Sandy soils are among the most unforgiving growing media on Earth. Their oversized particles create vast macropores that drain water almost as fast as it arrives, their organic matter content is typically meager, and their nutrients leach away with every heavy rain or irrigation event. For farmers in semiarid regions, where these constraints are compounded by heat and erratic rainfall, the result is chronically low productivity and high vulnerability to erosion by both wind and water. A new open-access review published in Discover Soil by a team at Brazil’s Federal Rural University of the Semi-Arid Region has now taken stock of how the scientific world has responded to this challenge, and the answer is a striking story of exponential growth around one deceptively simple material: biochar.
The study is a bibliometric analysis, a mathematical and statistical mapping of academic activity rather than a laboratory experiment. The researchers systematically searched the Web of Science database using the descriptors biochar, bio-char, biological charcoal, or agrichar in combination with sandy soil, then filtered the results to articles and review articles. That search yielded 543 publications spanning 1992 to 2024, with records from 2025 excluded because indexing was still incomplete. The corpus was then processed with two dedicated tools: VOSviewer version 1.6.18, which built co-authorship, citation, and keyword co-occurrence networks using thresholds of five minimum documents and five minimum citations, and the Bibliometrix extension version 3.0 in R, which generated rankings, three-field plots, and thematic clusters using the Walktrap algorithm and multiple correspondence analysis.
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