How do we know that biochar helps increase crop yields?
There is a large body of peer-reviewed literature quantifying and describing the crop yield benefits of biochar-amended soil. Field trials using biochar have been conducted in the tropics over the past several years. All showed positive results on yields when biochar was applied to field soils and nutrients were managed appropriately. Large scale field trials have recently begun on highly fertile Iowa Mollisols by the US Department of Agriculture’s Agricultural Research Service (USDA-ARS). First year results are positive, yet it will take several years before definitive results are available (Laird, D., 2009) There is also evidence from thousands of years of traditional use of charcoal in soils. The most well-know example is the fertile Terra Preta soils in Brazil, but Japan also has a long tradition of using charcoal in soil, a tradition that is being revived and has been exported over the past 20 years to countries such as Costa Rica. The Brazilian and Japanese traditions together pr
