Presence and potential for isolation of potassium solubilizing bacteria in mango, pitaya, and banana rhizospheric soils

Potassium solubilizing bacteria (KSB) are an important group in the soil ecosystem and have multiple growth-promoting activities for plants. The aim of the study is to evaluate the relationship of the total count of KSB with several biochemical parameters in banana, dragon fruit, and mango rhizospheric soils as well as potential for isolation of indigenous KSB strains with high K soluble activity. The results have showed that KSB are commonly present in soil samples. In the correlations with the total KSB, the total aerobic bacteria had the greatest impact followed by the total fungi, % P, pH, moisture, % N, % K, and % organic carbon, respectively. Of these, pH, moisture, % N, % K, and % organic carbon positively correlates with the total KSB. Conversely, the total aerobic bacteria, total fungi, and % P content have negative correlations. The K solubility analysis on agar plates has indicated a potential to collect highly active clones do not depend on the soil samples from these above plants. This research has shown the potential to detect and isolate hight activity indigenous KSB for development of KSB microbial fertilizers in the future. Keywords: distribution, potassium solubilizing bacteria, rhizosphere.