Effect of mulching, aqueous extract of Thymus zygis (L.) and Melia azedarach (L.), and intercropping with Coriandrum sativum (L.), on weed management, yield, agronomic and physiological parameters of bell pepper crop (Capsicum annuum L.)

Weeds, considered as a limiting biotic factor, remain a serious problem for farmers despite the evolution of agronomic science. Faced with this problem, the introduction of agroecological practices into the ecosystem can help to meet the challenges posed by current agricultural production systems towards efficient production methods that are more respectful of human health and the environment. The goal of this work is to study the effects of aqueous extracts of Melia azedarach (L.) (T2), Thymus zygis (L.) (T3), wheat straw mulching (T4), and intercropping of bell peppers with Coriandrum sativum (L.) (T5), on weeds management and yield of bell pepper crop, and to investigate qualitative and quantitative chemical compounds of aqueous extract of Thymus zygis (L.) Melia azedarach (L.), tested in the laboratory and in the field to understand their herbicidal properties and potential applications. The experiment was carried out at the Agroecology and Environment platform of the National School of Agriculture in Meknes, Morocco, in 2020–2021. Five treatments were tested in a randomized complete block design (RCBD) with three replications. Results showed that all treatments had a significant effect on weed density and biomass, yield, agronomic and physiological parameters of the bell pepper crop compared with the control. In addition, the efficacy of aqueous extracts of Thymus zygis (L.) and Melia azedarach (L.) in the field and laboratory on the germination of two weeds, was evaluated: Glebionis coronaria (L.) and Amaranthus blitum (L.). The intercropping system treatment showed the highest yield and yield component followed by mulching. The obtained results demonstrate that agroecological practices exert a noteworthy impact on the measured parameters, resulting in a substantial increase in yields without the incorporation of any chemical inputs. Specifically, the yields for T2, T3, and T4 exhibit an increase of over 50%, while T5 demonstrates a remarkable increase of more than 60% compared to the control.