Properties of biochar derived from wood and high-nutrient biomasses with the aim of agronomic and environmental benefits

Abstract

Biochar production and use are part of the modern agenda to recycle wastes, and to retain nutrients, pollutants, and heavy metals in the soil and to offset some greenhouse gas emissions. Biochars from wood (eucalyptus sawdust, pine bark), sugarcane bagasse, and substances rich in nutrients (coffee husk, chicken manure) produced at 350, 450 and 750°C were characterized to identify agronomic and environmental benefits, which may enhance soil quality. Biochars derived from wood and sugarcane have greater potential for improving C storage in tropical soils due to a higher aromatic character, high C concentration, low H/C ratio, and FTIR spectra features as compared to nutrient-rich biochars. The high ash content associated with alkaline chemical species such as KHCO3 and CaCO3, verified by XRD analysis, made chicken manure and coffee husk biochars potential liming agents for remediating acidic soils. High Ca and K contents in chicken manure and coffee husk biomass can significantly replace conventional sources of K (mostly imported in Brazil) and Ca, suggesting a high agronomic value for these biochars. High-ash biochars, such as chicken manure and coffee husk, produced at low-temperatures (350 and 450°C) exhibited high CEC values, which can be considered as a potential applicable material to increase nutrient retention in soil. Therefore, the agronomic value of the biochars in this study is predominantly regulated by the nutrient richness of the biomass, but an increase in pyrolysis temperature to 750°C can strongly decrease the adsorptive capacities of chicken manure and coffee husk biochars. A diagram of the agronomic potential and environmental benefits is presented, along with some guidelines to relate biochar properties with potential agronomic and environmental uses. Based on biochar properties, research needs are identified and directions for future trials are delineated.

Charcoal anatomy and NIR spectra of Spirostachys africana, Terminalia sp. and Colophospermum mopane in different carbonization process

“…6) material in P3 (450 °C-4 h) resulted in different behavior, also samples from S. africana at P1 (400 °C-40 min). This is in accordance with the chemical reactions [35] that occur during carbonization that can change or increase the organic compounds [36].…”

“…McBeath et al [35] described a clear relationship between production temperature, aromaticity and aromatic condensation in biochar in function of progressive dehydration, decarbonylation and decarboxylation reactions. During pyrolysis, temperature can change the chemical nature and increase the aromatic character of organic composites [36]. Ruptures in charcoal can be the result of regions with concentration of tension related to the high impermeability of heartwood [6].…”

Designer Biochars Impact on Corn Grain Yields, Biomass Production, and Fertility Properties of a Highly-Weathered Ultisol

“…Biochar is used as an amendment in agricultural soils to improve their physical characteristics [1][2][3][4] and to bolster important fertility properties [5][6][7][8]. Biochars' ability to improve soil fertility is explained by the composition of organic compounds, which rebuilds soil organic carbon (SOC) levels [9][10][11] and ash material, which are comprised of important plant macro-and micro-nutrients [12][13][14].…”

Preliminary assessment on the application of biochar and spectral‐induced polarization for wastewater treatment

“…(Domingues et al . () studied the electrical conductivities of biochars from various feedstocks and concluded that the concentration of soluble minerals in the initial biomass was the determining factor of EC of biochars. These minerals become an inherent part of the biochar surface groups, that is the charged chemical substances connected to the biochars surface, and play an important role in soil remediation and wastewater treatment processes.…”