Phosphate solubilizing bacteria isolated from three agroecosystems of Valle del Cauca (Colombia)

Abstract

Phosphorus (P) plays a role in energy transfer processes and chemical reactions in plant metabolism. Phosphorus is found in soils both in an organic form and a mineral form. Phosphorus availability in soils is limited by fixation processes, which include both its adsorption to mineral fraction and the precipitation reactions. In this work, the phosphate solubilization by native bacterial was evaluated in order to identify the most efficient bacterial, in three agro-ecosystems: sugarcane monoculture (CAÑ), grassland (PAST), and guadua ecosystem (GUAD) located in Palmira, Colombia. Five soil samples were assessed by treatment. First, the phosphorus-solubilizing bacteria were isolated by using Pokovskaya (PVK) assay. Then, phosphorus solubilizing capacity (CSF, Spanish acronym) was determined by measuring the halo generated in the isolated sample by 20 days. High CSF was found in five isolated samples: two in PAST, two in GUAD and one in CAÑ. In the literature reviewed was not reported the CSF of GUAD7 strain (Escherichia vulneris) as significantly high CSF (p<0.05). The strains with intermediate CFS (GUAD5 (Pseudomonas fluorescens), PAST7 (Acinetobacter oleivorans), PAST8 (Acinetobacter calcoaceticus) y CAÑ6 (Pseudomonas entomophila) have been reported in the literature as beneficial bacteria to soil.

Keywords

• soil phosphate
• soil management and conservation
• ecosystem services
• sustainability