Impact of phosphate-solubilizing and nitrogen-fixing bacteria on growth and yield of upland rice (Oryza sativa L.) in oil palm (Elaeis guineensis Jacq.) fields

Oil palm is typically planted in wider spacing (9×9m), creating gaps that can facilitate weed growth but also provide opportunities for intercrops like upland rice. Inceptisols, commonly used for oil palm cultivation, often have low yield potential due to limited phosphorus (P) and nitrogen (N) content and acidic soil pH. This limitation can be addressed by applying a biofertilizer mixture of Phosphate-Solubilizing Bacteria (PSB) and Nitrogen-Fixing Bacteria (NFB), which can enhance upland rice's growth and yield. This study investigates the impact of various doses of a PSB and NFB mixture on the growth and yield of upland rice grown alongside oil palm. Conducted from January to May 2024 at the Ciparanje Experimental Garden, Faculty of Agriculture, Padjadjaran University. The research utilized a Randomized Block Design (RBD) with six different treatment levels and four replications. The treatments involved applying different quantities of Pseudomonas sp. and Azotobacter sp. combined with carrier compost to the upland rice plants. The doses tested were 0, 10, 20, 30, 40 and 50 kg/ha. The results showed that the application of a mixture of PSB and NFB at a dose of 40 kg/ha was able to increase 33.48% of plant height, 38.14% of the number of leaves, 30% of the stomatal conductance index, and 32.91% of the number of grains per panicle of upland rice plants compared to without the application of a mixture of PSB and NFB. Meanwhile, intercropping upland rice on oil palm land did not affect the growth of oil palm plants.