Produção de girassol de corte (Helianthus annuus, L.) e de estátice (Limonium sinuatum, Mill.) em resposta a diferentes lâminas de irrigação em vaso

Abstract

Flowers have been appreciated by mankind for many centuries and their use includes food, medicinal, mystical and, mainly, ornamental purposes. However, irrigation in floriculture has been marked by empiricism wherefore it is important to study the efficient management of water application in these crops. Sunflower and statice crops to ornamental purpose for cutting were each submitted to two distinct experiments consisting of two substrates (EXP1, containing 2/3 soil and 1/3 coconut fiber; EXP2 containing 1/3 of Soil and 2/3 of coconut fiber) in pot cultivation at greenhouse. In each substrate/experiment, plants were submitted to different automatic irrigation sheets. The sheets consisted of irrigation by self-compensating drip irrigators of 1, 2, 3 and 4 L · h-1, constituting the treatments T1, T2, T3 and T4, respectively, which irrigated the correlated vessels simultaneously. The Simplified Irrigation Trigger (ASI) was installed in the T3 of each experiment, so that the applied sheet height depended on the activation time of the irrigation system, which is governed by the ASI. Established T3 as a control, it was evaluated if it would reach superior performance to T1 and T2, where water deficit was imposed, or even T4, where a surplus in soil moisture was imposed. All the sunflower pots flourished and the T3 treatments of both substrates presented better performances with a consumption of 15.59 L and 11.28 L per flower produced in EXP1 and EXP2, respectively. In general, the sunflower presented a response to the increment of irrigated water in a quadratic model. Also, in the sunflower cultivation the T3 treatment of the EXP2 experiment presented the best overall performance, even with better yield, producing stems with better standard (class) and a consequent better sales value. Not all pots with statice produced stems, having some pots more production and others no production. The response to water increment in the statice was linear and increasing, in general, in the various parameters evaluated. The number of stems produced did not show a significant response to water increment. The water consumption in the T4 treatments that presented the best performance in most of the parameters in both statice experiments was 41.20 L and 27.60 L per plant in EXP1 and EXP2, test period.