We recently paid a visit to David Guerena (PhD Candidate in soil science at Cornell University under Prof Johannes Lehmann) at his field sites in Vihiga, Kakamega, South Nandi and North Nandi, Western Kenya (about 30 minutes drive from Kisumu and Lake Victoria). David and his group have been working in the region for the past 5-6 years. As far as we can tell, this trial (utilizing approximately 20 independent farms) is the longest-running biochar field trial in Africa. David’s group supplied local farmers with biochar at a rate of 6 Tonnes/hectare each year in 2005, 2006 and 2007 for addition to the soil. The farmers utilized this biochar on roughly half their holdings. The farmers practiced their normal fertilization and cultivation regime on all holdings.
After 6 years of cultivation, the results are still astounding. As you can see from the anecdotal image above, the maize crops treated with biochar exhibit stalks 10-12 feet tall, often with 2 ears per stalk. Treatment of soils with biochar resulted in a 45% improvement in soil organic carbon (SOC) when compared with non-treatment. Biochar treatment also resulted in a crop yield improvement of between 2.2 and 2.9 tonnes of maize per hectare (Kimetu et al 2008). In a region like East Africa grappling with an emerging famine, the potential yield increases associated with biochar could save thousands of lives.
Now, David Guerena is working on a greenhouse trial in Kisumu to compare the soil and productivity effects of various ‘designer’ biochars produced under different reaction conditions. This research is crucial to determine the optimal biochar to improve different soil types in Kenya. We will keep a close eye on this great work. In the words of David, “The next agricultural revolution in Africa won’t be green, it will be black.”