Application of biofertilizers to increase upland rice growth, soil nitrogen and fertilizer use efficiency

Abstract High application of inorganic fertilizer has a negative impact on soil health. To reduce the use of inorganic fertilizers, one alternative is using biofertilizers. Biofertilizers are active inoculants made from living organisms that have the ability to mobilize, facilitate and increase the availability of nutrients through biological process. The experiment was conducted to study the effect of biofertilizers and inorganic fertilizers application on growth of upland rice, N-uptake and soil nitrogen. Biofertilizers were mixture of N-fixing bacteria (Azotobacter chroococum, Azospirillum sp.) and phosphate solubilizing microbes (Pseudomonas mallei, P. cepaceae, Aspergillus niger and Penicillium sp.). The field experiment used a Randomized Block Design (RBD) with ten treatments and three replications. The treatments were control, biofertilizers doses (50 kg ha−1 and 75 kg ha−1), inorganic fertilizers (50%, 75% and 100% of recommended doses) and combination of biofertilizers and inorganic fertilizers. The result revealed that 50 kg ha−1 biofertilizers + 50% inorganic fertilizer increased growth of upland rice (the number of tillers). In addition, the application of biofertilizers increased fertilizer use efficiency.