Microbiota do solo após a aplicação do extrato de sorgo em uma área com diferentes palhadas sob cultivo de soja

Abstract

Soil microorganisms play a crucial role in metabolizing allelochemicals released by plants, which can influence the composition and activity of the soil microbiota. The aim of this study was to evaluate the effect of applying sorghum extract (sorgoleone) as a bioherbicide to control weeds in soybean cultivation on the soil microbiota. The experiment was set up using a completely randomized design with two plots planted with grain sorghum (DOW 1G100) and common maize (SHS 7990 PRO3) to form straw and two sub-plots (treatments referring to the presence and absence of weed control with aqueous sorghum extract). There were five replicates made up of 1.5 m x 5 m plots and the following analyses were carried out: Microbial Biomass Carbon (MBC), Basal Soil Respiration (BSR), Metabolic Quotient (qCO2), Microbial Quotient (qMIC), Number of Viable Nodules (NNV), and Mycorrhizal Colonization (MC). The results revealed that the control combined with sorghum straw had a negative impact on the soil microbiota, reducing the microbial community and activity, increasing the metabolic quotient indicating physiological stress, and a decrease in the microbial quotient and the number of nodules per plant. In contrast, the use of maize straw showed stability in the microbiological quality of the soil. In general, the aqueous extract of sorghum and sorghum straw decreased the biological activity of the soil and negatively impacted the rate of carbon immobilization by the soil microbiota. The soil microbiota proved to be a quality indicator that was sensitive to the application of sorghum extract and the presence of different types of straw in the soybean crop.