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

²Agrotechnology Study Program, Faculty of Agriculture, University of Sebelas Maret, Surakarta, Central Java, Indonesia.

Email: sudadi_uns@yahoo.com

The research aims to find out the effect of biofilm biofertilizer formula and dose of organic fertilizer on phosphorus uptake and yield of shallot on Vertisols. The research was arranged in a completely randomized block design with two factors; dosage of organic fertilizer (0, 10, 20 ton ha-1) and the formula of biofilm biofertilizer (without BiO2, BiO2 1, BiO2 2, BiO2 3) and repeated three times. Variables observed included available-P, P-uptake, bulb number, and bulb weight. Data analyzed with an F test followed by DMRT at a 5% level of significance. The result shows that 20 ton ha-1 organic fertilizer decomposed with biofilm biofertilizer gives the highest P-uptake and plant dry weight which increases 322 % and 216 % to control treatment (0.50 and 1,26 g plant-1). The use of 10 ton ha-1 of organic fertilizer gives the highest bulb number and weight i.e 5,58 bulbs plant-1 and 116 g plant-1 increase 27% and 172% compared to control treatment. The influence of BiO2 formula only on plant height where the use of formula 1 increase plant height 13,5% (28.01 cm) compared to control treatment (24.65 cm).