Distinct Behavior of Biochar Modulating Biogeochemistry of Salt-Affected and Acidic Soil: a Review

Soil degradation refers to the decline in the productive capacity of the land in a region. Various factors responsible for soil degradation, viz., soil erosion, waterlogging, acidification, salinization, flooding, anthropogenic activities, and other environmental extremes, adversely restrict soil health in the long run. Regeneration or enhancing vegetative growth in degraded soils is one of the biggest challenges. However, it can be achieved through improving soil health on a sustainable basis which may bring about socio-economic changes in the region. A soil amendment is added to the soil to enhance its nutrients, organic matter, and soil biogeochemistry and finally to produce healthy vegetation. Thermochemically decomposed biomass (biochar) can improve the plant response under problematic soils by enhancing soil physicochemical and biological characteristics, viz., bulk density, hydrological properties, porosity, aeration, aggregate stability, CEC, nutrient bioavailability, ion exchange capacity, microbial diversity, and enzyme activity. Besides modulating soil dynamics, biochar promotes assistance to plant growth under saline soils by reducing oxidative and osmotic stress due to high salt deposits, lower phytohormonal levels, and conductance. This article reviews the biochar production, significant properties, and applicability under degraded soils for reversing soil deterioration. The present review paper also highlights (i) the effectivity of biochar towards the restoration of salt-affected and acidic soils, (ii) biochar interaction with soil physicochemical and biological indices, and (iii) biochar-associated ecological functions, enzyme activities, and crop response under saline and acidic soil ecosystems. Graphical Abstract