Selection and Characterization of Phosphate Solubilizing Fungi and Their Effects on Coffee Plantations

Abstract

The use of phosphate-solubilizing fungi in coffee cultivation is an alternative with which to reduce the use of fertilizers. The objective of this study was to analyze the mechanisms involved in the phosphorus solubilization of the fungal strains and to evaluate the effect of a phosphate-solubilizing strain on the coffee plants. For this, phosphorus-solubilizing fungal strains were selected for evaluation of their solubilization potential and phosphatase activity. Coffee plants were inoculated in the field with a phosphate solubilizing strain, and soil and foliar soluble phosphorus, as well as coffee bean yield, were quantified. Of the 151 strains analyzed, Aspergillus niger, Penicillium waksmanii, and Penicillium brevicompactum showed the highest solubilization. Aspergillus niger and P. waksmanii presented the highest soluble phosphorus values; however, P. brevicompactum showed the highest phosphatase activity. The P. brevicompactum strain inoculated on the coffee plants did not favor foliar phosphorus content but increased the soil soluble phosphorus content in two of the coffee plantations. The plants inoculated with the phosphate solubilizing strain showed an increase in coffee bean weight on all plantations, although this increase was only significant in two of the three selected coffee plantations.