Rodríguez Lylian, Salazar Patricia and Preston T R 2011 Effect of a culture of “native” micro-organisms, biochar and biodigester effluent on the growth of maize in acid soils.Workshop on Reducing Greenhouse Gas Emissions from Livestock and Soils (Editors: Reg Preston and Sisomphone Southavong). National Institute of Animal Science, Hanoi, 14-15 November 2011. httm://www.mekarn.org/workshops/GHG-CC/rodr.htm