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Adopting the concept of the waste to wealth approach, agricultural waste from maize cob could be transformed into a renewable form of energy through thermo-chemical methods of treating the biomass. This method can be utilised for biochar production. The utilisation of biochar has several significant applications. These applications include the enhancement of the soil through amendment, stimulation of crop production by a variety nutrient inputs in the soil, etc. In this research work, a biochar was obtained through a slow pyrolysis process of maize cob waste. This experiment was carried out using a small-scale muffle furnace and subjecting the feedstock to heating at different temperatures (300, 400, 500 °C). The biochar was produced and characterised by a proximate analysis, scan electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, while the surface area was determined by Saer's method. The effect of the temperature on the yield of the biochar was investigated. The results show that the biochar yield decreases with an increasing temperature for the maize cob biochar at 300, 400 and 500 °C. The results of the physiochemical properties showed that the temperature has a great impact on the physicochemical properties of the biochar. The biochar produced at 300 °C has the highest fixed carbon content of 60.5%. The largest surface area was (281.8 m2·g-1) at 500 °C. [ABSTRACT FROM AUTHOR]

Enhancement of soil fertility and mitigation of atmospheric greenhouse gases are potential benefits of biochar amendments with proximate links to microbiological processes, yet the impact of biochar on the soil microbial community is poorly resolved. Here, we assessed changes in bacterial community composition and microbial assemblage patterns with biochar amendment in two soils with contrasting fertility under two cropping systems; perennial grass and annual sweet corn rotation at two time periods. Overall, soil type exerted the greatest effect on the soil microbial community, followed by sampling time and cropping system which exerted a greater effect on the microbial community than biochar treatment. The influence of biochar on community composition was most pronounced in the highly weathered, low fertility Oxisol, than the high fertility Mollisol. We further investigated microbial assemblage architecture using random-matrix theory based molecular ecological network analyses. Microbial assemblage complexity increased with biochar amendment, with the largest impact associated with the Oxisol, accompanied by more negative OTU co-variations, indicating enhanced competition and/or niche partitioning in concert with an increase in the number of putative “keystone species”. Network analysis suggests that biochar addition, especially in the highly weathered, low fertility Oxisol, confers higher-level organization, competition, and complexity to the soil microbiome that may result in higher resistance to change due to environmental perturbation and thereby increase system sustainability. [ABSTRACT FROM AUTHOR]

Abstract: A life‐cycle assessment (LCA) of a low‐input, short rotation coppice (SRC) willow grown on different Danish lands was performed. Woodchips are gasified, producer gas is used for cogeneration of heat and power (CHP), and the ash–char output is applied as soil amendment in the field. A hybrid model was developed for the estimation of greenhouse gas (GHG) emissions from indirect land‐use changes (iLUC) induced by willow cropping on arable land (iLUCfood). For this, area expansion results from a general equilibrium economic model were combined with global LUC trends to differentiate between land transformation (as additional agricultural expansion, in areas with historical deforestation) and occupation (as delayed relaxation, DR, in areas with historical land abandonment) impacts. A biophysical approach was followed to determine the iLUCfeed emissions factor from marginal grassland. Land transformation impacts were derived from latest world deforestation statistics, while a commercial feed mix of equivalent nutritive value was assumed to substitute the displaced grass as fodder. Intensification effects were included in both iLUC factors as additional N‐fertilizer consumption. Finally, DR impacts were considered for abandoned farmland, as a relative C stock loss compared to natural regeneration. ILUC results show that area related GHG emissions are dominant (93% of iLUCfood and 80% of iLUCfeed), transformation being more important (82% of iLUCfood) than occupation (11%) impacts. LCA results show that CHP from willow emits 4047 kg CO2‐eq ha occup − 1 (or 0.8 gCO2‐eq MJ−1) when grown on arable land, while sequestering 43 745 kg CO2‐eq ha occup − 1 (or −10.4 gCO2‐eq MJ−1) when planted on marginal pastureland, and 134 296 kg CO2‐eq ha occup − 1 (or −31.8 gCO2‐eq MJ−1) when marginal abandoned land is cultivated. Increasing the bioenergy potential without undesirable iLUC effects, especially relevant regarding biodiversity impacts, requires that part of the marginally used extensive grasslands are released from their current use or energy cropping on abandoned farmland incentivized. [ABSTRACT FROM AUTHOR]

