Comportamento do girassol irrigado com diferentes níveis de salinidades da água.

Abstract

In Brazil, much of the territory is considered suitable for sunflower cultivation, which comes from gaining space in the deserved flower and seed production. The present work had as objective to verify the behavior of sunflower {Helianthus annum L. variety Embrapa 122 / V-2000) irrigated under different levels of water salinity in a protected environment vegetation). The treatments were composed of six levels of irrigation water salinity (ECa), Ni - 0.5; N2 -1.0; N3 - 2.0; N4 - 3.0; N5 - 4.0 and N6 - 5.0 dS in1 at 25 C, in a completely delineated design. haphazard. The experiment consisted of 60 experimental units, and from 41 days after transplantation (DAI), 30 units were used for flower production (Experiment I) and the another 30 for seed production (Experiment H); thus, up to 40 DAT, growth phase and development of the plant, the experiment contained 10 replicates distributed in the 6 levels of irrigation water salinity and from there (41 DAT) were distributed for each experiment, 5 repetitions. Every 10 days growth and development were evaluated by plants, stem diameter, bud diameter in phase R4, leaf number and leaf area. The phytomass Shoot and root dryness were quantified at the end of the experiment. For the Experiment I were The following variables were evaluated: chapter outer diameter (DE), number of petals in chapter (NP), flowering onset (IF) and postharvest duration (CPD). For Experiment II if evaluated the internal diameter of the chapter (Dl), achenes weight (PA), number of achenes (NA) and weight of 100 achenes (P100A). In the growth variables studied the plant height, stem diameter, leaf number and leaf area were reduced with increasing irrigation water, and the most drastic effect occurred on the leaf area. The number of petals in significantly decreased with the increase of salinity of the irrigation water, being the plants irrigated with low (0.5 dS m "1) and high electrical conductivity (5 dS m4) water with 27.8 and 17.46 petals, respectively. The weight of achenes and the number of achenes decreased 10.64 and 9.17%, respectively, due to the unitary increase in the electrical conductivity of the irrigation. Irrigations with water of different salinity cause salt accumulation in the soil, raising CEes on average 8.5 times for flower production and 9.4 times for seed. The levels of salinity of irrigation water used during both experiments provided, on average, increased electrical conductivity of drained effluent, 1.37 times for flower production and 2.2 times for seed.