The role of Azolla on improving nitrogen efficiency in rice cultivation

Nitrogen is essential for both vegetative and generative stages of plant growth. Nitrogen efficiency is related to plant growth, production cost, and fertilizer residue. Azolla has the ability to increase nitrogen fixation from the atmosphere. Thus, Azolla cultivation in paddy field is one strategy for improving nitrogen fertilizer efficiency and increasing plant vegetative and generative growth. The objective of this study was to evaluate the role of Azolla on improving nitrogen efficiency. This study was conducted from January to April 2018 in irrigated paddy field of Lubuklinggau Selatan II, Lubuklinggau. The study was laid out in a randomized block design arrangement with 4 replications. Treatments were combinations of Azolla and urea which were applied during vegetative and generative stages: 115 kg N ha-1 without Azolla (K1), 115 kg N ha-1 + 1000 kg ha-1 Azolla (K2), 86 kg N ha -1+ 1000 kg ha-1 Azolla (K3), 58 kg N ha -1 + 1000 kg ha-1 Azolla (K4), 29 kg N ha-1  + 1000 kg ha-1Azolla (K5), and zero N+1000 kg ha-1 azolla (K6). The application of 86 kg N ha-1 and 1000 azolla kg ha-1 (K3) increased 15.54% rice growth, 25.49% yield, and improved the N fertilizer agronomic efficiency (AE), agro-physiological efficiency (APE), utilization efficiency (UE), and N efficiency ratio (NER).