Isolation of potassium solubilizing bacteria in Andisol soil affected by the eruption of Sinabung

Abstract

The Sinabung eruption emits smoke and volcanic ash which will decompose into the main soil material and turn into effect the structure of Andisol that will be formed. This study aims to find isolates of potassium solubilizing bacteria in several thicknesses of volcanic ash. The research was conducted at the Laboratory of Soil Biology, Agriculture Faculty, Universitas Sumatera Utara. Potassium solubilizing bacteria was isolated using medium Aleksandrov. The results showed that 7 isolates were found in different thickness, in the soil sample there was 1 isolate (K1), at a thickness of 1 - <2 cm 2 isolates (K2, K3) were found, at a thickness of 2-5 cm there were 2 isolates (K4, K5), and at >5cm there were 2 isolates (K6, K7).