The potential of liquid formulation of biofertilizer using a consortium of plant growth-promoting rhizobacteria (PGPR)

One of the obstacles to increasing the production of organic rice in Indonesia is the declining productivity of the land due to the organic fertilizers applied having low nutrient contents, causing it to be insufficient to fulfill plant nutrient needs.Other sources of nutrients are needed to complement these organic fertilizers so that plant nutrient needs can be met.These complementary sources include biological fertilizers, or biofertilizers, which can increase the N, P, and K contents in the soil.A biofertilizer was developed using a consortium of banana stem bud indigenous microorganism (IMO) isolates, including five types of bacteria, namely Bacillus cereus strain ATCC 14579, Bacillus subtillis subsp.subtilis strain 168, Bacillus siamensis strain KCTC13613, Azotobacter sp., and Pseudomonas fluorescens.The purpose of this study was to determine the potential of various bacterial consortium liquid formulations as biofertilizers to increase soil and plant nutrients and the production of organic lowland rice.The study was conducted from February to August 2020 at the rice field belonging to a group of certified organic rice growers.The study employed a randomized block design with eight treatments, namely Treatment A (coconut water with molasses, carboxymethylcellulase, and arginine), Treatment B (coconut water with molasses, carboxymethylcellulase, arginine, and virgin coconut oil), Treatment C (soy soaking water with molasses, carboxylmethylcellulase, and arginine), Treatment D (soy soaking water with molasses, carboxymethylcellulase, arginine, and virgin coconut oil), Treatment E (soy boiled water with molasses, carboxylmethylcellulose, and arginine), Treatment F (soy boiled water with molasses, carboxylmethylcellulose, arginine, and virgin coconut oil), Treatment G (nutrient broth), and Treatment H (no treatment).The results showed that seven bacterial consortium liquid formulations of biofertilizer could increase the N, P, and K contents in the soil and plant tissues as well as organic lowland rice production.