Phosphorus Desorption from Fe and Al Oxides Mediated by Soil Microorganisms

Abstract

The capacity of soil microorganisms to desorb phosphorus (P) adsorbed to iron (Fe) and aluminum (Al) oxides was determined by impregnating paper strips with these oxides, adding P in quantities equivalent to the null points, and incubating the strips in Argisol and Latosol samples receiving increasing doses of glucose (0 to 10 mg g soil⁻¹). Glucose stimulated microbial activity and at the end of the incubation period 69 and 41 percent of the added carbon (C) had been released as carbon dioxide (CO₂) in the Argisol and Latosol. This stimulated activity resulted in increasing P desorption, reaching 66 and 67 percent of the adsorbed P in the Fe strips and 49 and 80 percent in the Al strips for the Argisol and Latosol, respectively. Therefore, microorganisms can desorb P adsorbed to Fe and Al oxides when stimulated by an easily assimilated C source. Fe- and Al-oxide-impregnated paper strips technique provided an adequate method to measure soil P desorption, as mediated by microorganisms.

Keywords:

• Brazilian tropical soils
• Fe and Al oxide paper strips
• glucose
• microbial activity

Additional information

Funding

The authors thank Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the scholarships of the authors and financial support of the research.