Biochar production and applications in sub-Saharan Africa: Opportunities, constraints, risks and uncertainties. (1st March 2015)

• Record Type: Journal Article
• Authors: Gwenzi, Willis; Chaukura, Nhamo; Mukome, Fungai N.D.; Machado, Stephen; Nyamasoka, Blessing
• Is Part Of: Journal of environmental management. Volume 150(2015:Mar.)
• Page Start: 250
• Page End: 261
• Publication Date: 2015-03-01
• Subjects: Biochar -- Carbon sequestration -- Climate change -- Crop productivity -- Energy provision -- Pyrolysis -- Smallholder agroecosystems -- Zimbabwe; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2014.11.027
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Sub-Saharan Africa (SSA) experiences soil degradation, food and livelihood insecurity, environmental pollution and lack of access to energy. Biochar has gained international research attention, but few studies have investigated the potential of biochar to address the challenges in SSA. This paper seeks to identify and evaluate generic potential opportunities and constraints associated with biochar application in sub-Saharan Africa using Zimbabwe as case study. Specific objectives were to; (1) identify and quantify feedstocks for biochar production; (2) review literature on the biochar properties, and evaluate its potential applications in agriculture, environmental remediation and energy provision, and (3) identify research gaps, risks and constraints associated with biochar technology. Biochar feedstocks in Zimbabwe were estimated to be 9.9 Mton yr −1, predominantly derived from manure (88%) and firewood (10%). This will yield 3.5, 1.7 and 3.1 Mton yr −1 of biochar, bio-oil and synthetic gas, respectively. Land application of the 3.5 Mton yr −1 of biochar (≈63% C) would sequester approximately 2.2 Mton yr −1 of soil carbon in Zimbabwe alone, while simultaneously minimizing the environmental and public health risks, and greenhouse gas emissions associated with solid organic wastes. Biochar potentially enhances soil and crop productivity through enhanced nutrient and soil moisture availability, amelioration of acidic soils and stimulation of microbial diversity and activity. Due to its excellent adsorption properties, biochar has potential applications in industrial and environmental applications including water and wastewater treatment, remediation and revegetation of contaminated soils and water. Biochar products have energy values comparable or higher than those of traditional biomass fuels; thereby making them ideal alternative sources of energy especially for poor households without access to electricity. Before the benefits of biochar can be realized in SSA, there is need to overcome multiple risks and constraints such as lack of finance, socio-economic constraints including negative perceptions and attitudes among both researchers and consumers, and environmental and public health risks. Therefore, there is need to conduct fundamental research to demonstrate the benefits of biochar applications, and develop policy framework and criteria for its production and subsequent adoption. Graphical abstract: Highlights: There is limited biochar research in sub-Saharan Africa including Zimbabwe. 9.9 Mton yr −1 of available feedstocks in Zimbabwe can produce 3.5 Mton yr −1 of biochar. The 3.5 Mton yr −1 (≈63% C) of biochar would sequester 2.2 Mton yr −1 of soil carbon. Biochar applications are; soil amendment, energy, industrial and environmental uses. Biochar is constrained by lack of finance, health risks and limited data in SSA.