Use of biochar and oxidized lignite for reconstructing functioning agronomic topsoil: Effects on soil properties in a greenhouse study

Abstract

Bekele, A., Roy, J. L. and Young, M. A. 2015. Use of biochar and oxidized lignite for reconstructing functioning agronomic topsoil: Effects on soil properties in a greenhouse study. Can. J. Soil Sci. 95: 269–285. Interest in the use of biochar as soil amendment has grown recently. However, studies evaluating its potential use for reclamation of disturbed agricultural lands are lacking. We studied the effects of amending clay, loam, and sand subsoil substrates with wood biochar pyrolized at 800°C, oxidized lignite (humalite), or labile organic mix (sawdust, wheat straw, and alfalfa; LOM) on soil organic carbon (C), microbial biomass, dry aggregated size distribution and penetration resistance in greenhouse. We also considered the co-application of LOM and biochar or humalite to the subsoil substrates as treatments where C from either biochar or humalite represented a stable form of C. The amount and composition of the mix of organic amendments was determined for each subsoil so that organic C levels of reconstructed topsoil would be equivalent to that of the corresponding native topsoil in the long term. Field pea (Pisum sativum L.) and barley (Hordeum vulgare L.) were grown in rotation in four sequential greenhouse studies. Results from soil analysis at the end of study II and study IV showed that subsoils amended with biochar or humalite had higher organic C than those with LOM only, regardless of soil type. Labile organic mix added alone or together with biochar or humalite to subsoil increased microbial biomass and decreased geometric mean diameter of the dry soil aggregates. The effects of biochar or humalite-only amendment on these soil properties were not significant relative to the unamended subsoil substrate. Simultaneous application of biochar or humalite with LOM can potentially be used for topsoil reconstruction and reclamation of disturbed agricultural lands, and to maintain soil quality in the long term. However, long-term field studies are required to ascertain the longevity of the desirable properties reported in this study and to assess effects associated with aging of biochar or humalite in the soil.

Holistic Assessment of Biochar and Brown Coal Waste as Organic Amendments in Sustainable Environmental and Agricultural Applications

“…N and P) retention (Leszczyńska and Kwiatkowska-Malina 2011;Arjumend et al 2015;Rose et al 2016) which is contrary to our results. However, in line with findings from this study, other experiments have also found limited N and P responses to BCW which are reportedly due to binding with humate ligands (Tahir et al 2011;Bekele et al 2015;Tran et al 2015). Phosphorus is mostly available at soil pH of 6.5-7 and, even if present in high concentrations, may have been predominantly insoluble due to the high acidity of the studied soil.…”

“…Indeed, owing to their unique inherent properties, different types of biochar and BCW when applied to soil at specific rates can yield additional short-to long-term soil benefits (e.g. build soil organic matter (SOM) stocks and stimulate fungal diversity) which may directly influence resource availability and soil productivity (Bekele et al 2015;Amoah-Antwi et al 2020a). Evidence of the long-term benefits (e.g.…”

Influence of wood-derived biochar on the compactibility and strength of silt loam soil

“…This biochar amendment raised the soil ρ from 1.45 to 1.52 Mg m -3 (Busscher et al, 2010;2011). Bekele et al (2015) also showed the PR of a loamy soil to be lowered by a WBC amendment. In contrast, Eastman (2011) WBC amendment not to have any significant effect on a silt loam soil PR one year after incorporation (Eastman, 2011).…”

Low-Rank Coal as a Source of Humic Substances for Soil Amendment and Fertility Management

“…Victorian brown coal had a short-term effect on the soil microbial community after 60 days of application, i.e., it temporarily increased the peroxidase and phenol oxidase activities, suppressed the heterotrophic respiration, and induced shifts among microbial populations [24]. Bekele et al [34] observed that leonardite amendment had no effect on microbial biomass carbon (MBC) of the receiving subsoil, while application together with labile organic mix resulted in intermediate MBC values. It is important to note that the current understanding of microbial colonization and its activity is mainly drawn from short-term studies; thus, more testing should be done yet, especially focusing on long-term studies.…”