Suplementação luminosa no fluxo de emergência e levantamento fitossociológico de plantas daninhas e, alterações no crescimento, produção e qualidade fisiológica de sementes de soja

Abstract

Light supplementation is a technology used in agricultural crops for production. However, this supplementation can alter the population dynamics of weeds in the field. In light of this, the objective of this study was to evaluate the emergence flow and phytosociological parameters of weeds, as well as the production, morphology, and physiological quality of soybean seeds as a function of different exposure times to field light supplementation. To achieve this, two field experiments were conducted at the experimental station of the Palma Agricultural Center/UFPEL. The first experiment consisted of quantifying the emergence flow of weeds present in the seed bank and the phytosociological parameters of weeds based on different exposure times to light supplementation. For this study, the seed bank of weeds present in the soil was surveyed. The study was conducted in a completely randomized design with three repetitions, and the treatments consisted of four light supplementation times (0, 15, 30, and 60 minutes). Light supplementation began immediately after sowing and lasted for 21 days. Weed emergence was monitored every three days during the same period. The second experiment focused on evaluating the morphological aspects of soybean plants under different light supplementation exposure times, also analyzing yield components, productivity, and the physiological quality of the produced soybean seeds. The completely randomized design was used with six repetitions, with each repetition consisting of one sowing line. Light supplementation started when the plants were at the V6 phenological stage and ended at the R6 phenological stage. Daily light supplementation influences weed emergence, especially for plants of the genus Amaranthus, and the species Richardia brasiliensis, which show higher IVE (Emergence Speed Index) when supplemented with 60 minutes of light. The Amaranthus genus was also the most frequent among the evaluated treatments and presented the highest values for the assessed phytosociological parameters. Daily light supplementation applied to soybean crops extends the plant cycle and influences morphology. Yield components are not affected by light supplementation. Additionally, the use of supplementary light does not interfere with crop productivity and indirectly influences the physiological quality of harvested soybean seeds.