Abstract

The present communication deals with the assessment of phosphate solubilizing bacterial community structure across artificially created fertility gradient with regards to N, P and K status of soil in the experimental site. 20 randomly phosphate solubilizing bacteria from each fertility gradient were isolated, purified and characterized through their insoluble mineral phosphate-source utilization patterns. Four insoluble phosphate sources; purulia rock phosphate (PRP), mussourie rock phosphate (MRP), crystalline iron and aluminum phosphate were charged in basic Pikovskaia solid medium. Growth pattern of the isolates on those phosphate sources was recorded. Different communities utilized different P-sources in different magnitudes. Size of isolates of low fertility gradient showing greater utilization efficiency towards diverse phosphate sources gradually reduced along the gradient of fertility. Data thus obtained from the experiment were filed to compute community structure of phosphate solubilizing bacteria through principal component analysis (PCA). On the whole, the community composition of phosphate solubilizing bacteria reduced gradually under the influence of cultivation and fertilization in different fertility gradient soils.

Key words: Fertility gradient, phosphate solubilizing bacteria, insoluble phosphate utilization, principal component analysis, community structure.