An in vitro study was undertaken to evaluate the compatibility of indigenous plant growth promoting rhizobacteria (PGPR) with commonly used inorganic and organic sources of fertilizers in tea plantations. The nitrogenous, phosphatic and potash fertilizers used for this study were urea, rock phosphate and muriate of potash, respectively. The organic sources of fertilizers neem cake, composted coir pith and vermicompost were also used. PGPRs such as nitrogen fixer; Azospirillum lipoferum, Phosphate Solubilizing Bacteria (PSB); Pseudomonas putida, Potassium Solubilizing Bacteria (KSB); Burkholderia cepacia and Pseudomonas putida were used for compatibility study. Results were indicated that PGPRs preferred the coir pith and they proved their higher colony establishment in the formulation except Azospirillum spp. that preferred vermicompost for their establishment. The optimum dose of neem cake powder supported the PGPR incidence when compared to lower and higher doses. As the concentration of rock phosphate increased, the population of PGPR was also increased whereas medium dose of MOP supported their growth and in the case of urea even at lower dose totally retarded the growth of bioinoculants. This study would give a prior knowledge on PGPR sensitivity with synthetic and organic manures in order to suggest the field recommendation on combined application of organic/inorganic/biofertilizers for improving the tea yield and also to protect soil health under integrated nutrient management approach.
B. Bagyalakshmi, A. Balamurugan, P. Ponmurugan and R. Premkumar, 2012. Compatibility Study of Indigenous Plant Growth Promoting Rhizobacteria with Inorganic and Organic Fertilizers used in Tea (Camellia sinensis). International Journal of Agricultural Research, 7: 144-151.