Soil Mehlich-3-extractable elements as affected by the addition of biochars to a clay soil co-amended with or without a compost

Abstract

Biochar has potential to sequester carbon and mitigate greenhouse gas emissions, and it may also contribute nutrients for plant growth in temperate climates. Nutrient availability in biochar-amended soil was assessed in a 338-d incubation study. The clay soil prepared with 4% w/w (dry basis) compost or without compost, then amended with wood-based biochar made at different pyrolysis temperatures (maple bark [Acer saccharum] at 400°C [M400], 550°C [M550] and 700°C [M700]) on a dry-rate basis of 5% (w/w). After moistening the soil mixture to 44% volumetric soil water content (equivalent to 70% water-filled pore space), soil mixtures were incubated in the dark at 22°C. Soil was sampled at days 9, 16, 23, 44, 86, 23 170 and 338 of the incubation. Biochar amendment increased the Mehlich-3 P, K, Ca, Mg and Cu concentrations, and reduced the Mehlich-3 Al and Fe concentrations at each sampling date, and M400 had the most significant effect on Mehlich-3 extractable nutrient concentrations. Compost addition also increased the amounts of extractable nutrients. These results suggested that M400 and carbon-rich compost promoted microbial growth and mineralization in amended soil. In addition, soil mixed with compost and amended with biochar had more Mehlich-3 extractable K than when compost or biochar were applied alone, probably due to greater growth and activity of soil K-solubilizing microorganisms. Overall, our study indicated that co-application of wood-based biochar and compost could improve soil fertility in temperate regions by increasing the availability of most plant macronutrients and micronutrients.

Biochar amendments for sustainable soil management

“…Our goal was to gather the most current findings that would help explain the functions of biochar in cold, temperate soils. In agroecosystems, biochar applications can boost soil nutrient availability while contributing to soil fertility (Gagnon et al 2022;Li et al 2022;Abedin and Unc 2022;Lévesque et al 2022b), and influencing crop productivity (Alotaibi 2022; Hung et al 2022;Shang et al 2022).…”