Manejo da supressão da lâmina de irrigação em arroz irrigado

Abstract

Rice is one of the main cereals cultivated and consumed globally, with emphasis on the Asian continent, the largest producer and consumer of the grain. The main objective of the work is to evaluate the effects of early suppression of the irrigation depth on the agronomic characters of the irrigated rice crop, specifically on the IRGA 424 RI genotype. Assessing productivity components components, mass of a thousand seeds, physical quality of the grains, such as plastered, whole and broken, physiological quality of the seeds and recommend the best suppression management for conditions similar to those of the experiment. Conducted under the conditions of the experimental teaching area of the Universidade Federal do Pampa, campus Itaqui- RS, during the agricultural years 2021/2022 and 2022/2023, using the cultivar IRGA 424 RI. A randomized block design with three replications was used, with treatments arranged equidistantly every 7 days after flowering (DAF). In the first year, the suppression periods were 7, 14, 21, 28 and 35 DAF, with the same suppression periods in the second agricultural year plus 42 DAF. They consider a control treatment, killing the irrigation depth until harvest, for both years. The results showed that, in the first agricultural year, the cultivar's cycle was 121 days, significantly influencing the productivity and physical quality of the grains, with a higher percentage of whole grains. In the second year, with a cycle of 138 days, there was significance for the percentage of chopped and stained grains. In the first agricultural year (2021/22), the recommended suppression for maximum productive potential was 36 days after flowering (DAF), the period after the R6 stage, the moment indicated for the beginning of suppression. For the second agricultural year (2022/23), the percentage of chopped and/or stained grains showed a negative influence when there is early suppression of the irrigation depth, indicating maximum efficiency at 49 DAF (0.66%). According to the results of this work, we can consider that it is not generally applicable, especially for genotypes with the same cycle characteristics and productive potential as the cultivar used here (IRGA 424 RI), as well as the cultivation conditions imposed here.