Métodos de controle de plantas daninhas em sistemas orgânicos: breve revisão

Weed management in organic systems of agricultural production is a major challenge to agricultural farmers. To solve this challenge, it is necessary to explore sustainable management practices and the development of new technologies. It should be emphasized that there are technological or biological alternatives that can be used in weed management in organic systems, and are used in large areas. Cultural, biological, mechanical and physical management strategies can be effective in controlling weeds, as well as reducing the use of chemical control in conventional agriculture. Thus, this literature review aimed to present some alternative methods of weed control and potential use in organic areas of agricultural production. Weed control methods in organic areas should always use integrated and sustainable strategies.O manejo das plantas daninhas em sistemas orgânicos de produção agrícola representa um grande desafio aos produtores. Para o enfretamento deste desafio torna-se necessário a exploração de práticas de manejo sustentáveis e o desenvolvimento de novas tecnologias. Ressalta-se que existe alternativas tecnológicas ou biológicas que podem ser utilizadas no manejo das plantas daninhas em sistemas orgânicos, e serem empregadas em grandes áreas. Estratégias culturais, biológicos, mecânicos e físicos de manejo podem ser eficientes no controle das plantas daninhas, bem como reduzir o uso de controle químico na agricultura convencional. Desta forma, esta revisão de literatura teve como objetivo o de apresentar métodos alternativos de controle de plantas daninhas e o potencial uso em áreas orgânicas de produção agrícola. Os métodos de controle das plantas daninhas em áreas orgânicas devem abordar sempre estratégias integradas e de forma sustentável

Allelopathic Potential of Plant Aqueous Mixtures on Euphorbia heterophylla

Euphorbia heterophylla is a widely distributed weed whose seeds can remain viable in the soil for years, competing with crops. Therefore, natural herbal preparations could be a solution for its more diversified management. This study investigates the efficacy and mode of action of aqueous mixtures of Urochloa ruziziensis stems and Sorghum bicolor roots and stems on E. heterophylla seed germination, seedling development, antioxidant enzyme activity, and respiration. Aqueous mixtures with concentrations of 0 (control), 250, 500, 750 and 1000 ppm were prepared. E. heterophylla seeds were treated with the mixtures and incubated under controlled conditions. Seedling development, respiration, and enzyme activity were assessed after 4 days of incubation and germination was analyzed after 16 days. Urochloa ruziziensis and S. bicolor mixtures presented allelopathic effects on E. heterophylla inhibiting root growth, root fresh and dry weights and induced mitochondrial alterations resulting in oxidative stress, increasing the antioxidant enzymes catalase and peroxidase. U. ruziziensis and S. bicolor aqueous mixtures were found to have potential in controlling the weed E. heterophylla in laboratory tests