A new bibliometric review from Brazil's Federal Rural University of the Semi-Arid Region maps 32 years of research on biochar for sandy soils. The study pulled 543 publications from Web of Science, covering 1992 through 2024. It tracks how the field grew from a single 1992 paper into a global research wave that peaked around 2021, with China leading publication volume and Germany leading average citation impact per paper. The review shows that biochar can improve water retention, nutrient availability, and carbon storage in sandy soils, but results vary widely with feedstock, pyrolysis temperature, application rate, and local conditions. Some studies found no improvement in water retention, and compost sometimes outperformed biochar blends. The authors call for more long-term field trials, standardized production protocols, and better integration with other soil management practices before broad prescriptions are made.
