kiln, a simple, manual and clean method consisting of a specially designed excavated hole in the ground. With it, 500 to 1000 kg of biochar can be produced per day without the need for expensive equipment or lengthy preparations. The farmers received course material so that they would be able to make biochar for their own farm afterwards. Participation of women during the workshops was good (around 50%).
The main findings from the workshops were that the simple manual technique works well for small-scale farmers in the low-income country of Kenya, but not in the upper-middle-income country of South Africa. In South Africa, there were clear requests from farmers for more advanced pyrolysis units to produce biochar. There was also more animal husbandry in South Africa than in Kenya, so there was great interest in compost-biochar formulations. Our suggestion is to calculate the cost-benefit for various biochar-based value chains in the local South African context in the current project, and use these assessments as a basis for applying for additional funding to set up such more advanced units, e.g. in a call for proposals in Science for Africa (deadline 15 January 2023).
During the field visits, 4 different short movies were made. These were shared with the farmers and posted on WhatsApp groups joined by farmers, YouTube, LinkedIn and NGI's social media channels. The films' themes were choosing the optimal farm, production of biochar, effects of biochar in soil, and inclusion and expectations of the farmers. The project objectives and partners were also presented on LinkedIn and in Whatsapp posts.
The field trials were set up at all three locations in Kenya and South Africa. In the experiments, we examine the effect of 9 different treatments, including different biochar dosages with and without mineral fertilization and animal manure. Continuous field follow-up consists of measuring soil moisture with TDR meters, as well as measuring the nitrogen balance. In addition, the soil in the various trial plots will be sampled before and after the trials, with the intention to gain insight into the effect of biochar on the soil's carbon storage and availability of nutrients.
For Kwale, the first soil sampling confirms that the right location was chosen in terms of soil quality and homogeneity. The first crop results from Kwale indicate that biochar has a modest effect.
The hope is that the project's results can be used to guide authorities on how biochar can be integrated into small-scale agriculture.
Biochar integration in small-holder agriculture is a transformative adaptation of the food production system to achieve climate mitigation, climate resilience and sustainable intensification. This project aim to quantify the contribution of biochar to climate change resilience, improved food security and profitability and to address knowledge gaps regarding biochar use in small-holder agriculture contexts in sub Saharan Africa. We will study the biochar contribution to climate change mitigation using a life-cycle analysis approach. Here, it is important to use a system perspective to assess both direct climate mitigation but also to consider trade-offs. Adoption of biochar will be dependent on profitability at farm level. We will therefore evaluate the cost-benefit of biochar integration and the impacts of produce quantity and quality on food value chains. Interaction between biochar and the nitrogen cycle will be studied to evaluate nitrogen use efficiency and the sustainability of nitrogen supply in the cropping system. We will also study the importance of biochar-soil-water-crop interaction for improved climate and (drought) resilience. We will use a range of state-of-the-art methodology from our respective disciplines. The consortium consist of a trans-disciplinary team of researchers from Sweden, Norway, Kenya and South Africa with a broad competence in system analysis, agronomy, soil science, agricultural economy, food technology and microbiology. We will interact with local farming communities in Kenya and South Africa and test biochar integration in on-farm trials but also utilize data from our on-going research in other countries. Our results can be utilized to guide policy development on how biochar can be integrated in small-holder farming systems, and how bottlenecks that prevents the integration can be identified and addressed. Increased use of biochar can contribute to Agenda2030, SDG1: No Poverty, SDG 2: Zero Hunger and SDG13: Climate Action.