Peru’s Kosñipata Valley is a biodiversity-rich region of the Peruvian Amazon, adjacent to the Manu Biosphere Reserve in the Southeastern part of the country. The area has been dominated by agriculture—mainly using slash and burn to convert forest land to agricultural land. This agricultural practice, along with legal and illegal mining in the area, has left many of the soils drained of nutrients and potentially contaminated with heavy metals. To investigate the potential of biochar to increase soil health in the area, researchers from Wake Forest University in the United States are partnering with the Asociación por la Conservación de la Cuenca Amazónica (Amazon Conservation Association) at a local field station—converting two abandoned pastures into field demonstration projects using biochar. The project team, based at Villa Carmen Biological Research Station, is led by biology professor Miles Silman and managed on the ground by graduate student Andrew Wilcox, both of Wake Forest University.
In addition to improved soils, a project aim is implementation of agroforestry principles in the sustainable management of native Amazonian bamboos. The main biochar feedstock is native bamboos (from the genus Guadua) as well as other local feedstocks. Although the project is focusing first on using bamboo due to the prevalence of the material, the area is so diverse with plant species (some of them invasive) that the team has access to many different feedstocks for biochar production.
The project is using a slow pyrolysis batch kiln designed in Australia by Dr. Stephen Joseph, but fabricated on location in Peru. It has a stationary steel cart with a kiln made of stainless steel and ceramic insulation. There is ducting to capture and combust the gas and vapor byproducts. Additionally, a fan provides high pressure air for the fire box and the unit is fitted with a water pump and nozzles to regulate the pyrolysis reaction. As noted, the unit can handle multiple feedstocks. It has a chamber volume of 4.5 cubic meters, producing ~200 – 400 kg of biochar per burn. A burn takes 4 – 6 hours to complete the full cycle including quenching the finished biochar.
The unit was installed at the site in May – June 2014 by the project team and local community members. The kiln was constructed in Lima by Russell Burnett and then transported up and over the Andes to the Kosñipata Valley in late June 2014 with final assembly taking place at Villa Carmen. While the unit was in transport, the team built a foundation using local supplies such as river stones to house the unit on-site.
The team has been producing a large amount of biochar since the unit installation; as of October 2014, they’ve completed over 100 burns. Along the way, they’ve worked with the design to optimize operations based on local conditions and availability of materials. For example, they found that rather than using industrial sealants, the best material to seal the kiln door is local clay, mined a hundred meters from the work site. Some of the dried clay will be mixed into subsequent batches prior to pyrolysis to mineralize the biochar.
A grinder arrived onsite in September 2014 to much anticipation. The team had a large stockpile of biochar ready to be ground prior to planting the field trials. They needed the grinder to process the biochar into a uniform size making it both easier to apply and more effective in soils.
Once the biochar was ground, the team started field trials using the most common crops of the region—pineapple, plantain, corn, and yucca (cassava)—to test a variety of biochar and biochar-compost treatments at different application rates. They are also characterizing the biochars’ chemical and physical properties to determine the best combinations and application rates for continued trials. An important component of the project is working with local farmers and agricultural associations for field trial implementation. Because the team is focusing on the major crops in the region, they have had strong support from the community. The hope is that if the field trials show positive results, they can expand the trials to a larger area with more farmers. Since the crops have different growth cycles, results can highlight the ability of biochar to improve short rotation crops such as corn and longer rotation crops such as pineapple.
In addition to working with agricultural field trials, the project is also looking at the potential of biochar to restore soils that are contaminated with mercury from gold mining. At this time, they are in the process of producing biochar for a researcher in Puerto Maldonado who is working on reforesting the mined lands in that region. Read more about that specific research in Spanish.