• Economic evaluation of the residual hemp biomass for energy or biochar production. • The hemp variety 'Fedora and CS' were selected as the best for multipurpose production. • The highest surface area revealed biochar prepared by slow pyrolysis at 700 °C. • The use of residual hemp biomass improves farmer economy of hemp growing. The aim of the article is to present the results regarding a comprehensive evaluation of the efficiency of Cannabis cultivation with an emphasis on the economic evaluation of the use of residual biomass either for direct energy use or for biochar production. The results of field experiments conducted in the Czech Republic showed great variability and adaptability of six tested varieties, out of which 'Fedora' and 'CS' were selected for further evaluation for energy and biochar production due to favourable yields of stem biomass (5.5 – 8.5 t DM/ha). Biochar produced from hemp biomass revealed texture properties which corresponded to quality commercial sorbents and met the limits related to the use in a variety of applications, e.g. soil amendment or water treatment. The economic analysis showed the advantage of residual biomass exploitation for the production of biochar, resp. for energy use as a by–product of the primary production of bioactive substances from Cannabis plants. The cost of obtaining 1 GJ of heat in the fuel is between 4.1 and 5 EUR, while another economic effect relates to the income from the sale of flowers for the extraction of bioactive substances. Concerning the conditions of the Czech Republic, the cost of biochar production from hemp biomass ranges, assuming the pyrolysis technology with the capacity 250 kg of raw biomass per hour, from 452 to 667 EUR/t (without excess heat utilization), and from 381 to 596 EUR/t (with excess heat utilization). [ABSTRACT FROM AUTHOR]

Miscanthus × giganteus Greef & Deu (giant miscanthus) is a perennial C4 grass grown worldwide for bioenergy production; however, there is concern about whether it can produce high yields on marginal soils in a temperate climate. The goals of this study were to determine whether giant miscanthus could establish and produce yields in Western North Carolina comparable to those in other regions and to determine whether fertilization and biochar could improve yields. At two field sites, Mills River (650 m) and Valle Crucis (830 m), fertilizer (0 and 100 kg NPK ha−1) and biochar (0 and 15 t ha−1) treatments were employed in a fully randomized block design. Genetically identical rhizomes were planted in spring of 2012 and allowed to grow for two growing seasons. No treatment effects were found for gas exchange, but rates were higher at Mills River than at Valle Crucis. There were no biochar or fertilizer effects on yields. First-year yields were greater at Mills River than at Valle Crucis (2.93 and 1.77 Mg dry weight [DW] ha−1, respectively). Overwinter survival rates were 100% at both field sites. Second-year yields were approximately 10× greater than in the first year (27.68 Mg DW ha−1 at Mills River vs. 30.12 Mg DW ha−1 at Valle Crucis). The high survival and growth rates during the first 2 yr demonstrate that this bioenergy crop is capable of growing in Western North Carolina and producing yields comparable to those in other areas of the country where this crop has been grown. [ABSTRACT FROM AUTHOR]

Energy access and waste management are two of the most pressing developmental and environmental issues on a global level to help mitigate the accelerating impacts of climate change. They are particularly relevant in Sub–Saharan Africa where electrification rates are significantly below global averages and rural areas are lacking a formal waste management sector. This paper explores the potential of integrating solar energy into a biomass pyrolysis unit as a potentially synergetic solution to both issues. The full design of a slow pyrolysis batch reactor targeted at biochar production, following a strict cost minimization approach, is presented in light of the relevant considerations. SPEAR is powered using a Cassegrain optics parabolic dish system, integrated into the reactor via a manual tracking system and optically optimized with a Monte-Carlo ray tracing methodology. The design approach employed has led to the development an overall cost efficient system, with the potential to achieve optical efficiencies up 72% under a 1.5° tracking error. The outputs of the system are biochar and electricity, to be used for soil amendment and energy access purposes, respectively. There is potential to pyrolyze a number of agricultural waste streams for the region, producing at least 5 kg of biochar per unit per day depending on the feedstock employed. Financial assessment of SPEAR yields a positive Net Present Value (NPV) in nearly all scenarios evaluated and a reasonable competitiveness with small scale solar for electrification objectives. Finally, SPEAR presents important positive social and environmental externalities and should be feasibly implementable in the region in the near term. [ABSTRACT FROM AUTHOR]