Cultivable bacterial diversity and early plant growth promotion by the traditional organic formulations prepared using organic waste materials

Abstract

Purpose: Traditional organic formulations are widely used as a plant growth promoters; however, the knowledge on the microbial aspect of traditional organic formulations is still limited. The aim of this study was to illustrate the cultivable bacterial diversity of various traditional organic formulations and their potential for early plant growth promotion. Methods: Five different traditional organic formulations such as 100 % panchagavya, 33 % panchagavya, plant extract with native microorganisms, commercial organic fertilizer extract with two percent leaf soil extract and commercial organic fertilizer extract with 2 % yogurt were prepared and used in this study. The liquid fraction of these traditional organic formulations were used to analyze the beneficial effect on plant growth by seed treatment and foliar applications. Results: Bacterial 16SrDNA analysis revealed that the isolates fell into forty-three different genera, which can be grouped into seven different classes, such as Alphaproteobacteria, Actinobacteria, Bacilli (or Firmibacteria), Betaproteobacteria, Cytophagia, Flavobacteriia and Gammaproteobacteria. Higher bacterial diversity was observed in cow dung followed by 33 and 100 % panchagavya. Radish and Chinese cabbage seed germination and growth were significantly improved by traditional organic formulations compared to control. Conclusion: The results of this study showed that the bacterial diversity changes depend on the type and concentration of ingredients used in traditional organic formulations. Substantial increase in plant growth by the traditional organic formulations indicates the suitability of using these organic preparations in eco-friendly agriculture.