Effect of biofertilizers and organic supplements on general and beneficial microbial population in the rhizosphere of black pepper cuttings (Piper nigrum L.)

The experiment was conducted at Cardamom Research Station, Pampadumpara (Kerala) during 2017 to study the influence of bio-fertilizers and organic supplements on general and beneficial microbial population in the rhizosphere of black pepper. Promising biofertilizers (Phosphorous solubilizing bacteria, Azospirillum and PGPR Mix I) and organic supplements (fish amino acid and humic acid) in sole and in combination were applied to the root zone of one month old black pepper cuttings. The results revealed that, application of bio fertilizers and organic supplements significantly increased both beneficial and non-pathogenic general microbial population (bacteria, fungus and actinomycetes) in the rhizosphere. Compared to sole application, combined application recorded maximum CFU g-1 soil. Among different treatments, application of Phosphorous solubilizing bacteria (5g) along with Azospirillum (5g), humic acid (0.2%) and fish amino acid (0.5%) recorded highest population of non-pathogenic general microbial population and was maximum at 45 days after treatment application. The survival of beneficial microbial population in the soil was also high for this treatment. The salient research findings from the study revealed the efficacy of biofertilizers and organic supplements in increasing the microbial fauna and improve soil health for better plant growth.