Efficient use of biochar and biofilm biofertilizer to enhance available phosphorus and increase yield of black soybeans in peat soil

Abstract This research aims to assess the effect of varying dosages of coconut shell biochar and BiO2 biofertilizer and to identify the combination treatment that produces the highest level of available phosphorus and yield of black soybeans in peat soil. The experiment used a Factorial Completely Randomized Design (FCRD) consisting of 2 treatment factors and 2 replications. Factor I was the dosages of coconut shell biochar (0, 0.2, 0.4, and 0.8 tons ha −1 ), which were incorporated into the planting hole. Factor II was the concentration of BiO2 (0, 5, and 10 ml plant −1 ), which was given twice per week. Variables observed included soil pH, organic-C, CEC, Exch-Al, Av-P, P-uptake, and black soybean yield. The results showed that the use of coconut shell biochar, BiO2 biofertilizer, and their interaction exhibited significant effect on all variables observed. The application of 0.8 tons ha −1 biochar and 10 ml plant −1 BiO2 treatment combination provided the highest levels of available-P (8.65 ppm) and black soybean yield (8.63 g seed plant −1 ), representing increases of 82.94% and 150.87%, respectively, compared to the control treatment. This yield is equal to 1.104-ton seeds ha − 1 with planting space of 25 cm × 25 cm and slightly higher than average of soybean yield in Indonesia. The result also showed that coconut shell biochar could be use in an efficient way to increase black soybean yield in peat soil.