Growth, Nutritional, and Yield Parameters of Wetland Rice as Influenced by Microbial Consortia Under Controlled Conditions

ABSTRACT

A pot culture experiment was undertaken under controlled conditions in the National Phytotron Facility to investigate the interactive effect of microbial inoculants—blue-green algae (BGA), Azospirillum, phosphate-solubilizing bacterium (PSB) Pseudomonas striata, vesicular-arbuscular mycorrhizal fungus (VAMF), and Azolla, individually and in combination with chemical fertilizers and/rock phosphate on the wetland rice (Oryza sativa L.) cultivar ‘PNR 381’. The microbial inoculants—BGA, PSB, VAMF, and Azospirillum—positively interacted with one another, resulting in significant improvement in yield and nutritional parameters. Application of biofertilizers also substantially improved soil (peat) fertility status by increasing the nitrogen (N), phosphorous (P), and organic carbon content. The biofertilizer combination BGA + PSB + VAMF + Azospirillum was best for improved growth and yield traits, nutritional status of rice, and sustained soil (peat) fertility. Azolla, which is a highly competitive organism, suppressed the growth of the other four inoculants. The inclusion of VAMF and PSB was observed to significantly improve the zinc nutrition of the paddy and the P utilization of the applied rock phosphate. A basal dose of nitrogenous fertilizer was essential for deriving maximum benefits from applied inoculants, thereby underlying the supplementary/complementary role of biofertilizers in efficient nutrient management in agriculture.

Keywords:

• Azospirillum
• Azolla
• biofertilizers
• BGA
• PSB
• rice (Oryza sativa L.),
• VAMF

ACKNOWLEDGMENTS

Dr. Chinnusamy Muthukumaravel is thankful to the Council of Scientific and Industrial Research, India for the financial assistance to conduct this work. The working facilities provided by the National Phytotron Facility and the Division of Microbiology, Indian Agricultural Research Institute, New Delhi, are duly acknowledged.