Potencial alelopático de plantas de cobertura na supressão de plantas daninhas e no desenvolvimento do feijoeiro

Abstract

Common bean (Phaseolus vulgaris L.) is a crop of great socioeconomic importance in Brazil due to its broad adaptation to different growing conditions and its key role in food security. However, weed interference limits crop productivity, particularly in sustainable production systems where herbicide use is restricted. In this context, allelopathy has emerged as a promising alternative for weed management through the use of cover crops capable of releasing bioactive compounds that affect weed germination and growth. Species such as chia (Salvia hispanica L.), sesame (Sesamum indicum L.), and quinoa (Chenopodium quinoa Willd.) have shown considerable potential for agroecological systems because of their high biomass production and weed suppression capacity. The present study aimed to evaluate the performance of cover crops in weed suppression and their effects on common bean development. The experiment was conducted under field conditions at the Experimental Farm of the Federal University of Technology – Paraná (UTFPR), Dois Vizinhos Campus, located in the municipality of Dois Vizinhos, Paraná, Brazil. According to the Köppen climate classification, the region has a humid subtropical climate, with mean temperatures ranging from 14 to 22 °C. The soil was classified as a typical dystrophic Red Latosol (Oxisol) with a clayey texture according to the Brazilian Soil Classification System. The experimental design consisted of a randomized complete block design with three replications. The treatments included chia, sesame, and quinoa grown both as monocultures and in intercropping systems. The evaluated variables included cover crop dry biomass, weed community dynamics through weed dry biomass at 30 and 60 days after crop emergence (DAE), and agronomic traits of common bean, including plant height at 30 and 60 DAE and the height of first pod insertion. Prior to statistical analyses, the biometric assumptions of the statistical models were verified using normality and homogeneity of variance tests, confirming the suitability of the data for analysis of variance (ANOVA). The results demonstrated a significant effect of the treatments on weed community dry biomass at both 30 and 60 DAE. The chia treatment promoted a reduction of more than 54% in weed dry biomass at 60 DAE compared with the untreated control, which exhibited the highest weed infestation, demonstrating its high suppressive potential. In contrast, the morphological characteristics of common bean, such as plant height and first pod insertion height, did not differ significantly among treatments, indicating phenotypic stability of the crop despite different levels of weed interference. It can be concluded that the use of cover crops with allelopathic potential represents a promising strategy for sustainable weed management in common bean cultivation, contributing to weed suppression without compromising the vegetative development of the crop. These findings reinforce the potential of these species as an effective tool to reduce dependence on chemical inputs and promote more sustainable agricultural production systems.