A Revista Brasileira de Ciências Agrárias é um periódico de divulgação científica publicado pela Editora da Universidade Federal Rural de Pernambuc

Cassava (Manihot esculenta) yields are severely affected by the interference of weed plants. Using cover crops for weed control appears as a sustainable alternative practice because it maintains the soil covered and reduces the need for herbicides. The aim of this study was to assess cassava crop yields and the soil chemical properties as a function of use of cover crops for weed management. Treatments were three cover crops (Brachiaria ruziziensis, Canavalia ensiformis, and Mucuna pruriens), chemical control, mechanical control, and treatment with no weed control. Cover crops reduced the diversity of species and the quantity of individuals of the weed community in cassava cultivation. The treatments with chemical and physical weed control achieved higher yields. The cover crops B. ruziziensis and C. ensiformis increased cassava yields by 30% and 14%, respectively, when compared with the treatment with no control. The cover crops increased the pH, MO, K, Ca, and Mg values when compared with the treatments with chemical and mechanical weed control. Brachiaria ruziziensis and C. ensiformis are recommended as a cover plants in cassava production systems in the Amazon region. The use of cover crops associated with cassava is a sustainable management option because, in addition to the suppressive effect on weeds, cover crops improve the chemical properties of soil, which may contribute to increasing cassava production in the long term.

The guaraná tree is a species known for the stimulating properties found in its seeds, leading to increased consumption and promising production. Cultivation is primarily carried out in family farming systems, and one of the challenges in the production process is the acquisition of seedlings. The conventional nursery system, which employs intermittent misting for the production of guaraná clones, raises the cost of seedlings, necessitating the exploration of alternatives to this approach. The aim of this study was to evaluate different conditions as alternatives to the conventional nursery system for rooting guaraná cuttings. The experimental design was entirely randomized, featuring three guaraná genotypes, BRS Maués, BRS CG 611, and BRS Luzeia, alongside two rooting conditions, the conventional nursery and a humid chamber with nebulization, with four repetitions. The rooting of guaraná clones was significantly influenced by the interaction between conditions and genotypes. The humid chamber with nebulization demonstrated superior root system characteristics among the tested conditions, with a rooting rate of 56.66% for BRS Luzeia. This method proved to be efficient and accessible for small producers, making it a satisfactory option for rooting guaraná trees.