Evaluation of biofilm biofertilizer from the western slope of Mount Lawu for enhancing Andisol soil fertility in pakchoi (Brassica chinensis L.) cultivation

Prolonged and excessive application of chemical fertilizers risks degrading soil quality. Biofilm biofertilizers offer a potential solution, but research on their effectiveness in Andisol soils is limited. This research intends to assess the potential of biofilm biofertilizer from the western slope of Mount Lawu to improve Andisol soil fertility in pakchoi cultivation and reduce the use of chemical fertilizers. The study had a completely randomized design with 6 treatments and 4 replications in an experimental setting in the greenhouse. The treatment balanced the dose of biofilm biofertilizer and chemical fertilizer. Based on the results of the study, the application of biofilm biofertilizer from the western slope of Mount Lawu both as a single fertilizer and its balance with chemical fertilizers was able to enhance the fertility of Andisol soil and pakchoi yield. Treatment 25% biofilm biofertilizer + 75% chemical fertilizer (B) gave the highest results in CEC (39.82 cmol(+) kg-1 or 87.74% higher than the control), N-Total (1.29% or 34.38% higher than the control), K-available (0.4 cmol(+) kg-1 or 42.86% higher than the control), and plant fresh weight (28.08 g or 37 times higher than the control). Treatment 100% biofilm biofertilizer (E) gave the highest results in P-Available (0.65 ppm or 116.67% higher than the control), bacterial population (6.02 Log 10 CFU g-1 or 25.94% higher than the control), and fungal population (2.8 Log 10 CFU g-1 or 42.13% higher than the control). The results can lessen the need for chemical fertilizers by 25%-100%.