Soils affected by salinity, which substantially limit agricultural productivity, are becoming an increasingly serious concern due to climate change and unsustainable land management practices. Biochar, a stable, carbon-rich material derived from biomass, has shown significant potential for mitigating the negative impacts of soil salinization. This paper examines the role of biochar in enhancing soil properties, promoting plant growth, and alleviating salinity stress. Evidence indicates that biochar improves key soil physical characteristics, including aggregate stability, porosity, and water-holding capacity, while also enhancing nutrient availability and cation exchange capacity. Moreover, biochar positively influences soil microbial communities, thereby strengthening soil health and increasing plant resilience to salt stress. Studies demonstrate that biochar can boost crop yields by an average of 29.3% through improving plant tolerance to saline conditions. This enhancement is linked to biochar’s ability to improve soil structure, facilitate nutrient cycling, and reduce toxic ion concentrations. Additionally, biochar contributes to climate change mitigation by sequestering carbon in soils and lowering greenhouse gas emissions. Nonetheless, potential drawbacks, such as the presence of toxic compounds or free radicals, must be carefully considered. This review highlights the importance of optimizing biochar production processes, including the choice of feedstocks (such as agricultural residues, organic waste, or halophytes) and particle size. It also identifies research gaps and suggests future directions, including the development of “carbon-neutral” or “carbon-negative” biochar systems through advanced pyrolysis or gasification techniques that minimize greenhouse gas emissions, promote sustainable agriculture, and support food security in salt-affected regions.
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