The Potential of Biochar to Ameliorate the Major Constraints of Acidic and Salt-Affected Soils

High salinity and severe acidity are the two primary constraints of acidic and salt-affected soil, leading to phytotoxicity of sodium (Na), aluminum (Al), and iron (Fe), as well as phosphorous (P) deficiency. Biochar, having high alkalinity and adsorption capacity, can be a potential bio-amendment to ameliorate these constraints. The current study aimed to assess the impacts of biochar addition on these constraints and the quality of the soil. A pot experiment was set up in a greenhouse using acidic and salt-affected soil mixed with five biochar rates (0 (T1), 2.5 (T2), 5 (T3), 10 (T4), and 20 (%, w/w, T5)); and experimental soil samples were taken on days 5, 15, 30, 60, and 100 to analyze for 11 parameters. The results showed that biochar addition (T5) enhanced electrical conductivity (EC), pH, and the concentration of exchangeable Na and potassium (K) by 24, 90, 13, and 1064 (%), whereas it reduced the concentration of Al and Fe by 93 and 66 (%), as compared to T1. The non-occluded P of the biochar-added soil was raised by 109 (%) in T5, relative to T1. The increased amount of exchangeable Na and K could originate from the added biochar, which may re-absorb Na after 2 months. The reduced magnitude of exchangeable Al and Fe could be involved in the increased pH, leading to the enhanced non-occluded P. In brief, biochar may worsen soil EC but mitigate the acidity-related constraints, leading to an enhancement of soil quality, eventually.