By Gerardo Ofelio Aldana
In addition to pressures to adapt to climate change, agricultural production demands include innovative and effective solutions to balance both food production and environmental sustainability (Lehmann and Joseph, 2015). Volatility in agricultural commodities, in parallel with population growth, have initiated an alarming concern as to whether the rates of agricultural production will be able to meet its future food demands. Recent years have shown an improvement in agricultural productivity, but future demands are uncertain, especially in light of environmental factors such as climate change (Sands et al., 2014). The climate problem is now extremely large and is drastically affecting our food production systems. What the future needs is solutions that will counteract a myriad of problems all at once. One such solution is biochar. As a potential means to counteract negative environmental effects and satisfy food demand for an ever-increasing population, it is important to understand the effects of biochar implementation within an agricultural system.
Biochar is the production of carbonaceous material derived from the thermochemical conversion of biomass in an environment limited of oxygen (International Biochar Initiative, 2017), and can be used for a myriad of applications supporting agricultural and environmental sustainability (Hale et al., 2015) as shown in Figure 1. Due to its physiochemical structure, biochar has been used to increase agricultural yield, amend infertile soils, reduce leaching of nutrients, store atmospheric carbon within the soil in order to combat negative anthropogenic climate related activities, absorb metallic pollutants, and mitigate pesticide pollution, among other beneficial aspects (Pereira et al., 2011; Millaet al., 2013; Reid et al., 2013).Though several biochar sources do not easily burn and charcoal is not typically made to address soil fertility issues, nevertheless there is a wide range of biomass that can be used to produce biochar materials of different characteristics, each biochar with its own benefit and impediment. Woody biomass, leaves, crop residues, grass, manure and sludge, amongst other biomasses, can all be converted to biochar via pyrolysis processes.
Figure 1. Benefits of biochar
Agricultural production inadvertently produces large quantities of agricultural waste, which may be a significant burden to environmental management. Agricultural waste disposal techniques such as incineration and landfill disposal are the common methods of waste management; however, these techniques are discouraged since they tend to create more environmental concerns such as leaching and greenhouse gas production(Jariaet al., 2017). Rather than incineration and landfill disposal, recycling and converting agricultural waste into biochar opens new futuristic opportunities leading to a zero waste agricultural production system.The addition of biochar to soils has been practiced for several centuries and observed in different traditional agricultural soil management systems around the world. In Belize, studies have found Mayan dark earth characterised as very fine biochar-rich soil containing relict clasts of resistant-burned sediments such as fishbone, conch shells, reef stone, and crab shells. A most striking discovery that greatly contributed and motivated biochar research was the anthropogenic dark earths or Terra Preta de Indio found in Central Amazonia, Brazil. These soils date back to some 8,000 years, and remain high in nutrient and soil organic matter even today, as seen in Figure 2.
Figure 2. Pictorial view of Latosol (right) and Terra Preta (left) soil horizon (Anderson and McLaughlin 2009).
If the widespread use of biochar is to be implemented, the knowledge of biochar and its impacts particularly within soil and agronomic contexts must be well established. Only if the user is confident of positive and cost effective benefits of biochar, when applied at particular rates, will a biochar market emerge. Work on the definition and stability of biochar is ongoing by established research groups and has been initiated in the UK, USA, Australia, New Zealand, Taiwan, and other countries. Several key factors are to be addressed such as better life cycle assessments of pyrolysis biochar systems, better techno-economic cost modelling, better comparative analyses of biochar versus other resource use options, and assessment of land use implications of biochar deployment.
The most commonly used pyrolysis reactors which have reached or nearly reached commercialization are the French/ Lambiotte reactor (http://www.lambiotte.com/), rotary drums (http://www.ethosenergygroup.com/, http://techtrade.de/), and amongst these are the auger reactors, pyrovac design and paddle reactor. In developing countries, the biochar cook stoves have been widely used for the production of biochar. These biomass cook stoves are less complex, low-pollutant emission units designed for domestic cooking and heating using different biomass feedstock, which produce biochar as a by-product (Lehmann and Joseph, 2015). There is a wide range of designs (over 400 types listed in the HEDON database; http://www.hedon.info/stoves+database) depending on purpose, scale, fuel used, materials of construction, etc. The Toledo Cacao Grower’s Association has produced and utilized biochar for increase in yield of cacao production, while the Maya Mountain Research Farm (http://www.mmrfbz.org/production/cacao), has also been producing biochar using biochar cook stoves (Figure 3).
Figure 3. Biochar cook stove constructed by the Maya Mountain Research Farm in Belize
In a developing country such as Belize, the removal of agrochemical contaminants has been problematic due to the lack of advanced pollution treatment methods; therefore environmental protection agencies seek cost-effective methods for the reduction of pesticide pollution.The application of biochar systems is quite appealing for the reduction of pesticide pollution, since in most developing countries there is a variety of readily available biomaterials such as agricultural and forestry waste for the production of biochar. Mr. Gerardo Ofelio Aldana has been studying the effects of biochar on agricultural soils, reserving key interest upon its effects on heavy metal and pesticide pollution persistency. At present, Mr. Aldana’s doctoral research based at Newcastle University, UK, focuses on the interaction of biochar and its effects upon the leaching persistency of pesticides within agricultural soils of Belize. He aims to understand stakeholder’s perspectives on the implementation of biochar within agricultural systems of Belize, as well as to provide sound scientific evidence as to whether biochar will be feasible for the attenuation of pesticides from agricultural land, thereby resulting in the protection of Belize’s natural and sensitive ecosystems. There is much needed research in order to determine the effects of biochar application upon agricultural yield in agricultural systems of Belize; in order to do this, joint efforts must be established amongst different agricultural stakeholders of Belize.
Editor’s Note: Gerardo Ofelio Aldana comes from the agriculturally active town of San Ignacio, Cayo, Belize. The beautiful rivers, trees and animals found in his hometown have been Gerardo’s utmost inspiration for pursuing a PhD with respect to Agricultural and Environmental Sustainability at Newcastle University, UK. When taking a break from the academic world, Gerardo enjoys singing and playing his guitar while lying in a hammock under a shady tree.