¹⁾ Soil Science Study Program, Faculty of Agriculture, University of Sebelas Maret, Surakarta, Central Java, Indonesia.

²⁾ Undergraduate student of Soil Science Study Program, Faculty of Agriculture, University of Sebelas Maret, Surakarta, Central Java, Indonesia.

Email: sudadi_uns@yahoo.com

The use of biochar can improve the physical, chemical and biological properties of the soil. The application of biochar is expected to further increase the effectiveness of BiO₂-biofilm biofertilizer in supporting rice growth so that it can provide higher yields. The purpose of this study was to obtain the optimal formula for the use of biochar and BiO2 for rice yields. The study was conducted in a greenhouse using a pot with a split plot design with three replications. The first factor (main plot) is the concentration of BiO₂ (0 and 100 %), the second factor (sub plot) dose of biochar (0; 15 and 30 tons ha^-1) and the third factor (sub-plot) method of use (mixed homogeneously to soil and is given at soil surface). The biochar used is sized to pass the 2 mm sieve. Observation variables include plant growth and yield as well as physical, chemical and biological properties of the soil. Statistical analysis using ANOVA followed by Duncan’s multiple range test. The results showed that the use of biochar up to 30 tons ha^-1 with the application of 100% concentration BiO₂ liquid biofertilizer showed an increase of rice growth and yield as indicated by the increase of plant height, tiller number and productive tiller number.