Changes in growth, microbial and enzyme activities in oil palm nursery in response to bioinoculants and chemical fertilizers

ABSTRACT

A study was conducted to assess the influence of bioinoculants and chemical fertilizers on survival and enzymes activity of microbes in rhizosphere and growth of oil palm seedlings. Bioinoculants namely Azotobacter chroococcum, Azospirillum brasilense, Bacillus megaterium, Frateuria aurantia and Glomus aggregatum were applied individually, combindly and integrated with chemical fertilizers. Most convincing and highly significant results for growth parameters, phosphatases, dehydrogenase and trehalase activity were observed in potting mixture with application of bioinoculants + 25% recommended dose of chemical fertilizers (RDF). Extreme levels of esterase in potting mixture were noticed under the treatment with bioinoculants + 50% RDF followed by bioinoculants + 25% RDF. The highest population of Azotobacter, Azospirillum, Bacillus and Frateuria in potting mixture was enumerated with consortium of bioinoculants + 25% RDF. Glomalin content and root infection recorded in Glomus aggregatum was ostensibly superior to rest of the treatments except consortium of bioinoculants + 25% RDF. Correlation analysis revealed significant and positive interaction between microbial population and enzyme activities. The study suggests that integrated use of bioinoculants along with 25% RDF play a significant role in enhancing oil palm seedling growth through increased microbial population and enzyme activity in rhizosphere.

KEYWORDS:

• Oil palm seedlings
• bioinoculants
• microbial population
• enzymes
• glomalin

Acknowledgments

The author acknowledges and appreciates the support of ICAR-Indian Institute of Oil Palm Research, Pedavegi, Andhra Pradesh, India for providing facilities for carrying out my research work.

Disclosure statement

No potential conflict of interest was reported by the authors.