Efeito da adição de carbono com ação prebiótica, extrato de aroeira (Schinus terebinthifolia Raddi) e herbicida no controle das plantas daninhas Picão-Preto (Bidens subalternans DC.) e Capim-Milhã (Digitaria ciliaris (Retz.) Koeler)

Abstract

The indiscriminate use of pesticides in modern agriculture has led to a series of environmental impacts, such as the contamination of ecosystems and the selection of resistant organisms. In this context, the demand for more sustainable and environmentally safe management strategies is growing. Currently, the use of soil microbiota activities is still underutilized in weed management, although it presents promising potential. The addition of compounds with a high carbon content can stimulate microbial growth, promoting the temporary immobilization of soil nutrients, especially nitrogen. This reduction in nutrient availability can alter the competitive dynamics between plant species, affecting the development of plants that are more responsive to nitrogen. Therefore, this study aimed to evaluate the potential of applying sucrose as a prebiotic carbon source for the soil, associated with the use of an aqueous extract of Schinus terebinthifolia Raddi and a chemical herbicide, in the post emergence control of black jack (Bidens subalternans DC.) and crabgrass (Digitaria ciliaris (Retz.) Koeler). The experiment was conducted in a greenhouse, using eight treatments and ten replicates. Plant phytometric parameters, chlorophyll a, b, and total chlorophyll content, and soil microbial activity, estimated by counting colony-forming units (CFU), were evaluated. The data obtained were subjected to analysis of variance, and the means were compared using Tukey's test at a 5% probability level. The results indicated that the addition of sucrose to the soil promoted an increase in microbial activity and significant reductions in the growth of the evaluated weeds, especially when associated with the herbicide. The combined treatments allowed for the maintenance of high levels of weed suppression even with the use of a reduced herbicide dose. Furthermore, physiological analyses demonstrated a reduction in chlorophyll content in the treated plants, indicating physiological stress. These results suggest that manipulating the soil microbiota through the addition of carbon may represent a promising strategy for integrating sustainable weed management systems, contributing to reducing the dependence on synthetic herbicides in modern agriculture.