Recommendations for stronger biochar research in soil biology and fertility

Abstract

Research on biochar, a product from the pyrolysis of biomass under limited or no oxygen conditions, has gained momentum in developing applications in areas ranging from improvement of soil fertility to pollution remediation, and from mitigation of climate change to use in the manufacturing of healthcare products such as supercapacitors (Ok et al. 2015; Wu et al. 2019). The burgeoning interest in biochar applications followed some of the early work on using biochar as a soil amendment (the current use of the biochar concept) (Woods et al. 2006). The number of publications with the term "biochar" (whether biochar as a soil amendment or a fuel) in the title, abstract, or keywords has gone from just one publication in 1998 to 3210 in 2020, based on a search on Web of Science (accessed on February 1, 2021). Glaser et al. (2002), published in Biology and Fertility of Soils (BFSO), provided one of the earliest studies on the subject by reviewing the effect of combustion procedures on the physical and chemical properties of biochar (using the term "charcoal" at the time). Five papers published in 2007 that dealt with biochar's environmental applications stood out as highly influential; those papers dealt with biochar as a soil amendment (Chan et al. 2007; Rondon et al. 2007; Warnock et al. 2007), or as a carbon-negative

Effect of Six Different Feedstocks on Biochar’s Properties and Expected Stability

“…Biochar is frequently described as a final product of pyrolysis processes of agricultural leftovers, forestry biomass, or other various organic wastes [1]. As a soil amendment, it gained particular popularity in recent decades, which is reflected in numerous publications [2][3][4]. Potential benefits from biochar application into the soil are often described as a win-win solution, due to the positive impact on the environment and solving the problem of organic waste utilization [5,6].…”

Impact of Eisenia fetida earthworms and biochar on potentially toxic element mobility and health of a contaminated soil

“…The chemical and physical properties of biochar depend on the feedstock used, the pyrolysis process applied, the temperature, and the heating rate (Cai et al, 2021;Subedi et al, 2017). In particular, high pyrolysis temperatures (>550 °C) may lead to biochars with high pH, high cation exchange capacity (CEC), high specific surface area, high porosity and aromaticity, and low polarity (Sizmur et al, 2017;Subedi et al, 2017).…”

Applying Cassava Stems Biochar Produced from Agronomical Waste to Enhance the Yield and Productivity of Maize in Unfertile Soil

“…The principal constituent of biochar was highly stable carbon [47,51,56,68]. The CSB showed decreased N, H, and O contents at pyrolysis temperatures greater than 400 • C [28,29,69,78]. The N contents of CSB decreased as it was released continuously during the pyrolysis process.…”

“…Therefore, the wide variety of feedstock provides different biochar properties [11,13,15,[20][21][22][23]. In addition to raw materials for biochar production, pyrolysis conditions also affect the properties of biochar and the final behaviour of the resulting biochar in the soil [9,13,[24][25][26][27][28][29].…”

“…Using biochar in agriculture is intended to achieve two goals: improving and enhancing soil properties to benefit cultivation [35][36][37][38] as well as increasing agricultural productivity [22,[39][40][41]. The soil improved the physicochemical and biological properties by the mechanism of biochar in the soil [24,28,[41][42][43][44]. Biochar can also be used to treat soil contaminated with heavy metals and reduce toxin contamination in the environment [45][46][47], revitalize salt-affected soil, [48], enhance carbon storage in the soil [42,49,50] and carbon sequestration in plant biomass to tackle long-term climate change [24,31,49,51,52] for soil resource management, and facilitate the development of sustainable land use [53][54][55][56].…”