Open AccessDOI
Biochar Application to Soils - A Critical Scientific Review of Effects on Soil Properties, Processes and Functions
TLDR
A critical review of the current state of knowledge regarding the effects of biochar application to soil on soil properties and functions is provided in this paper, where the main focus is providing a sound scientific basis for policy development, to identify gaps in current knowledge, and to recommend further research relating to biochar applications to soils.Abstract:
Biochar application to soils is being considered as a means to sequester carbon (C) while concurrently improving soil functions. The main focus of this report is providing a critical scientific review of the current state of knowledge regarding the effects of biochar application to soils on soil properties and functions. Wider issues, including atmospheric emissions and occupational health and safety associated to biochar production and handling, are put into context. The aim of this review is to provide a sound scientific basis for policy development, to identify gaps in current knowledge, and to recommend further research relating to biochar application to soils. See Table 1 for an overview of the key findings from this report. Biochar research is in its relative infancy and as such substantially more data are required before robust predictions can be made regarding the effects of biochar application to soils, across a range of soil, climatic and land management factors. Definition In this report, biochar is defined as: “charcoal (biomass that has been pyrolysed in a zero or low oxygen environment) for which, owing to its inherent properties, scientific consensus exists that application to soil at a specific site is expected to sustainably sequester carbon and concurrently improve soil functions (under current and future management), while avoiding shortand long-term detrimental effects to the wider environment as well as human and animal health." Biochar as a material is defined as: "charcoal for application to soils". It should be noted that the term 'biochar' is generally associated with other co-produced end products of pyrolysis such as 'syngas'. However, these are not usually applied to soil and as such are only discussed in brief in the report. Biochar properties Biochar is an organic material produced via the pyrolysis of C-based feedstocks (biomass) and is best described as a ‘soil conditioner’. Despite many different materials having been proposed as biomass feedstock for biochar (including wood, crop residues and manures), the suitability of each feedstock for such an application is dependent on a number of chemical, physical, environmental, as well as economic and logistical factors. Evidence suggests that components of the carbon in biochar are highly recalcitrant in soils, with reported residence times for wood biochar being in the range of 100s to 1,000s of years, i.e. approximately 101,000 times longer than residence times of most soil organic matter. Therefore, biochar addition to soil can provide a potential sink for C. It is important to note, however, that there is a paucity of data concerning biochar produced from feedstocks other than wood, but the information that is available is discussed in the report. Owing to the current interest in climate change mitigation, and the irreversibility of biochar application to soil, an effective evaluation of biochar stability in the environment and its effects on soil processes and functioning is paramount. The current state of knowledge concerning these factors is discussed throughout this report.read more
Citations
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Journal ArticleDOI
Biochar as a sorbent for contaminant management in soil and water: a review.
Mahtab Ahmad,Anushka Upamali Rajapaksha,Jung Eun Lim,Ming Zhang,Nanthi Bolan,Dinesh Mohan,Meththika Vithanage,Sang Soo Lee,Yong Sik Ok,Yong Sik Ok,Yong Sik Ok +10 more
TL;DR: Due to complexity of soil-water system in nature, the effectiveness of biochars on remediation of various organic/inorganic contaminants is still uncertain.
Journal ArticleDOI
A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis
TL;DR: In this paper, a statistical meta-analysis was performed with the aim of evaluating the relationship between biochar and crop productivity (either yield or above-ground biomass) with an overall small, but statistically significant, benefit of biochar application to soils on crop productivity, with a grand mean increase of 10%.
Journal ArticleDOI
Hydrothermal carbonization of biomass residuals: a comparative review of the chemistry, processes and applications of wet and dry pyrolysis
Judy A. Libra,Kyoung S. Ro,Claudia Kammann,Axel Funke,Nicole D. Berge,York Neubauer,Maria-Magdalena Titirici,Christoph Fühner,Oliver Bens,Jürgen Kern,Karl-Heinz Emmerich +10 more
TL;DR: The wet pyrolysis process, also known as hydrothermal carbonization, opens up the field of potential feedstocks for char production to a range of nontraditional renewable and plentiful wet agricultural residues and municipal wastes as discussed by the authors.
Journal ArticleDOI
Biofuels production through biomass pyrolysis - a technological review.
TL;DR: More than two hundred publications have been reviewed, discussed and summarized, with the emphasis being placed on the current status of pyrolysis technology and its potential for commercial applications for bio-fuel production as mentioned in this paper.
Journal ArticleDOI
Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects
TL;DR: In this article, the impact of pyrolysis temperature and the type of biomass on the physicochemical characteristics of biochar and its impact on soil fertility is discussed, and a review succinctly presents the impact.
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