Impact of herbicides on the microbial biomass and orthophosphate-solubilizing microrganisms in rhizosferic soil grown with sugarcane

摘要

This work aimed to evaluate soil microbial biomass carbon (MBC), phosphate solubilization potential (PSP), and relative phosphate solubilization potential (RPSP) in the rhizosphere soil of sugarcane cultivars after herbicide application. The trial was installed under field conditions in a conventional tillage system, using a completely randomized block design with four replications. The treatments corresponded to two sugarcane varieties, RB86-7515 and SP80-1816, and the herbicides ametryn (2,000 g ha-1), trifloxysulfuron-sodium (22.5 g ha-1), trifloxysulfuron-sodium + ametryn (37 + 1,463 g ha-1), sulfentrazone (750 g ha-1), and an untreated control plot. The herbicide was applied when plants presented 3 to 4 leaves. Soil samples were collected at 7, 14, and 28 days after herbicide application (DAH) for the MBC, PSIF, and RPSP evaluations. MBC in the rhizospheric soil of RB86-7515 was less affected by the herbicides at 7 DAH, compared to SP80-1816. Trifloxysulfuron-sodium stimulated PSIF (21.11%), while ametryn reduced its activity. Sulfentrazone did not affect PSIF. The sugarcane varieties tested varied in their capacity to associate with soil microorganisms, resulting in different responses of the soil microbiota to the herbicides.