Association of phosphate solubilizing microorganisms with phosphate sources: agronomic parameters, P availability and enzymatic activity.

Abstract

Phosphorus is classified as one of the essential elements in plant nutrition. However, due to its dynamics in the soil, only a small fraction is available to plants. Considering this fact, added to the environmental and economic impacts related to the excessive application of phosphate fertilizers, alternatives have been sought that can promote the solubilization and better use of P by crops, among them the use of phosphate solubilizing microorganisms (MSP), which may promote greater P cycling in the production system. The objective of this project is to evaluate the effects of the association between phosphate solubilizing microorganisms and phosphate sources, regarding the availability of P in the soil and its nutritional use by maize. The research will be conducted at the Department of Soil Science, at ESALQ/USP, in Piracicaba, SP. The experimental design will be in randomized blocks under a factorial scheme, with 4 replications, considering the following factors: Inoculation: commercial product "Omsugo", strain A, strain B and consortium of strains A and B, both selected by the team from the genetics department of the ESALQ/USP, and without inoculation; Phosphate sources (60 mg/kg): Bayovar natural phosphate and soluble phosphate (TSP), in addition to a control without P application. The experiment will be conducted in a greenhouse for 45 days, with periodic measurements of maize biometry, as well as soil sampling at the end to evaluate the availability and fractions of P and activity of the enzyme acid phosphatase. It will also be determined maize dry mass and P accumulation in plant tissue. Data will be analyzed using the SAS® statistical package.