Each biodigester discharged into a hole in the ground lined with plastic to avoid soil contamination of the effluent.The total volume was 560 litres and the liquid phase occupied 420 litres. One biodigester was charged with fresh cow manure collected from an animal consuming urea-treated straw supplemented with cassava root waste. The second biodigester was charged with manure from pigs consuming a mixture of sugar cane juice and cassava root waste supplemented with fresh duckweed (Lemna minor). Water was added to each type of manure to give a solids content of 40 g/litre. Approximately 20 litres of each mixture were added daily to the biodigesters to give a liquid retention time of 20 days. The manure (cow and pig) used to fertilize the plots was taken from the same source as used for the biodigester. The effluents (cow and pig) were collected from the discharge pits of the biodigesters every three days for application to the experimental plots.