Effects of earthworms and plant growth-promoting rhizobacteria (PGPR) on availability of nitrogen, phosphorus, and potassium in soil

Fuyong Wu, Judy hon chi Wan, Shengchun Wu, Ming Hung WONG*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Both earthworms and plant growth-promoting rhizobacteria (PGPR) are ubiquitous and important for promoting circulation of plant macronutrients. Two series of laboratory experiments were conducted to investigate the effects of earthworm casts and activities on the growth of PGPR, and the inoculation of earthworms and PGPR on the availability of N, P, and K in soils, respectively. During a short incubation period (0-34 h), the extracts of earthworm (Pheretima guillelmi)-worked soil significantly (p < 0.05) increased the abundance of the three species of PGPR, including N-fixing bacteria (NFB) (Azotobacter chroococcum HKN-5), phosphate-solubilizing bacteria (PSB) (Bacillus megaterium HKP-1), and K-solubilizing bacteria (KSB) (B. mucilaginous HKK-1), in Luria-Bertani (LB) broth. There were synergistic effects of dual inoculation of earthworms and PGPR on increasing the concentrations of NH, NaHCO3-extractable P, and NH4OAc-extractable K in the corresponding soils. Bioavailable N in the dual inoculation was 4 to 24 times those inoculated with earthworms or NFB alone, respectively. The significantly higher concentrations of bioavailable N and P in the dual inoculation of earthworms and NFB or PSB may be due to the higher abundance of PGPR and/or higher activities of urease and acid phosphatase than those of single inoculation of NFB or PSB, respectively. Dual inoculation of earthworms and PGPR would be most effective in reducing the need for chemical fertilizers in agriculture.

Original languageEnglish
Pages (from-to)423-433
Number of pages11
JournalJournal of Plant Nutrition and Soil Science
Volume175
Issue number3
DOIs
Publication statusPublished - Jun 2012

Scopus Subject Areas

  • Soil Science
  • Plant Science

User-Defined Keywords

  • Dual inoculation
  • Earthworms
  • Nutrient turnover and transformation
  • PGPR
  • Soil enzyme activity

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