Microbiological integration for qualitative improvement of vermicompost

Authors

• Sujit Mal ¹
• G.N. Chattopadhyay * ²
• Kalyan Chakrabarti ³

1. College of Agriculture, Susunia (Extended Campus of Bidhan Chandra Krishi Viswavidyalaya),Chhatna, West Bengal, India
2. Seacom Skills University,Kendradangal, West Bengal, India
3. Ex-Institute of Agricultural Science, Calcutta University, 35 Ballygunj Circular Road, Kolkata, West Bengal, India

Abstract

Purpose This study was carried out to assess the effect of integrating microbiological fortification with vermicomposting process on biofertilizing quality of vermicompost as well as improvement of the availability of nitrogen and phosphorus in the product.
Method A mixture of cow dung and vegetable market waste (1:1) was used for vermicomposting with Eisenia foetida as the decomposer earthworm @ 10 no.of worm kg^-1 substrate. Nitrogen fixing and phosphate solubilizing bacteria (NFB and PSB)Azotobacter chroococcum and Pseudomonas fluorescens were integrated with this composting process at varying  doses viz. 0,5 and 10 g kg^-1 substrate under different combinations. Changes in the population of these two bio-fertilizing microorganisms and the availability of relevant nutrients in the substrates were monitored periodically to assess the behaviors of these microorganisms and their effects on the produced vermicompost.
Results All the inoculations resulted in substantial increments in population of both NFB and PSB over the control. However, the increments were more prominent for NFB than the PSB. Significant increments in the amount of mineralized nitrogen and solubilized phosphate over the control were observed in almost all the treatment combinations.
Conclusion Integration of nitrogen fixing and phosphate solubilizing bacteria with vermicomposting process resulted in substantial enrichment of the product. This benefit was observed not only in terms of increased availability of the two major plant nutrients of concern viz. N and P, but also in significant improvement in the population of the inoculated microorganisms turning the product into a potential source of bio-fertilizers.

Highlights

• The effects of integrating nitrogen fixing and phosphate solubilizing bacteria (NFB and PSB) with vermicomposting process on availability of N and P and also the bio-fertilizer supplying capacity of this microbiologically fortified vermicompost were assessed in this study.

•  Inoculation of different combinations of Azotobacter chroococcum and Pseudomonas fluorescens   in the vermicomposting process of cow dung and vegetable market waste mixture incubated with Eisenia  foetida  showed significant increase in the population  of these two bio-fertilizing microbes.

• Enhanced occurrences of these bio-fertilizing microbes resulted in improved availability of the relevant nutrients viz. N and P in the resultant vermicompost . Significant increments were recorded in almost all the treatment combinations, of which combined use of NFB and PSB @ 10 g kg^-1 each appeared to be the most effective.

• The study showed integration of nitrogen fixing and phosphate solubilizing bacteria with vermicomposting process to improve the availability of these two nutrients in the product. In addition, this biologically fortified vermicompost appeared to act as a rich source of N and P bio-fertilizing microbes, thus minimizing the necessity of separate application of these bio-fertilizers.

Keywords

• Microbial fortification
• Bio-fertilizer population
• Compost quality
• Nutrient availability
• Vermicomposting