Manejo de irrigação e datas de semeadura para otimização da produção de girassol ornamental de corte

Abstract

The crop of ornamental cut sunflower (Helianthus annuus L.) has excellent characteristics, such as rusticity and adaptability, which enable its production in different edaphoclimatic conditions. Although it is predominantly cultivated in a non-irrigated system, knowing the water requirement of this crop is of great importance, since all physiological processes can be interfered by stress or water deficit. Given the above, this study aimed to evaluate the water requirement of the sunflower crop. Data obtained from a field experiment carried out in the experimental area of UNIPAMPA, on the Campus located in the municipality of Itaqui, on the western border of Rio Grande do Sul, were used. The experimental design was randomized blocks in a 2 x 2 factorial scheme, with factor A being the sowing dates and factor B the irrigation conditions (irrigated and non irrigated), with 4 replications. The first sowing was carried out on 12/02/2022 and the second sowing on 01/02/2023 with transplants on 12/11/2022 and 01/12/2023, respectively. Water supply for irrigated treatment was carried out through drip hoses. Soil moisture was monitored using ABNT class B tensiometers, at a depth of 30 cm. Data on height, number of leaves, phenology and flower productivity components at harvest were collected. The data obtained in the field experiment were submitted to analysis of variance (ANOVA). The performance of the ornamental cut sunflower crop in the irrigated system was higher when compared to the non-irrigated system, thus reaching high quality indexes of the floral stems. Irrigation provides better qualitative characteristics to the ornamental sunflower crop, thus generating stems with greater growth and providing better development for the crop. Under rainfed conditions, the crop obtained low qualitative characteristics.