Isolation and Identification of Phosphate Solubilising Bacteria from Potato Rhizosphere on Andisol

Abstract

Andisol soil is a very strong soil that binds phosphate nutrients, because most of it is bound by allophane clay minerals which can retain P up to 97.8%. Therefore, P in the soil available for plants is very little found, while the total P in the soil is high. Where the P nutrient is one of the essential nutrients that plants need to grow and produce well. The availability of P in Andisols soil can be done by giving phosphate solubilising microbes to providing P nutrients to plants. The using of phosphate solubilising bacteria as the inoculants simultaneously increased the uptake of P by plants and increase production. Therefore, a study aimed to isolate, identify phosphate solubilising bacteria to the species level and to test the phosphate dissolution rate of potato plant rhizosphere on andisol soil in Tongkoh-Karo Regency. Isolation can be done by the spread plate method on solid pikovskaya media, the phosphate dissolving activity was tested qualitatively by looking at the appearance of clear zones around the colony, measuring the phosphate dissolution index and identifying the isolates using PCR 16S rRNA. Four phosphate solubilising bacterial isolates were successfully obtained from the potato plant rhizosphere from andisol soil in Tongkoh-Karo regency. Where each islote are BPFT 1: Bacillus cereus, BPFT 2 : Bacillus pseudomycoides, BPFT 3 : Bacillus cereus and BPFT 4 : Bacillus amyloliquefaciens. BPFT 4 (Bacillus amyloliquefaciens) has the highest phosphate dissolubility index, which is 6,00.