EFFECTS OF BIOSOLIDS APPLICATION ON SWEET SORGHUM BIOMASS, WATER USE EFFICIENCY AND ETHANOL PRODUCTION

Abstract

The effects of biosolids application to sweet sorghum crop were examined during the years 2009-2011 at Central Greece. Considering sweet sorghum as a possible alternative crop for biomass and bio-ethanol production in Greece in the near future, the present research focuses on the biomass productivity, water use efficiency, and ethanol productivity of this crop as affected by the application of biosolids. Three treatments with three replications were organized in a randomized complete block design as follows: a) Biosolids application, b) Inorganic fertilizer application (same amount of N, P, K as the biosolids), and c) Control (no application of fertilizer or biosolids). The supplied amount of water was the same for all treatments and equal to the 100% of the daily evapotranspiration. The results of this study showed that biosolids application of 5 Mg ha(-1) to sweet sorghum crop increased the production of fresh and dry biomass by 15.4% and 13.2%, respectively, compared to the fresh and dry biomass produced by the application of inorganic fertilizer to the crop. Additionally, water was used more efficiently by the crop when biosolids were applied to the soil. Finally, the biosolids application produced about 14.3% more ethanol (theoretical) compared to the fertilizer application. In conclusion, the biosolids application to sweet sorghum crop transcends the fertilizer application in biomass productivity, water use efficiency, and theoretical ethanol production. Biosolids application can replace the application of fertilizers and also save valuable irrigation water which can lead to energy saving in agriculture.