ABSTRACT
Resource oriented sanitation has emerged as a need to improve the efficacy of excreta treatment schemes, to reduce the environmental pollution from their disposal and to improve soil fertility. In urine diverting dry toilets, storage alone is inefficient for faeces treatment due to poor hygienization, incomplete decomposition as well as high losses of organic matter and nutrients. The purpose of this study was to assess the effect of stored faeces and bio-waste treated via lactic acid fermentation supplemented with biochar soaked in urine on the growth, yield and yield components of corn in a two year field experiment. Also the soil quality was assessed. Lactic acid fermentation of faeces and bio-waste was performed under limited oxygen conditions in earth pits covered with plastic foil by the addition of microbial inoculum and molasses. The effect of fertilizer was compared to an unfertilized control; a lacto- fermented mix (faeces, bio-waste, molasses and microbial inoculum) without biochar; stored faeces; cattle manure; urine and mineral fertilizer. In addition, during the second year, a vermi-composted lacto-fermented mix supplemented with biochar was applied. Differences among the treatments concerning corn growth parameters, yield, yield components and soil quality were evaluated using the Dunnet test of multiple comparisons. The lacto-fermented mix supplemented by biochar significantly improved plant height (p < 0.05 and confidence interval CI with two negative values) compared to all fertilizers during the first production year and compared to the control, stored faeces and vermicompost during the second year. This fertilizer also achieved a significantly higher corn yield compared to all other fertilizers during the first and second production year, except for the lacto-fermented mix without biochar and the mineral fertilizer, which showed no significant yield and yield component difference (p > 0.05, CI with both positive and negative values). With regard to the soil quality, bulk density was reduced during both years, while the soil potassium content increased during the first production year. The nitrate concentration significantly improved in comparison to the control, stored urine and stored faeces amended plots.
