Wastewater sludge and sludge biochar addition to soils for biomass production from Hyparrhenia hirta

The aim of the study was to determine the performance of sludge biochar compared to unprocessed wastewater sludge on production of Coolatai grass (Hyparrhenia hirta) as a potential forage and energy crop species. Pot trials were conducted to determine the nutritive quality and yield of Coolatai grass using chromosol soil amended with wastewater sludge and sludge biochar. The application of biochar combined with fertiliser was found to have the highest effect on the yield producing more than double of the plant dry matter comparing to unamended chromosol soil conditions. The combination of biochar and fertiliser treatment also increased some of the important chemical characteristics of Coolatai grass, such as the metabolisable energy and crude protein composition compared to control, wastewater sludge and fertiliser treatments.