Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: See item for full text / AFRIKAANSE OPSOMMING: Sien item vir volteks

<p>   </p> <p>Biochar and charcoal cannot properly be discussed without understanding the diverse technologies available for their production. This is because approximately 70% of wood harvested worldwide is burned for energy and this, in addition to unstainable agricultural activities, has caused a massive increase in deforestation and contributed to climate change. Due to this, current global interventions are focused on promoting sustainable approaches through the expansion of agricultural technologies in countries where the deforestation rate keeps increasing due to overdependency on unsustainable and inefficient conversion technologies. It is therefore obvious that African regions cannot be left out when talking about the impact of global agriculture and charcoal production. Not only is 95% of all household energy used in Africa derived from burning wood in the form of charcoal and firewood, but sub-Saharan Africa regions also contribute 62% to global charcoal production. Since sustainability approaches are of global concern and must be understood from different perspectives and regions, this work analyzed sustainable agriculture and climate mitigation strategies using charcoal and biochar production as indicators. From a sustainability point of view, the study categorized this assessment into three chapters to help understand the preferences of local producers in relation to technologies used and the necessary actions or interventions needed for future improvements.</p> <p><br></p> <p>In the first chapter, 492 charcoal producers from Ghana were interviewed with semi-structured questionnaires to understand the demographics of charcoal producers, species used for charcoal, and how these producers intend to sustain the charcoal industry in terms of acquisition of wood resources/raw materials. This helped to analyze how the demographics of charcoal producers influence the charcoal production industry, characterize some wood species suitable and acceptable for sustainable charcoal production, and to recommend some necessary interventions toward sustainability.</p> <p><br></p> <p>In the second chapter, the heating characteristics of the most common indigenous species and exotic species identified in the first chapter were examined for their charcoal production properties (yield and calorific values) using the most common conversion technology available in the study area (earth mound). The heating/calorific values of these species were also determined using a ballistic bomb calorimeter. This also helped in examining the impact of the common charcoal production technologies on the qualities of charcoal produced and their corresponding impacts on the environment. Additionally, this chapter identified that most charcoal production species have longer rotation times with added values other than being used for charcoal. Furthermore, inappropriate conversion technologies minimize charcoal yield and quality; therefore, developing more efficient and affordable conversion kilns would increase charcoal production efficiency and improve the sustainable production of charcoal.</p> <p><br></p> <p>Based on the recommendation from chapter two, chapter three focused on building transferable skills and knowledge to help smallholder farmers and charcoal producers to fabricate cost-effective retorts/kilns for biochar and charcoal production. Through the process, we reviewed, selected, redesigned, and manufactured three common global conversion technologies and tested their potential for sustainable biochar and charcoal production using wood and crop stubbles (corn husk, corn cob, and sorghum residues). This helped in proposing best techniques and technologies suitable for biochar and charcoal production based on their production and use variables. It was therefore concluded that when farmers gain more knowledge and skills in manufacturing relevant and cheap technologies at their convenience, they could make the right subsequent choices towards sustainable agricultural practices.</p> <p>  </p>