Isolation of phosphate-solubilizing bacteria from subtropical soils with different fertilization histories

Marcelo Bevilacqua Remor,Kathleen Jeniffer Model,Danielle Medina Rosa,Mariana Sbizzaro,Silvio César Sampaio,Juliana Maria Matter

doi:10.14393/bj-v36n3a2020-47955

Marcelo Bevilacqua Remor, Kathleen Jeniffer Model + Show 4 more

Open Access

https://doi.org/10.14393/bj-v36n3a2020-47955

Copy DOI

Abstract

Phosphorus is one of the most abundant chemical elements but has a low bioavailability index. Therefore, microrganisms play a fundamental role in providing insoluble phosphorus to plants. The objective of this study was to evaluate the capacity of bacteria to solubilize inorganic phosphates in soils with different fertilization histories. Soil and rhizosphere samples were collected from a Red Distroferric Latosol, including a control without mineral or organic fertilizer (C), treatment with mineral fertilizer (MF) according to the needs of each crop, and treatment with organic fertilizer [300 m3 ha-1 of swine wastewater (SW)]. The medium containing calcium phytate presented more colony-forming units (CFU) for all fertilization histories, and growth in treatments C and MF was 50% higher than treatment with SW. CFU values in soils treated with SW were lower than those in the other treatments, and the diversity of insoluble phosphate-solubilizing bacteria (PSB) was higher in treatment C. These results indicate a negative relationship between phosphorus concentrations and the number of PSB.

Highlights

The presence of nutrients in the soil is essential for agricultural productivity
Phosphorus unavailability is accentuated in soils of tropical regions because the bioavailable phosphorus reacts with Al3+ and Fe3+ in acidic soils and with Ca2+ in alkaline or calcareous soils, and these elements remain immobilized to the soil in the form of aluminum phosphates, iron phosphates, and calcium phosphates (ZHU; LI; WHELAN, 2018)
According to the treatments applied in each crop cycle (KESSLER et al, 2014), three distinct soil types were selected for sample collection: control without fertilization (C), soil treated with mineral fertilizer (MF) according to the needs of each crop, and soil treated with organic fertilizer [300 m3 ha-1 of swine wastewater (SW)]

Summary

Introduction

The presence of nutrients in the soil is essential for agricultural productivity. Among the nutrients required by plants, phosphorus constitutes a paradox because it is one of the most abundant chemical elements in the earth’s crust but has the lowest bioavailability index, i.e., low solubility and high fixation in soil. The limited bioavailability of phosphorus in the soil limits agricultural productivity requiring replacing this element to meet the needs of the crops. In contact with soil, a percentage of the bioavailable phosphorus is immobilized by sorption and precipitation (AWAIS et al, 2017; ZHU; LI.; WHELAN, 2018). Phosphorus deserves special attention because, in contact with the soil, reacts rapidly with the medium and is converted into forms that plants cannot uptake. A strategy to increase phosphorus availability in agricultural systems is using microorganisms

Objectives

Methods

Results