Biochar boosts tropical but not temperate crop yields.

Biochar boosts tropical but not temperate crop yields.Scientists believe that biochar, the partially burned remains of plants, has been used as fertilizer for at least 2,000 years in the Amazon Basin. Since initial studies published several years ago promoted biochar, farmers around the world have been using it as a soil additive to increase fertility and crop yields. But a new study casts doubt on biochar's efficacy, finding that using it only improves crop growth in the tropics, with no yield benefit at all in the temperate zone. A team of researchers from the United Kingdom, Portugal, The Netherlands, Canada and the U.S. gathered data from more than 1,000 experiments conducted around the world that measured the effect of biochar on crop yield. By using meta-analysis, an advanced statistical technique that analyzes many studies at the same time, they performed rigorous testing to determine whether the beneficial effect of adding biochar depends on geography. Biochar boosts tropical but not temperate crop yields.