Soil structure characteristics, functional properties and consistency limits response to corn cob biochar particle size and application rates in a 36-month pot experiment

Abstract

<jats:p> The particle size (PS) and application rate (RA) of biochar influence soil–biochar interaction with concomitant effects on soil chemical and physical properties. However, limited studies exist that quantify how biochar PS and RA, acting solely or together affect soil structure characteristics and functional properties. This study investigated the effect of PS and RA of corn cob biochar on soil water retention (SWR) and aeration indicators such as relative gas diffusivity, structural characteristics such as pore size distribution and pore organisation, and consistency limits of a tropical sandy clay loam soil. A pot experiment was conducted using two biochar PSs (&amp;lt;2 and 2–4 mm) and four biochar RAs of 0, 20, 40 and 80 Mg ha−1. Both intact soil cores (100 cm3) and disturbed bulk soil samples were collected after 36 months of amendment for measurements of soil chemical and hydraulic properties, and consistency limits. Biochar application of 80 Mg ha−1 significantly (P &amp;lt; 0.05) increased soil organic carbon and SWR. However, plant available water was neither affected by biochar PS nor RA. Further, biochar PS and RA acting solely or together did not significantly modify air permeability, consistency limits and estimated soil pore continuity, organisation and tortuosity. Further studies are needed to confirm whether the overall lack of significant changes in these soil properties after 36 months of amending with corn cob biochar also pertains to other biochar feedstock and soil types. Such information is useful in selecting suitable biochar amendments that improve soil conditions for crop growth. </jats:p>

Impact of biochar on nutrient uptake by tomato, residual soil properties and acidity indices in acid Inceptisol of Meghalaya

“…The data pertaining to electrical conductivity of postharvest soil as influenced by biochar as a component of integrated nutrient management is given in Table 4 RDF + biochar 2 t ha giving highest value of 0.46 dS m . This was also observed to be at par over all other treatments corroborating the previous findings (Obour et al, 2020;Usman et al, 2016;Agegnehu et al, 2015;Cely et al, 2015).…”

Gas permeability and water retention of a repacked silty sand amended with different particle sizes of peanut shell biochar

“…Garg et al (2020) explored gas permeability (k g ) of biochar-amended sandy soil at different degrees of compaction. Obour et al (2020) investigated the k g of sandy clay loam amended by corn cob biochar with two different particle sizes. However, existing studies considered a limited range of matric potential (i.e., near saturation).…”

“…Obour et al. (2020) investigated the k g of sandy clay loam amended by corn cob biochar with two different particle sizes. However, existing studies considered a limited range of matric potential (i.e., near saturation).…”

Effect of Biochar on Soil-Water Characteristics of Soils: A Pore-Scale Study

“…In sandy soil, biochar, which will be most effective when it has high porosity and an irregular shape [29], can improve physical properties [22] and soil water-holding capacity by changing the distribution of soil pores [30,31]. However, controlling the biochar particle size and application rate, Obour et al [32] found no significant overall change in the pore structure and function of the sandy loam tropical soil after 36 months of amending corn cob biochar. Jeffery et al [33] used biochar pyrolysis at 400 • C and 600 • C and mixed it with different proportions and found that the water-holding capacity of sandy soil did not change significantly.…”