A growing body of research suggests that biochar, a charcoal-like material made from plant and agricultural waste, could play a major role in improving soil health and supporting more resilient forests. A new review study brings together over two decades of research to evaluate how biochar affects soil quality and tree-based crops, while also highlighting important risks and knowledge gaps.
“Biochar has enormous potential as a sustainable tool for improving soil and supporting tree growth, but its success depends on how and where it is used,” said the study’s lead author. “Our goal was to provide a balanced understanding of both its benefits and its limitations.”
Biochar is produced through a process called pyrolysis, which heats organic materials such as wood, crop residues, or manure in a low-oxygen environment. This process creates a stable carbon-rich material with a highly porous structure. These properties allow biochar to retain water and nutrients in soil, making them more available to plants over time.
The review finds that biochar can significantly improve soil structure by increasing porosity and aggregation. This helps roots grow more easily, enhances water infiltration, and reduces erosion. In many cases, soils treated with biochar also show higher water retention, which is particularly valuable in drought-prone regions.
In forestry systems, these improvements translate into measurable benefits for trees. Studies analyzed in the review report increases in tree biomass, improved drought tolerance, and enhanced resistance to pests and diseases. In some cases, tree growth increased by more than 20 percent, while overall biomass gains reached over 40 percent in certain species and environments.
Another major advantage is carbon sequestration. Because biochar is highly stable, it can store carbon in soils for decades or even centuries. This makes it a promising strategy for mitigating climate change while simultaneously improving land productivity.
However, the study emphasizes that biochar is not a one-size-fits-all solution. Its effectiveness depends on factors such as the type of feedstock used to produce it, the temperature of production, soil conditions, and the species of trees involved.
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